----- Original Message -----
From: "Jerry Lehrer" <jerryleh@xxxxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Saturday, August 20, 2005 2:11 PM
Subject: [rollei_list] Re: Bellows on 2.8D?
Richard,
It is exactly a diaphragm, such as the one in your body which
separates your lungs and heart from your entrails. It also has
penetrations for your esophagus etc. Analogous to the penetration
for the lens in the Rollei. In engineering and mathematics, it is
called a membrane.
Jerry
Richard Knoppow wrote:
----- Original Message ----- From: "Carlos Manuel Freaza" <cmfreaza@xxxxxxxxxxxx> To: <rollei_list@xxxxxxxxxxxxx> Sent: Saturday, August 20, 2005 6:30 AM Subject: [rollei_list] Re: Bellows on 2.8D?
>I don’t wish to enter in a new discussion about a
> technical word meaning; however I’d like to write my
> opinion on the now called “TLR bellows”. Talking about
> an operative photographic camera, a bellow could allow
> to vary the focal length, the camera focal plane,
> depth of focus and depth of field, to rise and to tilt
> the lens or the focal plane, the typical sample is the
> large format camera, but you can find accessories for
> 35mm and MF cameras with bellows to perform these
> functions at least partially; there are special MF
> cameras like the Mamiya C 330 and the Rollei SL 66
> that working like rigid cameras have bellows for some
> active specific photographic purposes.
> The short fabric tube –really it seems a lining- added
> around the back of the Rolleiflex TLR taking lens does
> not perform any of the functions described above, it
> only does an almost redundant insulating task and then
> it is not a true photographic bellow IMO.
>
> All the best
> Carlos
>
None of the requirements you add above is necessary for a
definition of bellows. A bellows (ther is no singular in
English) is a flexible coupling allowing a seal. There are
many non-photographic applications of bellows. The bellows
in the Rollei is not a pleated bellows, as is familiar on
other cameras, but neither is the "bag" bellows used for
wide angle lenses on some view camereas. It is, however, a
flexible, light-proof, cloth coupling, with a single fold,
coupling two sliding parts in the camera. There is no other
term in English which describes what it is. It is not
strictly a diaphragm, diaphragms usually are rigid in two
dimensions and flexible only in one.
Note also that "bellows" is used as a name for various
forms of air pumps, for instance the variety used to
increase the draft of a fire, or supplying air to certain
musical instruments, for instance pipe organs, concertinas,
accordians. Bellows have even been used to make steam
locomotive boilers flexible (didn't work very well).
Now, lets discuss how many angles can dance on the head
of a pin, how many on the point, does it matter if they are
waltzing or jitterbugging?
--- Richard Knoppow Los Angeles, CA, USA dickburk@xxxxxxxxxxxxx
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