P3D Re: TechPan 4x5?

[Brian Reynolds <reynolds@xxxxxxxxx>]

John Toeppen wrote:
> Fritz Brown  wrote:
>> "Better yet, shoot for 4x5 transparencies to begin with.  Tech Pan
>> is available in sheet film.  Duping an image, even going to a
>> larger film size, is never going to give the resolution you can get
>> from the original"
> 
> My suggestion of shooting it in 35mm is driven by the ease of using
> a Realist and the cost of film.  This also allows you to shoot a few
> and select the best.  4x5 cameras don't travel easily.

4x5 isn't that inconvenient.  I can fit a 4x5 pinhole camera, a couple
of boxes of film (Polaroid and Kodak Readyload), holders, my meter and
various odds and ends in the same bag I used to carry my Pentax gear
in.  If I'm using my Speed Graphic I can just carry it by it's handle,
or use a somewhat larger bag to carry everything.

The cost isn't that different from other formats per square inch.  One
sheet of 8x10, four sheets of 4x5, and one roll of 120 or 135 all have
the same area, which in turn sets how much chemistry is used and what
the processing costs.  For prints the labs I use charge based on the
size of the final print, not the size of the film.  No, I can't drop
my Readyloads at the corner one hour lab and get free second prints or
film, but I wouldn't leave my 35mm (what little I use these days) at a
one hour lab either.

My shooting style is different with 4x5 (and to a lesser degree 120).
I select the best composition and then shoot one image.  I don't shoot
as much, but I get many more keepers, and the cost winds up about the
same.  Since I do photography for relaxation, I don't care how long it
takes to make that one shot.  If I was still using 35mm I'd probably
take the same amount of time to shoot more frames and still keep only
one or two.

My first stereo pair was taken with a 4x5 pinhole camera using
Polaroid Type 54 film (B&W ISO 100).  It's on my web page.  It's not
particularly good (bad scan and some Polaroid processing problems),
but it was good enough to show me that this works and get me to invest
more time and effort into doing stereo photography.

I have tried 4x5 stereo with Ektachrome 100Plus and my Speed Graphic,
but unfortunately I had serious light leaks with my Polaroid holder
and the new Kodak Readyload packets.  I've since gotten a Kodak
Readyload holder, but I haven't done any 4x5 stereo since my first
attempt.

> I have done some contact printing of holograms using sun light at
> 1500 lp/mm.  TechPan will do 5-600 lp/mm.  Since my vision fails to
> resolve anything smaller than 25 microns (20 lp/mm)I would fail to
> see the difference in the final image. Remember that the f64 club
> got 50 micron spots - 10 lp/mm in a contact print!  An f8 enlarging
> lens should do 5 micon spots and 100lp/mm, far better than we can
> see - if properly done.

Visual resolution is usually measured as an angle.  That way viewing
distance is automatically compensated for.  I believe (but may be
wrong) that normal vision without magnification has a resolution of
about one arc minute (1/60 degree).  Line pairs per millimeter measure
are what the film can record (at a specific contrast ratio), not what
you can see.  Whether or not a certain number of lp/mm is "sharp"
depends on the viewing distance.

Contact prints will always be higher resolution than enlargement (on
the same paper).  There is no way for a 35mm negative to be enlarged
to an 8x10 print and have higher resolution on the print than a
contact print from an 8x10 negative (assuming both negatives were made
to be sharp).  If you optimize it (by picking the appropriate pinhole
diameter and film to pinhole distance), an 8x10 pinhole camera can
produce contact prints that are at least as good as can be enlarged
from a 35mm negative simply because the final print doesn't need to be
enlarged.

You might see 100lp/mm in the aerial image from a really excellent
enlarging lens, but you'll never see that on paper.  Paper (and most
films except for Tech Pan) can not record 100lp/mm.

Something to remember was the that f64 group was primarily a reaction
against Pictorialism, not a move towards maximum sharpness.  They
wanted images that looked like photographs, not images that looked
like something else (mainly paintings).  They did not always shoot at
f/64, and I don't think they all used 8x10 cameras (or contact
prints).

-- 
Brian Reynolds                  | "Dee Dee!  Don't touch that button!"
reynolds@xxxxxxxxx              | "Oooh!"
http://www.panix.com/~reynolds  |    -- Dexter and Dee Dee
NAR# 54438                      |       "Dexter's Laboratory"