Mirror Lenses - a rehabilitation in the digital age?

Discussion in 'Nature' started by philaret, Nov 1, 2006.

  1. I have read a few threads about mirror lenses which seem to have died away around 2002. Although it is accepted that mirror lenses can yield excellent images, for the most part they are believed to be the ones to avoid in favor of a used regular tele (perhaps with a used teleconconverter). It is usually stated that you can get an excellent used combo a little under $1000. I believe it is time to reconsider these opinions with a digital SLR in mind. Indeed, mirror lenses are much maligned for: 1. Inferior sharpness 2. Low maximum aperture 3. Less saturated colors and lower contrast. 4. Nasty bokeh (although here opinions differ). Indeed, with film one is forced to use a fast one developed to a higher than usual gamma and saturation (if you can do it). This is invariably associated with a drop in quality due to large grain and reduced sharpness of a fast film. However, things work differently in a digital SLR, where one can use ISO 800-1600, in camera sharpening and increased contrast without such a precipitous drop in quality as it used to be with even the best film. Should not we 'rehabilitate' the mirror lenses now?
    00IdpJ-33279784.jpg
     
  2. I use to use the 500/8 Canon FD mirror lens for sports and birds and the like. I liked it.
    Didn't like the out-of-focus "donuts" you'd get in some landscape shots. You'd still have
    to contend with those in digital, and I'm not sure how such a lens would fare with a FF
    sensor. Interesting idea, though.
     
  3. Hi Alexander,

    One of the other problems with mirror lenses is that they are so light that it is tempting to shoot them hand-held. But it's almost impossible to get sharp photos with any 500mm or 1000mm lens that is hand-held!

    You ask a very interesting question, though. It would be interesting to see if one COULD shoot hand-held if the mirror lens is attached (via a T-mount) to a digital SLR that has body-based image stabilization (such as the new Minolta-based Sony DSLR).

    Sincerely,

    Dave
     
  4. Mirror lenses can be quite sharp and show good contrast, especially after a little digital tweaking:

    See http://www.bobatkins.com/photography/tutorials/mirror.html for some comparison shots of a 500/8 mirror lens and a Canon 500/4.5L.

    What you can't get rid of is the lousy "bokeh" in slightly out of focus areas due to the effects central obstruction. I don't think opinions really do differ on this. Everybody hates it.

    My tests showed that performance with a TC was pretty bad too, much worse then the Canon lens.

    Speed isn't so much of an issue with digital and good quality at ISO 800 and even 1600. You can get 500/5.6 mirror lenses if f8 isn't fast enough.

    I still have my Tamron 500/8 mirror lens. It's so small and light compared with a "real" 500mm f4(.5)L that it has its uses when I have to travel with limited room and an eye on weight.
     
  5. I am glad this issue isn't really dead, and there is hope that the lens manufacturers read this. The lens in my example was deliberately the cheapest in my collection, and I like my trusty Tamron 500mm, which happens to have a tripod mount, too. A good point was made about the in-camera stabilization. Minolta, by the way, is the one manufacturer to have made an AF mirror lens and I am wondering if they are going to revive it now. What I was trying to say is that in the digital age we are no longer limited with one and the only film that happens to be loaded in the camera at the time a shot is taken, but with some knowledge, can adjust the camera settings to match the light and the lens. As for the 'donuts' of the image, I believe they can be taken care of, at least in a subset of situations, by a similar algorithm that is used to eliminate 'red eye' and scratches, as well as by applying a Gaussian blur to the entire background. Another point is that most current mirror lenses cover more than a 24x36mm frame (they can be used in medium format with some modification), but perhaps a 1000mm mirror designed specifically for the APS digital frame would not be that huge and could even autofocus?
     
  6. I've been thinking about buying a mirror lens myself. I would like to do some bird photography which is impracticle with my RB67. I'm thinking the new Pentax K100D and a Tamron 500 mirror might be a nice combo. Especially on the wallet.
     
  7. I love mirror lenses! I use a Nikkor 500/8 Reflex lens for birding and astrophotography all the time. Used by itself, it produces some fairly sharp, saturated, contrasty pictures; used with teleconverters, it becomes an inexpensive super-telephoto. I used to occasionally shoot Fuji Provia 400F slide film with this lens, but now on a Nikon D80, I use it even more often; the ability to instantly fine tune exposure on a DSLR makes a mirror lens much more user-friendly and versatile in a digital world than it was with a film camera. The bokeh donuts don't really bother me, in part because I've never really had a picture ruined by them: if you are careful with composition and background lighting, you can avoid the donuts. This photo (cropped) was shot on a Nikon D80 with Nikkor 500/8 hand-held at 1/640 at ISO 800. If I had used a tripod and a slower shutter speed the photo would be sharper, but by then the bird would be in the next county (the guy next to me with the Canon EOS-1DS Mk.II and EF 600/4L USM IS lens on a Wimberly gimbal head and Gitzo tripod couldn't get this shot in time). I say that DSLRs have given mirror lenses new leases on life! http://
    img.photobucket.com/albums/v291/SpeedySub/DSC_0110.jpg
     
  8. SCL

    SCL

    As I indicated many posts ago, my Tamron cat lens beat out my Canon and Nikon cats. In the end, however, I wasn't using it frequently enough and so I sold it earlier this year. Now in the long end I'm solely using an old Nikon 300/2.8 manual and Leica 400/6.8 and 560/5.6 manuals. Much heavier than the mirror lenses, but producing more consistently pleasing results. The "bokeh" issue with cats can frequently be minimized by judicious selection of lighting or composition.
     
  9. Could it be because there are no mirror lenses with anti-shake, stabilization control? I'm ignorant of such. Inform me!

    Does Canon use in-camera image stabilzation on any of their still cameras? I use XL-* digital video cameras which perform fairly well with such a feature. Might be interesting if in a still camera, but I have to hear from the Canon pros.
     
  10. I have the Minolta 500 AF mirror and a Minolta 5D digital. Maybe I should go out and see what I can achieve hand-held and mounted on a tripod. The lens is very light and when I was using it more on my 600si's I always thought it was very sharp (though the out of focus highlights did tend to be distracting). On my Minolta 5D it would be the equivalent of 750mm/f8. That means either 1/1000th of a second or higher or a tripod. Of course the vibration reduction might buy me a stop or two. I find it works very well with other lenses but I mostly shoot from tripods.
     
  11. It's not just out of focus highlights appearing as donuts. It's any part of the background (or foreground) that's somewhat out of focus being very "confused" and patterned.

    If everything is at infinity, or if you are doing a closeup with a distant background, things can look OK. It's when your subject is 30ft away and your background is 50ft away. Sometimes this can totally ruin an image.
     
  12. I absolutely agree that mirror lenses are a worthwhile investment for photographers today who don't want to sink big bucks into large, high quality telephoto lenses. I still own a Tamron 500mm and a Sigma 600mm. mirror lens from the "old days," and I have found them fun to use in the field with my DSLRs. This is even more the case now that I own a D200, since you can set the camera body to meter with non-CPU lenses (formerly I used trial-and-error metering, which with digital really is pretty easy). The big advantage in my experience is that you can set the camera ISO to a very high level and can consequently eliminate to a great extent the camera shake issues that are largely responsible for the reputation of mirror lenses as "unsharp." I have been able to get very good bird photos handheld using my mirror lenses, and this was only rarely the case when I used film. As for color/saturation/contrast issues, the truth is that you can tweak these factors in Photoshop to mitigate these problems.
    00Ie9d-33284584.jpg
     
  13. "Minolta...made an AF mirror lens...I am wondering if they are going to revive it now."

    It has been revived and is available under Sony brand for the A-100. I believe it is optically exactly the same lens, but still.
     
  14. pvp

    pvp

    Mirror lenses never died away. They have been built and purchased right up to the present day, and if you can appreciate their unique qualities they're great.

    I, too, once owned a Canon FD 500/8 mirror lens. It was then, and I believe would still be, the sharpest long lens in my arsenal, if I still owned it. Unfortunately, I couldn't stand the crappy bokeh, so I dumped the lens and put the proceeds toward a 300/2.8. I, for one, will not go there again.

    You can rehabilitate a three-legged horse all you want, but in the end it'll still lose the race.
     
  15. ShunCheung

    ShunCheung Administrator

    IMO, the problem remains that it is very tough to focus mirror lenses because they are f8 (500mm) or f11 (1000mm) so that you'll have a very dim image in the viewfinder. The fact that the viewfinders on the low-end Canon (D-Rebel family, 10D, 20D and 30D) and Nikon DSLRs (D50, D70) can only make things worse. Regardless of how great your optics is, if you cannot properly focus it, you'll have a lot of problems.

    20 years ago I bought a Nikon 500mm/f8 mirror, and that is the sigle biggest lens-purchasing mistake I have ever made.
     
  16. The thing that made me stop using it in the first place was not the doughnuts (I kind of liked that) it was the strange hard double lines you got from non point light sources. Look at that bird about halfway down the thread. The branch highlights are repeated as a double line. I hate that. If you can frame it right you can't tell it from any other lense, but I hate those double lines.
     
  17. It looks as though the main issue with mirror lenses is not sharpness, color or contrast, but generally speaking 'the bokeh', which receives the most of the negative comments. IMHO this is a sign of rehabilitation ;-). There seems to be no second opinions on the statement that DSLRs offer more robustness in using a mirror lens due to a higher quality at high ISO setting. Despite varying the ISO on the fly, it seems that nobody is taking advantage of other in-camera image controls offered by a DSLR. It also seems that the majority is using a 500mm mirror lens. My 'secret agenda' in starting this thread was, among other things, to get opinions on the 1000mm mirrors, where there is little competition (even with a $10K budget, Shun) from the regular tele lenses. Also, the dohnut problem becomes less prominent as the focal length increases. The other question I still have is about the possible changes in construction of future mirror lenses. As I said, most current mirror lenses cover more than the standard 35mm frame. It looks plausible that a smaller secondary mirror would be needed to cover the smaller digital sensor. This would also produce a 'thicker dohnut', perhaps to the point it could be recognised by a local pixel patterning software and eliminated?
     
  18. ShunCheung

    ShunCheung Administrator

    If you want 1000mm, just add a 2X TC onto a 500mm/f4. If you start from a 600mm/f4, you can get 1200mm. Those combos don't give you the best optics in the world, but neither is a 1000mm/f11 mirror lens. Those long teles are expensive, though.
     
  19. Sure, Shun. These combos are not really a 'competition', they were not meant to be owned by an individual (although there is no rule why you shouldn't). In fact, you do not have to sell a kidney to rent a lens of this class at a profi rental here in Toronto. The longest lens I see listed right now is EF400/2.8 L II USM ($150.00 for a weekend, $600.00 for a week). Add $20/day for a TC. Given that this could have been my film costs, renting is definitely a possibility. However, for the same money I can own the most powerful mirror lens. This is what the buzz is all about.
     
  20. Sorry, but I simply don't buy the argument. Over the years I've used several mirror lenses,
    from 500 mm to 1400 mm (Questar telescope). The single advantage they had over
    regular optics was small size, but that came at a very steep price in image quality. None
    of them came
    even close to the degree of sharpness possible with a good 500 mm refractive telephoto
    (Canon 500/4 IS, in this case). And none were close to the sharpness possible with that
    500 mm 'stretched' to 1000mm with 2X converter. The Questar's optics are superb when
    used as a telescope and theoretically could probably have achieved good sharpness as a
    lens, except for unavoidable problems with camera shake (even with MLU), wind, and
    convection cells, which were made worse because its very small aperture (~ f16) precluded
    high shutter speeds and introduced diffraction effects.

    Poor optics are even more problematic with APS and DX-format DSLRS than with film,
    because digital sensors mercilessly reveal optical flaws that could be overlooked on film.

    In addition to the issues with optical quality, all of these mirror lenses yielded positively
    obnoxious out-of-focus effects except under restrictive and unusual conditions (e.g.,
    plain blue sky as background). The 'doughnut' effect from bright out-of-focus areas was
    NOT less obvious with the 1400 mm Questar, although that's partially due to the small
    aperture.

    Lack of aperture control is another big drawback of mirror lenses, at least IMO. I
    frequently want the option of stopping down a bit for added DOF -- not possible with any
    mirror lens I'm aware of.

    Finally, a Canon 500/4 + 2X converter yields a 1000/8 combination that is stabilized and
    costs less than $6K at current B&H prices.
     
  21. ShunCheung

    ShunCheung Administrator

    Maybe I am fortunate. As I said, back in 1987, I bought a Nikon 500mm/f8 mirror, used it for a couple of years and told myself that I would never used a mirror lens again. In 1992 I bought a 500mm/f4 P and a few years later upgraded to the AF-S version, which I still own today.

    A used Nikon 500mm/f4 P is not that expensive. There is no auto focus, but neither does any 1000mm/f11 mirror. Your mileage may vary and there are certainly fans of mirror lenses, but to put it bluntly, from my point of view, my photo opportunities are too valuable to be wasted on any mirror lens. In particular, if you are talking about a 1000mm/f11, your problem is worsen in two ways compared to a 500mm/f8: you lose one stop of speed and all your vibration issues are worsen because you double your focal length.
     
  22. Shun, I did the same thing with a 500mm of about that vintage. A couple years ago I repurchased the newer version and it is a tad better. But there is no comparison against a good Nikkor tele and a cat. PhotoShop sure helps with my biggest concern: contrast.
     
  23. There's a certain element of talking "apples and oranges" here. I don't think a lot of people would argue that a 500mm. mirror lens is the equal optically of a great big 500mm. f4 refractive tele. The issue is, *for the price difference* (which, even if we are talking old, used, manual focus lenses) is considerable)is the mirror lens a reasonable purchase for a digital photographer? I say, absolutely. The small size and portability are actually huge advantages in many situations. Shun mentions the focusing issues, but the truth is that with digital one can afford to snap several photos to get one shot, i.e., you can shoot several exposures while fiddling with the focus ring. Bokeh issues are real *for some photos* but not others. The truth is that for most people's purposes the very slight difference in resolution between a good mirror lens and a good quality large refractive tele is not all that great, and skillful post-processing can render the difference even smaller. The bottom line (which is important here): one can pick up a good used mirror lens (and in my experience owning both, the Tamron 500 is every bit as good as Nikon's own) for a veritable song. Ebay seems to have a number of very cheaply made mirror lenses listed, but there is also currently a Tamron with a 2x telextender included for less than $200. A steal! Again: if someone is interested in everyday, heavy-duty telephoto work, a mirror lens is certainly not the equal of a larger, faster, refractive lens. But for many people, the objective is occasional use in very particular situations. A mirror lens can get you surprisingly good wildlife and scenic shots in most circumstances, particularly not that digital has made the technical issues easier to cope with. I frequently use my mirror lenses cradled onto a bean bag on a post or other support, and the results are quite acceptably sharp. The original poster asks about 1000mm. lenses. He might consider the Celestron or Meade lenses that are made primarily as "telescopes." Optically these are reputed to be decent, and they are inexpensive. However, keep in mind that the longer the focal length and hence the greater the distance between camera and subject, the more problems will be encountered not only in terms of vibration, but also atmospheric interference (this is true for any kind of tele, of course).
    00IfO9-33317584.jpg
     
  24. Thank you everybody for a very informative exchange of opinions and the images. Particularly Douglas, for a very balanced and thoughtful answer. Perhaps I should have asked "With high ISO capability and all those image controls, don't DSLRs reduce the gap between mirror and high-end refractive lenses?" I think from the posts the answer is a definite yes. I never meant 'close the gap'. In other words, if you have invested in a digital body (which is about half the price of a high end lens), you got an instrument in your hands which allows you to 'squeeze' more from a mirror lens. I particularly like the idea of 'focus braketing'.
     
  25. ShunCheung

    ShunCheung Administrator

    You can easily bracket exposure because if you know it is between f5.6 and f11, you can take a few samples in between. If you don't know where the focus is, how can you bracket the focus? In particular, if you are taking about shooting a bird that can move a little, or a bird standing on a branch that is moving a bit under the wind, you are going to have a lot of problems.

    Again, I am using some strong words here. My shooting opportunities are valuable. Even though you give me a mirror lens for free, I will not waste my time on one. And I don't even mind any donut-shape out-of-focus highlights. Focusing problems and the slowness of such lenses so that you cannot freeze action are my primary problems with mirror lenses.

    However, your requirements may be different from mine. If a mirror lens works for you, by all means use it. If you go thru the same learning exercise and frustration I went through 20 years ago, please don't come back and tell us that nobody has warned you about it.
     
  26. These are links to two images taken with different mirror lenses The first one was taken with a Vivitar 500mm.

    http://img223.imageshack.us/my.php?image=vivitar500mmmirrorfe6.jpg

    The second was taken with a Tamron 500m SP

    http://img100.imageshack.us/my.php?image=tamron500mmspmirrordy7.jpg

    The difference is quite noticible. Both were taken with the same camera, with the same film, using a tripod & cable release within a minute of each other.

    Also, although both lenses are stated as being F8, the Vivitar was always a stop slower that the Tamron. The darker viewfinder that the Vivitar gave made it a lot harder to focus.

    Would suggest steering clear of the Vivitar, or any of the cheap 3rd party mirrors on sale on ebay unless you have seen what they are capable of beforehand.
     
  27. Shun and I have gone back and forth about mirror lenses for several years now, and the debate will probably continue for years to come. He must have truly had a TERRIBLE experience twenty years ago :)).
     
  28. Thank you, David, for giving and example of two different mirror lenses. Running on a mediocre mirror lens is not that uncommon and you are not safe with a DSLR here. I have been thinking for a day whether I should comment on Shun's latest post about '20 year old frustration' and a 'warning'. I believe 20 years ago the first autofocus SLR was just out, the Minolta Maxxum 7000, and autofocus was still more of a curiosity. And I am not sure if there was any decent color film with ASA 800+ at that time. I got my Tamron 500mm between '93 and '95 and it took me a couple of years to master this lens and understand its shortcomings. For a while I mostly shot black and white, because I had full control over film speed and contrast. But then came the films with flat crystal technology and life became somewhat easier. At this point of the discussion I feel compelled to present another image which I got today walking around a nearby provincial park. Cloudy day, grey doves with not a lot of contrasty detail to focus on, sitting in the shade amidst a lot of branches...I think everybody would agree that this is a tough situation to focus both manually and automatically. I took several shots in succession using that 'focus float' technique, I also bracketed exposure. One is here for you to judge. With film, you would stand more than a 50% chance ending up with a weak image. No postprocessing except downsizing, but camera image controls (contrast, sharpness and saturation) were set to max.
    00IgMe-33341584.jpg
     
  29. Alexander, since you asked us to judge (I think)....

    On a small web image like your mourning dove picture, it's not possible to tell much about
    sharpness (unless the lens is awful). With respect to other qualities, it's certainly a matter
    of personal opinion, but I'm very definitely in Shun's camp here: I simply loath the way
    mirror lenses render contrasty, out-of-focus areas. IMO, FWIW, apologies for being blunt,
    etc. etc.: the dove image is ruined by those distracting, obnoxious double-edged blurred
    branches. It doesn't matter how sharp and contrasty the in-focus subject is if the image
    as a whole is marred by an ugly background.
     
  30. Here is the larger version of the doves:

    http://img71.imageshack.us/img71/184/img0061ap6.jpg

    However, opinions indeed differ whether out of focus shapes ruin the image or not, as I said in my original posting. Besides, obstructing foreground shapes are rather difficult to remove by postprocessing, while with the background it is fairly easy using 'Gaussian blur'in Photoshop. I was tempted to do this, but I think it is more informative to show the image as it was taken.
     
  31. Besides, obstructing foreground shapes are rather difficult to remove by postprocessing, while with the background it is fairly easy using 'Gaussian blur'in Photoshop.
    In my experience it's only "easy" to remove or smooth out annoying background components if the shapes you're trying to remove are not close to the main subject of the image. Otherwise, it's a royal pain and often impossible to do cleanly -- and even when it is possible, it's extra work.
    I don't always agree with Shun but I'm with him 100% here. As he says, by all means use a mirror lens if it suits your purposes. I'm sure it's possible to make good images with one, although I never succeeded. Personally, I've no wish to waste time with a lens that is effectively crippled for a big fraction of the images I'm likely to take, and imposes a large amount of additional postprocessing work to boot.
     
  32. Here is a shot from the Minolta Maxxum 500/8 on the 5D (1.5x crop) so effectively 750mm. The picture and a piece from the top edge. Not too bad.
    00IgWV-33347384.jpg
     
  33. And here's a shot of a house way up on the hillside with the same lens. On the digital the contrast seems to be lower but it's not bad.
    00IgWW-33347484.jpg
     
  34. ShunCheung

    ShunCheung Administrator

    A couple more comments: (1) If you want to show sharpness, a small web image is completely meaningless. To demonstrate it, crop a samll but meaningful portion from your image to 511 pixels across and show us the actual pixels, e.g. the eyes of an animal. (2) Photography is not about showing one successful shot. There are plenty of people who argue that AF is not necessary for sports photography, and they promptly show 1 good sports image shot with manual focus, 1 image.

    You can get 1, or a few, lucky shots occasionally. What we haven't seen are all the rejects. Without showing all the rejects, you are providing a misleading argument. Another thing with the Minolta is that it has an AF mirror lens; I don't know how well that AF works, but as a friend of mine puts it, AF would be God send for mirror lenses, because accurate focuing is the primary problem. That is a problem you will encounter for every shot you take. And unless you are getting an AF mirror, any Minolta result doesn't apply.

    It is exactly right that 20 years ago, AF had just started. That was why there was still a market for mirror lenses back then. Today, most major brands don't bother to make them any more because people are accostumed to the higher standards from AF now.

    The bottomline is that I think Alexander is completely convinced that a mirror lens is the way to go. The best way to find out whether that approach works for you is to try it yourself. I did 20 years ago.
     
  35. To continue the argument: :)) Shun alludes to a significant issue here when he rejects the validity of a web image to demonstrate "sharpness." I've long maintained that too many photographers make a near-fetish of "absolute sharpness" at the expense of handling characteristics, convenience, and yes, price, which is a real-world consideration, particularly for amateur photographers. Sure, I would like all of my lenses to be absolutely maximally sharp, but until I win the lottery, I often have to make some compromises. The truth is, most of us are NOT using our cameras to make gigantic blowups for public presentation. And even if we were, the truth is that at the distance from which the average person views a poster-sized photo, slight differences in sharpness don't really make all that much difference. The point is to "get the photo in the first place." I think that those of us who have posted images taken with mirror lenses have shown that you can indeed get some pretty good shots using these lenses. At the same time, for every one that is a keeper there are probably twenty or thirty that are tossed (this is similar to what happens with "digiscoping," another imperfect but surprisingly popular way that people on a budget can get into long-lens photography). But so what? Unlike film photography, digital photography makes it possible to delete those twenty or more crap shots at absolutely no cost! Bottom line: for those of us who mostly use our photos to make fairly small enlargements and yes, for web presentation, a mirror lens can be a very useful tool that is well worth the modest cost. I say this as someone who owns a couple of "big glass" teles and knows that ultimately, the quality thus obtained is superior. But frankly, I often go out to take photos under circumstances where committing to a giganto-telephoto rig complete w/tripod just isn't practical. Sometimes the mirror lens is just the thing (or else my 80-400mm. VR zoom, but even that was pretty costly), and I know that if I hadn't brought along the smaller lens I might not have brought the camera out at all and I would have ended up with no photos at all.
    00IgqX-33358284.jpg
     
  36. Well, first off, I am indeed completely in Douglas camp. And, not to sound offensive, Shun, I now know what kind of photographer you are. You made your choice 20 years ago. ;-) With the risk of being trivial, sharpness is not only something to be demonstrated 'on the pixel level'. I am happy you requested that. That identifies you with a certain crowd. Another point of view is that sharpness is not only a characteristic of a lens, it is also an illusion and sharpening algorithms use this feature. Much like special effects in movies use other illusions of the eye. We will go off topic if we start arguing that sharpening of a scanned film image does not do the same job as sharpening of a digital image. What I really wanted to demonstrate with the latest image is that the illusion of acceptable sharpness can be achieved with a mirror lens image. Probably because its rays hit the digital sensor at the right angle. Which makes it more usable than before. You cannot do this with an old expensive wide angle lens. For digital sensors these will have to be designed from scratch. And finally, I believe photography is about creating an image that is appealing to yourself, to other people and ultimately to a market. That is associated with a lot of rejects! All the time. Fortunately, as Douglas mentioned, we do not have to pay a huge price for them anymore.
     
  37. And, not to sound offensive, Shun, I now know what kind of photographer you are. You made your choice 20 years ago. ;-) With the risk of being trivial, sharpness is not only something to be demonstrated 'on the pixel level'. I am happy you requested that. That identifies you with a certain crowd.
    Hmm. So, did you check out Shun's portfolio before you offered up these condescending statments about "what kind of photographer" he is? IMO, he's quite a good one, and if he's in a certain crowd that gets fine results by avoiding equipment with obvious optical warts, then I'm gonna apply for membership.
     
  38. There is nothing in my post, Mark, that identifies Shun as a bad photographer. My statement is not 'condescending', but it is 'classifying' to the same extent he is trying to say I am convinced mirror lens is a way to go. Now, I recall Shun's portrait is obscured by a Contax 645. What about Zeiss Mirotars? "Carl Zeiss Mirotar T* 500mm f4.5, one of the fastest ultra-telephoto lenses in the world today. This lens design has totally eliminated chromatic aberrations so prevalent in conventional high-speed lenses of this class..." Granted, this lens is neither cheap nor small, but do you have doubts it is a quality optics? The last of them, the 500mm, I believe, was re-designed only 2 years ago. Any 'condescending' comments about Zeiss?
     
  39. ShunCheung

    ShunCheung Administrator

    Alexander, you are getting off topic. What does my portrait and Zeiss have to do with this discussion and debate? If you disagree with my opinions, that is fine. When you start making personal comments, it become a problem.

    An image on the web may be 600 pixels across. At 300 DPI, that means a 2-inch or 5cm tiny print. That is why a typical web image cannot show the true sharpness and can easily hide a lot of problems. Cropping out the actual pixels is a simple way to demonistrate true sharpness at a level that a lot of us can easily understand.

    If all you care about are tiny prints or web images, you indeed don't need a whole lot of quality. In that case I would say just use a 300mm/f4 or 400mm/f5.6 AF lens, and make the crop in PhotoShop afterwards. Obviously with that level of extreme cropping, the final result will be mediocre, but at least you don't need to struggle with focusing with a dim viewfinder in every picture you shoot.
     
  40. Any 'condescending' comments about Zeiss?
    Sure. Happy to. If the Zeiss Mirotar is a mirror lens, it will produce out of focus highlights that are, in my opinion, butt-ugly. And it doesn't have a diaphragm, so there is no control over depth of field. That's just the nature of the reflex-optics beast.
    I think Shun is offering good advice, based on considerable experience. You have a different opinion and are welcome to it -- but that says nothing about the value and pertinence of Shun's viewpoint.
     
  41. "...feisty bunch of guys wondering if a $150 500/8 lens will take as good a photo as a $1500
    500/4 lens."
     
  42. "...feisty bunch of guys wondering if a $150 500/8 lens will take as good a photo as a $1500 500/4 lens."
    I sure wish the last part ($1500 500/4 lens) were true.
     
  43. Shun, I mentioned Contax because this looks like your favorite system and because you said: "Today, most major brands don't bother to make them [mirror lenses] any more because people are accostumed to the higher standards from AF now." A hint that you may not be entirely accurate even for your favorite system. Tamron still makes an umptienth version of their mirror lens, which received only positive marks in this discussion. If you can find their 350/5.6, it is even better. My purpose was to collect opinions from people who actually shoot with mirror lenses, so that we could identify the 'lemons' and pinpoint the good ones. It is you who imply that I am trying to push my point of view by deceiving the public with appropriately scaled images, or worse, that my standards of quality are too low. When I scaled a 8 megapixel image to 1024 pixel on the long side, it is not enough for you to judge the sharpness! If you have time, go to http://www.photographyreview.com/, find reviews on Zeiss Mirotar 500/8.0 and wonder how different they are. Unfortunately, they are not about digital. -My- purpose was to find it about the performance of specific lenses with digital sensors. I think we succeeded in collecting a few benchmarks that people can use in the future. More would be very welcome. BTW, their prices, Jeff H, spread all the way from $50 to your 500/4 refractor price and do not exactly correlate with the quality. Finally, I do not find a 20D viewfinder image dim, even at F/9. But it is small and with a certain kind of vision problem this can be difficult. I sure miss the autofocus with the Tamron, but I am waiting for my chipped EOS to M42 adapter (thanks to Bob Atkins who pointed us to it) and hope to improve on what I get right now.
     
  44. pvp

    pvp

    Mirror Lenses are Crap
    [​IMG]
    Any questions?
     
  45. This has been interesting. I gave up trying to use my Meade 102 mirror lens for serious wildlife shots many years ago. It still works fine for visual spotting and occasionally as an astronomical telescope. If you want to try something new, make it an APO short-tube refractor. Yes they are fixed aperture, a bit longer and heavier than a mirror, but sharper and priced in the same range as CATS. Checkout your telescope retailers for options. In the long run, it always seems to be a compromise tho'. The really crispy-sharp APOs are expensive as are the OEM long lenses for cameras!
     
  46. I have a Rubinar 500m F/5.6 mirror lens. Great on some aspects, bad on others.
    Pros:
    - compact, light
    - very short minimum focus distance
    - f/5.6
    - quite nice focus ring (very precise)
    - no chromatic abberations, no vignetting
    - quality/price ratio

    Bads:
    - sharpness not of a high level, but correct though. Mine was second-hand and in a bad shape when I got it. I had to realign the lens (very difficult job) to get good results. I don't know if brand new ones get this optimization from the beginning.
    - f/5.6 but because of the partial reflexion of mirrors, effective aperture was around f/8.0
    - my main complain: no aperture setting ring. When you shoot 3 meters away, depth of field is very very shallow (around 2-3mm). The background is completely blurred, *but* you can't have a bird completely in focus.
    - for Canonists, I recommand to get a AF-Confirm chip to help manual focus: depth of field is so shallow (with this 500 f/5.6) that you need to be very careful at focus.

    If you are on budget, this lens is great. BUT not usable on any subject. It is a nice toy for bird photography IF you can be close to them and have a not-so-close background.
    The donut-like bokeh is often a problem, but if you care, you can play with it and get good results. Not on all pictures, but you can.
     
  47. It is not clear, Jean-Jacques, if your experience refers to using a Rubinar on a DSLR or on film, but obviously certain point are the same. And, so that Shun, Mark and others do not think I am an unconditional adept of mirror lenses, I should add that using a mirror lens at 'macro' distances is THE biggest problem IMO (3m is 'macro' for a 500mm lens!). Since stalking some insects is difficult with a typical 100mm macro (+1.4X TC), on a full-frame DSLR is conserned (or film), I once got a 300mm Rubinar and tried it at short distances. Well, the donuts are the worst obstruction in this range. While you can shoot a dragonfly at a considerable distance, even in those places where you cannot physically get closer, you get a really weird looking image wherein tiny dohnuts line up every bright area, while there is little or no background problem. However, getting small animals completely in focus at close distances can be a challenge for any lens, since it can be tough to choose a spot over which to align an autofocus sensor and choose the right depth of field. I did not use the other Rubinars except the 300mm, but they are better built than some of the plastic Japanese mirror lenses and sharper/contrastier than they are. However, Rubinars are a by-product of the Lytkarino optical factory making large telescopes and there is little hope they will be optimized for digital sensors, while pricier mirrors may well be optimized in the future. Finally, IMHO Alan's image would not look good with any lens stopped to the same F-stop. The background is bright and really distracting unless you have one of those 500 F/4s. But then at F/4 the whole bird may not be in focus ;-). A powerful flash may be in order to isolate the bird from the background. With the risk of being slammed again for low quality, here a 2-minute fix for Alan's image.
     
  48. The background is bright and really distracting unless you have one of those 500 F/4s. But then at F/4 the whole bird may not be in focus ;-)
    In which case, if you are using a standard telephoto, you can stop down.
     
  49. This is an undisputable point, Mark. Slamming down mirror lenses should begin with "...but they do not have an iris", not with anything else previously mentioned. Some of them did, but as a general rule they do not have one. However, stopping down in Alan's shot, as I said, may not really salvage the situation. And, what if you got a lens with a 6-blade iris?
     
  50. pvp

    pvp

    Alexander, I did make a version of the heron photo with the background selected and blurred. While that's a possibility with images intended for prints, it seems like a lot of extra effort when you could start with a lens that doesn't mangle the image before it even reaches the film.

    Also, not very feasible when shooting transparencies that are intended for projection. (Yes, some of us still do.)

    Mirror lenses are crap. They are a liability much more often than an asset.
     
  51. Thank you, Alan, you did give yourself away. Perhaps understandable since we are so far now from the original question (have to scroll too far back). Slides for projection. Right! I can't agree more. All slide films with 400 ASA or more are crap! If I were to make slides, I'd be hard pressed to pick a mirror lens (well, maybe a Zeiss Mirotar would do). But I was asking about the age of -easy- ASA 1600 shooting, 'photoshopping' and LCD projectors or HDTV. Like it or not, this is the way we are going to show our images. Do mirror lenses deserve a better place in this world? Or do all newbies to DIGITAL telephotography have to go through all those crappy tele-attachments, and 20-year old refractors Ebay is bursting with, because you guys keep saying 'o-oh, crappy bokeh, o-oh, no iris..., start saving toward your 3K lens". Any but the most expensive recently designed refractors (APO, LD, SD etc) have chromatic aberration. Sharpening only makes it worse. In contrast, spherical aberration in mirror lenses is (apparently) correctable by sharpening, and it looks as if 'perceived sharpness', observed under normal conditions, not at 'pixel level' is good even in crappy plastic mirrors. At this end I must confess I love slides. But this year I find it difficult to develop slide films here in Toronto, even buy E6 chemicals, and B&H refuses to export them. ;-(
     
  52. Alexander, my answer about the Rubinar was for both film and digital, but I really start using it when I came to digital, thanks to the ISO button ;)<BR>
    Yes, you're totally right about high ISO giving a second life to these lenses. But to keep a decent image, I didn't go above 800ISO with my 350D/RebelXT.<BR><BR>
    IMHO, image quality provided by this lens remains constant whatever you used, digital (APS-C) or full 24x36mm surface. Some people even report nice results with 6x6 format!<BR>
    Honestly speaking, I think that it will not be a lens you would use forever (because of the "bads" of my previous post), but given its quality/price ratio, you will have a lot of fun with it.<BR>
    This was about the Rubinar. A Celestron or Meade may be better optically, due to their newer coating technology, and better mechanics, but I have no "proof" about this.<BR>
    <BR>
    Now, I own a Sigma 120-300 F/2.8 EX HSM. I think it's a much sharper lens, it has AF, it's 1.5x bigger, twice the weight, but it's much more versatile (combined or not to a TC). Last but not least, 10+ times the price...
     
  53. I had a Sigma 600 a few years ago and eventually sold it. It was fun for a while, but eventually I just didn't use it that much. They're slow and in spite of being small for what they are, they're still big. Mine hogged a large part of my camera bag. Mirror lenses are a product that seem like a good idea but that eventually gets forgotten about in the closet, like a $1200 treadmill, or a fancy kitchen gadget for making perfect deep-fried onion rings. If I were going to invest in a tele lens, I'd go for a good 300 f4 (do they still make those?), and just crop. The resulting image will probably be better, and the lens will be much more versatile. My problem was never really absolute sharpness--it was steadiness. I actually like those donut highlights (of course, I never met a donut I didn't like....):
    00Ijzq-33429284.jpg
     
  54. I ran across this article online that deals with the possible rebirth of mirror lenses in the digital age:

    http://www.nobell.org/~gjm/photography/fdadapter/mirror.html

    Definitely interesting, at least to some of us :)).
     
  55. Thank you, Douglas, for the link. The author of the article started from the same observation as I did when I started this discussion. Oddly, however, he mentions that Photoshop can fix contrast and saturation but says nothing about sharpness. Furthermore, comparing an old Sigma mirror lens model to a modern L-zoom lens ($1500) is not exactly fair. On a previous topic, the weather has been bad last week, so I did not have a chance to use my chipped M42/EOS adapter that was mentioned before. An interesting detail, though, which was not mentioned in Bob Atkins review is that the adapter has not only the chip but a small pin which tells the camera that a lens is attached. BTW, Chinese and HK versions of such adapters, also currently offered on Ebay, come with a suggestion to place a piece of paper under the body lever to achieve the same effect. Bob's comments about the finish quality of the adapter were, IMHO, somewhat overoptimistic. For my specimen some sandpaper work was necessary to make it mount flawlessly on a Tamron EF TC. Is there already a thread on rebirth of old refractors in M42 mount in the digital age?
     
  56. ShunCheung

    ShunCheung Administrator

    Interesting Douglas. I am glad that you provided the link instead of me. Even a cheapo 55-200mm f5.6 zoom (after cropping) provides better results than a 600mm/f8 mirror.

    That is exactly in line with what I suggested earlier: If you need no more than small prints, which is the limitations for mirror lenses anyway, you are much better off getting a 300mm/f4 and crop. In this digital age, it is much easier to crop in PhotoShop, something we couldn't do with slides before.
     
  57. Shun and Douglas, actually, I am guilty of not looking closely at the 3 lens comparison at first. Now, the comparison is really not accurate. The shutter speed used for the mirror lens is a lot longer than for the other two, while the focal length and potential camera shake is larger. While it is mentioned that a tripod was used and the best of 3 shots etc, it is still possible that camera shake was not taken care of. The 'cheapo' was used at its best aperture and with a shutter speed not actually requiring a tripod. This picture just shows one of the common flaws of <using> really long lenses, not the quality difference. Also, if you look closely, at the top of the images the sharpness is comparable, while at the bottom the mirror lens image is quite simply out of focus. This measures the ability of an autofocus camera (forced to refocus for each shot) against a person's eye of unspecified age ('... not a poor student anymore'), who apparently did not use manual focus for a while. We had better pictures shown during this discussion.;-). I'd love to see a quality affordable 300/5.6 refractor with LD glass (imagine how small, light and sharp it could be) coming out, but it seems they are not going to happen. Then, surely, I could crop.
     
  58. ShunCheung

    ShunCheung Administrator

    You can keep making excuses for mirror lenses for all you want. The bottomline is that if you get a 300mm/f4 AF or even a cheap 55-200 f5.6 zoom, you have the advantage of AF, a larger aperture (so that you can use faster shutter speeds) and in some cases IS/VR. All of those advantages make 500mm/f8 type mirror lenses a very poor choice in the digital age.

    But if you prefer mirror lenses regardless of the facts in front of you, that is your choice.
     
  59. I provided that comparison web page to liven up the discussion, and to point out that there are no photographic miracles out there :)).
    Mirror lenses are not easy to use and are incredibly prone to vibration. Etc.

    STILL, I can speak from my own experience and assert that I have obtained some very satisfactory results using a mirror lens, particularly in bird photography. In looking over the better photos I've achieved with mirror lenses I ponder whether I could have gotten the same results using a 200mm. setting on a zoom lens and additional enlargement, and I find it hard to believe that I could.

    Again: if you follow the ebay listings for a while you can find a pretty decent 500mm. or 600mm. mirror lens for under $200. Compare that with even a used, older manual focus good-quality refractive 500mm. lens, which I doubt you'll find for less than around $1500. HUGE difference!!! I still think that given the high ISO settings and fast shutter speeds one can enjoy with DSLR's, it's a worthwhile investment for certain types of photos.

    And by the way, just to stir the pot further, here's an interesting comparison by Bob Atkins of a Tamron 500mm. mirror lens with a much pricier Canon tele:

    http://www.photo.net/learn/optics/mirrors/

    The Tamron aquits itself surprisingly well. The entire discussion in the thread that follows Bob's post is interesting.
     
  60. Well put, Douglas! Actually I was aware of Bob's article before I started this and I had the Tamron for about 10 years. I think our friend Shun got a little carried away by slamming me down for my alleged mirror lens advocacy, recommending a 55-200. I am sure most people will be disappointed by this lens except for when using it all the time at F/11. But a really good point I could not make, but you did now, is that, surprizingly, in the digital age, the gap between a consumer tele-zoom quality and a serious telephoto <widens>! This is because old and/or cheap refractors are not a solution, their optical flaws are too noticeable on a DSLR, and independent manufacturers like Sigma, Tamron and Tokina are dropping 400mm lenses they once offered, in favor of zooms. I had Tamron 200-400mm before but I sold it as soon as I got a DSLR, because it was not that much better than a mirror at the long end. And the autofocus missed all the time. Out of curiosity, I emailed Tamron USA yesterday and asked about the current situation with mirror lenses. The answer came almost in a second and the person there wrote that those were discontinued some time ago and it was not even certain if a mirror lens would work on a digital (???). I think it has to be put in plain English that people looking at those CZJ Telemegors (a huge but actually a 3-element lens), Russian Tairs (also a lens designed in 1954), and cheap Japanese refractors are on the wrong track and if they want to try bird photography, they should hunt down a Tamron mirror lens, and perhaps, with sufficient dedication present, start saving toward a modern refractor.
     
  61. ShunCheung

    ShunCheung Administrator

    Douglas, the comparison is no longer a 500mm mirror vs. a 500mm/f4 tele. I have chosen the latter since 1992 and as far as I am concerned, that debate was over a long time ago.

    The point is, based on the article you provided, a cheap Canon 55-200mm/f5.6, after cropping, beats a 600mm/f8 mirror by a wide margain. And that zoom is a $200 lens, new:
    http://www.bhphotovideo.com/bnh/controller/home?O=Search&A=details&Q=&sku=300600&is=GREY&addedTroughType=search

    Therefore, any price and weight advantages from the mirror lens you try to claim are gone. You can question the methodology of that tester, but since you introduced that article into the discussion, it'll be up to you to verify it.

    And I am NOT recommending any cheap 55-200. I would pay a bit more and get a used 300mm/f4 AF, which I am sure is superior to the zoom, as I wouldn't buy a tele slower than f4, anyway.
     
  62. Ok, I'll question the methodology of the tester, ok? His little experiment is hardly the last word, and if that's what people have taken it to be, then I am truly sorry for calling our attention to it.

    To be honest, I put more stock in the methodology and results of Bob Atkins. I think we all know who he is and that he is very knowledgeable about photography.

    Ultimately, however, I base my viewpoint upon my experience with my mirror lenses. I am fully aware of how difficult it is to get optimal results with them, but I also have numerous photos that prove to me that they can sometimes produce terrific images. If I had only $200 to spend on a lens for taking bird photos, I would definitely prefer to invest in a good cat lens than to try to use a 55-200mm. zoom. That's just me.

    It seems to me that this discussion is really reaping diminishing returns. People seem pretty entrenched in their positions. So this is my last comment :)))
     

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