16mm f/2.8 AIS sharpness

Discussion in 'Nikon' started by chuck, Aug 18, 2016.

  1. I just got a second hand 16mm f/2.8 AIS lens. The lens has a rear mounted filter installed. I took some exploratory pictures with. At f/2.8, the center sharpness was great, but the peripheral sharpness is disappointing to say the least. It is so unsharp that it looks quite soft and fuzzy even on the camera's rear LCD display. At f/11, the edge sharpens up quite a lot, but only compared to f/2.8. It is still quite soft and showing lots of radial chromatic aberration is looked at closely.
    Is this normal for this lens?
     
  2. With a fisheye at f/2.8, I think DOF is an issue. Something in the center of a fisheye shot is probably not in the same plane of focus as the corners. Just my guess.
     
  3. Hmmm, that's a possibility. What is the expected of focal field for a fisheye? Is it extremely concave or convex? I assumed it was intended to be somewhat flat like most lenses.
    Also, since I plan to use this lens for night sky photography, it would be a major problem if when the center is focused on infinity, the edges are focused nowhere near infinity.
     
  4. I know nothing about your particular lens, but many fisheye lenses, present and past, pretty much have depth of field from a few inches to infinity. I suspect that curve of field is NOT the problem. per se.
    However, the infamous Hypnoken [R o ck w e l l] (for which a link is not allowed here) does comment on fuzziness for this one.
    Google™ "Nikkor 16mm f/2.8 AIS"
     
  5. My experience of the f/2.8 AiS fisheye was similar - I shot a lot hand held at f/4 and f/5.6 because I got phenomenal depth of field for what I required at relatively open apertures but when I had a 14 inch print made up (@ f/8 I think it was) I found all the corners distractingly soft and mushy. The AF-D f/2.8 version was no better in my opinion.
    I now use the older AiS f/3.5 version which I find considerably better in this respect than either of the manual or auto f/2.8 versions.
    It's possible that my findings are specific to individual copies of these lenses but of the 3 I've tried I much perfer the f/3.5 despite it being a manual focus lens.
     
  6. No, fisheye's don't have huge DOF as some suggest - it all depends on how large you are viewing the image.
    Unfortunately, the 16/2.8 AIS is just not that good of a lens (as well as the AF-D version). Yes right from f/2.8 it's super sharp in the center, but never really obtains good sharpness on today's high MP sensors. The 16/3.5 AI is a far far better lens for sharpness right from f/3.5 on up. Get a 16/3.5 AI if you can find one - you won't be disappointed unless you really need f/2.8.
     
  7. What would be the best fullframe fisheye option for Nikon?
     
  8. No, fisheye's don't have huge DOF as some suggest - it all depends on how large you are viewing the image.​
    This is universally true about depth of field, but the point is that any given part of a fisheye image is actually viewed at a very small scale in relation to the whole field -- thus everything from near to far will look sharp enough to a human eye.
    I have some fisheye-type lenses that have no focusing ring at all, given the (apparent) depth of field.
     
  9. Hi,
    I've owned the 16mm f2.8 AIs version, the Minolta 16mm f2.8 MC Rokkor-X, and presently own the 16mm 2.8 Af-D
    Nikon lens. I have never seen any issues with any of them. I have read that Nikon tweaked the optics of the AF version
    making it the best performer. I tend to agree, and would recommend buying the newest version. I have not seen any of
    the issues mentioned here. I get nice results using it for astrophotography as well
    My fisheye and 14mmm f2.8 AF have huge DOF, it's a matter of physics. (Stopped down of course)
    Regards,
    Rick
     
  10. One issue about fisheyes is that focus remains important despite the large depth of field because often objects get included that are spaced from very close to very far away and, as the depth of field is so great, none of them will become a satisfying blur: they will appear clearly in the image but, on examination, will obviously not be crisp. So it remains important to focus on your center of interest, in my opinion, to maximize the sharpness impression. I am not at all surprised to learn that there is visible CA in an AIS fisheye.
     
  11. No, fisheye's don't have huge DOF as some suggest - it all depends on how large you are viewing the image.​
    This is universally true about depth of field, but the point is that any given part of a fisheye image is actually viewed at a very small scale in relation to the whole field -- thus everything from near to far will look sharp enough to a human eye.
    I have some fisheye-type lenses that have no focusing ring at all, given the (apparent) depth of field.​
    It all depends on the size of the viewed image and the viewing distance. Do a little cropping and you'll quickly find that parts of the image will no longer look sharp. Yes some fisheye units don't have focusing at all, but with today's high MP sensors the non-critical sharpness will quickly become apparent if you are printing/displaying large and are viewing up close. Film was just not that demanding so you could get away with a less-sharp lens and still get a nice image.
    But it is true that at small apertures, appropriate focusing, and viewed small just about everything in a 16mm fish will be apparently in focus.
     
  12. Go over to here:
    http://nikongear.net/revival/index.php/topic,4069.0.html
    for comparisons between all three Nikon 16mm fisheyes.

    Personally I've owned:
    1x 16/2.8 AIS
    1x 16/3.5 AI converted
    3x 16/3.5 AI (true AI versions)
    and tested against:
    16/2.8D
    Sigma 15/2.8.
    The 16/3.5 AI comes out the sharpness winner over all of them.
     
  13. I can definitely say at f/2.8 my 16/2.8 AIS is nowhere near as sharp at the corners as the shots illustrated in the Nikongear.net page above. The edges for my lens are so soft at f/2.8 that they look conspicuously soft and mushy in the view finder and on the camera back LCD monitor. I probably have a bad sample.
     
  14. I particularly like the AF version. It does what I want it to do.
    Here's my favorite photo taken with the lens: https://flic.kr/p/BMQf9V
    Here are some examples of what I did with the lens. It's not just a specialty lens, but my ultra-wide angle. https://www.flickr.com/photos/nathantw/albums/72157627247430991
     

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