500mm f/8 mirror lens

Hi, folks

I'm thinking of going into bird photography. What I've got is a PK-

mount Makinon 500mm f/8 mirror lens which I suppose is a lot cheaper

than the long lenses. Would anyone please advise if this is a good

lens for this purpose? It's very light but I find the viewfinder a

bit dim and the image smaller, compared to my 10x binoculars. Why is

this so? Thanks for your comments/suggestions.

Mirror lenses have some disadvantages with two advantages to regular primes. First the advantages: low price and low weight.

Now the disadvantages:

Constant aperature of f8 - which is why your viewfinder is dim. If you look through a lens at say f2.8 the image will be brighter than one at say f4 and much brighter than at f8.

Weird shaped out of focus areas that look like crescent shaped doghnut highlights. It can be a good effect, but you will have a hard time getting rid of it.

Usually the image quality is less than a good prime, but of course you aren't paying much for the lens so some things are given up.

In addition to the problems noted above:

1) Poor contrast with subjects in the photo.

2) Even a tiny amount of wind tends to cause them to shake the mirror, returning less sharp photos.

I sometimes use one (800mm ) for photographing the moon. But the donoughts noted above look very unnatural and is a huge problem with water. I also seem to recall they had a very limited depth of field.

If you are in the market for a longish lens and want to go on the super cheap, a 400mm f6.3 T-mount lens isn't bad, it's better generally than a mirror lens anyway. These lenses are also very light (they technically aren't telephoto lenses) and it shouldn't be that had to find one under $50.

But I also agree a mirror lens, used properly can be a lot of fun and it certainly costs a lot less than most of the other alternatives.

Well, between the advantages of mirror lenses compared to regular ones, is also the total lake of chromatic aberration. Regular lenses show a lot of it outside the center when shoot at open aperture. This means that, with a mirror lens, if the subject in the picture takes the entire frame or almost, it will be as clear at the corners as it is in the center. Of course, at 500mm you won't rise anymore the issue of a possible curved DOF, as the viewing angle is too small to read any DOF curvature. So, the differences between center and corners to a regular 500mm lens will come from the chromatic aberration only!

In other order of things, in the previous answer here is something confuse, that I'll try to make clear, if I got the point. Douglas said: "Even a tiny amount of wind tends to cause them to shake the mirror, returning less sharp photos." Well there are two issues here: first, the shaking from the wind, that doesn't come from the lens, but from the tripod's legs. Secondly, the issue with shaking the mirror, might refers maybe to the camera's mirror that shakes the lens when returning. There are two mirrors here: the lens type and the camera' mirror, and this made me confused. So, it is true that the camera's mirror shakes the lens when shooting, but this has nothing to do with the "mirror" lens. It has to do with the focal length of 500mm and the shooting technique. As the focal length cannot be changed, here is a simple technique to avoid the lens shaking from the camera's mirror: keep the camera with BOTH hands when shooting (the lens on the tripod, of course), and depress the shooter with the finger, never with a cable release!

As for the wind (again): chose a tripod other than a light-weight, one having ROUND section legs, not to large in diameter (!!!), but made out of THICK material. Put also some "rubber protection" on the first sections of the legs, not to protect your hands in the winter or the tripod anytime as it is said, but to absorb the vibrations. The tripod for wildlife is exactly the opposite of a studio tripod. For wildlife tripods, is good to be not as stable in order to be easily manipulated, but they have to be rigid enough to avoid shaking from wind. Studio tripods have to be very stable like a table, but don't need to be as rigid because there are no vibrations in a studio, and the focal lengths used there are not as long as those used for wildlife. Voila!

In a word, EXERCISE! I burned at least 5 rolls of film in order to get used to my 600mm Sigma, and was on the point to sell it for 2 bucks. But now I master it even at 1/60 of a second (80% good shoots) and with some luck even at 1/30 (50% good shoots)! Still, I think at it more like to an urban lens than to a wildlife one� because of the donuts!

Thank you for your comments and suggestions. Actually, I bought this lens in 1983 (lens lust?) but have used it only on very few occasions. I lost interest in it after a short while because of the unsatisfactory photos that I took. After reading your replies, I can see that there's more to it than just pointing the lens at a subject and pressing the shutter button. Armed with this new knowledge, I will use it again and hopefully my photos will improve. If they do, I'll post some in this forum for you to comment on. Again, thanks a lot.

PS Is it possible to take photos using my binoculars (10 x 50)instead of my mirror lens? The images that I see through them are very bright and sharp. Just a thought.

I have a 500/8 Tokina mirror. My experience is that you need to understand the limitations of these lenses and stay within them. If you do this then the results can be pleasantly surprising. If you dont then the results can be very poor!

You need to keep the speed high so you need plenty of light. Even with a tripod I try to keep the speed at 1/1000, so 400 film is a requirement as is a dose of nice bright sunlight. I think that they are much more prone to shake because of their light weight.

As an alternative I use a 400/5.6 which produces better shots more often and was also quite inexpensive - in FD mount. The single stop gain does make a difference?

I have 600 mm f:8 Sigma mirror. It gives crisp pictures if you focus it correctly and don't shake. Both requirements are often difficult. Objects which are out of focus create double images (points become doughnuts) and this looks very annoying. The best (and the only I'm afraid) policy is to take pictures without resolvable background.

Mirror lenses are light and cheap and dark. You can buy one second hand even if you don't use it much.<div></div>