[rollei_list] Re: Macro with Enlarging Lenses on the SL66?
- From: Marc James Small <msmall@xxxxxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx,<rollei_list@xxxxxxxxxxxxx>
- Date: Sun, 10 Sep 2006 01:49:53 -0400
At 04:12 PM 9/9/2006, John Wild wrote:
Rollei made adapters that fitted into the bayonet lens mount of the
SL66. One had a small pilot hole that could be bored out to take a large
format lens in shutter or anything else that could be fitted; one was
machined to take M35x.75 100mm Luminar; one was machined M39x1 for the
M-Componons & enlarging lenses; one was for Luminar and other microscope
lenses.
This is interesting stuff, John. Zeiss Ikon only sold a single set
of adapters for the 100mm Luminar and that was only for the
Contarex. The SL66 adapter would be worth it just for the 100mm Luminar mount!
M-Componons are NOT in M39x1 -- that tragic mistake was also made by
FED, Prewar, and Canon, Postwar. The proper dimensions of true LTM
are 39mm by 26 turns-per-inch Whitworth. Why Whitworth? As
Whitworth was the standard thread for microscopes, even those made in
Germany, and so Oskar Barnack had lots of gear capable of cutting
Whitworth threads and lots of technicians able to work in Whitworth
when he designed the original LTM, so Bob's your uncle. Every
attempt to mangle this into 39mm by 1mm DIN has led to dismal failures.
The third mount you mention was the standardized thread for
microscope objectives adopted in the 1860's by the Royal Microscope
Society: this is generally known in the trade as the " Royal
Screw" but folks often fail to get the humor in the term. The
proper dimensions for this are 0.8" by 36 turns-per-inch, again in
Whitworth. (Whitworth, incidentally, was the only thread design
developed without regard for production cost: it is simply the best
in terms of durability, reliability, and retention, but it has been
superseded by lesser designs such as SAE and DIN which are
considerably cheaper to produce.) Most macro lenses are in Royal
Screw, be they Leitz Photars or Zeiss Luminars or Carl Zeiss Jena
Mikrotars. These lenses always yield MF coverage (I am willing to be
convinced to the contrary, but I believe this to be true) and many
yield coverage on larger cut-film sizes. Linhof for years sold Royal
Screw adapters for their cut-film cameras. I do not own an SL66,
though I undoubtedly should do so. I do own a Hasselblad 2000FC/M,
though, and have a Royal Screw adapter, thanks to Charlie Barringer,
which allows me to make MF slides of the esoterica of lens markings
and the like. There is nothing which quite makes the point as
emphatically as does a MF slide of, say, a cross-bar T marking on a
Carl Zeiss lens. Depth of field? We don't need no
stinkin' DOF: just focus VERY carefully!
Probably the most accessible scholar of macro lenses is Willem-Jan
Markerink. His web site
http://www.a1.nl/phomepag/markerink/microlen.htm
is highly recommended. Willem-Jan and I have sparred occasionally
over varying values for optical registration on various camera mounts
but his work on macro lenses is nonpareil and most highly recommended.
Marc
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