13 Jun
2010
13 Jun
'10
11:18 a.m.
On Sat, 12 Jun 2010, Tony Duell wrote:
The other trick, if you can do it is to fit the lens
back-to-front. Most
camera lenses are designed to work with a larger object than image
distance. Byu turning it round you reverse this, which is a help for the
short object distances in close-ups.
I NEVER reverse the lens when photographing anything unless I am going for
a magnification (image larger than object). When the object is larger
than the image, you are in the realm of "normal" lens design. Enlarger
lenses, in particular, are designed for ~1" (25.4mm :-) "film", with
~10"
"object" (print paper). Direction of photon flow is irrelevant - most
enlarger lenses are designed for about the magnification level that you
would want for photographing a sircuit board, or a sheet of paper.
Also, enlarger lenses are generally designed for FLAT FIELD, which can be
a major plus.
When photographing the innards of a chip, an individual cold solder joint,
postage stamps, coins, or the like, THEN lens reversal becomes worth
considering.
The problem is that you genrally loose all automatic
coupling to the
lens, which means it's not a lot of use with modern
electronically-controlled cmaeras. The Praktica PLC/VLC series had a
special pair of afapater rings to maintain full aperture metering even
when the lens was fitted backwards, but I've not seen this for anything
remotely modern.
My micro-four-thirds is the first camera that I have ever seriously owned
where the camera attempted to communicate anything to the lens, (I haven't
unwrapped the Exakta that I was given months ago, andI haven't used the
other SLRs in ~40 years), and shooting in "no lens" mode lets me use my
lenses (manual focus, manual aperture). If the only prioblem is an "auto"
aperture, there are a few adapters available that let you connect a dual
cable release (similar to that supplied with Visoflex) in order to
"simultaneously" stop down the lens and trigger the camera, or just
duct-tape the stop-down linkage and do it manually. The lenses for the
4x5 and 8x10 cameras are all manual.
But, I may soon try to disassemble the camera firmware.
I am not sure whether Panasonic's code to refuse to operate with generic
batteries! is really a "safety issue" as they claim, or just greed.
--
Grumpy Ol' Fred cisin at xenosoft.com