[rollei_list] Rolleiflex FT focusing mechanism
- From: CarlosMFreaza <cmfreaza@xxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Wed, 27 Oct 2010 09:52:51 -0300
After Emmanuel message I took the FT focusing mechanism issue more
seriously, I did a deeper comparison between the Rollei traditional
focusing mechanism (f.e.2.8F) and the FTele focusing mechanism via
detailed diagrams and disassembled cameras images and they show that
while both cameras share several pieces (at least they look identical,
perhaps some sizes could be different), the FT has parts at the heart
of the focusing mechanism that are new really, you can see a sort of
wire and a channeled gear someway linked to this wire (more visible in
the third photograph), in fact the second and third photographs
captions in German talk about a "rope" mechanism for a longer
movement regarding the camera standard, it means I was wrong thinking
the new F&H wouldn't invest for the tooling to produce the FT and this
investment could be one of the bankruptcy causes. I really thought
that the 1,5m nearest focusing distance was obtained via the new lens
optical formula mainly thanks to some powerful elements combo as
commented in some forums and with some slight modifications for the
focusing parts.
Now it looks clear to me that while the FT focusing mechanism is based
on the TLR standard one, it had changes enough to be considered a new
one and I think Emmanuel is right from this point of view, this closer
focusing distance using mechanical means is a technical achievement
that the old F&H couldn't reach during their bests years for the TLR,
at least for production purposes (and they always looked for this
improvement, a Sommermeyer Tele production prototype obtained 1,3m but
Rollei was dedicated to the Rollei 35 and SL 66), this improvement
comes behind the times completely BTW.
Beyond the original Rollei Fototechnik statement about the FT
production suspension for economical and market conditions reasons, I
only found this F&H GmbH 2006 in German (I did not find an English
version) announcig the FT production for the 2006 Photokina, it says
"...Thanks to a new focus mechanics, the nearest focusing distance was
improved regarding the the '60's previous model of 2.60 ms on 1.50 ms
clearly...", anyway the new FT focus mechanism is not mentioned in the
sales brochures as I wrote:
http://www.franke-heidecke.net/files/images/0906_Rolleiflex4.pdf
Carlos
PS: We still need a complete technical explanation about the FT
focusing mechanism development and the way it works exactly, Prochnow
was very ill when he wrote the third edition Report II introduction in
June 2008 ( perhaps he was writing due to some contract) and according
he wrote me in September 2007 "... I have my own health problems,
Rollei is far away!.."
2010/10/26 CarlosMFreaza <cmfreaza@xxxxxxxxx>:
> 2010/10/26 Emmanuel Bigler <Emmanuel.Bigler@xxxxxxxx>:
> "...> Regarding the tele rollei :
>> The new 4,0FT must have a different focusing mechanism since the
>> closest focusing distance is now 1.3 metre.
>>
>> The old R-TLR tele had a closest focusing distance of 2.6 metre,
>> almost exactly what you would extrapolate by keeping the same amount
>> of travel of the front panel for a 80 mm focusing at 0.9 metre (the
>> minimum distance increasses like the square of the focal length,
>> .9*(135/80)^2 is about 2.6 metre)
>>
>> The amount of travel required to focus from infinity down to 1.3 metre
>> for a 135mm lens is 14 mm, this is almost twice the actual value of
>> the standard R-TLR.
>>
>> So either it is a different cam with 14 mm of travel, or another
>> different focusing system, but it cannot be exactly the same cam as
>> used on a standard (and tele) R-TLR.
>
> Thanks Emmanuel.
> I wrote that the FT focusing system looks very similar regarding the
> traditional Rollei TLR focusing system but I did not write it was
> identical, however the FT focusing system shown in the 2007 F&H
> photographs (I quoted them previously) most parts look _identical_
> regarding the focusing system used for the TLR from the first
> Rolleicord in 1933 and then it must be a different cam and not a
> different focusing system (one of the cams is visible in part in the
> second photograph).
> The FT minimal focusing distance is not 1,3m, it is 1,5m; the FT Tele-
> Xenar is a new dedicated design for the FT only.
>
> Carlos
>
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