Soft Edges 85mm at 1.8

Discussion in 'Nikon' started by andrea_magugliani, Nov 8, 2010.

  1. Dear All,
    I recently purchased the Nikon 85mm 1.8D for shooting portraits and street life as part of my Kit on a D300.
    After a shooting session in Kuala Lumpur, Malaysia, I realized that it is quite soft on the edges when shooting in daily light at 1.8. I shot all my portraits at 1.8 because I wanted to test the blurry bokeh of the lens, no complainings about it, but if I could come back I wish I shot at 2.8/5.6. What is your experience with this lens? Same soft edges at 1.8? Which aperture would you recommend?
    Thanks
     
  2. I never noticed anything like that before. It is not a flat field lens, so maybe it has to do with shooting close to your subject and the distance at the edges being further away from the focus point at the center.
     
  3. Andrea, I believe that most lenses are soft at the edge at their maximum aperture. Stopping down just a bit can make quite a difference. You will probably find many comments like yours on a great variety of lenses.
     
  4. I have the 85mm f/1.8, an don't find it soft at the edges, at least not when shooting with an APS sensor such as the one on you have on the D300. Could you post an example? Are you sure that the edges of the frame were in focus?
     
  5. @Arthur: I'm going through some forums and I found many other comments of this kind about other lenses as you said. The softness that I'm experiencing on my shots is on the edges of the head for instance or, if the face is slightly dangling on the left the right side will be tiny soft even though I was focusing on all the face!
     
  6. Test your lens on a flat surface, e.g. like a barn door, a wall, a fence etc. to eliminate the out of focus possible problem.
     
  7. Realistically this is not the best quality glass, its a classic case of "you get what you pay for" but , like frank said, you may want to toy with the AF fine tune adjustment on your D300 and see if that helps.
    Personally id sell it and get the 1.4d version.
     
  8. @Steven: I know Steven that the 1.4 would be the best buy but I had to save for many months to buy the 1.8 and an upgrade now is definitely not in my plans.
    I have no idea of how to set the AF tune adjustment, is it on the menu of the D300? (I'm at work now and I don't have the camera with me).
    Would you be so kind and petient to tell me how to do it?
     
  9. Sure Andrea! turn on the D300, press "menu" then scroll down to the little wrench, then scroll to the right,
    there is a list of options, scroll down till you get to "AF fine tune"
    then scroll to the right again and you will see a prompt, asking AF on/off click to ON then scroll down , to
    the right and you will see a meter with +/- 20 on it, try small adjustments, take a pic and see what
    happens, if not happy, return to zero and turn it to off.
    good luck.
     
  10. The softness that I'm experiencing on my shots is on the edges of the head for instance or, if the face is slightly dangling on the left the right side will be tiny soft even though I was focusing on all the face!​
    The focus plane is very thin @F1.8. At about 4-5 feets, the focus plane is maybe a couple centimeters...
     
  11. Dear Andrea, you write: "The softness that I'm experiencing on my shots is on the edges of the head for instance or, if the face is slightly dangling on the left the right side will be tiny soft even though I was focusing on all the face!". I think you never checked the DOF with some computerprogram. At a focussing distance of 1.5 meter this lens has a DOF of - and + 1cm with an aparture of 1.8!! You cannot focus on 'all the face', usually you focus just on one eye. When you want your face completely sharp you need an aperture of for instance 8, then your zone of 'sharp' focus extends from circa 1.45 to 1.55meter. Try it out! Its so easy with digital...
     
  12. Jan, thank you for your comment. I think I start understanding. indeed when I took the portraits I was talking about I was quite close to the subject, therefore as you said the DOF was - and +1cm at 1.8. If I want the face to be sharp therefore I need to stop at 8...
    Thanks!
     
  13. I`m afraid you first need to read about Depth of Field in photography for higher enjoyment. This lens is a pretty good one, and with such fast aperture you have many creative possibilities. And if you mind about corner sharpness... forget the f1.4 version; I can tell you that it`s way softer.
     
  14. oh yeah, way softer, go get em kiddo!!
    good luck Andrea on your wild goose chase
     
  15. Unless you are shooting a flat subject (like a brick wall) with your camera set up perfectly perpendicular to the subject, at f1.8, it would be virtually impossible to tell if the lens was soft due to a problem with the lens or shallow DOF. I suspect the latter.
     
  16. I agree. We're talking about razor-thin depth of field, here - that reality is going to impact everything you're seeing at portrait distances. Do some tests with static objects to understand just how thin DoF is when shooting with larger apertures at portrait distances - you'll see that "softness" is likely "out of focus."
     
  17. The point on limited DoF is certainly true, and also should take into account that the AF may start to work against you for some subjects. But, just one other observation, I really like my 85 f/1.8, but frankly wide open it's not a very sharp lens, in my experience. So some level of softness wide open, to me, seems completely normal. If I need sharpness from this lens, f/2.8 at least. And at the closer distances, that still leaves a shallow enough DoF anyway :)
     
  18. The point on limited DoF is certainly true, and also should take into account that the AF may start to work against you for some subjects with that little depth of field.
    But, just one other observation, I really like my 85 f/1.8, but frankly wide open it's not a very sharp lens, in my experience. So some level of softness wide open, to me, seems completely normal. If I need sharpness from this lens, f/2.8 at least. And at the closer distances, that still leaves a shallow enough DoF anyway :)
     
  19. Some practical suggestions here:
    1. For the problem you have described, you don't need a Nikon 85mm f/1.4, like someone suggested.

    2. For most portraits, get the eyes in focus, and don't worry if other parts of the face are slightly softer. If your depth of field is very small and the person's head is not facing you square, get the more prominent eye in focus. Particularly when shooting wide open at close distances, you will not be able to get the entire face in focus.

    3. If you really must test the sharpness of your lens, do as others have suggested and photograph a flat object like a wall, but make sure to put the camera on a tripod. To make conclusions about lens sharpness doesn't make sense without solid camera support.
     
  20. Your lens is behaving normally, you simply want it to do something it can not.
     
  21. Realistically this is not the best quality glass, its a classic case of "you get what you pay for" but , like frank said, you may want to toy with the AF fine tune adjustment on your D300 and see if that helps.
    Personally id sell it and get the 1.4d version.​
    Steven, in fact, as it has been pointed out to you already, the 1.8 is pretty much known to be the sharper of the two 85 D (the new 1.4 AFS not counted). The 1.4 has better build, better out of focus rendition (especially front one, which is sometimes not so good on the 1.8), better (for portrait purposes) color rendition, and it is of course faster. But it is softer. Not dramatically so, but it is, especially off center. This is most likely a conscious design decision by Nikon, given the intended purpose of either lens: the 1.4 is optimized for portrait work, the 1.8 for more general purpose / journalism shooting. Then again, by f4 they are both sharp corner to corner.
    To the OP: the 85 1.8 has perhaps the best wide open behavior I have seen among the fast primes I own (I don't own any exotic stuff like 200 f2), but it is by no means perfect at 1.8, more so in the corners. But the DOF is tiny and I would not dare judging sharpness at the corners at 1.8 except for 1) distant city scenes, so that you can assume everything is at infinity or 2) test cases where you have carefully tested the alignment of the lens with a flat surface being photographed. Keep in mind that at 2m distance, DOF on DX from a 85mm at 1.8 is just 4cm.
    It is of course possible your lens is faulty: if it is, quite likely it should also show asymmetry in its sharpness (like the right corners being sharper than the left ones). You may want to test for this...
    Ciao
    L.
     
  22. **Moderator please delete wrong forum**
     
  23. I have the 85/1.8 and wouldn't use it wider than f/2.8. Not only for edge sharpness, but for overall image sharpness as well. My friend has the 85/1.4 and I've tested both the 85/1.4 and 85/1.8 side, with a tripod, on the same subjects. The 85 is a better lens, but the differences are moreso standout when you open wider than f/2.8. The 85/1.4 is sharper at f/1.8 than the 85/1.8 at f/1.8. Edge sharpness is better as well. I have examples I can post, but they're at home so I'd have to do it later.
     
  24. I don't actually think that the combination of D300 + 85/1.8 focuses accurately with AF, at least in low light. The DOF is too thin, the AF mechanism too rough and the tolerances in the focus too great.
    In practice I only the the f1.8 setting for low light; for portraits the DOF starts to be pretty small already at f2.8.
     
  25. Yes concur with Jose Angel, you need to learn about DOF before you determine there is something wrong with the lens. Of course the edges would be soft in that situation, why would you expect anything else given the very narrow DOF? If you think that there is a real problem wide open, then you have to shoot a totally flat subject and yes, it may be a little softer at the edges when wide open. Many of the so called great lenses could have a little softness in the corners wide open. Lenses are a series of compromises between flatness of field, sharpness in the center, sharpness at the edges, overall contrast and color rendition. Just keep shooting with it and learn it's limits and strengths.
     
  26. Your lens doesn`t need to be wrong; as said, faster lenses use to be sharp at the center but not at the edges... the compromises mentioned above. From what I see both lenses should perform very closely. Check how the faster aperture on the f1.4 version is penalized with a lower resolution power and corner performance. The f1.8 is not so far from this issue. Anyway, there are many other parameters that need to be taken into account.
    Just for fun I have made a chart with the data provided by photozone.de for their 85mm primes test (see C.P.M.`s link above).
    Recommended apertures? Looking at this chart I`d say the lens is great from f2.8 on, being optimal at f5.6. Maximum corner performance at f8-f5.6.
    Anyway, this is only a chart. In the real life, it doesn`t help to make a good photo. A good book certainly helps.
    00XeUX-300257584.jpg
     
  27. if the edges are still soft at f/8 then you really have a problem.
     
  28. Dear All,
    Thank you for your precious comments and advice. I will definitely go carefully through a good photography book about DOF and I will also make different tries with stops from 1.8 to 8.
    At the end, if the results don't convince me, I will try to work on the AF from the camera settings.
    Thanks again
    P.s. This is a shot taken with the 85mmat 1.8
    http://www.flickr.com/photos/24412297@N05/5154041161/
     
  29. Andrea,
    I see nothing wrong in this example picture at all, I also like it very much..
    Wonderfull shooting !!! :)
     
  30. Andrea: Your portrait is correctly focused on the near eye, and there are no visible problems with the lens.
     

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