Kent Shafer
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Posts posted by Kent Shafer
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I've had my Marchioni Tiltall for (gulp) about 50 years. Maybe 20 years ago, I replaced the top covering with automotive cork gasket material; don't remember what type of cement I used. It has worked fine ever since. I've used the tripod mostly with a Calumet monorail (rotating back) or Hasselblad so haven't needed to tip the head on its side.
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Here's a link to an online calculator you may find helpful: https://www.scantips.com/lights/subjectdistance.html
It shows that with a standard 24 x 36 mm sensor and a 500 mm lens, the subject distance will be about 21 times the size of a subject that just fills the short dimension of the frame.
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Got it—thanks!
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No, that is the version prior to the current style. The current one has been made since sometime in the 70s!
Thanks. Maybe this one's about the right vintage to go with my 1960 Technika IV, which is what I was hoping for.
Thanks again for all your help!
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Kent:
Depth of field is the nearest and furthest points of APPARENTLY sharp focus in front of the lens. This is determined by the focal length of your lens, the point focused on the aperture used and the circle of confusion.
Depth of focus is the area behind the lens where the image plane must be positioned.
Bob, yes, exactly right. Depth of focus, rather than depth of field, would seem to the relevant consideration in determining the precision required in camera construction.
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Your question relates to depth of focus, that is, the distance between the farthest plane in front (toward the lens) of the perfect plane and the farthest plane rearward from perfection within which the image will be in acceptably sharp focus. The answer depends on the focal length of the lens, the f/stop used, the subject distance, and one's definition of "acceptably sharp."
I'm no expert on this stuff, but I found your question interesting so took a look at the Wikipedia article on depth of focus. The article has various formulas for calculating depth of focus, including this simplified, rough-justice one that eliminates the focal length and subject distance variables:
t ≈ 2Nc,
where t is the total depth of focus, N is the f-number, and c is the circle of confusion (the "acceptably sharp" variable). A commonly used value for c for 4x5 film is 0.1 mm. Using that value, the simplified formula would yield the following depth of focus ranges:
f/4.5: 0.9 mm
f/8: 1.6 mm
f/22: 4.4 mm
Since those are total ranges, front to back, the margin for error in camera construction would be half the calculated amount. Say about plus or minus 0.5 mm for wide-open shooting. Using the good advice from earlier posters, it seems you could achieve much better precision than that.
Of course, hardwood will expand and contract a bit with changes in humidity, which could eat up some of the margin for error.
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Thank you!
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Hello, Mr. Salomon. You are so great to provide this service!
Could you please tell me the date of manufacture of my Technika, serial no. 68476?
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Nikon F and 55mm f/3.5 Micro-Nikkor (early, compensating version); Kodak Gold 200
The wonderful Tiltall tripod was invented by the sons of the inventor of the ice cream cone. You could read about its history here. I bought mine new in 1969.
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I used to have a Nikon 9000 connected to an old Windows Vista machine used only for scanning. When the Nikon died, I sent the whole shebang off to recycled-electronics-heaven and bought a Plustek 120. While I liked the Nikon better, the Plustek works fine, and I now have lots more free space on my desk. Life goes on, I guess.
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Three more old Yashica-Mat images from the streets of Detroit.
Desert Inn (Formerly the Algiers Motel, site of the infamous Algiers Motel incident.)
Hasselblad Guy
Speedy KAYO
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Back in 2010 I tried to do this myself with an 85mm PC. The cable seemed too short. As I maneuvered the parts this way and that, being very careful not to break the cable … I broke the cable. Nikon USA charged $300 for the repair.
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Nikon Wednesday 2022: #38
in Nikon
Posted
Nikon F, 105mm f/2.5, Kodacolor II