Determing optimum stop for a lens

[leica dream]

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I understand that every lens has a stop at which it performs best. Is there an easy way to determine that stop, or is it by trial and error for each lens?

Richard

[earleygallery]

For most lenses it's around f8, give or take a stop.

 

But f8 may not be the best setting to use in any given situation. Use the f stop you want to achieve the image you want.

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http://www.l-camera-forum.com/leica-forum/leica-m-type-240/342232-diffraction-limitation-m240-v-nd-filters-3.html#post2877744

[Herr Barnack]

If by "best" you mean "sharpest," it would be the middle apertures. If your lens apertures range from f/1.4 to f/16, shoot at f/5.6 or f/8 in order to get maximum sharpness of the in focus elements of your image.

Edited February 4, 2015 by Carlos Danger

[bocaburger]

My experience varies depending on the vintage of the lens. The newer generation of fast (f/2 and wider) seems to reach their best across most or all of the picture area by f/4 with little to no improvement stopping down further, until it starts to regress at the diffraction limit (f/11-16). The majority of my lenses (70's-80's) see major improvements by f/4-5.6 but continue to improve out to the corners until perhaps f/11. Older lenses I have (mostly LTM's) seem to reach their peak around f/8-11.

[spydrxx]

Puts often gives his best informed assessment of the optimum aperture for each lens in his latest Compendium. Short of looking there, I basically agree that for many older lenses about 1-2 stops from wide open is often optimal. I used to run lens tests on my m3/4 body, but it got to be a bore and often seemed to confirm the previous adage. I periodically noticed that the optimum aperture wasn't necessarily the same for digital and film though.

[250swb]

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I understand that every lens has a stop at which it performs best. Is there an easy way to determine that stop, or is it by trial and error for each lens?

Richard

 

Over the years you get a feel for it without having to do tests or reading boring books and reports, but f/4, f/5.6, f/8 are the perennial favourites. Any f/stop is good if it achieves a good photograph, which is a photograph that isn't boring or purely about technique.

 

Steve

[LocalHero1953]

Turning the question round, when was the last time anyone took a photo at a stop selected because it was the lens's "best"? Rather than for DOF or exposure reasons.

(I never have).

[Jennifer]

Turning the question round, when was the last time anyone took a photo at a stop selected because it was the lens's "best"? Rather than for DOF or exposure reasons.

(I never have).

 

Very true.

[bocaburger]

Turning the question round, when was the last time anyone took a photo at a stop selected because it was the lens's "best"? Rather than for DOF or exposure reasons.

(I never have).

 

I have but only on lenses where there is a quite abrupt difference between adjacent f-stops, and that is not common, usually it's a gradient. Two lenses I can think of are the pre-ASPH 90 Cron @ f/2 where it is softer and lower in contrast and gives me a more forgiving portrait rendition. By f/2.8 it's up to the crackling sharpness of the recent Elmarit-M at the same aperture. Another lens is the CV 15mm, where f/5.6 stands out significantly from f/4.5 and f/8. It's basically my fixed aperture with that lens. DOF is pretty much more than anyone needs at any aperture with that lens, and shutter speeds for handholding are also somewhat insignificant. I'd rather switch ISO than aperture.

[jcraf]

Turning the question round, when was the last time anyone took a photo at a stop selected because it was the lens's "best"? Rather than for DOF or exposure reasons.

(I never have).

 

Well, actually, I tend to do this quite often in situations where f stop is not a critical part of the image making process. Armed of course with a working knowledge of the particular lens' optical performance and 'best' f stop.

[LocalHero1953]

Well, actually, I tend to do this quite often in situations where f stop is not a critical part of the image making process. Armed of course with a working knowledge of the particular lens' optical performance and 'best' f stop.

 

What sort of situations would those be? (I'm curious, not challenging you).

 

I should be more nuanced in my declaration: like bocaburger, knowing how a lens behaves does influence how I use it. The 7.3cm Hektor is "exciting" when opened up fully, but I'll close it down to get more restful OOF. The ZM Sonnar 50 is nicely soft opened up, but pin sharp closed down a bit. But with my modern Leica lenses I don't notice enough difference to counteract more important judgement calls.

[leica dream]

Interesting input, thanks you.

As I usually shoot Aperture Priority to suit the depth of field I want I just wondered whether my choices should be influenced bu some sort of optimization.

Richard

[spydrxx]

Very true.

 

I often do this for artistic reasons....for instance the "rendering" or "Leica glow" rather than the DOF. I'm rarely driven by DOF considerations.