[pure-silver] Re: (sligthly OT) Film flatness in a 4*5 holder
- From: "Rob C" <forum@xxxxxxxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Wed, 04 Apr 2007 12:27:31 +0100
I don't think anyone could answer your question with 100% certainty for several
reasons.
For starters, if the film is loose in the holder, then it may be tilted one way
or another and also the center may or may not be in the correct plane.
And it depends on what you have focussed on in the subject. i.e. was the focus
point in the center of the frame.
Also, some IR films have no antihalation layer and different IR films will
react to halation in different amounts. This may cause some films to appear
less sharp than others.
And was your subject planar and fill the frame completely so that you would
expect the same sharpness from edge to edge.
And was your lense at optimum aperture to obtain sharpness edge to edge.
Depth of focus increases the closer your subject is to the camera so if you
want to remove depth of focus as a significant factor from your testing, do
some macro shots. But of course you then have to worry about depth of field
which is much reduced. But then if your subject is planar then depth of field
won't be an issue either.
So your test results would depend on many factors and I guess it also depends
on what you are supposed to be testing. i.e. subjective or objective tests.
Rob C
=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you subscribed,)
and unsubscribe from there.
Other related posts:
