hints on improving film flatness in folders

I have a rather nice Kodak Monitor 620 Special (as has been

previously mentioned on this forum). I only ever buy cameras to use

and the Kodak is no exception. This means rerolling 120 film onto

620 spools which is a pain in the wotsit, so I like to maximise the

quality of the images I produce with it. The camera produces images

which are appreciably sharper than any of my 35mm equipment, but not

as sharp as produced by my Kowa super 66 or my Agfa super isolette.

I wonder whether the larger format ( 6 x 9 as opposed to 6 x 6 ) is

at least in part the culprit as a result of the film bowing. I

should say that I do stick fairly rigorously to using f16. Are there

any commonly used methods for improving film tension and/or flatness

in folders such as this?

Why don't you try shaving the ends on the 120 rolls? I had some fun at a friend's house with an old Agfa 620 camera. I took a box cutter and shaved the plastic reels down to the edge of the paper. I know others on this forum use files or a belt sander.

Often the back of the camera gets too much attention. Tension doesn't hold film flat, the pressure plate does. The Monitor, and all it's relations have the means to achieve flat film - two rails and a plate.

 

The front end must lock rigidly and consistently in the same place. This means no backlash, rattles or shakes. The other parameter is parallellism. The planes of the lens and film must agree. If not, the center can be sharp with a progressive softness extending to the edges with the long 6x9 emphasizing the problem.

 

Let's not forget the ever clever dimwit who, before you, lost/broke/forgot an element and slipped in a foreign one, thinking you wouldn't notice.

 

Finally, "it's not as sharp as my Fuji." No. Not today. Not next week. Not ever. But they can be awfully good and fun to use. No Hasselbladski will ever try to keep up with you leaping river rocks.

 

By the way, trim the spools with a pocket knife - dustfree.

Um, back when, the fiends at Modern Photography recommended putting a thin piece of glass in the gate of a Pentacon 6 to cure its film flatness problems. Don't know if the same can be done with a Monitor, but its worth trying.

 

Its lens should be better than the one (which? Apotar? Solinar?) in your Super Isolette, but (a) there is some variability within product line and (b) they're both old cameras and the Monitor may have had more/worse abuse.

Film flatness is an issue when some parts of the image is sharp and another - no. If the image is soft across the frame then there is possibly some other reason. Of the possible reasons: the lens are not parallel to the film (already mentioned), the infinity focus (hence all the focusing scale) is not adjusted properly, the shake of lens/shutter assembly (possible due to strong springs on, for instance, 3-blades Compurs) or just lesser contrast and the visual impression of less sharpness. Concerning the infinity shots I was told that in most front-cell focusing folding cameras the maximum performance of the lens is probably at medium distances (5-7m) and it is better to focus at this distance and stop down to f16-22 to cover infinity by the depth of field.

 

Normally, at f16 film flatness should have a minor effect, unless the pressure plate is really bad. I observed this issue on my Bessa with Skopar at f5.6 but then it disappears. There are several hints to improve film flatness: to wind film slowly and just before taking photo, not to let the camera front open quickly, some people recommend loading under the rollers (if there is enough room and if the surfaces are smooth).

 

In general all 6x6 folders I've tried (Super Ikonta with uncoated Tessar 70 f3.5, Balda with Ennagon 75mm f3.5) have better subjective sharpness+contrast and lpmm details under the loupe than any of 6x9 folders I've tried (uncoated Tessar 105 f4.5, Skopar 105 f4.5, coated Apotar 105 f4.5, Radionar 105 f4.5 Industar 110 f4.5) even in the sharp bits of the frame (if the film flatness was an issue). Possibly due to the larger coverage of 6x9 more compromises in lens design was required and flatter field curvature, not sure, but would like to know why.

 

Regards,

Jaroslav

I have in the past used a thin bit of foam behind the presure plate to give it a bit more push as the things get weak as they age. The resulting slides do look sharper. I have never tried to refine the technique to get the most out of it though.

I have a collimator which allows me to look through the lens while winding the film. I can see if the film plane is consistent. The biggest improvement to most folders that I see is to add drag to the supply spool. I usually do this by sticking those 3/4 inch diameter green felt pads (available at hardware stores to keep lamps from maring your tables) on the top or bottom of the spool. I use a 1/4 inch one hole punch in the center of the pad. Sometimes I have to place a pad in the camera for the spool pad to rub against. They have never left fibers on my film. This cures many problems of film flatness for just pennys. I would be glad to test your camera for you

to see if it needs this. You can test it yourself by putting in a test roll of film and leaving the back open. Wind the film and when you let go of the film wind knob, does the film supply keep moving?

There should be significant tension.