Film image not focusing on left side
I have been testing out a Perkeo 6x6 folding camera. At infinity setting I am getting the center of the negative sharply focused. However, the left side is blurry. See example attachment. This fuzziness is less apparent in shots focused 60 ft or less.
I have tried measuring the parallelism of the lens and the back film rollers and, within my accuracy limits, they seem OK. The lenses are clean and very clear.
Looks like the film is not flat at the exposure plane. I don't know this camera, but can you open the back (or remove the lens), load (sacrifice) a roll of film, advance it across the exposure opening, and see if it is flat?
If it looks like most folders I've seen, the image would be upside down, so the problem would be on the leading (take-up) side of the film, yes?
As Sirius Glass says, with different words, I came back to this, thought about something else - see if the take-up mechanism is lifting or distorting that right end (looking from the back) when advancing, and leaving it that way. Does this happen on every frame?
Is this present on all rolls? The film is not wound tightly over the rollers?
Or maybe the lens and shutter have been removed and were not put back correctly. Or, on the worst case, the lens has been disassembled and reassembled incorrectly.
Front standard not locking correctly or maybe wobbling. Where is the shutter release, on the body or on the lens?.
Such a fuzziness should be apparent even on ground glass, using the loupe. A bit of work of course due the tiny image.
May be you did not strech the film between right roll and left roll. You need to play with winding knob to strech the film before exposing. It must be tight but dont rip the film also.
My Leica had it , I went a famous repairman 400 kilometers far and he hold the body and pressed the plate with two fingers and everything sat where it might be sit before.
Press the plate with two first fingers and check from the side , does it parallel to film and cover.
Good luck ,
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Thanks everyone. The standard is rock solid, the film is always wound tightly. I believe the back plate is allowing a movement of the film further away from the lens at the take up side. I have applied a little pressure and it moved. Another test roll I think.
Once again, I appreciate your ideas and suggestions.
Correction NOT the left take up side but the right, new roll side.
take a piece of waxedpaper and tape it on the film gate / place where your film would sit to be exposed.
open your shutter up / bulb, and get a loup and focus your camera and see if with the stretched tight
waxed paper the image is sharp from edge to edge. if it isn't ... your lens is off-kilter
if it is sharp from edge to edge it might be something like a roller or pressure plate not being right ..
and you need to have it straightened, unless, you want to use that affect as an effect and have it part of your signature
good luck !
Last edited by jnanian; 12-09-2012 at 05:39 PM. Click to view previous post history.
I had a similar problem and it turned out to be the pressure plate not being flat
I am not familiar with the Perkeo, but on other 120 folders the film runs over a set of needle rollers on either side of the film frame: keeping the film tight against these rollers is a large part of what keeps the film flat. There is usually a leaf spring that rubs against the film feed roll to provide tension as the film is wound on. If the spring is weak or missing, or if one of the rollers has gone missing, then you might see the problems you have described.
Another common problem area are the leaf springs at the back of the pressure plate. They are usually slotted and slip under the heads of a set of rivets. If a spring has come unsprung then the pressure plate won't work correctly. Also, if these springs have become weak there can be problems.
Often bending the spring back a little bit will restore things to good order.