Luddite Frank
Well-known
I have noticed this "tendency" (?) with various German folders (as well as American wooden plate-cameras), that when the camera is opened-up, the plane of the front standard does not appear to be parallel to the film plane.
Most recently, I have observed this with a "new" Zeiss Super-Ikonta 6x9/20 camera (model 530/2; pre-war ?). It appears as though the end of the film standard opposite the bed is tilted slightly back towards the camera... I have examined the camera for evidence of being dropped or "tweaked" at some point, but can find none... I am very reluctant to go bending things to try and correct this situation, but fear that if I can see this "variance" with my naked eye, that the lens plane and film plane may be out of whack enough to affect image quality...
Any thoughts / suggestions ?
Thanks,
Luddite Frank
(PS: I can understand some variances with 100+ year-old wooden plate cameras, due to the "organic" construction, but a metal job like a Zeiss should be fairly stable ?)
Most recently, I have observed this with a "new" Zeiss Super-Ikonta 6x9/20 camera (model 530/2; pre-war ?). It appears as though the end of the film standard opposite the bed is tilted slightly back towards the camera... I have examined the camera for evidence of being dropped or "tweaked" at some point, but can find none... I am very reluctant to go bending things to try and correct this situation, but fear that if I can see this "variance" with my naked eye, that the lens plane and film plane may be out of whack enough to affect image quality...
Any thoughts / suggestions ?
Thanks,
Luddite Frank
(PS: I can understand some variances with 100+ year-old wooden plate cameras, due to the "organic" construction, but a metal job like a Zeiss should be fairly stable ?)
Solinar
Analog Preferred
Before do anything else, you'll want to check the collimation of the lens at infinity. Rick Oleson has a brief description of how to this using the back focus method, as shown below.
http://members.tripod.com/rick_oleson/index-123.html
It's best to use a SLR of which you have an available longish fast lens, i.e. a 135/2.8 or 180/2.8 lens. Both cameras are set with their apertures wide open and the focus set to infinity. On the ZI Super set the shutter to T or B with a cable release. I make my plastic targets from old CD jewel cases that I cut with a band saw. Make the plastic target as wide as the paper backing on 120 film and long enough to cover the film gate all the way to the spools.
If you make your marks on the target all the way across the film plane you'll be able to check the focus collimation accross the entire frame.
http://members.tripod.com/rick_oleson/index-123.html
It's best to use a SLR of which you have an available longish fast lens, i.e. a 135/2.8 or 180/2.8 lens. Both cameras are set with their apertures wide open and the focus set to infinity. On the ZI Super set the shutter to T or B with a cable release. I make my plastic targets from old CD jewel cases that I cut with a band saw. Make the plastic target as wide as the paper backing on 120 film and long enough to cover the film gate all the way to the spools.
If you make your marks on the target all the way across the film plane you'll be able to check the focus collimation accross the entire frame.
fidget
Lemon magnet
I have experienced this recently in two out of two Moskva 5 6x9 folders. I think I posted about this, asking for ideas as to "how-to" get them parallel. just as you say, I didn't want to go bending anything as it locked into fairly stable position, just the wrong position.
I've put this down to the infamous QA for these.
I am surprised that you have found this in quality German folders.
In one case of my Moskvas, although I have yet to carry out more measurements, it looks like a missing gasket/packing ring between the lens assy and its mount plate allowed the anti-rotation pin to hold the assy off the plate a little, so could be an easy (or easier) fix.
good luck, without bending.....
Dave
I've put this down to the infamous QA for these.
I am surprised that you have found this in quality German folders.
In one case of my Moskvas, although I have yet to carry out more measurements, it looks like a missing gasket/packing ring between the lens assy and its mount plate allowed the anti-rotation pin to hold the assy off the plate a little, so could be an easy (or easier) fix.
good luck, without bending.....
Dave
Ernst Dinkla
Well-known
Of the 4 MF folders that I have the Iskra has the most rigid and still correct strut construction. The German Agfa Record II and the Voigtläder Bessa I are better on that aspect than the Kodak Monitor 620 while the last uses twice the amount of metal IMHO. The main problem is too much "play" of the lensboard. Easy to test by holding the body in one hand and the lensboard in the other hand.
I have seen a comment somewhere that the Polaroid 110A (LF folder) has a good construction but my experience of the 3 Polaroids (110A, 120 and 150) I bought is that the relative weak struts at the front were bended on 2 and there's "play" in the locking system at the base of the struts in all 3. It can all be adjusted though with simple tools and some insight. As one of them will be sacrificed for parts I most likely will use the struts to strengthen the existing struts of another one.
So on origin of cameras and the strut quality: in my case it is Ukrain 1, Germany 2, United States 3,
Ernst Dinkla
Ernst Dinkla
Well-known
Forgotten to add that older less flexible bellows that have been flattened for a long time when locked in the camera tend to pull the lens carrier board to the camera when opened. Either new bellows or applying plasticiser/wax on them will cure that problem. As some strut designs lock the lens board at one side that pulling force will make the lens board no longer parallel to the film plane.
The Record II shows that problem most in my folders.
Ernst Dinkla
The Record II shows that problem most in my folders.
Ernst Dinkla
fidget
Lemon magnet
I managed to find a couple of hours to play with my Moskva 5 lens panel. I re-assembled it with some good gasket material and found that it was still not parallel to the film plane.
(I check by resting the backless camera on a good straight alloy extrusion so that it sits on the two film rollers at each side of the film gate. Then I hold a 60cm steel rule edge on to the lens bezel in the centre of the rule. I measure the distance from each end of the rule to the base piece of alloy. If the measurements are the same, it must be parallel).
My checks show that there is a difference of around 1 to 1.8mm between the ends of the rule (60cm) which I think, equates to 0.15 to 0.27mm across the film gate.
I can't see any difference across an image projected onto ground glass at full aperture, but then that is nothing like a 12x16 enlargement. this is better than it was and is better than the other Moskva was too, so I will try a roll, especially checking for focus changes across the frame.
FWIW, I noticed that the lenses/panels were tipped the same way, towards the closing position, and wonder if the distortion could be due to "enthusiastic" pressing on the lens assembly when collapsing it. The Moskva is a little awkward to get moving when collapsing.
Dave.....
(I check by resting the backless camera on a good straight alloy extrusion so that it sits on the two film rollers at each side of the film gate. Then I hold a 60cm steel rule edge on to the lens bezel in the centre of the rule. I measure the distance from each end of the rule to the base piece of alloy. If the measurements are the same, it must be parallel).
My checks show that there is a difference of around 1 to 1.8mm between the ends of the rule (60cm) which I think, equates to 0.15 to 0.27mm across the film gate.
I can't see any difference across an image projected onto ground glass at full aperture, but then that is nothing like a 12x16 enlargement. this is better than it was and is better than the other Moskva was too, so I will try a roll, especially checking for focus changes across the frame.
FWIW, I noticed that the lenses/panels were tipped the same way, towards the closing position, and wonder if the distortion could be due to "enthusiastic" pressing on the lens assembly when collapsing it. The Moskva is a little awkward to get moving when collapsing.
Dave.....