Leica III film leader trimming - theory of operation

[tmorgan]

Okay, I got a Leica III and had fun reading the excellent instructions on trimming the film

leader and loading.

<br>I trimmed and loaded and then I had fun shooting some rolls.

<br>Then I visited the local photo store and was describing how I was trimming the leader

and the owner whipped out a really low number serial Leica screw mount body and a roll

of film, whacked the leader *off completely*, made fun of me for the elaborate leader

trimming ritual and said "Here, wind this on".

<br><br>It worked fine.

<br><br>

That made me curious to know, what is the theory of operation here -- what is the

purpose of shaping the longer leader?

<br><br>Thanks for any info.

<br><br>&nbsp&nbsp&nbsp...Tom M

[Troll]

If you don't trim, then one of these days the camera sprocket teeth won't engage the film sprocket holes, chew up the film, and little pieces of film will get into the mechanism and lock up the works and you'll have a dead camera and a nice repair bill on your hands. Keep trimming -- it ain't worth the aggrivation or expense.

[jeff voorhees]

Hi Thomas-

 

I mean no offense to anyone here who may work in or own a camera shop but I have always wondered at the arrogance found in some of these places. It is as though they are in possession of some arcane knowledge and want to lord it over the uneducated. Sorry for the rant.

 

I've never put out the cash for an ABLON template but I find I trim pretty nice leaders using the tiny scissors in my small Swiss Army knife. I agree with Bill, Leitz must have known something about potential jams or damage by not trimming.

[todd frederick]

It's my understanding that in the LTM cameras there is a track into which the film needs to feed when you start the winding process. If the leader is too short, you will be trying to jam the film into that track without knowing it. A longer leader will allow the film to move smoothly into the track. Be sure the leader only extends from the film cassete when you load it. When you start winding, the full film will slide into the track. It's improtant. Also, when you start the winding, look at the sprockets to be sure the film is feeding correctly before you replace the bottom. Sometimes the take-up spool is not positioned securely and the spool will turn but the film will not advance. I learned the hard way. You will waste a few exposures, but it's worth it.

[cosina_snap]

Trim or pay later. You just need 4 inches of the trimmed leader. Make sure you don't cut in the middle of the sprocket hole and round off the cut in front of the hole. Doesn't matter if you round the start of the leader or not.

[todd frederick]

Correction to the above: If the take-up spool is not positioned correctly and does not engage the sprockets, the take-up spool WILL turn, but it will just keep on turning, and will not stop for proper spacing of the image positions.

[charles_stobbs3]

If I remember correctly a recent thread here decided you should cut 24 holes out of the top row (if you don't use a template).

[peter_a__nyc_]

Charles, I'm getting good results when removing 11 holes.

[peter_a__nyc_]

To clarify my previous post: Eleven holes plus the narrow factory trimmed leader, which is

about 8 already, makes a total of 19 holes from the end of straight-cut film.

[dan flanders]

Imagine my surprise when I first encountered the short leader phenomenon and tried to load my old III that had performed without a hitch since before WW2. That's right, the upper edge of the film jammed against something and the sprocket holes refused to engage the sprocket. I didn't notice whether the rewind knob was turning and thought I shot a whole load only to find a pile of film chips when I removed the baseplate. Forunately none got into the shutter. I had been spoiled by the ability to examine things before closing the M3 and had become complacent about proper film alignment. It was then that someone told me why I had gotten away with loading the short leader without a hitch. Anyhow, since then a small pair of scissors is standard in my kit and I am almost religious in trimming my leaders. Of course the best way is to trim them before even putting the cartridges in you kit and avoiding the chore in the field. All kinds of smart-asses will call you a sap but you can chortle to yourself anticipating the time THEY come face to face with Murphy's Law.

[huw_finney]

Try loading a non trimmed leader with the shutter on 'B' you can see the film crinkling, trim, you know it makes sense.

[tmorgan]

Thanks to all for the info, especially Bill.

<br>

I see the idea: With the sprockets engaging on one side only, a correct alignment is well

established by the long leader take up, before the sprockets on the other side begin to

engage.

<br><br>

&nbsp&nbsp&nbsp...Tom M

[richard s.]

I totally agree, trim. That said, on holiday recently I found myself without the means to

trim the film and a beautiful shot - decided to risk it and carefully loaded the film

untrimmed. Worked out fine and have since burned another couple of rolls (trimmed) with

no problems.

[david_maxwell2]

FYI - For the sake of completeness or in case one forgets the swiss army knife - you can load without the long trim without chewing film, IF you slip a thin card (e.g. business card) between the film and the shutter curtain, immediately after inserting the film into the camera. I've tried it but frankly it seems just as slow as trimming and thereﾒs always the risk of the card damaging the shutter. Plus you can trim your film leaders ahead of time, while you have to mess with the card each time. This method was shown in ﾓAmateur Photographerﾔ a couple of yearﾒs ago.

Cheers

David

[charcoal]

If you're desperate and have no means of trimming the leader, the following will work. Set the camera for a time (not bulb) exposure and release the shutter. Take off the lens, and you'll be able to guide the film properly into the film channel. Replace the lens,take the camera off the time exposure and proceed as usual.

[dan flanders]

For several years now I have used a supply of extra takeup spools. Make up a supply at liesure; trim the leader and stick the end into the takeup spool. Rewind the leader into the cartridge and wrap the combo in foil. All you have to do then is remove the foil, pull out the necessary leader length and drop the assembly into the camera. Obviously, assure that the sprockets are engaged and the sprockets are turning before replacing the baseplate. It has saved me much time and worry.