[pure-silver] Depth of Field (35mm vs. 4x5 or 8x10)
- From: "Michael Healy" <emjayhealy@xxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Thu, 28 Oct 2004 23:52:16 -0700
I'm wondering whether someone might be able to confirm or elaborate upon a
couple
questions I've been kicking around, regarding depth of field and lens length.
About a year ago, I shot a 35mm image of a piece for my my partner's portfolio.
This was
cast glass, of several boat-like objects, each about 8-9" long, which she
attached to a
sheet of glass about 1 foot wide by 1.5 feet deep. I shot this piece on a sheet
of black
velvet, on 35mm film, using a 100mm lens. Depth of field was hairy, but I
managed to
get enough of it. The piece fills the frame very tightly. It is very dramatic
and disturbing,
and it has sufficient depth of field. One of the better images I've shot for an
artist's
portfolio.
Some months later, I finally was able to purchase a 210mm lens for my 4x5
camera. I
wanted very badly to replicate this image for my own portfolio. So I tried to
reshoot it on
4x5. It was a disaster. I spent several days replicating the shot, but I could
NOT, for the
life of me, achieve the depth of field I'd gotten on 35mm. After doing some
research, I
think I realized a couple things. The main problem seems to be that to achieve
the same
DofF in 4x5 as in 35mm, assuming a 4x5 lens that is equivalent to the one used
in
35mm, one must station the 4x5 at the same distance from the object as was used
in
35mm. IE, when I chose a 210mm lens (4s5) to replace the 100mm lens (135), I
was
wrong to move the 4x5 closer to equivalently fill the frame. I was wrong to
conclude that
this would produce the same result. Rather, the same result will be achieved by
maintaining the same camera-to-subject distance. Of course this means that the
object
will appear no larger or smaller on the 4x5 image as it did on the 35mm image.
As soon
as one moves the camera closer (to fill the frame), one starts losing DofF.
Those of you
who have worked with 4x5, can you confirm this one way or the other?
Stemming from this: Supposing this is the case, and supposing a client has a
desire to
see their close-up image on 4x5 instead of (yuk!) 35mm, I'm thinking: I shoot a
closeup
detail of a sculptural object in 4x5, and there's little DofF. I do it with
35mm, and I'm able
to get plenty of DofF, but at the cost of a tiny image. Here's what I'm
wondering. If I were
to enlarge that 35mm slide, yes, it would show a loss of resolution; but if it
already HAD
captured deep depth of field, then wouldn't the enlargement retain the depth of
field?
And if I was unable to replicate this depth of field in 4x5, for having to move
the camera
too close, then wouldn't the 35mm enlargement's DofF be retained, and be more
satisfactory visually, than the 4x5's shallower DofF? What I'm saying is, is it
better to
shoot 35mm and enlarge, w/ all its shortcomings, than to get a great 4x5 that
never
achieved satisfactory DofF? or will the enlargement of 35mm deplete the sense
of DofF,
and end up looking no better than the 4x5 with its inadequate DofF?
I have to add that I am not talking about paper prints, and conventional
viewing
distance. I am talking about slides (or negs), and the actual level of detail
that will come
through under a loupe on a light table.
One reason I am asking is that for some time now, I have had absolutely no
available
darkroom; so while it would seem to be easy enough to just shoot a 35mm neg and
enlarge it for comparison to a 4x5 neg or slide, I don't have the luxury. I
have no
darkroom at all. So is there someone who already is familiar with these issues,
that they
can confirm or disagree, and explain one way or the other?
Mike Healy
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