5 Jul
2011
5 Jul
'11
3:42 p.m.
On 05/07/2011 21:11, Tony Duell wrote:
The autofocus might or might not -- decent ones will, and all sensible
SLRs can turn the auto off. Which, actually, is what you'd want for
closeup work, especially repetitive work with a fixed stand.
Sure, but I was thinking of resolution not depth of field. And I'm sure
you have lenses that don't open up as wide as f/8 ;-) same as I do.
--
Pete Peter Turnbull
Network Manager
University of York
To answer
Tony's question, in general, yes of course you can use rings,
bellows, and all the other things with digital SLRs. I suspect he knew
that, maybe he was asking if Dave has access to those things.
Actually, I didn;t know if such thinbgs were useable with all digital
SLRs. I realise that optically it must be possible, but since modern
equipment seems to be universally designed to make mildly complex things
impossible, I wondered if there was some gotcha, like the exposure meter
or autofocus wouldn't bahave and the camera would refuse to record an
iamge as a result. How will the automatic coupling work if you turn the
lens round? Most
DSLR lenses that I've seen lack manual control of aperture, etc so you
might have problems.
It doesn't work, but many DSLR lenses do allow manual control. Almost
all of mine do.
Ideally, stop
the lens down about halfway
or just a bit more; that's when most lenses are at their sharpest.
This depends on the subject. For flat subjects like fiche, I would agree
with you (most lenses have a peak resolution around f/5.6 or f/8). For
3-dimension subjects, like bits of classic computer, you may need to stop
down further to get enough depth of field.