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View Full Version : 6 x 24 (~cm) or 2 1/4 x 9 1/2 ??



Daryl
07-04-2005, 08:06 PM
Like panorama?

I had my 120 'test roll' out doing some measurements and thinking of 6x17 again, when an old thought returned to me. Why not 6x24 ?? The image would be 9 1/2 to 10 inches long and there is a good 14 inches of leader on a 120 roll. Put the little red window in the right spot and shoot 3 frames per roll - 4, 8 and 12.

Anybody try this? Attached files http://f295.f295.org/uploads/4to16x24possible_7606.jpg (http://f295.f295.org/uploads/4to16x24possible_7606.jpg)

ImageMaker
07-04-2005, 09:17 PM
Yike!!

That way, you shoot more film even if you shoot fewer images!

I've have sworn you couldn't load a camera that wide without fogging the beginning of the first frame, but 14 inches of leader might be just enough (you could always put a length of that brown, water-activated packaging tape on the leader to extend it a few inches if necessary)..

No, I have no idea how you'd print or scan such a negative...

Tom Persinger
07-04-2005, 09:19 PM
use an 8x10 enlarger or a flatbed scanner!

:)
tp

ImageMaker
07-05-2005, 08:20 AM
Well, that's true -- my Arcus 1200 can scan 8x10 negatives on the glass (do all three frames from a roll of 120 in a single load), but then I have to contend with Newton rings. And my glassless carrier will only accommodate 120 up to 6x9 format.

And I will *not* consider an 8x10 enlarger -- my bathroom barely accommodates my 4x5 enlarger.

taco
07-05-2005, 04:48 PM
Like panorama?

I had my 120 'test roll' out doing some measurements and thinking of 6x17 again, when an old thought returned to me. Why not 6x24 ?? The image would be 9 1/2 to 10 inches long and there is a good 14 inches of leader on a 120 roll. Put the little red window in the right spot and shoot 3 frames per roll - 4, 8 and 12.

Anybody try this?
Marie No√ęlles panoramic camera shoots 4 pictures 6x18, that makes 3 pictures 6x24, but without having seen your camera I don't understand understand your counting: Where is the little red window in this camera? Left, middle or right? If it's left (seen from the backside) you are right, but if it's right, you are not left but wrong ;D . Then you should shoot frames 1, 5 and 9
taco

Daryl
07-05-2005, 09:45 PM
Right you are Taco. And DVZ's camera has the window in the center for 6x17 because it is a curved film plane in a rectangular box, so he uses 2,5,8 and 11.

Where the window resides dictates the sequence: 3(n), 3(n)-1 or 3(n)-2 where n is the negative frame number.

Daryl
07-06-2005, 09:05 PM
Uh-Oh.

Ran across this 11 x 4 inch Fine Box at the local 'A C Moore' crafts store.
There's plenty of room for a 120 roll to fit inside.
It was a 50% off sale, so the total came to $4.24.

60mm focal length is too short for 6x24. (53x 130-degree view on 6x24?)
As Iím pretty happy with the coverage of a 30mm on a 6x6 which gives a
90 x 90-degree view, a 125mm on 6x24 should give a 27 by 90-degree view.

If Iím going to use this box, I will have to figure out how to do an extension.
I just might get a second one of these boxes and stack them or a slightly smaller box to mount on the front like an extension bellows.

Wait a second, I like the idea of 50 x 120 degree view!
Anyone know how to make a home-made center filter??
Attached files http://f295.f295.org/uploads/newbox_7948.jpg (http://f295.f295.org/uploads/newbox_7948.jpg)

Tom Persinger
07-06-2005, 10:48 PM
that is one FINE box....

ImageMaker
07-07-2005, 09:45 AM
Why bother with homemade center filters? It's almost certainly simpler to make the camera to accommodate a curved film plane. You might need relfexing rollers (mounted on the "lid") to push the film "down" into the body and keep it tracking on the rails, but that's *still* going to be easier than making a center ND. And it'll save you a hundred bucks or more on filters unless you already have what you need.

Of course, you really only need a horizontal gradient -- how about stacking a pair of grad ND in opposite orientations? If you already have the filters, that might be cost effective.

Daryl
07-07-2005, 08:22 PM
There has got to be other ways to contend with the cosine fourth law.
I prefer the rectilinear. This is where I wish I had the tools to construct precision mechanicals.
My claytax showed how to illuminate with a lot of front rise. It's not a lens! Use tilt!
http://www.creativegalleries.com/duckworth/pinhole/claytaxpyramidoid/ClaytaxPyramidoid6x6.htm

If I could take the axis of the pinhole (coupled to a rocker following a sine function) and still maintain
center alignment, the pinhole would act like a lighthouse swinging back and forth in a 120 degree swath - spending more time out at the edges and moving quickly past center.

Or, better yet, the pinhole is at an angle centered in a rotating disk - throwing illumiation farther out on the film plane.

((What was the name of that vintage super-wide that had the propeller on the front that acted like a center filter?)) Attached files http://f295.f295.org/uploads/movingholew_2354.jpg (http://f295.f295.org/uploads/movingholew_2354.jpg)

ElrodCod
07-07-2005, 08:38 PM
Daryl, you made some great shots with your supercool Claytax. I'm looking forward to seeing what you work out with the Superwide Panorama. Brainstormin' rocks!

ImageMaker
07-07-2005, 08:56 PM
Daryl, moving the hole won't help you -- the film at the edges of a wide frame is still a lot further from the hole than at the center, so you'll still have inverse square law fall-off. With your proposed 6x24 and 60 mm focal length, you're varying from 60 mm to about 135 mm at the edges, which is close to 2.5 stops.

The "rocking" motion you suggest might work if you could make a slit at the focal plane have that kind of motion -- the simplest way I can see offhand is to use an electric motor to drive the slit with power delivered through a linear potentiometer powered from the center (so the slit would move fastest at the center, slower at the ends); microswitches at the ends would reverse the slit motion to it scans repeatedly.

Which seems a serious violation of the KISS principle...

Daryl
07-07-2005, 09:36 PM
. . . . Which seems a serious violation of the KISS principle...

Ah Hah! *:D Which is why I won't pose yet adding another dimension to the problem.

Well, I found a spare box left over from my Bondax construction that looks like it's a near perfect fit for either 90mm, 102mm or 127mm FL. (~around 36x109 degrees, ~32x102 degrees or ~26x90 degrees respectively)

What's the fall off there? Attached files http://f295.f295.org/uploads/witholdboxw_7639.jpg (http://f295.f295.org/uploads/witholdboxw_7639.jpg)

taco
07-08-2005, 05:53 PM
Daryl, you made some great shots with your supercool Claytax.


::)
I believe I missed a link somewhere. What in (hell or heaven, you have the choise) is this Claytax?????
taco)

Daryl
07-08-2005, 07:31 PM
(Taco, 4 posts above your last.)


Well, Ladies and Gentlemen,

I regret to inform you that after careful measurements of the inside room after positioning the spools, the largest I can go with this box is not quite 21cm. The air has departed the inflated balloon.

BooHiss!
This goes on the shelf labelled- *"Think about it for a while".
Maybe I'll make it a 6x17. *:-/

Now, there is someone out there with real tools that should come in here and seize the concept. *>:(

I know you are out there reading this and you know you're reading this too. >:(

ImageMaker
07-08-2005, 11:51 PM
Well, let's see -- with your original 60 mm focal length on 6x17, you'd have almost exactly 1.5 stops fall-off, which is just about acceptable for negative film. Push it out to 90 mm with that second box, and you'd have just under one stop. Throw in a half stop factor on top of your usual reciprocity correction and either one should produce acceptable negatives.

Of course, you could build the long box in a way that would let the film spools sit ahead of the (sharply angled) edges of the image space and still get 6x24 out of it (though it might be interesting to load). Think of the way the film spools are positioned in old box cameras (I know you have one or two of those) -- you might just get everything in, given the box is close to two inches inside depth. A 90 mm focal length on 6x24 would still only be about 1.5 stops and plenty wide angle for most folks...

Hint: build the works on the shallow piece and slip the deep one over it, instead of vice versa...