Lens contrast: how much does it really matter?

[pdeeh]

The OP doesn't say he prints digitally. He says he scans. And he refers to printing, and to his darkroom skills.
That doesn't make it a "digital thread"

[Steve Smith]

The title of this thread should read "Lens contrast: how much does it really matter when I print digitally?" and posted on another forum.

It's also a valid question if printing optically.


Steve.

[jnanian]

OK so all of my lenses (rangefinders, mostly) are fairly old: Zeiss-Opton and Leica. I haven't done any comparisons but the difference in contrast doesn't really stand out. I scan (a sin here?) my negatives mostly and print my few favorites. It works out fine, i guess, but I'm not that good in the darkroom or meticulous about my metering/developing/scanning/printing.

Well for certain focal lengths/speeds modern lenses are more practical (Zeiss and CV mostly). The general agreement is that for b&w film low contrast is preferable, but does it really make that much of a difference?

hi

to answer your questions directly .. it really doesn't matter at all.
if you are happy with the results you get with your optics
and your processed film, then don't change anything .. but if you aren't satisfied ...

there are always going to be people who talk about lenses and their contrast and sharpness
and "stuff" but in the end it is the results that matter.
as for dark room and technical skills, they are just learned and practiced ...
like pretty much anything else.

good luck !
john

[CPorter]

The general agreement is that for b&w film low contrast is preferable, but does it really make that much of a difference?

Whether or not a high flare lens is "preferrable" (not for me) with b&w is debatable for sure, but IMO, the short answer is that you can certainly experience a flare factor of 2 (one stop) to 4 (2 stops) with a lens that is not coated or poorly coated. The newer lenses of today and I guess even as of a decade or so ago are pretty well coated, I would think.

[Thomas Bertilsson]

It does matter with regard to film speed. When I use my old Summitar lens I can easily shoot Tri-X using an exposure index of 400 - box speed. When I use a more modern lens, I have to lower my exposure index to something like 250 to get the same shadow detail. This is probably due to flare, but it does have an impact on the final contrast of the negative, and how it prints.
But once you know this, it's easy to compensate for it, and it's not really something to worry about anymore. It is just one variable of many that affect negative contrast.

[Michael R 1974]

The general agreement is that for b&w film low contrast is preferable

Not really. Keep in mind that flare does not simply reduce overall contrast. It reduces contrast primarily in the shadow values.

Lens flare varies from lens to lens depending on various factors including the optical formula/number of elements, coatings, the mechanical design of the lens (baffling etc), and shooting aperture. Of course, the lighting in the scene to be photographed has a major impact.

In general, the biggest differences would be observed between an uncoated lens with many elements/groups and a coated lens with a simpler optical design. The difference between say an otherwise similar single coated and multi-coated lens would be much smaller.

[dsmccrac]

Hopefully this is not too much of a stupid detour from the OP's question. If it is feel free to ignore ;-)

Ignoring the effects of aging on a lens, what are the criteria that determines its contrast levels? Some lenses are famous for it (and it is considered sought after by some) such as a lot of Konica Hexanon lenses and certain Russian ones amongst many others. I presume coatings are a big component. I presume materials are a big deal as is the actual design. Were designers looking to build contrasty lenses or was that just the way they were coming out? Clearly everyone wants a 'sharp' lens but contrast seems to be a slightly different beast and clearly lots of folks think stuff can be too contrasty. Contrast, sharpness and acuity do not seem to be entirely synonymous.

Sorry if these are stupid questions. I have been wrapping my head around lens contrast (and the related issue of the role of the lens in colour reproduction).

[puketronic]

skimmed through the responses, very good discussion.

Just to clarify a few things.

I scan my negatives and make wetprints in the darkroom. I care about my wetprints and negatives more than I care about my scans...
I have no problems with the contrast levels of my current lenses but I have not tried anything modern. I would be interested in perhaps changing lenses mid-roll. Say for instance a 1950's 50mm Sonnar with a 2012 28mm Biogon. Things like that.

[ntenny]

I have no problems with the contrast levels of my current lenses but I have not tried anything modern. I would be interested in perhaps changing lenses mid-roll. Say for instance a 1950's 50mm Sonnar with a 2012 28mm Biogon. Things like that.

It's hard to do a real-world apples-to-apples test. For instance, if you change lenses mid-roll, it's hard to separate "this lens is sharper" from "the coffee finally caught up with me and I started focussing better", or "this lens is contrastier" from "the light got contrastier". There's also that 62 years of aging on the Sonnar to think about---maybe the coatings aren't all they once were, or whatever, and the results could tell you something about old vs. new lenses but not necessarily about "classic" vs. "modern" lenses.

If you don't have problems, I think you shouldn't worry too much about the theoretical alternatives. The question is interesting, though, and I suspect careful testing would turn up some surprises.

-NT

[AgX]

Contrast, sharpness and acuity do not seem to be entirely synonymous.

Actually in my reply I rather thought oft micro-contrast (which effects acuteness)



-) lens aberrations effect microcontrast

-) flare (lack of coating, bad barrel design, lack of lensshade) effects both overall contrast and microcontrast)


Acuteness is the empiric description of what we by vision call sharpness.