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Leaf Shutter questions for project camera



 
 
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  #61  
Old September 20th 04, 06:06 AM
Glenn Barry
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I had the same sort of camera built out of a Copal #3 shutter attached
to a plate, which was in turn attached to a horseman 6x9 revolving back
adapter for 4x5. Without the 4x5 camera plate obviously. Thichness was
spot on.

I used it to shoot a 16mm Sigma fisheye with the outher hood removed for
a full circle, before I bought a 8mm Sigma fisheye. The 16mm fisheye is
significantly sharper than the 8mm.

An easier version is to use a Mamiya Press Universal back, they are also
available for standard Mamiya RB and other 6x7 and 6x9 backs. The back
adapter is thinner, and with my upcoming incarnation will have swing and
tilt movements, when I can nail down a design I'm happy with. This will
need a copal #1 shutter for this capability, so vignetting would
probably occur with the PC Nikkor.

A copal #3 will virtually go straight on and should have no vignetting.

Though from a thickness and opening perspective a shutter between Copal
#3 and Copal #1 would be best suited.

I used an extension tube with the rear section removed and just threaded
into the Copal #3 to hold the lens, though I am going to change that
with a threaded piece from SK Grimes to make it thinner, and sturdier.

Glenn

Gordon Moat wrote:

Dan Fromm wrote:


. . . . . . . . . . . .

If you and especially BobM will go to
http://www.largeformatphotography.in...ic/499521.html
you'll see a discussion of front-mounting. The news from it is that
if the shutter can be placed much closer to the lens than to the film
plane adequate coverage can sometimes be obtained, i.e., even a
"small" shutter need not cause vignetting.



Great discussion link. That formula included for calculating vignetting really helps with
this. This also indicates that my thought of reversing the shutter to move the shutter plane
closer to the rear element is not a bad idea.



I don't think a cheap Afga folder is a good starting point for a wide
angle camera that uses a lens made for a 35 mm camera. Yes, you can
get them for very little, but you'll have to make a new short bellows,



There would actually not be any room for a bellows. The 46.5 mm mounting to film plane
distance, means that a somewhat flat plate fitting will solve the light tightness. The lens is
barrel focus, so moving the shutter and lens forward or back as a unit is not needed.


a new front standard,



Hard mounted shutter to body, with a bayonet mount on the shutter. Then the lens is supported
on the bayonet. I think most shutters should be strong enough that a mounting failure should
not be an issue. However, there may be some shutters that are not very strong, so maybe a lens
cradle might be an addition.


and something to hold it parallel to the film
plane and allow focusing travel.



Using Nikkor lenses with focusing helical built into them eliminates any need for a focusing
mount system on the camera. The PC-Nikkor shift lens also has shift capability built in, and I
have considered tilt movement as not conducive to hand held imagery usage.


6x9 folders are built to focus a
normal lens for 6x9, so are too long to make infinity with a lens that
makes infinity with its flange (Nikon example) 46.5 mm from the film
plane.



Yes, I would need to remove the lens mount, and the door from the folder body. After that, it
would no longer be a folder camera. The funny thing is that the Nikon lens on a shutter,
mounted to the folder body, is about the same overall length as the original folder in open
position. I still think that is fairly compact, though obviously the converted camera will
weigh much more.



You have access to a machine shop. You be better off making a
complete camera more or less from scratch than to try to rework a 6x9
folder.



I might actually do one like that, and just use an RB67 back (or similar). As a start, the
folder body is nice because the stamped steel construction is very rigid, and very compact in
size. Anything milled to hold film would be larger, and bulkier, though body weight might be
close.



I wouldn't try a long lens for a 35 mm camera in front of a Copal 1 on
my Century, as the shutter will have to be closer to the film plane
than to the lens' exit pupil. Even if the lens was capable of
covering 2x3 at infinity, the shutter would prevent that. That 35mm
lenses corner resolution is not as good as their central resolution is
a strong hint that they can't cover 2x3.



That is the tough part, that will only be confirmed by exposing some film. I am still leaning
towards a dummy, non working shutter at first (just a round lump of metal), and testing using
a lens cap shutter.



I wasn't being frivolous when I suggested you start from a Century
Graphic. I don't have experience with the 35 ApoGrandagon, but a
poster on www.graflex.org reports using one on a Century.



It should fit (the Nikkor shift lens), though it would be close. Of course, that is a much
larger camera body, and slightly tougher to use hand held.


The
shortest lens I use on mine is a 38/4.5 Biogon, next shortest a 47/5.6
SA. Its a shame that John Stafford didn't buy a Biogon from me when I
had a heap of 'em, also that you didn't.



I guess at the time I had not considered how I would use a wide view in my imagery, or my
work.


To reiterate what I've
already said many times, mine cover 84 mm with good sharpness and
illumination. They are optically the same lens as is used in the SWC,
mechanically somewhat different.



Oh, I do believe they are quite good. Also, I know the coverage I will get might not allow any
movements, though it is pieces already in my possession . . . so not a difficult experiment.
Besides, I will call this project an experiment, until I can figure out if it works well
enough for continued use.



I appreciate that since you have a 35 PC-Nikkor in hand, you'd rather
use it than buy another lens.



That was the most expensive part of this, though I have used this particular lens quite a bit.


So you're trapped in what is at best a
local optimimum. I susggest that you find the global optimum and
decide whether it is better enough than where you are now to be worth
moving to. It might not be, but you owe it to yourself to do the
exercise.



I am okay with finding that it might not work that well. I think some of the experience of
this could lead to other directions, or even better solutions. Building the first one is the
tough part.

Thanks for all your help, the great links, and the suggestions.

Ciao!

Gordon Moat
A G Studio
http://www.allgstudio.com/gallery.html Updated!

  #62  
Old September 20th 04, 09:12 PM
Gordon Moat
external usenet poster
 
Posts: n/a
Default

Glenn Barry wrote:

I had the same sort of camera built out of a Copal #3 shutter attached
to a plate, which was in turn attached to a horseman 6x9 revolving back
adapter for 4x5. Without the 4x5 camera plate obviously. Thichness was
spot on.


I think the Copal #3 is a good choice, and was one of the first dimension checks I investigated.
This shutter with Nikon bayonet mount was on a rare NPC made Polaroid camera. Unfortunately, Copal
shutters are also much more expensive than other choices, and tougher to find used without a lens
attached.


I used it to shoot a 16mm Sigma fisheye with the outher hood removed for
a full circle, before I bought a 8mm Sigma fisheye. The 16mm fisheye is
significantly sharper than the 8mm.


The fisheye lenses sound like interesting choices. I would have to imagine that distortion was
huge, though the images would have been unusual. Any chance you have some sample images on the
internet?



An easier version is to use a Mamiya Press Universal back, they are also
available for standard Mamiya RB and other 6x7 and 6x9 backs. The back
adapter is thinner, and with my upcoming incarnation will have swing and
tilt movements, when I can nail down a design I'm happy with. This will
need a copal #1 shutter for this capability, so vignetting would
probably occur with the PC Nikkor.


The Mamiya backs are more numerous at large sizes than others, and I still might go in that
direction. I would make a body smaller than 4x5 size, and much smaller than an RB, since I want
this to be mostly for hand held shooting, with occasional tripod usage.

I have dimensions for Copal #1 and the same size Copal Press. Even the Press version without
aperture blades (Polaroid macro cameras, some Oscilloscope cameras), comes too close to vignetting.
It might work for 645 sized film area, but not much larger. It might be that I only get good images
near 645 size, though the 6x7 or 6x9 back idea gives me more room to mask or just to crop the final
image frame.



A copal #3 will virtually go straight on and should have no vignetting.


Great, except the costs. I started looking into Alphax and Ilex shutters as alternatives.



Though from a thickness and opening perspective a shutter between Copal
#3 and Copal #1 would be best suited.


The shutter body thickness has been a slight issue. Shutters between those sizes are rare. The Ilex
#3 seems to be a good choice, and I just located one recently. I should have it within this week,
and then I can check fit and dimensions. The iris opening is 34.5 mm, and the front and rear
opening are about 45 mm and 48 mm respectively. I might also try out a reversed shutter mount to
get the shutter plane closer to the rear of the lens.

Front threading on a Copal #3 is 58 mm, and the Nikon bayonet ring outer diameter is 56 mm. The
match is close enough to easily fit one into the other. With a smaller Ilex, the idea is either to
use the four screws and mount it to the shutter face, or given enough material, machine it to fit
into the shutter. I will know more once I have the Ilex #3 here, and can do some mock-ups.



I used an extension tube with the rear section removed and just threaded
into the Copal #3 to hold the lens, though I am going to change that
with a threaded piece from SK Grimes to make it thinner, and sturdier.


I was also thinking of cannibalizing an extension tube. Another option is a broken Nikon parts
body, and pulling the bayonet mount off that. On the rear, I want to have as close to a flat plate
design as possible. Hopefully, I can come up with a design that can be compact, and easy to
duplicate.


Glenn


Thanks Glenn!

Ciao!

Gordon Moat
A G Studio
http://www.allgstudio.com Updated!

  #63  
Old September 20th 04, 09:12 PM
Gordon Moat
external usenet poster
 
Posts: n/a
Default

Glenn Barry wrote:

I had the same sort of camera built out of a Copal #3 shutter attached
to a plate, which was in turn attached to a horseman 6x9 revolving back
adapter for 4x5. Without the 4x5 camera plate obviously. Thichness was
spot on.


I think the Copal #3 is a good choice, and was one of the first dimension checks I investigated.
This shutter with Nikon bayonet mount was on a rare NPC made Polaroid camera. Unfortunately, Copal
shutters are also much more expensive than other choices, and tougher to find used without a lens
attached.


I used it to shoot a 16mm Sigma fisheye with the outher hood removed for
a full circle, before I bought a 8mm Sigma fisheye. The 16mm fisheye is
significantly sharper than the 8mm.


The fisheye lenses sound like interesting choices. I would have to imagine that distortion was
huge, though the images would have been unusual. Any chance you have some sample images on the
internet?



An easier version is to use a Mamiya Press Universal back, they are also
available for standard Mamiya RB and other 6x7 and 6x9 backs. The back
adapter is thinner, and with my upcoming incarnation will have swing and
tilt movements, when I can nail down a design I'm happy with. This will
need a copal #1 shutter for this capability, so vignetting would
probably occur with the PC Nikkor.


The Mamiya backs are more numerous at large sizes than others, and I still might go in that
direction. I would make a body smaller than 4x5 size, and much smaller than an RB, since I want
this to be mostly for hand held shooting, with occasional tripod usage.

I have dimensions for Copal #1 and the same size Copal Press. Even the Press version without
aperture blades (Polaroid macro cameras, some Oscilloscope cameras), comes too close to vignetting.
It might work for 645 sized film area, but not much larger. It might be that I only get good images
near 645 size, though the 6x7 or 6x9 back idea gives me more room to mask or just to crop the final
image frame.



A copal #3 will virtually go straight on and should have no vignetting.


Great, except the costs. I started looking into Alphax and Ilex shutters as alternatives.



Though from a thickness and opening perspective a shutter between Copal
#3 and Copal #1 would be best suited.


The shutter body thickness has been a slight issue. Shutters between those sizes are rare. The Ilex
#3 seems to be a good choice, and I just located one recently. I should have it within this week,
and then I can check fit and dimensions. The iris opening is 34.5 mm, and the front and rear
opening are about 45 mm and 48 mm respectively. I might also try out a reversed shutter mount to
get the shutter plane closer to the rear of the lens.

Front threading on a Copal #3 is 58 mm, and the Nikon bayonet ring outer diameter is 56 mm. The
match is close enough to easily fit one into the other. With a smaller Ilex, the idea is either to
use the four screws and mount it to the shutter face, or given enough material, machine it to fit
into the shutter. I will know more once I have the Ilex #3 here, and can do some mock-ups.



I used an extension tube with the rear section removed and just threaded
into the Copal #3 to hold the lens, though I am going to change that
with a threaded piece from SK Grimes to make it thinner, and sturdier.


I was also thinking of cannibalizing an extension tube. Another option is a broken Nikon parts
body, and pulling the bayonet mount off that. On the rear, I want to have as close to a flat plate
design as possible. Hopefully, I can come up with a design that can be compact, and easy to
duplicate.


Glenn


Thanks Glenn!

Ciao!

Gordon Moat
A G Studio
http://www.allgstudio.com Updated!

  #64  
Old September 20th 04, 09:12 PM
Gordon Moat
external usenet poster
 
Posts: n/a
Default

Glenn Barry wrote:

I had the same sort of camera built out of a Copal #3 shutter attached
to a plate, which was in turn attached to a horseman 6x9 revolving back
adapter for 4x5. Without the 4x5 camera plate obviously. Thichness was
spot on.


I think the Copal #3 is a good choice, and was one of the first dimension checks I investigated.
This shutter with Nikon bayonet mount was on a rare NPC made Polaroid camera. Unfortunately, Copal
shutters are also much more expensive than other choices, and tougher to find used without a lens
attached.


I used it to shoot a 16mm Sigma fisheye with the outher hood removed for
a full circle, before I bought a 8mm Sigma fisheye. The 16mm fisheye is
significantly sharper than the 8mm.


The fisheye lenses sound like interesting choices. I would have to imagine that distortion was
huge, though the images would have been unusual. Any chance you have some sample images on the
internet?



An easier version is to use a Mamiya Press Universal back, they are also
available for standard Mamiya RB and other 6x7 and 6x9 backs. The back
adapter is thinner, and with my upcoming incarnation will have swing and
tilt movements, when I can nail down a design I'm happy with. This will
need a copal #1 shutter for this capability, so vignetting would
probably occur with the PC Nikkor.


The Mamiya backs are more numerous at large sizes than others, and I still might go in that
direction. I would make a body smaller than 4x5 size, and much smaller than an RB, since I want
this to be mostly for hand held shooting, with occasional tripod usage.

I have dimensions for Copal #1 and the same size Copal Press. Even the Press version without
aperture blades (Polaroid macro cameras, some Oscilloscope cameras), comes too close to vignetting.
It might work for 645 sized film area, but not much larger. It might be that I only get good images
near 645 size, though the 6x7 or 6x9 back idea gives me more room to mask or just to crop the final
image frame.



A copal #3 will virtually go straight on and should have no vignetting.


Great, except the costs. I started looking into Alphax and Ilex shutters as alternatives.



Though from a thickness and opening perspective a shutter between Copal
#3 and Copal #1 would be best suited.


The shutter body thickness has been a slight issue. Shutters between those sizes are rare. The Ilex
#3 seems to be a good choice, and I just located one recently. I should have it within this week,
and then I can check fit and dimensions. The iris opening is 34.5 mm, and the front and rear
opening are about 45 mm and 48 mm respectively. I might also try out a reversed shutter mount to
get the shutter plane closer to the rear of the lens.

Front threading on a Copal #3 is 58 mm, and the Nikon bayonet ring outer diameter is 56 mm. The
match is close enough to easily fit one into the other. With a smaller Ilex, the idea is either to
use the four screws and mount it to the shutter face, or given enough material, machine it to fit
into the shutter. I will know more once I have the Ilex #3 here, and can do some mock-ups.



I used an extension tube with the rear section removed and just threaded
into the Copal #3 to hold the lens, though I am going to change that
with a threaded piece from SK Grimes to make it thinner, and sturdier.


I was also thinking of cannibalizing an extension tube. Another option is a broken Nikon parts
body, and pulling the bayonet mount off that. On the rear, I want to have as close to a flat plate
design as possible. Hopefully, I can come up with a design that can be compact, and easy to
duplicate.


Glenn


Thanks Glenn!

Ciao!

Gordon Moat
A G Studio
http://www.allgstudio.com Updated!

 




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