Rolleiflex Automat weird problem

Hello

I get a Rolleiflex Automat camera,
and found the next problem:
On open aperture ( F/3.5 ) fucusing on film and
focusing screen corresponds,
but when I close aperture the focusin of taking lense moves,
and on F/5.6 aperture to get sharp image on infinity
I must focus at 1.3 meters.

I just have no idea how it is possible.

Regards
Dmitry.

(Dmitry Poplavsky) wrote in message . com...
Hello

I get a Rolleiflex Automat camera,
and found the next problem:
On open aperture ( F/3.5 ) fucusing on film and
focusing screen corresponds,
but when I close aperture the focusin of taking lense moves,
and on F/5.6 aperture to get sharp image on infinity
I must focus at 1.3 meters.

I just have no idea how it is possible.

Regards
Dmitry.

I have no answer but I am sure a number of us here are interested in
how this gets resolved. So please keep us informed.

(Dmitry Poplavsky) wrote in message . com...
Hello

I get a Rolleiflex Automat camera,
and found the next problem:
On open aperture ( F/3.5 ) fucusing on film and
focusing screen corresponds,
but when I close aperture the focusin of taking lense moves,
and on F/5.6 aperture to get sharp image on infinity
I must focus at 1.3 meters.

I just have no idea how it is possible.

Regards
Dmitry.

I have no answer but I am sure a number of us here are interested in
how this gets resolved. So please keep us informed.

In message , Dmitry
Poplavsky writes
Hello

I get a Rolleiflex Automat camera,
and found the next problem:
On open aperture ( F/3.5 ) fucusing on film and
focusing screen corresponds,
but when I close aperture the focusin of taking lense moves,
and on F/5.6 aperture to get sharp image on infinity
I must focus at 1.3 meters.

I just have no idea how it is possible.

Regards
Dmitry.

Check the inside of the taking lens - has one of the elements fallen
off?
--
----------------------------
Paul Friday

In message , Dmitry
Poplavsky writes
Hello

I get a Rolleiflex Automat camera,
and found the next problem:
On open aperture ( F/3.5 ) fucusing on film and
focusing screen corresponds,
but when I close aperture the focusin of taking lense moves,
and on F/5.6 aperture to get sharp image on infinity
I must focus at 1.3 meters.

I just have no idea how it is possible.

Regards
Dmitry.

Check the inside of the taking lens - has one of the elements fallen
off?
--
----------------------------
Paul Friday

I have run across this problem with several older TLR cameras, mainly
Yashica but also on Rollei and Ikoflex. The aperture is not at the nodal
point for the lens so as you adjust the focus the aperture cuts into the
cone of light and causes the in focus area to shift, adjusting the lens to
film distance brings the lens back into focus. This is very easy to see
when using an autocollimator. The Rollei and Ikoflex cameras had best
infinity focus set to f/5.6, the YashicaMat had infinity focus set at f/8
(infinity focus as I am using it here is when the focus knob is at infinity
and I adjusted the diaphragm until I got the sharpest image on the film
plane). Going past the sharpest f/stop caused the image as viewed through
the collimator to go out of focus again. I did take one of the shutters
apart and it was clear that the shutter was not the original for the camera
as the lenses did not sit in the shutter completely full depth thread. I
recently had to change out a shutter in an Autocord and I ran into the same
problem, solution was to measure the depth the lenses were in the original
shutter and adjust the lens the same in the replacement shutter.

karl


"Dmitry Poplavsky" wrote in message
om...
Hello

I get a Rolleiflex Automat camera,
and found the next problem:
On open aperture ( F/3.5 ) fucusing on film and
focusing screen corresponds,
but when I close aperture the focusin of taking lense moves,
and on F/5.6 aperture to get sharp image on infinity
I must focus at 1.3 meters.

I just have no idea how it is possible.

Regards
Dmitry.

I have run across this problem with several older TLR cameras, mainly
Yashica but also on Rollei and Ikoflex. The aperture is not at the nodal
point for the lens so as you adjust the focus the aperture cuts into the
cone of light and causes the in focus area to shift, adjusting the lens to
film distance brings the lens back into focus. This is very easy to see
when using an autocollimator. The Rollei and Ikoflex cameras had best
infinity focus set to f/5.6, the YashicaMat had infinity focus set at f/8
(infinity focus as I am using it here is when the focus knob is at infinity
and I adjusted the diaphragm until I got the sharpest image on the film
plane). Going past the sharpest f/stop caused the image as viewed through
the collimator to go out of focus again. I did take one of the shutters
apart and it was clear that the shutter was not the original for the camera
as the lenses did not sit in the shutter completely full depth thread. I
recently had to change out a shutter in an Autocord and I ran into the same
problem, solution was to measure the depth the lenses were in the original
shutter and adjust the lens the same in the replacement shutter.

karl


"Dmitry Poplavsky" wrote in message
om...
Hello

I get a Rolleiflex Automat camera,
and found the next problem:
On open aperture ( F/3.5 ) fucusing on film and
focusing screen corresponds,
but when I close aperture the focusin of taking lense moves,
and on F/5.6 aperture to get sharp image on infinity
I must focus at 1.3 meters.

I just have no idea how it is possible.

Regards
Dmitry.

karl.kathy wrote:

I have run across this problem with several older TLR cameras, mainly
Yashica but also on Rollei and Ikoflex. The aperture is not at the nodal
point for the lens so as you adjust the focus the aperture cuts into the
cone of light and causes the in focus area to shift, adjusting the lens to
film distance brings the lens back into focus. This is very easy to see
when using an autocollimator. The Rollei and Ikoflex cameras had best
infinity focus set to f/5.6, the YashicaMat had infinity focus set at f/8
(infinity focus as I am using it here is when the focus knob is at infinity
and I adjusted the diaphragm until I got the sharpest image on the film
plane). Going past the sharpest f/stop caused the image as viewed through
the collimator to go out of focus again. I did take one of the shutters
apart and it was clear that the shutter was not the original for the camera
as the lenses did not sit in the shutter completely full depth thread. I
recently had to change out a shutter in an Autocord and I ran into the same
problem, solution was to measure the depth the lenses were in the original
shutter and adjust the lens the same in the replacement shutter.

Right solution (adjusting the lens to original element spacing), wrong
reason for the focus shift. Focus shift is due to uncorrected spherical
aberration (or less frequently to longitudinal chromatic aberration;
this is usually not large enough to see as focus shift). Closing the
aperture always requires moving the lens further from the film (focusing
closer, by the scale), because the center of the lens has a longer focus
than the edge. When the elements are spaced correctly, this does not
occur because the spheric aberration is corrected.

--
The challenge to the photographer is to command the medium, to use
whatever current equipment and technology furthers his creative
objectives, without sacrificing the ability to make his own decisions.
-- Ansel Adams

Donald Qualls, aka The Silent Observer http://silent1.home.netcom.com

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

karl.kathy wrote:

I have run across this problem with several older TLR cameras, mainly
Yashica but also on Rollei and Ikoflex. The aperture is not at the nodal
point for the lens so as you adjust the focus the aperture cuts into the
cone of light and causes the in focus area to shift, adjusting the lens to
film distance brings the lens back into focus. This is very easy to see
when using an autocollimator. The Rollei and Ikoflex cameras had best
infinity focus set to f/5.6, the YashicaMat had infinity focus set at f/8
(infinity focus as I am using it here is when the focus knob is at infinity
and I adjusted the diaphragm until I got the sharpest image on the film
plane). Going past the sharpest f/stop caused the image as viewed through
the collimator to go out of focus again. I did take one of the shutters
apart and it was clear that the shutter was not the original for the camera
as the lenses did not sit in the shutter completely full depth thread. I
recently had to change out a shutter in an Autocord and I ran into the same
problem, solution was to measure the depth the lenses were in the original
shutter and adjust the lens the same in the replacement shutter.

Right solution (adjusting the lens to original element spacing), wrong
reason for the focus shift. Focus shift is due to uncorrected spherical
aberration (or less frequently to longitudinal chromatic aberration;
this is usually not large enough to see as focus shift). Closing the
aperture always requires moving the lens further from the film (focusing
closer, by the scale), because the center of the lens has a longer focus
than the edge. When the elements are spaced correctly, this does not
occur because the spheric aberration is corrected.

--
The challenge to the photographer is to command the medium, to use
whatever current equipment and technology furthers his creative
objectives, without sacrificing the ability to make his own decisions.
-- Ansel Adams

Donald Qualls, aka The Silent Observer http://silent1.home.netcom.com

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

Donald Qualls wrote in message .. .
karl.kathy wrote:

I have run across this problem with several older TLR cameras, mainly
Yashica but also on Rollei and Ikoflex. The aperture is not at the nodal
point for the lens so as you adjust the focus the aperture cuts into the
cone of light and causes the in focus area to shift, adjusting the lens to
film distance brings the lens back into focus. This is very easy to see
when using an autocollimator. The Rollei and Ikoflex cameras had best
infinity focus set to f/5.6, the YashicaMat had infinity focus set at f/8
(infinity focus as I am using it here is when the focus knob is at infinity
and I adjusted the diaphragm until I got the sharpest image on the film
plane). Going past the sharpest f/stop caused the image as viewed through
the collimator to go out of focus again. I did take one of the shutters
apart and it was clear that the shutter was not the original for the camera
as the lenses did not sit in the shutter completely full depth thread. I
recently had to change out a shutter in an Autocord and I ran into the same
problem, solution was to measure the depth the lenses were in the original
shutter and adjust the lens the same in the replacement shutter.

Right solution (adjusting the lens to original element spacing), wrong
reason for the focus shift. Focus shift is due to uncorrected spherical
aberration (or less frequently to longitudinal chromatic aberration;
this is usually not large enough to see as focus shift). Closing the
aperture always requires moving the lens further from the film (focusing
closer, by the scale), because the center of the lens has a longer focus
than the edge. When the elements are spaced correctly, this does not
occur because the spheric aberration is corrected.

I get your drift but wonder if spherical aberration is ever fully
corrected in these lenses. I had the idea that if you wished to avoid
spherical aberration then you should stop down a bit so that the edge
of the lens contributed less to the image. Then, of course, you would
expect a lengthening of the focal length. But I had no idea it would
have such a dramatic effect. Also, if the diaphram were not at a nodal
point due to a replacement of the shutter mechanism, then I would have
thought there would either be some vignetting coming in or even a
darkening in the centre of the image when the aperture was adjusted.

Just looking through the back of a camera so you can see through the
front lens when the aperture is adjusted you can see that at smaller
apertures there is no contribution from the edge of the front element.

I know from the Tessar design that spherical aberration is a problem
and that is why the front housing of the lens itself blocks light
coming from extrenme angles at the edges. If you have a Tessar at full
aperture and look though the back then at the edges and in the corners
you can see that the lens housing is blocking off some light and
introducing vignetting in the process. If a camera has a problem as
originally described in the thread then I would have to wonder if the
front element was set deeply enough into the housing to block this
unwanted light as it should be blocked. Could it be that someone has
made an adjustment to the camera to get rid of what they perceive as
vignetting at wide apertures not knowing that this is necessary and
part of the lens design to minimise spherical aberration? This would
explain the extreme effect on the focussing at various apertures.