The Same, Only Different; Format, Angle Of View, And Image Quality

If a picture is really brilliant, you don't have to worry about grain or sharpness or anything else: to quote Mike Gristwood, late of Ilford, "How much good would it do you to know the technical details of any one of Henri Cartier-Bresson's pictures?"

By the same token, if a picture is really bad, no amount of technical brilliance is going to save it. It's the pictures in between where the difference shows. A picture that is sharp and tonally excellent will look better than one that isn't: technical quality tips the balance.

(Left) Selective enlargement of porch, St. Martin's (Alpa). This is part of a 6x enlargement from the Alpa shot. The half-tone effect is beginning to show. For comparison I did a 12x enlargement from the Voigtländer shot. We haven't printed both pictures because you couldn't really see the differences in reproduction. You need to look at the two prints side by side, but the difference is like looking through a telescope which is just slightly out of focus, then seeing how the details jump out when you focus properly. Or if you wear glasses, looking at the medium format shot after the small format shot is like putting your glasses on.
(Right) Porch of St. Martin's (Voigtländer). The first picture was shot on my Alpa 12 S/WA using the 35mm f/5.6 Rodenstock APO-Grandagon (no rise) and 6x9cm Ilford HP5 film. Many people use a center-grad filter to even out the illumination on the film. I don't because I like the slight vignetting I get with the unfiltered lens. If you compare this with the identical shot taken on my Voigtländer Bessa-T and the 15mm f/4.5 Ultra-Wide-Heliar, the grain is much more apparent in the Voigtländer shot, and not just because I used Kodak Tri-X, which is actually less grainy than HP5 in many developers. There is a creaminess of tonality in the Alpa shot. Although theoretically the two lenses have the same angle of coverage, the 15mm covers just a bit more. My own reaction when I compared them is that the smaller format shot tends to distance you from the subject, while the medium format shot invites you in.
All Photos © 2005, Frances E. Schultz, All Rights Reserved

And switching to medium format makes a difference.

This really came home to me when I started to use a Voigtländer 15mm f/4.5 Ultra-Wide-Heliar with my 35mm Voigtländer cameras. I already had a 35mm f/5.6 Rodenstock APO-Grandagon for my Alpa, and I normally use it as a 6x9cm format camera. The calculated angles of coverage of the two are almost exactly equivalent, so I should get similar pictures, right? Wrong!

At first I wondered if it was because my Alpa 12 S/WA has a rising front (shift, hence S/WA): a 15mm shift lens on 35mm would be quite something. But after looking hard at the pictures, I decided that this was a secondary consideration. Basically, it has a lot more to do with grain, sharpness, tonality, and--more than I expected--the way I use the cameras.

To begin with, if you want a borderless 8x10" print from 35mm, you have to enlarge your negative about 8.5x. The more you enlarge it, the more the grain will show. A borderless 8x10" print from 6x9cm, however, is only about a 3.6x enlargement.
Likewise with sharpness. The greater the enlargement, the more the shortcomings of the negative are magnified, including lack of sharpness. Even the sharpest negative will no longer look sharp if you enlarge it too far. A 12x16" print--as big as most people dare go from even a first-class 35mm negative--is just over 12x. From 6x9cm it is only about 6x.

Less obviously, resolution and sharpness are not the same thing. Resolution is the fine detail that a camera-lens-film-developer combination can reveal, usually measured as the number of black and white line pairs resolved per millimeter (lp/mm). A resolution of 50 lp/mm on the film is regarded as reasonable, and should be achieved on most reasonably sharp films by any half-decent 35mm system and most good rollfilm systems, while 100 lp/mm is regarded as excellent and it is achieved only by top-grade 35mm systems. On roll film, 80 lp/mm is first-class and 90 lp/mm is exceptional.

St. Martin's (Voigtländer). In order to try to understand why my medium format shots were so different from my 35mm shots, I shot two general views of this church. I didn't try for an identical viewpoint: rather, I wanted to express the isolation of the "church without a village." This is the 35mm shot, on Kodak Tri-X. As I often do when shooting with a wide angle lens, I filled the foreground with shadow. A yellow or orange filter would have given more differentiation between the steeple and the sky, but I should have had to cut a gel and tape it carefully over
the back element.

St. Martin's (Alpa). With the Alpa, shooting on 6x9cm Ilford HP5 Plus, it was easy to use a deep orange filter and let the sky dominate the shot. Again I have used shadows to break up the foreground. I deliberately didn't use rise, to keep the comparison as close as possible.

Sharpness or "acutance," on the other hand, is the abruptness of the transition between a black area and a white area. Even at a knife edge, there is always a tiny bit of grayness between black and white as a result of emulsion thickness, lens resolution, grain size, and developer formulation. High sharpness means a very quick transition: low sharpness, a slower, more graded transition.
You can artificially enhance sharpness via "acutance" developers. With a dilute developer, and the bare minimum of agitation, the developer is soon exhausted in areas of high density. In adjacent areas of low density, there is still a surplus of developer. The result is an exaggeration of densities where light and dark meet: slightly too low on the light side, slightly too high on the dark side. These "edge effects" create the impression of more sharpness, though they actually reduce maximum resolution.