Mythbusted, Double exposures with III (c/f) ?

[pb908]

i had fix few IIIc and IIf/IIIf, as far as i can remember, neither of them can do double exposure properly. i believe this may "conflicting" with what you ever know (have you ever tried it ?)

the reason behind this fact is this picture below :

this is the lower side of film sprocket gear.
the top part is the mechanism that pull the film and the shiny one is the one which connects the drum mechanism. as you can see, there is linkage (notch) in the shiny part and a black notch in behind belong to the top part.

during cocking the film, the top part notch (black) will push and rotate the shiny notch from the lower part for 1 full cycle to the right. so the default position before and after cocking is the same as the picture (the black notch is behind the shiny notch). the different is the lower shiny gear is under tension due to shutter has been cocked.

what happen when you push the shutter button? it will push a rod inside the top part and will push the shiny part down. when the notch of the shiny part is disengage with the top one, it will (by the spring force of the drum) rotate 1 rotation in reverse to the cocking direction (at the same time, the 1st curtain opens, and the shutter dial in the top of camera is rotating). it will stop at the same position again. once you remove your finger from the shutter button, the shiny part again move up and their notch are engaging.
When you advance the film to the next frame, the top notch will push the shiny notch again. so normal condition = black notch behind shiny notch.

a quote from cameraquest ltm camera page says "if you want double exposures, ALL you have to do is turn the high speed dial in the opposite direction until it catches. That re-cocks the shutter, and you can take another shot"

in fact what will happen if i turn the speed dial on the top of camera is it will turn the lower shiny gear to the right (cocking direction) so the top part notch is left behind (not advancing the film). at the time when the rotation of shiny part is almost finished, the notch now is in the back/behind of the upper part notch, and as you continue move the speed dial until it "click", the lower notch will push the upper notch a little bit to the right => this means your film will be "advanced" a little bit.

so your 2nd exposure may just miss the original frame. as the proof, i search on the web and get few report :
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"I've read online, that all you need to do in order to take a double exposure with a Leica IIIf camera is to re-cock the shutter, and shoot again. I've done this, but it seems whenever I do it, the film partially advances, and causes and the second exposure only covers half of the photo. This also causes issues as there is now a partial shot that which spills over onto the adjoining empty frame."

from http://www.flickr.com/groups/leica_lllf/discuss/72157608682210718/

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"So I've been using a Leica IIIc for a while, and have finally found out how to make multiple exposures. The problem I have with it, is that each time I make an exposure and cock the shutter a second time, the film moves ever so slightly forward, actually a little more than a 1/4". It does this for every shot like this picture.."

from : http://www.thephotoforum.com/forum/beyond-basics/200539-double-exposing-leica-screwmount.html

===
what if you "hold" the film rewind know tightly while advancing the top dial ==> you will feel so hard to advance in the end of the cocking cycle, and you may rip off the film sprocket holes 🙁

another issue happen after that :
once you make the 2nd exposure, you push the shutter button and the shiny part will rotate a full rotation to the left, stop at the same position. once you remove your finger from the shutter button, the shiny part again move up and it still in the wrong condition (shiny notch behind the upper notch

So when you want to advance to the next frame, you will rotate the film winding knob "freely" almost 1 full cycle until the top notch behind the shiny notch, and from that point you will need to wind 1 more cycle until you hear the click sign of cocking is done. that's mean, after every multiexposure frame, you will lost the next frame as it will wind almost 2 frame for the next exposure.

so, did i busted the myth?

 

[pb908]

in contrary, i can do double exposure perfectly and safely with my M2 & M3.

 

[sevo]

... as you continue move the speed dial until it "click", the lower notch will push the upper notch a little bit to the right => this means your film will be "advanced" a little bit.

You are aware that doing a double exposure on most Leica II/III contemporaries meant pushing the rewind button and holding on to the rewind knob while advancing the transport? Compared to that, the Leica double exposure, while not entirely uncoupling the transport, doubtlessly was safe and accurate - and (just like on the former) the accuracy could be increased by taking up all slack and holding the rewind knob tight while cocking the shutter.

 

[pb908]

...the Leica double exposure, while not entirely uncoupling the transport, doubtlessly was safe and accurate..

try to hold the film tight and let's see if it will ripp the film hole off. this will lead to failure to advance the film afterward.
so how can we say it is safe mechanism if it can't entirely uncoupling the film transport?

and accurate ? everytime you try to do double exposure, you can choose to have the frames don't overlaps correctly + waste the next frame empty, or you rip off the film hole + waste the whole film empty.

i believe i see somewhere in zorki/canon (i forget), they made the shape of the lower notch not like a block but like a rail, so when it pass the upper notch, it will ride down and jumps the upper notch into the correct position. that's better & safer than leica II/III (f/c)

 

[colyn]

Double exposure in the screw Leica is done by turning the main speed dial counter-clockwise till it latches.. This does not turn the sprocket nor does it advance the film. There is no need to tighten the film or hold the rewind knob..

 

[Dralowid]

Age has clouded my memory and double exposures are something I haven't done for a very, very long time...

Colyn is very nearly right but he misses one element. On a screw Leica the sequences was always:

First exposure as per normal.

To reset the shutter for the second exposure depress the shutter release and while holding it down turn the shutter speed dial back counter clockwise (without lifting it). Once it is turned back as far as it will go (or just past the speed on which it was set), let go of the shutter release and you are ready for the next exposure.

The film will not have moved, all you have done is re-cock the shutter.

Not a clue what you'd do on an M6...but this is the ltm forum.

Michael

 

[pb908]

Age has clouded my memory and double exposures are something I haven't done for a very, very long time...

Colyn is very nearly right but he misses one element. On a screw Leica the sequences was always:

First exposure as per normal.

To reset the shutter for the second exposure depress the shutter release and while holding it down turn the shutter speed dial back counter clockwise (without lifting it). Once it is turned back as far as it will go (or just past the speed on which it was set), let go of the shutter release and you are ready for the next exposure.

The film will not have moved, all you have done is re-cock the shutter.

Not a clue what you'd do on an M6...but this is the ltm forum.

Michael

i agree Michael, that it is possible and maybe the best solution without any modification, but not that easy to be done as per the myth said. So either we can say the myth is busted and we can start a new myth that it is doable but not that easy.