This idea i previosly posted in the bottom loading thread.

I don't like the slack of the film after loading. Sometimes i cannot see the rewind lever/spool move during winding. i wonder, if there were a spring in the rewind mechanism to tension the film if it would improve film flatness in the frame during use.

Would the film curve more under tension, i doubt it? of course the tension would be designed to be small - not enough to rewind the film, but enough to take up the natural slack in the film spool.

-- steve (leitz_not_leica@hotmail.com), May 30, 2002

Answers

Its enough to just turn the rewind knob to take up the slack. If you don't do this and cannot see the rewind knob turning, you can't really be certain that the film is advancing properly.

-- Robert Marvin (marvbej@earthlink.net), May 30, 2002.

After loading the film and attaching the back, and then shooting off to false frames, you should the use the rewind lever to tension the film. I do this, and my rewind lever movers, like it's suppose to, from the get-go.

-- Glenn Travis (leicaddict@hotmail.com), May 30, 2002.

if one is observant the natural curve of the film (like of a poster stored in a tube) in the film canister will spin the non-ratcheted rewind crank leaving the film slack-try it the next time you either rewind or load your film: when you rewind your finished roll let go of the crank. the lever will spin and one must take-up the slack in order to rewind further.

feel what i'm writing about?

-- steve (leitz_not_leica@hotmail.com), May 30, 2002.

Contax devised a vacum plate for the RTSIII camera to 'suck' the film absolutely flat. This makes some sense as small variations in the film plane will defeat all our attempts at accurate focusing and lens sharpness. From what I have read, the effect is minimal - perhaps on the first frame or two on the roll it makes a real difference.

-- raharris (porsche993@austin.rr.com), May 30, 2002.

With Leica M/R, first of all, after loading film, YOU must turn the rewind crank to tighten the film, until you feel tension, then continue to crank to film advance lever to bring counter to '1', during which time you should see the rewind crank rotates.

Leica camera DOES have spring to prevent the rewind crank unravel and thus keep the film always stretched.

This is not the case with many other cameras, with these cameras, even if you turn the rewind crank to take up the slack, but once you let go the rewind crank, it unravels rapidly.

Leica pays attention to small details. That is why Leica is such a nice system.

-- martin tai (martin.tai@capcanada.com), May 30, 2002.

With my M2/M3, once the rewind is tightened, it stays that way, exerting a back pull on the film to keep it tight. But with my M6, if you take up the slack on the rewind, it loosens right up when you let go.

-- Bob Fleischman (RFXMAIL@prodigy.net), May 30, 2002.

You can see the efect of tightening the rewind knob on the film, by taking a dud film with no lens on body, take a shot at the B setting (so you can see the film behind the shutter when looking thru the lens mount). Youll most likely notice that the film looks pretty flat anyway.

-- Karl Yik (karl.yik@dk.com), May 31, 2002.

Bob, M6 does not have rewind crank brake ? That is too bad, apparently Leica is cutting corners. I think all Rs still retain this feature

-- martin tai (martin.tai@capcanada.com), May 31, 2002.

"I don't like the slack of the film after loading. Sometimes i cannot see the rewind lever/spool move during winding. i wonder, if there were a spring in the rewind mechanism to tension the film if it would improve film flatness in the frame during use"

The spinning of rewind crank does not necessarily indicate slackening of film to cause film to curve. It depends very much on whether the film pressure plate presses on the film tight enough.

Like using glassless mask for 35mm enlarger, you put a roll of negative carrier, clamp down the mask to hold the negative frame tight, let loose the roll of negative, it rolls up at the carrier but in no way affect the flatness of negative.

Minox 8x11 camera works that way-- the film strip is taped to take up spool at one end, the other is complete loose in cassette, not secured to any spool ( unlike 35mm cartridge ); but Minox pressure plate holds negative tight, even one end of film strip is completely loose, it does not affect film flatness.

Most 35mm SLR ( Leica R included ) does not press on film hard enough due to film plane channel architecture which permit film to wonder back and forth within 200 micron channel; therefore, for those camera that does not have rewind crank brake, the spinning of rewind crank after tightenning does cause film curl; hence in order to prevent slackening of film, a rewind crank brake is necessary

I suspect that M6 has a tighter pressure plate then Rs, and the spinning of rewind crank may not cause film curl at film plane. on film,

-- martin tai (martin.tai@capcanada.com), June 01, 2002.