@jimgalli has posted here about Cirkut cameras -- IIRC he has at least one of the BIG ones (10" film). I seem to recall it's paper header and tail like 220, but that may be a modern accommodation for the rarity of original backing paper.
Don't neglect the challenges of developing film six inches wide. You could probably modify a Paterson or Jobo reel to do it in a regular daylight tank, but I envision some fun and games trying to load hand cut film into a reel (and with a Paterson, at least, you'd need the four-reel tank -- measured in 35 mm reel heights -- to accommodate a 6" wide roll). Then you'd still be limited to five feet of film at once, the length of a 35 mm or 120 roll.
Gears are specific to the actual measured focal length of the lens. There is a program that will calculate them, but you need to measure the exact focal length of the lens first. If there are no nail holes where the gear scale would have been on your camera, then your Cirkut back was likely added later. Fit varies, so make sure everything goes together smoothly, and you should check focus at the slit to make sure it matches the ground glass/film holder back. I assume this is a governor type Cirkut back (has a speed control)?
Do you have gears? How many, and which? It sounds like you have a rapid rectilinear type lens? Not a Turner Reich?
Even though it is not your long term interest, you will probably want to start with shorter pans to sort things out. These cameras are generally pretty fussy. It would be nice to get someone familiar with them to help check it out and get you up to speed.
Reading the manual for the 6 or 8 Outfit is a start.
If you have the paper degree band around your large gear (Cirkut tripod top), just look at the degree scale to find the approximate amount of film used for the focal length. Or run the camera dry with the clutch engaged and the largest gear for 360 degrees with the counter starting at zero and it will give you a very good idea of film pull for longer distance shots. Film pull depends on the gear used; closer, or longer focal length use a smaller gear and that will pull more film per pan.
Did you get a complete original kit with original lens and matching gears? If so it's quite easy to calculate film use. Put a piece of paper around the take up drum and cut it so it's an exact match for the circumference. Write the exact measurement down. Now every time the numbered gear makes a 360 revolution it pulls exactly that amount of film. The rest is math. How many teeth in the big sun gear. How many teeth in the drive hear. how many revs to make 360. Add up the numbers.
Send us pictures of what you've got. Pictures worth a 1000 words.
Gears depend on the exact focal length of the individual lens. Focus is by the ground glass, so if that is correctly matched to Cirkut back the focus will be fine, but the wrong gear will make things come out to wide or narrow though obviously sharpeness will be affected too. I have had fan and governor #6 Outfits (plus 8, 10, and partial 16" Cirkuts). My current #6 Outfit uses 52t and 51t for the original 8"/14" lens. You can just try and see how it looks. Try a short scene at 50 feet or so with you 51t; see how the width of the negative matches the ground glass. Obviously doing this near you darkroom is handiest; I take a view across my street from my porch for this purpose.
Originally there was a printed band around the rotating head that was marked in degrees that showed film pull for each rotation. They are often missing.
Even with original machined gears these can be fussy beasts. Mr. Galli has tamed a few of them.
Now for your 360 degree picture. Leaving out nitpicky details, a swing lens camera like your Al-Vista pivots the lens on its nodal point, so an 8 inch lens (about 203mm for the rest of the world) would be 8" from the film which would be held in a partial arc of a circle with an 8" radius.
The Cirkut camera usually is not pivoting on the nodal point of the lens, but simulates that with the gears pulling the right amount of film to correspond to circle of that circumference. With an 8" (203mm radius) you get a circumference of just a bit over 50 inches (about 1.25 meters), so your 360 degree picture should be about that long if focused at infinity. As you focus closer by extending you lens, it effectively becomes that much longer for this purpose, so your picture will be a bit bigger.
The Cirkut not pivoting on the lens nodal point complicates calculating gears for closer distance but works fine when sorted out.
I'm rusty at this so hope I haven't messed that up.
Really, the only limit is the energy available in the spring wound motor. In theory if it was electrified and your film load was much longer than standard you could keep right on going past the 360 point. The wider the angle the bigger the gear the faster the camera moves around the axis the less film used. From memory a 170mm lens would need a 66 tooth gear which is common from the bigger 10 outfits. I havent tried that because I have no interest in wide angle full circle shots.
Did you get a complete original kit with original lens and matching gears? If so it's quite easy to calculate film use. Put a piece of paper around the take up drum and cut it so it's an exact match for the circumference. Write the exact measurement down. Now every time the numbered gear makes a 360 revolution it pulls exactly that amount of film. The rest is math. How many teeth in the big sun gear. How many teeth in the drive hear. how many revs to make 360. Add up the numbers.
Send us pictures of what you've got. Pictures worth a 1000 words.
Enjoyed flipping through your pictures. Hey if the printed gear works consider doing gears as a side biz for the rest of us who are too retarded to figure out 3D printing.
So then for the sake of easy math, if you have 290 sun and 58 pinion, 360 degrees is five full revolutions. So if the circumference of the take up drum is 9 inches, it'll take 45" of film to make a 360 degree image. 58 tooth is a viable gear for a 190mm lens.
For testing I use 70mm Aviphot film. In the dark you just hand center it on the supply spool and wind a bunch on emulsion side out, tape directly to the take up drum, no paper leaders, and let her rip. 70mm is plenty to see for a test. Tell you everything you want to know. Unload in the dark and slide it into a piece of 2" ABS pipe for developing. Quick and dirty but you'll get information very cheaply that way.
Below are calcs I did for gears for my #6 outfit for all gears beginning at 24 teeth and ending with 66 teeth. Given in inches and mm focal length. So if you have a dandy old 210 G-Claron you go down the list and find it should work at infinity with a #53 gear. Etc. Don't lock yourself into using the original lens. These beasties seem to particularly love Artar's and other simple 4 element lenses. A 203 f7.7 Kodak would want a 55 tooth gear. If you focus at 50 ish feet instead of infinity you go to the next smaller gear because your lens has rolled forward 4mm etc. etc. 360mm = a 31 gear. Test test test with the 70mm film and once it's dialed in, use up some 6" or 5" film.
Gearcalcs6
Gear calcs #6 Cirkut = EFL where gear matches perfectly multiplier=438.46
gear EFL_inches EFL_mm
24 18.27 464.03
25 00000 000
26 00000 000
27 16.24 412.48
28 15.66 397.75
29 15.12 384.03
30 14.62 371.23
31 14.14 359.254
32 13.7 348.03
33 13.28 337.48
34 12.89 327.55
35 12.52 318.2
36 12.18 309.35
37 11.85 300.99
38 11.54 293.07
39 11.24 285.56
40 10.96 278.42
41 10.69 271.63
42 10.44 265.16
43 10.2 258.99
44 9.965 253.11
45 9.74 247.48
46 9.53 242.1
47 9.32 237
48 9.13 232
49 8.95 227.3
50 8.76 222.74
51 8.6 218.37
52 8.43 214.17
53 8.273 210.13
54 8.12 206.24
55 7.97 202.48
56 7.83 198.87
57 7.7 195.38
58 7.56 192
59 7.43 188.7
60 7.3 185.6
61 7.19 182.57
62 7.07 179.62
63 6.96 177
64 6.85 174
65 6.75 171.3
66 6.64 168.7
If you've built a film slitter, make up lots of 6" but use the 88mm leftover from the cut for testing. Good use of the leftover 240mm turned into 152. 88mm remains would work perfect for testing.
Below are calcs I did for gears for my #6 outfit for all gears beginning at 24 teeth and ending with 66 teeth. Given in inches and mm focal length. So if you have a dandy old 210 G-Claron you go down the list and find it should work at infinity with a #53 gear. Etc. Don't lock yourself into using the original lens. These beasties seem to particularly love Artar's and other simple 4 element lenses. A 203 f7.7 Kodak would want a 55 tooth gear. If you focus at 50 ish feet instead of infinity you go to the next smaller gear because your lens has rolled forward 4mm etc. etc. 360mm = a 31 gear. Test test test with the 70mm film and once it's dialed in, use up some 6" or 5" film.
Gearcalcs6
Gear calcs #6 Cirkut = EFL where gear matches perfectly multiplier=438.46
gear EFL_inches EFL_mm
24 18.27 464.03
25 00000 000
26 00000 000
27 16.24 412.48
28 15.66 397.75
29 15.12 384.03
30 14.62 371.23
31 14.14 359.254
32 13.7 348.03
33 13.28 337.48
34 12.89 327.55
35 12.52 318.2
36 12.18 309.35
37 11.85 300.99
38 11.54 293.07
39 11.24 285.56
40 10.96 278.42
41 10.69 271.63
42 10.44 265.16
43 10.2 258.99
44 9.965 253.11
45 9.74 247.48
46 9.53 242.1
47 9.32 237
48 9.13 232
49 8.95 227.3
50 8.76 222.74
51 8.6 218.37
52 8.43 214.17
53 8.273 210.13
54 8.12 206.24
55 7.97 202.48
56 7.83 198.87
57 7.7 195.38
58 7.56 192
59 7.43 188.7
60 7.3 185.6
61 7.19 182.57
62 7.07 179.62
63 6.96 177
64 6.85 174
65 6.75 171.3
66 6.64 168.7
Below are calcs I did for gears for my #6 outfit for all gears beginning at 24 teeth and ending with 66 teeth. Given in inches and mm focal length. So if you have a dandy old 210 G-Claron you go down the list and find it should work at infinity with a #53 gear. Etc. Don't lock yourself into using the original lens. These beasties seem to particularly love Artar's and other simple 4 element lenses. A 203 f7.7 Kodak would want a 55 tooth gear. If you focus at 50 ish feet instead of infinity you go to the next smaller gear because your lens has rolled forward 4mm etc. etc. 360mm = a 31 gear. Test test test with the 70mm film and once it's dialed in, use up some 6" or 5" film.
Gearcalcs6
Gear calcs #6 Cirkut = EFL where gear matches perfectly multiplier=438.46
gear EFL_inches EFL_mm
24 18.27 464.03
25 00000 000
26 00000 000
27 16.24 412.48
28 15.66 397.75
29 15.12 384.03
30 14.62 371.23
31 14.14 359.254
32 13.7 348.03
33 13.28 337.48
34 12.89 327.55
35 12.52 318.2
36 12.18 309.35
37 11.85 300.99
38 11.54 293.07
39 11.24 285.56
40 10.96 278.42
41 10.69 271.63
42 10.44 265.16
43 10.2 258.99
44 9.965 253.11
45 9.74 247.48
46 9.53 242.1
47 9.32 237
48 9.13 232
49 8.95 227.3
50 8.76 222.74
51 8.6 218.37
52 8.43 214.17
53 8.273 210.13
54 8.12 206.24
55 7.97 202.48
56 7.83 198.87
57 7.7 195.38
58 7.56 192
59 7.43 188.7
60 7.3 185.6
61 7.19 182.57
62 7.07 179.62
63 6.96 177
64 6.85 174
65 6.75 171.3
66 6.64 168.7
Jim, am I reading this right? Let’s say I use a 180mm lens. If I were to focus on something closer and had to expand my bellows to 210mm would I use a 53t gear? Or is this just for infinity?
Sorry for long delay. On vacation and discovered Photrio had been relegated to spam folder which I hope I have fixed. But yes. That's correct although unlikely. A 180 clear out to 210 would be like 5 feet away from the subject, but the general idea is correct. So much so that you can focus at infinity first, make a pencil mark, then focus on your object and make a second pencil mark and count millimeters to select the gear.
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