Distance between leading edges

"Jack Middleton" wrote in message
...
Hi!

The other night I had this crazy idea of making my own back for the 120.
The idea is to make it versatile so that I can do some creative
experimentation with it without breaking my budget or other cameras. One
of the first obstacles is the film transfer mechanism. Ideally I would
like to switch between framesizes (645, 6x6, 6x7, 6x8, 6x9, 6x12, 6x17).
The last two will probably need a separate back though. The distance
between the leading edges of the images on the film is problematic. My
eyeball examination would give 48mm for the 645, 64mm for the 6x6, and
93mm for the 6x9 (in metrics as are the framesizes). Are these correct?
How about the other formats? Are the standardised somewhere? And the big
question: how to keep them even when the film is winding around the
spool? Any info/ideas appreciated.


Sinar makes a multi-format back called the 'Zoom'. Might be worth trying to
get a look at one to see how their mechanism works - it's probably possible
to hire them.


Peter

Hi!

The other night I had this crazy idea of making my own back for the 120.
The idea is to make it versatile so that I can do some creative
experimentation with it without breaking my budget or other cameras. One
of the first obstacles is the film transfer mechanism. Ideally I would
like to switch between framesizes (645, 6x6, 6x7, 6x8, 6x9, 6x12, 6x17).
The last two will probably need a separate back though. The distance
between the leading edges of the images on the film is problematic. My
eyeball examination would give 48mm for the 645, 64mm for the 6x6, and
93mm for the 6x9 (in metrics as are the framesizes). Are these correct?
How about the other formats? Are the standardised somewhere? And the big
question: how to keep them even when the film is winding around the
spool? Any info/ideas appreciated.

Jack

Jack Middleton wrote:
eyeball examination would give 48mm for the 645, 64mm for the 6x6, and
93mm for the 6x9 (in metrics as are the framesizes). Are these correct?
How about the other formats? Are the standardised somewhere? And the big

Only standard are what you want. Different companies tend to have a habit
of being a little different.

question: how to keep them even when the film is winding around the
spool? Any info/ideas appreciated.


Use a red window? For 6x12 count two 6x6 frame numbers. For 6x18 count two
6x9 numbers.

Nick

Nick Zentena wrote:
Jack Middleton wrote:

eyeball examination would give 48mm for the 645, 64mm for the 6x6, and
93mm for the 6x9 (in metrics as are the framesizes). Are these correct?
How about the other formats? Are the standardised somewhere? And the big


Only standard are what you want. Different companies tend to have a habit
of being a little different.


question: how to keep them even when the film is winding around the
spool? Any info/ideas appreciated.



Use a red window? For 6x12 count two 6x6 frame numbers. For 6x18 count two
6x9 numbers.

Nick

I most likely will stay clear of 6x12 and 6x17 in the beginning, so that
leaves the problem sizes 6x7 and 6x8 for which there is no support in
the medium itself. Unfortunately my camera can't handle those sizes, so
I can't even measure their properties. I wonder how picky is the machine
that processes the films.

Jack

Jack Middleton wrote:


I most likely will stay clear of 6x12 and 6x17 in the beginning, so that
leaves the problem sizes 6x7 and 6x8 for which there is no support in
the medium itself. Unfortunately my camera can't handle those sizes, so
I can't even measure their properties. I wonder how picky is the machine
that processes the films.


Do you mean develop the film? It doesn't care at all. A roll could have
one long frame on it. It's only when it comes to printing that it's an
issue. But with all the slight differences between the companies I can't see
it being that big of an issue. I think somebody did a thread awhile back on
frame size and various cameras. They all seemed slightly different.

Nick

"Jack Middleton" wrote in message
...

I most likely will stay clear of 6x12 and 6x17 in the beginning, so that
leaves the problem sizes 6x7 and 6x8 for which there is no support in
the medium itself. Unfortunately my camera can't handle those sizes, so
I can't even measure their properties. I wonder how picky is the machine
that processes the films.

Jack

Why not build your own back but use the dividing mechanism from say a Mamiya
Press back?

Mike wrote:
Why not build your own back but use the dividing mechanism from say a Mamiya
Press back?

Excellent idea! Seems like I'm going to start a search for wrecks for
parts to cannibalize. Had a look on that Sinar Zoom 2 Rollfilm Holder
that Peter mentioned, to create something like that would be perfect.

Jack

Nick Zentena wrote:
Do you mean develop the film? It doesn't care at all. A roll could have
one long frame on it. It's only when it comes to printing that it's an
issue. But with all the slight differences between the companies I can't see
it being that big of an issue. I think somebody did a thread awhile back on
frame size and various cameras. They all seemed slightly different.

Nick

Some backs let you change the format on the fly without changing the
film. I would guess printing those films would need a human to recognize
the frames or some fairly advanced recognition software. Most likely
the machine that does the printing will expect the frame to start
within certain narrow parameters. Would like to know what those are so
that I can make sure to stay within.

Jack

On Sat, 27 Mar 2004 14:15:28 +0200, Jack Middleton
wrote:

Mike wrote:
Why not build your own back but use the dividing mechanism from say a Mamiya
Press back?

Excellent idea! Seems like I'm going to start a search for wrecks for
parts to cannibalize. Had a look on that Sinar Zoom 2 Rollfilm Holder
that Peter mentioned, to create something like that would be perfect.

Jack

Another solution might be to use the Shen-Hao 6x12 back. Not a bad
price and it is multi-format, and has different windows for

6x4.5, 6x6, 6x9 and 6x12. The native format is 6x12 and comes with a
metal mask for 6x9. I guess you could order the other masks of have
them made.


- Mike

Back to go to what kind of front? ;-) The simplest and cheapest would be
to scavenge a folder, put in a mask (many were setup for using thin masks
already), and use the existing film winding mechanics (and bellows etc.?).
An example using "postcard" folders of the past for panoramic use could
easily be re-masked with 120 film for any size format, see
http://medfmt.8k.com/mf/postcard.html Some of the older folders also had
a ground glass insert you could focus with too ;-) And the lens could
usually be shifted up/down and tilted/swung in its mount, for much more
flexibility than current consumer cameras ;-)

instead of a back for a LF (or miniview MF) camera, you can simply use an
existing film holder and scavenge a spare dark slide to cut as a mask for
multiple shots (use a clear plastic overlay marked for the cutout position
on the ground glass for focusing/composition). This is an old trick with
panoramic shooters, use 6x12cm at top of frame, then flip the mask over
and use it to expose the bottom half of the same 4x5" sheet.

regards bobm
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