Hey smarter-than-me-people: what do you make of this article?

[altec2]

http://www.photodo.com/topic_138.html

It argues that:

To conclude, with a wide aperture and short depth of field the sharpness is better with a larger format. When the lens is stopped down to get a deeper depth of field the difference between the different formats decreases. Above about f5.6 for 35 mm (f11 for 6x6 cm, and f22 for 9x12 cm) the difference in focus between the formats is insignificant. But this is only before we consider the film's effect on sharpness.

[Peter Gomena]

Two things:

First, take the source. It is written for a 35mm lens producer who is arguing the strengths and benefits of the format.

Second, the comparison is based on mtf curves and analyses of test charts.

It's a great apples/oranges article that tells me very little about actual photographs. If there is no real quality difference between formats, why are there different formats?

Peter Gomena

[Old-N-Feeble]

I'll take a Minox over 8x10 ANY day... LOL!!! I AM JOKING, folks.

[Louis Pacilla]

Two things:

First, take the source. It is written for a 35mm lens producer who is arguing the strengths and benefits of the format.

Second, the comparison is based on mtf curves and analyses of test charts.

It's a great apples/oranges article that tells me very little about actual photographs. If there is no real quality difference between formats, why are there different formats?

Peter Gomena

+1. Very well put Peter.

[Ken Lee]

Comparing image 6 (4x5) to 4 (35mm), the author proposes "This image is the sharpest one, but the difference to 35 mm is suprisingly small."

He's entitled to his opinion, but it all depends on what we mean by "surprisingly" and "small"

That being said, it's encouraging to know that with careful technique, smaller formats can perform as well as larger formats. It can be helpful, when traveling, to work with smaller, lighter equipment. Sandy King has shown some astonishing large prints made with a Mamiya 7 on Fuji Acros film. When shot at their best apertures, those lenses are among the best available in any format. When processed in a tanning/staining developer like Pyrocat HD, fine grain films that are held flat become very powerful capture devices.

[Jay DeFehr]

I'm no mathematician, but it seems he's stacking the deck against larger formats. The equation he uses to arrive at the various apertures seems dubious to me. When he divides 150/50 to get three, he's using linear units, but then he applies linear units to a geometric progression, and that doesn't seem right to me. To me, 3 x f/8 is not f/22. 2x f/8 = f/11, 2 x f/11= f/16, and 2 X f/16 = f/22. That seems a huge discrepancy. I'm not sure I buy his rationale for decreasing the aperture of the larger formats, at all. Doesn't the difference in CoC/enlargement factor equalize the differences in dof at a given aperture, given equal perspective and magnification? It seems his entire argument is based on the premise that larger formats must stop down more than smaller formats to achieve comparable dof, and I'm not convinced that's true.

Also, am I the only one who thinks the 35mm Tmax doesn't look sharper than the 9x12 Tri-X? And isn't there more to image quality than sharpness?

It's not news to me that films like Tmax and Acros allow for very high quality images from small formats, especially when paired with very high quality lenses, but I think the argument that the differences in formats is not significant is specious and I think the data is not very reliable.

I think the important differences between formats are in the way they can be used. If you want to shoot handheld, in low light, LF has little to offer over smaller formats.

[polyglot]

If you consider only diffraction as your source of unsharpness, then he is right, there is basically no difference between formats for a given depth of field. However, diffraction is not usually the limiting factor except in some very special cases with the very best optics... which means that most 35mm lenses don't reach their best until about f/8-f/11, which is the same DOF as about f/28-f/38 on 4x5. If you're willing to trade away some depth of field, greater sharpness is available from the larger formats.

The above analysis also assumes infinitely fine-grained film, so smaller formats lose out there as well because the film (or pixel pitch) can be limiting even where diffraction is not.

Way Beyond Monochrome has a nice graph illustrating the interaction of aperture diffraction, format size and max supportable print size (from lines per picture-height). Short version is: there really is a (resolution) benefit to shooting larger, though it's less than the ratio of film sizes would lead you to expect. The downside of course is that you need much more light.

[Bruce Watson]

To conclude, with a wide aperture and short depth of field the sharpness is better with a larger format. When the lens is stopped down to get a deeper depth of field the difference between the different formats decreases. Above about f5.6 for 35 mm (f11 for 6x6 cm, and f22 for 9x12 cm) the difference in focus between the formats is insignificant. But this is only before we consider the film's effect on sharpness.

Hate to tell 'em, but there's a hell of a lot more to photography, in any format, than just "sharpness".

[E. von Hoegh]

Fallacious.

[DrTang]

dumbest thing I ever read


All they are doing is testing film and lenses - big whoop

the point is..one has to enlarge the 35mm neg X times to view it... and the large format neg..many less times if any


The point of taking photos is to look at them (in theory I guess).. so they are only comparing at half of the finished equation



"...viewed with a microscope..." - - -hahahahah - yeah right