Posted by Jim on September 18, 2000 at 20:05:55:
In Reply to: Re: 23 roll holder film flatness problem posted by Gilles Langlois on August 24, 2000 at 18:18:30:
: Hi!Even though the Graflex roll film back are holding the film
flatter than every other type of roll film back,it should be those
with the small rollers near the window.Apparently some "23" model
were delivered with these but they are more likely to be on the
later version,Singer/Graflex RH/8-RH/10-RH/12 and RH/20.I have
added rollers to my "23" model but it was not an easy process to
find the custom parts.You can make a test in jamming something
between the frame of the the window and the film to hold it tight
and flat and this way you will see if the problem is really
there.But it is a known fact that without the roller,specially at
wide aperture,you can have sharpness problem.Hope all this
helpful,Gil. I recently bought a Century Graphic with the
101mm
: : Ektar lens. I have not neen able to get sharp
: : negatives with it and I believe that the problem is
: : that the film is not quite flat against the pressure
: : plate.It seems to bulge through the 6x7 window. The
: : camera, roll film back, and lens are in excellent
: : condition. Could this bulging of 1 to 2mm be the cause
: : of the out of focus negatives? I've set the focus at
: : infinity and nothing in the depth of field is sharp.
: : Could newer film be thiner and more flexible than roll
: : film in 1950?
The difference in film flattness between an old roll back (one with the knob to wind the film) or the newer ones (with a lever and the stainless steel rollers on each side of the opening for the film to be exposed that keep the film flatter) is quite a bit at the edges, but the negatives, if the camera was correctly focused, would not be that extremely out of focus.
It sounds like you are focusing the camera with the rangefinder, which often in these cameras can be off due to jolts, bumps, etc. There are sections of the graflex.org information pages for setting the rangefinders.
Try this. Put the camera on a tripod. Have the dark slide in the film holder and the film loaded correctly. Take the roll holder off the camera, and open the shutter and open up the lens aperture setting to wide open, and focus the scene you wish to photograph on the rear focusing screen.
Then stop down the lens aperature to the f/stop you need, close the shutter and set it at the shutter speed you need, etc. Insert the roll film holder, remove the dark slide, and take the picture. shoot a full roll of film in this manner, removing the holder with the dark slide in and refocusing each time, making pictures at various distances from the camera and at various aperature openings. then you will know whether it is the roll holder-since all the images should be correctly focused. Most times the problems of the older roll film holders show up as unsharpness at the edges of the film especially with photos taken at the wider (smaller number) aperatures. The center of the negatives should be sharp no matter what holder you have. Hope this helps, Jim