Film Flatness/Buckling Problem: Update

Todd Frederick , Sep 13, 2002; 08:06 p.m.

With regard to the question asked below concerning film flatness in cameras where the film bends back on itself around inserts (Mamiya, Hasselblad, etc) I ran a field test. I had a roll of film in my Mamiya 645e for at least two weeks, on exposure #1. If the film buckled, it would appear on frame #2. I ran the roll on many objects around the house and yard. The photo above is frame #2, full frame, and, if the buckling occured in the image area itself it would appear as a fuzzy band unfocused across the image horizontally. The aperture was f/5.6. Both frame one and frame two are identical showing no evidence of an out of focus band. I can only assume that, with the Mamiya insert, the bend occurs between frames. Looking at the insert construction, that seems to be the case. When I processed the film, I felt the film for evidence of uneveness, and, yes, there was a definite bump across the film where it bent back on itself...it felt like a small "speed bump" in a road. However, based on the images I produced, some taken in quick succession, and some waiting 30 minutes or more, all images are sharp with no evidence of an out of focus band. I feel much more confident using this camera now, after running this simple test, and I am not concerned with out of focus areas on my images due to film bending. However, I do think it is wise to load the film just before using the camera, and not to leave the film in the camera for extended periods of time, just to be on the safe side.

Responses

Jay . , Sep 13, 2002; 08:40 p.m.

>>With regard to the question asked below concerning film flatness in cameras where the film bends back on itself around inserts (Mamiya, Hasselblad, etc)<<

Todd, I have no film flatness problem with my Hasselblad backs (3 A12's with "12" in the release button, the generation just before the current ones with darkslide holders)even if I leave film in them for a month (which rarely happens but it has happened). I can't speak for the inserts in the Mamiya 645E but there might be something more than just smoke and mirrors to the fact that a Hasselblad film back alone costs more than the entire 645E kit with insert, lens and winder.

Charles Barcellona , Sep 13, 2002; 09:09 p.m.

There is an article on the Zeiss website about film flatness in rollfilm cameras. Its informative, but... it seems that the "problem", can only be seen on film in the most critical shots, ie test targets.

Todd Frederick , Sep 13, 2002; 09:42 p.m.

Jay and Charles,

I did not have film flatness problems with either Hasselblad or Mamiya inserts over years of use. The only problem I had with Hasselblad backs was light leaking in the baffles, which should be serviced and replaced every two years or so, under heavy pro use. I **never** had any problems with Mamiya film inserts. I think they are very well designed, and the film bend is at the space between frames. Mamiya 645 camera systems and inserts have been around since the mid 1970s, and the inserts have remained unchanged and are used in most Mamiya 645 system today. I am convinced, by my field experience over 30 years, that these two systems (Hasselblad...very expensive; and Mamiya...very economical) are designed to avoid this problem.

I read the Zeiss article, and I seriously think it makes this to be much more of a problem than actually exists, based on my personal field experience. "Bench Testing" is quite different from field photography. I've enlarged 645 negs to 30x40+ with no problem and will be using my new lightweight AE 645e tomorrow with similar images in mind. I'm not concerned, but am pleased that I ran one more test on this today.

My advice...go out and take photos. Not to worry!

Mountains from molehills, IMO.

Charles Barcellona , Sep 14, 2002; 04:06 a.m.

I agree Todd - I've never seen the problem. BTW, the same "problem" exists in 35mm films.

Olivier Truan , Sep 14, 2002; 09:24 a.m.

I don't agree, Todd. You can see my test results here: http://www.photo.net/photodb/ photo?photo_id=1009793

Todd Frederick , Sep 14, 2002; 09:47 a.m.

Oliver,

When I try to access you test, it says "URL Not Found." I'll try again later.

Olivier Truan , Sep 14, 2002; 10:00 a.m.

Sorry, my mistake, it was not selected for public view. Now it should work!

Sal Santamaura , Sep 14, 2002; 10:36 a.m.

In my response to Todd's first thread, I said:

"Actual photographic implications, if any, depend on your specific working conditions, and should be determined by individual test."

It's heartening to see that this time several people have taken that advice rather than dismissing the problem as fantasy/conspiracy. By the way, test targets aren't the only flat subjects out there. Anyone photographing planar objects at large apertures with a reverse curl back will suffer the same problems that Olivier's results revealed. Also note that, contrary to intuition, poor focus caused by this deficiency will become more severe with shorter focal length lenses.

Todd Frederick , Sep 14, 2002; 11:19 a.m.

Oliver...Try as I may, I still can not access your URL site for the test you ran.

Also, my point was not that there is no back curl (or whatever you want to call it) but it seems to fall on the space between frames with my Mamiya 120 inserts. Has anyone tried measuring that? I might try later today...it's not possible to measure while in the camera since the insert must be in the camera to turn, but I might try rolling it by hand outside the camera and measuring and marking each frame on the paper to see where the space between frames falls on the insert...I'm guessing it will be the point where is bends.

I have examined the roll I took again and again with a strong lupe, and nowhere are there any bands of unsharpness across any image frame, even the one that was bent for three weeks.

I'm going out now to use the camera for some portraits at the beach.

Frank Kimble , Sep 14, 2002; 12:49 p.m.

Todd, take a negative and lay it on your insert with the exposed area matching the hole in the mask, this should allow you to see where the film sits in relation to the rollers.The area between exposures is fairly small. On my Bronica ETRSi, the roller is just outside the exposure, but the diameter is 7/16 inch so part of the next frame is around the roller. The larger diameter seems to help prevent the problem. My autocord has an extremely small roller but the film path does no bend backwards like the SLR's.

Bob Chong , Sep 14, 2002; 03:13 p.m.

RE: why the URL won't work

Somehow, a extra space got added in the URL given above. Cutting and pasting shouldn't be that hard, but so be it.

http://www.photo.net/photodb/photo?photo_id=1009793

Olivier Truan , Sep 14, 2002; 03:32 p.m.

Sorry folks and thank you Bob! The problem is that I have a bug in IE, I can't see what I write when I write it.

Todd Frederick , Sep 15, 2002; 12:11 a.m.

For me this seems to be a non-issue, but, I guess some cameras have serious problems in this regard.

I just returned from a day at the beach photographing a wedding client of 8 years ago and their 2yr old daughter at the same spot we did their engagement portrait.

I used the Mamiya 645e...a wonderfully user-friendly unit!

When I got home I had one full roll left in the camera that had not been exposed. I removed it in the darkroom and felt for the bend areas, since it was left in the camera for over an hour. The bend areas could be felt distinctly.

The bend areas were exactly at the edges of the frame where the space is between frames. Since all of the Mamiya 645 units use the same film inserts, all the way back to the original M645, I would suspect they all behave the same. The 645AF may use different inserts (though I doubt it), but the Super and Pro do use the same inserts as the 645e and earlier models.

The bend is between frames. I have a full length processed roll in front of me now, and the spacing between frames is quite wide: 8 to 10mm (1cm). This corresponds to the area spacing on the rollers on the inserts between image frames.

This is consistent throughout the roll.

Also, I have not had any problem of this nature with the two Hasselblads and two RB67 units I previously owned.

Oliver, are you using a Mamiya 645AF for your test? Also, I thought the 645AFD was the digital (no film) unit?

What camera did you use for your newspaper test?

I can not imagine any company making a high grade Pro unit where the bend is centered in the middle of the frame. That's both insane and irresponsible, not to mention stupidly poor engineering!

What about Bronica and Pentax and Rollei SLR MF cameras? Do these have similar problems?

I'm not concerned with using my Mamiya 645e, even if I leave the film in for an extended time, since it seems evident that these units are expertly designed to place the bend between frames and not affect the image area, based on my tests and measurements.

Olivier Truan , Sep 15, 2002; 09:45 a.m.

Todd, the 645e is not a problem, you're right, the buckle is in between frames. Unfortunately Mamiya did change their winning horse, and they exchanged for a bad one. The 645AFD, which is BTW a nornmal camera with both analog and digital back compability, has the buckles right in the middle of the frames. Yes: highly irrespondible. I used the 645AFD for my test. That's it for me, I will either exchange the backs for some modified ones, or exchange the whole setup, for which I spent several thousands of dollars, for a 645 Pro TL.

Ferdi Stutterheim , Sep 15, 2002; 11:52 a.m.

The Rolleiflex SL66 has the same kind of back as the Hassy. The Rolleiflex SLX and 6000 cameras have a modern design and lack of film flatness due to bending is not a problem. Not in practise and not even in theorie.

Todd Frederick , Sep 15, 2002; 06:37 p.m.

This has been a useful discussion for me, and I hope for others. Forced me to look closer at how the film backs operate and focusing issues.

I still can't believe that the AFD puts that bend right in the center of the image frame. That is a very poor design.

I was reading the mamiya 645 AFD ad this morning to see if I could determine what kind of camera it is...the ad is very unclear. After reading it I did not know if it was film or digital. As you said, I guess it's both. That's a lot of money for a bad film winding design.

My studio friend used a Mamiya AF...I wonder if that earlier version had the same problem.

The Mamiya 645e does not have interchangable backs, but I'm seriously thinking of getting another one so I have color and B/W capability. They are compact and light weight. At that price it's one of the best camera buys around...in my opinion.

Thanks for all the help and suggestions.

Olivier Truan , Sep 17, 2002; 07:33 a.m.

This an update of what has been going on so far. I mentioned my problems on the Mamiya forum. Mamiya did not respond so far. I also complained to robertwhite.co.uk where I bought my camera. They responded within one hour and offered to exchange my backs for modified ones free of charge. This process takes 4 - 5 weeks. I am very pleased to learn that Robert White is not only the cheapest, but also offers great service. I will keep my system and will test the new backs - I'll keep you posted. Thank you all for your input!

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