Archived posting to the Leica Users Group, 2001/10/20

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Subject: Re: [Leica] dumb question now a long answer
From: "Don Dory" <dorysrus@mindspring.com>
Date: Sat, 20 Oct 2001 20:45:01 -0400
References: <B7F729FA.2539%ternahan@sonic.net>

Trish, as I love close focus to macro it will be a pleasure to answer.

Bellows; an adjustable extension tube, think of a view camera attached to a
camera.  Slow and deliberate but for 1:1 reproduction ratio's and closer
really the hot ticket.  You typically lose control over the diaphragm unless
your system allows a double cable release system to stop down the diaphragm
before the shutter trips.  You should probably use a camera that allows TTL
metering so you can easily set whatever reproduction ratio you want.

1.4 APO extender; magnifies by 1.4 and you lose one stop of light.  That
means that a 200mm lens becomes a 280mm.  The 1.4 APO in the Leitz stable is
highly corrected for chromatic aberrations so if you are using a APO prime
lens you retain the correction.  Because the Leitz 1.4 has a snout it will
physically fit only some of their lenses mostly the telephoto APO
designation lenses, but for specifics ask.  I bet that you could use the 1.4
on a body, then mount a bellows unit, then a lens to get more magnification
than the bellows alone.

2X APO extender; much the same applies except magnifies two times and you
lose 2 stops of light.

Macro adapters: here I believe you are discussing the two element cose up
lenses that Leica and others produce.  They work just like reading glasses,
let you focus closer.  Benefits are that you can focus closer than your
normal lens can, you don't have any exposure compensation, they are small
and light, and you don't lose your lens correction for infinity.  Most
lenses are designed to produce their best quality at about a 1/10
reproduction ratio and degrade as you focus closer.  Downsides to these
critters is that even the best of them provide a curved field so for flat
subjects you need to stop well down.

If on the other hand you were asking about extension tubes, they extend your
lens usually a fixed distance further from the film allowing you to focus
closer.  You lose light in a ratio to your focal length used; one stop for
50% focal length.  Benefits are no glass to degrade the image, cheap, and
light weight.  Downside is that for the most part you only get on
magnification with each lens/tube combination.  Some people would use the
focusing mount for the viso as a variable extension tube which would allow
some choice in magnification.

Right angle viewers let you focus the camera 90 degrees from normal.  These
are very useful devices when you want an unusual angle.  To name a few,
groundlevel, over your head say on a tripod raised way up, around corners or
from the side.  This assumes your right angle viewer pivots so you set up
your camera or shot then figure out a way to see what you set up.  Also, the
better ones allow you to increase magnification so focusing is more exact.

Focusing rail: lets you set up your shot then adjust focus by sliding your
rig forward or back and in some cases sideways.  These are wonderful for
fine tuning composition when you have lights and reflectors set up from the
camera.

Off camera flash cord: lets you get your TTL flash off your camera and
direct it to mimic the sun.  Extremely useful when you have stopped down to
F11 or so to have a some depth of field, lost four stops to extension, and
have blocked the natural light with your camera and would like to photograph
a dragonfly eye.

If you have more questions please ask.

Don Dory
dorysrus@mindspring.com

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In reply to: Message from ternahan <ternahan@sonic.net> ([Leica] dumb question)