85 f/1.4G AF-S Focusing and Fine Tuning

Discussion in 'Nikon' started by lee_vgg, Nov 21, 2010.

  1. Trying to figure out if there's a focusing issue with my new 85 mm f/1.4G AF-S lens. Seems like the 70-200 is sharper at f/2.8 in the center, which is surprising. Although it is a very sharp lens.

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    I went through and Fine Tuned my D300s and checked all my lenses (all using a tripod and triggered from a laptop). I settled on having to Fine Tune the default by +15! I then Fine Tuned the 85 mm by -10 but didn't need to Fine Tune the 70-200 at all. One strange thing I noticed was that with the default set to +0, changing the Fine Tuning for the 85 mm didn't make any difference for the lens. Prior to fine tuning I noticed it had difficulty locking on focus for a subject that was equal to the width of one focus point.
    Maybe I'm being too critical? From what I read though I shouldn't have to Fine Tune or question this lens at all, which has definitely been true of my 70-200.
    I can post the sequence of Fine Tuning shots if folks are interested, as well as some other comparisons (70-200 @ 70 mm vs 85 mm for example).
    Any thoughts would be appreciated,
    Lee
     
  2. bms

    bms

    I have both lenses, both are sharp. Maybe a sample variation?
    00Xj3p-304635684.jpg
     
  3. Well, seems about as sharp as your example. I knew my 70-200 was sharp but geez, didn't think it would be sharper than the 85. I guess I'm still a bit worried because of the seemingly absurd fine tuning I had to do.
     
  4. It doesn't surprise me that the f/1.4 is softer. What if you shoot at f/2 or f/2.8? Is it as sharp, or not?
     
  5. Lee,
    Did you try at differend distances too ? ( like 1m , 2m 3m, ...infinity, each lens has its optimum subject to frontlens distance ...), if your tipod is at the same distance from the subject, there is already a difference here...
    Since the 85mm 1.4's are designed as "portrait lenses"mostly, it is not does not surprise me that they are a little "soft" ( the 1.4D is appreciated for its "Signature" ...)
    BTW : Was the 70-200 set at 85mm ? ( I cannot see that from the samples..) ?
     
  6. "Seems like the 70-200 is sharper at f/2.8 in the center, which is surprising. Although it is a very sharp lens"​
    I`d not be surprised. My sample is also sharper than e.g. my 105VR which I consider very sharp, too.
    Anyway, there are several parameters related to this issue. You say you have been working on the "Fine Tune" feature but,
    • Have you performend a "real life" focus test? (I mean, other than shooting to that focus test prints at 2 feet, -what C.P.M. says-). I like to use a very wide metric tape at the distances I use to shoot.
    • Have you used "Live View" to check if certainly it`s an inherent resolution difference? Using live View you will "almost" assure optimal focus, a must if you`re testing lens sharpness. I`d compare your AF to MF (using Live View) shots.
     
  7. ( ... too late for editing)
    • If your MF shots (using Live View) are sharper than the AF shots, you`ll probably have an AF system issue, to be then fixed with the AF Fine Tuning feature.
    You don`t mention which version is your 70-200. Mine is the VRII.
     
  8. Seems like the 70-200 is sharper at f/2.8 in the center, which is surprising.
    Just to check: did you use a tripod for the shots? I would first start by setting the camera to tripod mode live view and focusing the lens manually very carefully by zooming in all the way. Turn off live view, use self timer or cable release and shoot. Repeat this five times with both lenses and choose the sharpest result for each lens as reference picture. Then proceed to do tests with autofocus. For testing AF you should also shoot a paper with a distance scale at a 45 degree angle to see if AF works correctly in the canonical test case and how far you may need to adjust it, if any.
    The 85/1.4 is a lens designed for portraits and it has rendering which makes people look good. This means that it doesn't accentuate fine detail in skin, whereas the 70-200 II is just the opposite, high contrast, a little harsh for portraits but excellent for more technical subjects. The older version of the 70-200 should be quite comparable with the 85 except that I'd expect cleaner images from the 85. You might be seeing just this difference in the rendering characteristics of the lenses.
     
  9. I'm probably out of my depth here but seem to remember an article a year or so ago in PhotoTechnique magazine on spherical aberration in fast lenses, includng the Nikon 85mm f/1.4 (the D version in that article). The gist of it was that with these lenses the point of sharpest focus would change as the lens is stopped down—the smaller the aperture, the greater the shift—and that the increased depth of field from the smaller aperture never maks up for the shift.
    I believe the suggested workarounds, none of them all that satisfactory, were to fine tune auotmatic focus for a specific aperture and distance, to focus at the shooting aperture, or to learn to compensate manually, such as by focusing on the tip of a person's nose if you want the eyes sharp.
     
  10. I guess it's a big ask for a 1.4 lens wide open to be up to the 70-200 at 2.8. The D version has corners that were almust unsuable at 1.4

    You may find the test on mans urovs interesting; in a comparision of the 85 against the 70-200 at 2.8, the 85 easily wins. (I can't post a link due to photo.net bloacking it!? Google search as one word).
     
  11. You should test the lens optically first using manual focus and/or moving the camera to find optimal focus and then see how sharp it is (resolution).
    Only after that is it possible to test if you have a focusing problem or not.
     
  12. bms

    bms

    Well, I saw you shot at 2.8 above... Hmm... Mansurov seems to suggest that it is better than the AF-D but still looks a little fuzzy at 2.8 when shooting test charts. For me it is sharp enough, though the 70-200 VRII is pretty amazing....
     
  13. I guess it's a big ask for a 1.4 lens wide open to be up to the 70-200 at 2.8
    The OP's images are both at f/2.8.
     
  14. Thanks everyone for the responses. To answer a couple questions:
    • Shot on a tripod tethered to a laptop
    • 85 mm was at f/2.8 in this example (hence my concern. Also have a f/1.4 I can post)
    • 70-200 was at 200 mm, for the same FOV and the same physical location as the 85 mm (also have an example at 85 mm that I can post)
    Couple ideas from people that I liked:
    • Use Live View (I tried this but it wouldn't activate - was it b/c I had it tethered to LR?)
    • Use Manual Focus, compare the differences (not sure how I would "know" it was focused, other than the green dot on my D300s. Obviously Live View would help if it would activate)
    • Use a text chart (I did the fine tuning with a book turned 45 degrees, I'll post some examples)
    Over the holidays I'm going to test it out in the real world and will post some additional comparisons (fine tuning, focal lengths, and real world shots).
    Thanks all,
    Lee
     
  15. I have one on order so the variation with the tests mansurov posted worries me. I'll be sure to test it to make sure I have a good one since the lens is almost the same cost as the 70-200 VII!

    Try doing some tests at infinity to eliminate focusing issues.
     
  16. 70-200 was at 200 mm, for the same FOV and the same physical location as the 85 mm (also have an example at 85 mm that I can post)
    I think I don`t understand this: Are you saying that at the same focus distance (physical location?), the same field of view is possible with either the 85 prime or the 70-200 @200mm????
    not sure how I would "know" it was focused, other than the green dot on my D300s.
    The electronic rangefinder aid is not the best system to trust... it`s easy to get wrong focus in critical situations (even when the dot is green).
     
  17. Jose,
    Oops, I misspoke there. The 70-200 was further back. To get the same FOV I had to move it back and then zoom in, since the 85 mm can focus closer.
    Lee
     
  18. There's a thing called a focus ring on the lens.
    Its a while since I was in the business, but I never relied on AF to choose the correct focus in a portrait....not when you might only be dealing with a couple of inches or less of dof.
    I had the 85/1.8. It was better than the 1.4. I also had three versions of the 70/80, 200. The 70-200/2.8 was sharper. I also found the AF-D version to be superior.
    What was the most recent lens I used for portraits? The manual focus 105/2.5Ai , $150 on ebay. Smokes both of these other lenses. Just because its new and expensive does not mean its better. I also use an old 80-200 f4 Ais a lot because its also sharper.
     
  19. ....And....many portrait lenses... like the DC ones, are not ultimately as sharp as some normal lenses for one very good reason: If you take a head and shoulders, let alone a face shot of a bride with an ultra sharp lens, you will be on photoshop for a couple of days editing out all the skin imperfections, pimples, dodgy foundation, open pores etc in all their glory. You won't be thanked.
    Many wedding photographers find out this the hard way. There are many posts in the Wedding forum about this very problem. The"not so sharp is best" lesson is one we learn over time. The quality of an image rendered by a particular lens has its own unique look. Its also why lots of people go with the 85/1.8 instead. Its also why Nikon lenses have a different signature look to Leica for example. It's not a "which is best issue" or "which is sharpest" look at all. It's which look do you like more. And that takes a long time to discover.
    Thats why its important to do the research and read the forums so that you can make an informed decision.
    Going back to your two image comparisons. If you were to delete the 80-200 shot and pretend you never saw it, you may say that the 85 shot has got a nice smooth texture to it, and its as sharp as you would need. I wonder why? Its because Nikon know that the 85 lenses will be used a lot for portraits. Some pros feel that this look is perfect for portaits...and for all the above reasons.
     
  20. I suspect the real 'problem' here is that the 85mm is not specifically Close Range Corrected. The confusion with FOV and Focal Length (above) almost implies that both are at or very near to their closest focus. As mentioned above, the 85mm is a specific length for portraiture (on FX) so not really best at closest quarters.
    There used to be a well known problem with how bad the 80-200mm 2.8D was at the very close ie near end, guess the newer 70-200mm has fixed that!
    I have the 85mm 1.4 D and the older 80-200mm AFS and the later is sharper at most working distances, but I wouldn't normally use it for portrait shots. The slight inherant softness of the 85mm, up to nearly maybe f4, makes it very skin friendly. I use them both on a D300, so the v.soft corners don't affect me.
    The question that always bugs me in this sort of comparison is, should they both be shot wide open which is never going to be really sharp or simply 2 stops down? To set the same aperture on both is not really fair to the slower lens (seems to be good here though..:). Fast zoom versus even faster fixed length is always going to be problematic.
    Having said all that... I would have expected more from the new lens 2 stops down! I guess finding out whether it is a focussing problem or a lens resolution issue is of more relavence here.
     
  21. Use Manual Focus, compare the differences (not sure how I would "know" it was focused, other than the green dot on my D300s. Obviously Live View would help if it would activate)​
    Change the focus ever so slightly (or move the camera) and shoot a range of images. Then pick the sharpest one.
     
  22. Read back through the posts.....err .....why doesn't Live View work? Which software are you using? It would make this an easier problem to sort out.
     
  23. Shadforth,
    Wow really unhelpful comments. "There's a thing called a manual focus ring" haha, thanks, I didn't realize that. You're two good points were the use of older lenses, which I completely agree with. One of my favorite lenses currently is the 135 f/2.8 AI-S. I also understand about the desired sharpness for portraits, though I've been shooting portraits with the 70-200 and have been quite happy with the sharpness. That said, I haven't been shooting brides with veils, instead more business and family environmental images.
    Mike,
    Thanks for the good point about focusing distance. You're right that I'm close to the minimum working distance, so perhaps that's an issue.
    All,
    I've decided to send this back. I doubt that it's really got any issues, but after handling it I don't like the size / feel. It's just slightly too large a diameter and I feel like I'm going to drop it every time I take it off the camera. I've ordered a 85 f/1.4 D and am hoping it feels better in my hands. I'm ok with the differences it offers, including the cost savings.
    Thanks,
    Lee
     
  24. Hey Lee, how did the Nikon AF 85mm f/1.4 D work out for you? Good decision or did you send it back also? What are your findings with this lens?
     
  25. I've been having problems auto focusing the 85mm 1.4g. I bought a copy locally. Tested it at home that night. Took a hundred shots and determined it was defective. It was typically front focusing by roughly a couple of inches at a focal distance of 10 feet.
    I return it the next morning. That afternoon, they call me back, saying they tested it and said it was fine. I went to the store, watched them test it, and did some tests of my own. It did front focus a few times, which they saw, but when doing tripod tests, three out of four shots were pretty good. This shouldn't have been good enough to convince me, but it was. So I bought it again, and tested it for a couple of weeks. Almost all shots in a typical indoor family setting were slightly out of focus. Enough to where I tried everything to take crisp auto-focus shots with it, but had minimal success. Mostly front focusing still, but a bit inconsistent.
    So I return it again and ask for another copy. A couple weeks later, another copy arrives. That was yesterday. So I test it in the same way I tested the other one, which was mostly typical indoor family shots, and am frustrated to find the same thing. Front focusing. I tried the AF Fine Tune and it helps at about +15. But it's still inconsistent enough for that to be an unacceptable solution. (Not to mention, you don't expect to have to compensate for manufacturing variances when dealing with highly regarded equipment like this.)
    So after reading through this thread, I tried Live View. Live View seems to be much better, but I need to do more controlled testing.
    My 24-70 2.8g and 105 2.8g are much more positive and accurate with focusing (albeit at f2.8 it has moredepth of field). My 35 1.4g is also much more positive and accurate with focusing, even at f1.4 (albeit at 35mm it has more depth of field). As far as I'm concerned, those three lenses are "perfect" and I really expected the 85 1.4g to have those characteristics.
    The body is a D700 with firmware 1.02. I'm using continuous focus, with the center "pip"(?). I've tried the other pips with similar results. For the brief test in the store, we used their body as well and noticed "okay" focusing with roughly 25% front focusing by "a little bit" (where the target focus point was mostly in focus, but the focus zone (depth of field) was mostly in front of the target, with the sharpest point being in front of the target).
    I did almost all of my testing on f1.4. When I did some limited testing on f2.8 it was still front focusing, although it became less of an issue because the target focal point would be included in the focused range due to increased depth of field.
    Another interesting bit, which may not be relevant, but when I display the focus point on playback, the pip the indicates the focal point is not exactly where my target focus pip was. It's off by about one pip height. I just checked that with one of my other lenses and it looks similar.
    Another thing is that the AF "hunts" more than I would expect. Even occasionally on a tripod aimed at a simple stationary object.
    What tests would you recommend? I got some good ideas from this thread. I'll try tripod test at close, medium and long focal distances, f1.4, f2.8 and f5.6, different lighting conditions, shutter speeds, AF, live view and manual focus.
    Or is this all just a waste of time? Should I just return it? Did I really get two bad copies and the third will be a charm? I believe so, but I'm trying as hard as I can to convince myself that the lens is good, and that I'll simply figure it out. If I conclude it's bad, I want to be absolutely sure and have a repeatable and obvious case when I return the lens.
    I'm tempted to get the last gen 1.4 or even the 1.8. But I'm a big fan of the Nano Crystal Coat.
    (Sorry for hijacking the thread. I wasn't sure if I should have posted this separately. My issue sounds quite similar.)
    I can post pictures later after more controlled tests.
     
  26. So I've been using the 85 f/1.4 D for a while now and love it. It's focus is fantastic and the images are superb. Eric, I felt like you when reviewing the lens, growing frustrated whether I was just being overly picky or not. In the end I felt better about buying the less expensive D version that 1) I like the look and feel of better and 2) focused how I expected without any work on my part. I'm not too concerned about nano coating or the latest blah blah blah to be honest. That said, I'm not using the lens for my sole income, though previous to the latest G version, pro photographers didn't have any problems using the D version. You can test forever but if it doesn't feel / perform like you think it should, then it's probably going to bother you forever (or it would've for me at least).
    lee
     

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