Yes Richard, I have seen again the Rolleicord IV and
really it has a membrane or diaphragm that appears
when you put the focus mechanism at the minimum
focusing distance, it has a reddish color and it's
very different regarding the system for the 2.8C,
while the 2.8C is similar to your 2.8E, (it moves
following the lens movement as Todd explained), the
Rolleicord IV membrane or diaphragm(there are no
"bellows" here) is invisible till you advance the
lens to the minimum focusing distance (0.80m), that
was the reason I did not see it before. As Prochnow
wrote, the diaphragm, (or short "bellows" or membrane
or whatever) looks different according each
"calculation".
The Rollei TLR cameras anti-reflection system are very
effective according my experience; of course, as you
wrote, it is not perfect if you shoot into the sun,
but for this case it sometimes helps to obtain a bit
of flare control enough for some detail in the photo.
Perhaps that issue about the roller reflection seen in
some cameras has something to do with problems for
this "diaphragm".-
All the best
Carlos
--- Richard Knoppow <dickburk@xxxxxxxxxxxxx>
escribió:
----- Original Message -----
From: "Carlos Manuel Freaza" <cmfreaza@xxxxxxxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Saturday, August 20, 2005 4:56 PM
Subject: [rollei_list] Re: Bellows on 2.8D?...an
answer from
Mr Prochnow
>I think he understood the question Patric, he
answered
> that the ring in the back of the lens is like a
> diaphragm to save quality in difficult situations;
> difficult situations are a strong backlight photo,
a
> photo where the sun appears directly, some other
> strong light source, the diaphragm could help to
save
> image quality, that is its function, a light trap.
> The second part could need more explanation. I
> commented him in the last part of my question that
I
> had not seen the diaphragm in the Rolleicord IV
(I'll
> look again tonight), and then he answers that the
> diaphragm can look different for every
calculation, I
> think he meant that the diaphragm is calculated
> different for different models and then they look
> different. In fact my Rolleiflex 2.8C 2.8/80
Xenotar
> and my Rolleicord IV 3.5/75 Xenar look very
different
> in the taking lens back and both are like new in
this
> part.-
>
> All the best
> Carlos
Aha!!! I just looked at three Rolleiflex's and
my
Rolleicord IV. There is a short tube at the back of
the
taking lens in the two older Rolleis (an "Old
Standard" and
a late MX), this tube appears to act as a sort of
internal
lens shade. The Rolleiflex 2.8E does NOT have this
tube,
rather it has the short bellows (or diaphragm or
membrane or
whatever). This also appears to act to prevent
scattering of
extra-image light, at least when the focus is racked
out.
Rollei seems to have payed a lot of attention to
preventing internal reflections. The inner tube or
bellows
and the light baffles in the later cameras for
instance.
Rollei also has an effective lens shade.
BTW, none of this stuff is effective for bright
light IN
the image, such as shooting into the sun. A lens
shade works
primarily to eliminate flare or ghost images from
extra-image light getting into the lens. It can also
limit
the amount of extra-image light where the lens
coverage is
significantly larger than the film. The internal
tube acts
as a crude field stop limiting the projected light
from the
lens from striking anything but the film. The
baffles tend
to stop reflection of light that does strike the
internal
surfaces of the camera which otherwise would strike
the film
causing flare. I have discovered by shining a
flashlight
into a Rollei that the edges of these baffles can
reflect a
surprizing amount of light despite being painted
with a good
anti-reflection paint.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
---
Rollei List
- Post to rollei_list@xxxxxxxxxxxxx
- Subscribe at rollei_list-request@xxxxxxxxxxxxx
with 'subscribe'
in the subject field OR by logging into
www.freelists.org
- Unsubscribe at rollei_list-request@xxxxxxxxxxxxx
with
'unsubscribe' in the subject field OR by logging
into www.freelists.org
- Online, searchable archives are available at
//www.freelists.org/archives/rollei_list
__________________________________________________
Correo Yahoo!
Espacio para todos tus mensajes, antivirus y antispam ¡gratis!
¡Abrí tu cuenta ya! - http://correo.yahoo.com.ar
---
Rollei List
- Post to rollei_list@xxxxxxxxxxxxx
- Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe'
in the subject field OR by logging into www.freelists.org
- Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with
'unsubscribe' in the subject field OR by logging into www.freelists.org
- Online, searchable archives are available at
//www.freelists.org/archives/rollei_list
