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The Same, Only Different; Format, Angle Of View, And Image Quality
By Frances E. Schultz January, 2006
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.
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(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
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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.
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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.
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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.
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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.
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