Discussion in 'Leica and Rangefinders' started by Troll, Jan 16, 2019.
Is it really 24mm x 36mm, or is it a little less to allow space between the negative images?
I just measured a neg from an M6. It is 26mm x 24mm
That can't be right, that's basically square. You probably mean 36mm x 24mm.
Of course! 36mm x 24mm!
OK, so what is the distance across 8 perforations?
I suspect it is common to figure out film strip length, or exposures per roll, by using 36mm/frame.
A 100 foot, or 30.5m roll, should give 30500/36 exposures (847 for those without a calculator),
but that doesn't allow for tongues and such.
I haven't used bulk for a number of years, but the average 36 exposure roll of 35 mm film is 5 feet long - so, 100 / 5 = about 20 rolls yield from 100 feet of bulk.
I always figured 19 rolls, with 38 exposures, tongue, and enough to attach onto the spool.
But anyway, it is 2mm or so between frames, so maybe 38mm.
Depends on the camera AND lens. On my Barnacks, wide angle lenses produce a slightly larger negative than normal or tele lenses.
Yes, wide-angle lenses will make slighter wider frames on the film -- especially the older 21mm lenses that project deeply into the camera body. I used to have a 1963-vintage 21mm lens that made frames so wide, they were difficult to cut apart on the light table. When I traded up to a Leica M6, I replaced that 21mm with a newer model that didn't block the meter sensor with such a deep rear lens element.
Regarding bulk loading from 100 feet of film, I used to make 30-exposure rolls instead of the standard 20, 24, or 36 exposures. Why? Because when cut into six strips with five frames per strip, they fit into archival plastic film pages while leaving enough room at the top to write the roll number, date, and subject matter -- all fitting onto an 8x10 contact sheet. By contrast, a 36-exposure roll completely fills a plastic page without leaving room on the proof sheet for the information.
You need a leader, but not a tongue, in the sense one needed a curved leader for Leicas before their backs opened. It suffices to cut the leader square, with a full web separating the last sprocket holes from the end. With early bulk feeders you simply counted the turns. Later versions had a sprocket-driven frame counter. You can get 40 exposures into a cartridge without scrunching the film.
Early M Leicas clamped the leader under a leaf spring on the takeup spool. Later Leica added a slotted spool, and one simply slipped the leader in one slot, loading from the bottom. The Nikon F back was removed completely, and had a slotted spool with one tooth to engage the first sprocket hole, then wind the film emulsion side out. When rewinding, the leader slipped off those teeth without a hitch. Most amateur cameras in my time had a spring metal tooth, then wound the film emulsion side in. That tooth would often tear the last notch, leaving a bit of film to tickle the inner workings.
My archival pages are oversized, holding 7 strips of 6. I cut the rolls from the end to front, leaving one or more frames on the leading end, filling out the length with the blank leader to make it easier to handle. Commercial film usually has the capacity for 38 frames.
Yes, short or long tongue. I don't think it makes much difference, unless you load the camera
in the dark and trust the film to have always be kept dark. (Many come in transparent plastic cans.)
Most cameras that I know, need at least a little tongue. The slot only covers half the width.
The Leica spools I know have the spring covering half the spool, and enough
to make it harder to get a square cut end in.
The Canon QL, though, should do fine with square cut ends.
I found it easier with a long leader. I cut a longer leader.
Cut a diagonal off the leading edge. There's no need to get fancy. Even that was unnecessary with my Leica M2 and M3. You did have to remove the spool for loading. The base plate fit nicely in a shirt pocket or the palm of you hand, unlike the removable back of a Nikon F1.
If the camera winds exactly 8 perfs for every frame there should be about 2mm of space between frames.
That is what I thought.
Now, how big is the hole in enlarger negative carriers?
You don't want it exactly the size of the image, as misalignment will give a
black line in the print. Well, I suppose one should crop that off, but I don't remember
ever having a hard time getting the negative within the hole, with space between
frames coming through.
It would seem that the distance of 8 perfs should be well known, though.
I do remember that 126 film for instamatic cameras, and I believe also 110,
has pre-exposed frame boundaries, such that in printing, one never has to wonder
about what is outside the printing frame.
That depends on the carrier. Ones I've used, e.g., Besseler, are larger than the image area, but not large enough to show the sprocket holes. There were also glass carriers, essential for MF and up. I seldom used one, because there are 6 surfaces to clean instead of only two. If you belong to the "sprocket hole" cult, I suggest using a glass carrier.
The pitch of perforations on 35mm camera film is 0.1866". So 8 perfs is 37.91712mm. So the gutters between 36mm long exposures should be just shy of 2mm.
You are quite right to be suspicious. However, most companies--if they make any adjustment at all-- do that in the viewfinder, not the picture size on the film itself.
Separate names with a comma.