What are the best lenses when shooting fully stopped down?

[Pii]

Most of us should know by now what are the best lenses when shooting wide open. If not, just read the forum once or twice and you will know for sure. But do we know what are the best lenses when shooting fully stopped down? Or what is the maximum f stop and how good it is comparing to the lens sweet spot?

Hope you will help me with that

[BRunner]

Unfortunately this depends more on media used. With digital sensors (especially high MPx) you'll hit diffraction limit pretty soon. 5DmkII is already diffraction limited at f11 and the more you stop the lenses, the more is final image degraded. With 15MPx crop camera, you can see effects of diffraction already at f8.

[Orio]

[poilu]

the limit is f5.6 for full frame and f4 for crop
this explain why all lens look the same at f8, good lens are leveled down by the diffraction
read this faq http://forum.mflenses.com/faq-for-crop-t31975.html

for 4:3, the best stop is around F2.8, after diffraction is the limit
on the graph you can see that the borders don't get better by stopping more than F2.8
that mean that it doesn't worth to give money to anything slower than f2.8 on a m4:3

[Pii]

[Arkku]

Most lenses of any notable quality should be approx. equal in terms of sharpness fully stopped down, due to diffraction limiting the resolution. On the latest DSLRs you will be unable to reach the sensor's maximum resolution already from around f/5.6 (although some lenses are still softer near image edges so those areas will continue to improve). But “fully” stopped down you're pretty much turning the lens into a pinhole. =)

Note that while having “smaller pixels” (e.g. more megapixels in the same size of sensor or the same number in a smaller sensor) means that the camera “hits” its diffraction limit sooner, this does not mean that those cameras suddenly start to perform worse than cameras with “larger” pixels, it just means that you will not be able to take full advantage of your cameras resolution. So it's not necessarily “bad” to stop down beyond the diffraction limit, and indeed in some sense it would be the “best possible” situation for those settings to have your resolution limited only by diffraction, but you should be aware of this limit so you can decide whether you need to compromise elsewhere (e.g., less depth of field) to obtain the results you are looking for.

(Also note that most depth of field calculators on the internet do not take diffraction limits into account and suggest that depth of field increases indefinitely when stopping down, when actually at some point diffraction will prevent the definition of “in focus” from being reached at all.)

Film has the exact same physical limit as a digital sensor, but since a piece of film the same size as a digital sensor will nowadays result in effectively less resolution, it's like having a low-megapixel sensor where the diffraction limit is not seen because the system resolution is limited elsewhere. Shooting medium or large format film will give a huge increase “tolerance” for diffraction (and any other error), since for a given output size the enlargement ratio is smaller (and indeed, that is why larger formats have better image quality, at the expense of size and, well, expense).

[Orio]

[Arkku]

[Attila]

[ManualFocus-G]

Hehe say what you mean Attila Diffraction on a 7d should kick in at around f7.1 and for the 5d classic its something like f13 (someone please correct me if I'm wrong on that one). In real life? I haven't noticed it on my 18mp 60D, in fact images seem to get sharper until about f16...weird!

[Orio]

[danfromm]

http://www.normankoren.com/Tutorials/MTF1A.html

[dsmlogger]

[fuzzywuzzy]

Article about diffraction, including a diffraction calculator for various sizes of sensor and megapixel densities:

http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

[kds315*]

a) could be PLEASE use educated language - assuming that educated people are talking here

b) the laws of diffraction cannot be bent, see Dan Fromm's link

c) for macro, different values have to be applied as diffraction sets in much earlier depending on magnification (I'm not going into details here)

d) poilu: you're massively off, I have to agree.

For macro work:

[iangreenhalgh1]

I shoot all my landscapes fully stopped down with both my NEX-3 and EOS 10D, should I be instead using f8 or f11 to avoid diffraction?

[Orio]

[iangreenhalgh1]

I mostly use my Tokina 17mm and Hexanon 3.5/28 for landscape work, I like the deep focus effect and that is indeed why I shoot fully stopped down. As I tend to do stitched HDR panos I already have a lot of PP work on my hands, combining 20-50 exposures.

[Pii]

It just sounds not right for me.

F2.8 for 4/3, F4 for crop and F8 for full frame. And I always read that the best you can get is about F5.6-11 on any platform depends on lens.

Loads of mathematics. Will read everything. But I think we need to simplify it a bit. The results could be bend by using different sensors.

Some says F4 is the max for crop, some that the max is about F16.

[buerokratiehasser]

The diffraction is always there, it is just that at larger apertures, other problems (slide film losing contrast at 100 lp/mm, crappy lens, razor DOF etc) take precedence.

The diffraction makes something like gaussian (?) blur out of a single point; formulae for estimating limits differ as to how much degradation is ok. (Often forgetting to multiply with 2 or 1.7 or anything to account for Bayer sensor)

Common wisdom says f8 for crop, f11 for 35 mm.. as above, that depends on where your other limits are! There are lenses that do 200 lp/mm and above, and film materials (notably, monochrome) that resolve this easily, for this application, the limit hits at 5.6 or 4 obviously

This is also why using larger film does not help that much, because it is diffraction-limited at the same apertures as 35 mm (a little leeway due to slightly crappier MF lenses, but not much), and DOF of f5.6 with 4x5" is basically nil. Oooo..kay that's why these are t&s cameras, but still.

[GrahamNR17]

Can I propose that it doesn't matter? If you need maximum DoF, then use the smallest aperture. No point having an image that is technically superb but not pictorially what you wanted to achieve?

I have spent so many years trying to get the technical aspects right, that I never took a photo I wanted to look at. Now I just take photos and the technical things come second.

To be fair, I am not a good photographer, artistically speaking, but I know for many of you that is not the case.

[buerokratiehasser]

The point is, when you sludged your image anyway, lens sharpness is irrelevant. You would have to select for other criteria.. minimum aperture, rectilinearity, color, color fringes although these usually go away

[poilu]

what I mean is that it doesn't worth to spend big money for lens that are used after f2.8 because diffraction will kill their resolution
on this chart I collect lens resolution for Zuiko 40-150, Zuiko 14-42, Zuiko 12-60, Zuiko 35 macro and Summilux 25
you can see that no Zuiko lens can match the resolution of the Summilux at F1.4, that it is not related to diffraction but to lens quality
the Summilux have resolution limited by diffraction after f2
the other lenses have so low resolution that diffraction doesn't impact them the same
a lens like the 40-150 at 150 is so bad that it still improve at f8
if a lens on a m4:3 improve from f5.6 to f8, it just mean it is a very poor lens

[danfromm]

[poilu]