A No. 0 close-up lenses? What's THAT?

xkaes

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Here it is. I don't have it, but it's obviously not a No.10. I can't find out anything about it. I have a Kenko No.5, so I know they use the typical diopter system -- unlike Minolta, which had a No.0 -- which is really a #0.94 (basically a #1).

Anyone know -- or care to guess?

 

Focomatter

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Appears that Kenko used arbitrary numbers like Nikon. Diopters are diopter units and thus not called number something. A diopter equals 1/focal length of the close-up lens in meters. A +1 diopter lens has a FL of 1 meter; a +2 diopter has a FL of 0.5 meters, etc.
 

ic-racer

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Yes the Minota "0" is the infinity lens which is a weak negative lens.

With respect to Kenko, I just waw they are making the close up lenses with magnetic attachment. I think I spent half my life screwing and unscrewing my Nikon close up lenses. I'm goning to look for a set of those Kenko. Though, as you indicated, they don't list a "0" lens on the website, so it is a mystery lens.
 
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reddesert

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Just measure the focal length yourself. Hold it some distance away from a wall or screen and move it toward and away until you get a focused image of some subject further away. Easier if you have a bright subject (like a flashlight several meters away) and the wall/screen is in shadow/darkness. When you get it in focus, the distance from lens to screen is close to the focal length, or you can use the lens equation with subject and image distances to be a little more accurate.
 
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xkaes

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As I said, I've got a Kenko No.5 and it is a #5 diopter lens with a 200mm focal length (1000/5 = 200), so I had assumed that Kenko did not have some strange coding system, like Minolta.
 
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xkaes

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ic-racer said:
Yes the Minota "0" is the infinity lens which is a weak negative lens.
Click to expand...

That Minolta No. 0 lens is for it's 16mm II camera. I'm referring to the Minolta No. 0 for their 35mm SLR cameras that were made in 49mmm, 52mm, and 55mm thread sizes. Unlike the distance lens for the 16mm camera, the 35mm No.0 was a close-up lens with a diopter of #0.94 -- a focal length of 1,063.8mm, and designed for longer than normal lenses.
 
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xkaes

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reddesert said:
Just measure the focal length yourself.
Click to expand...

I'd do that if I could, but as I mentioned, I don't have the lens -- "Here it is. I don't have it, but it's obviously not a No.10".

I just ran across it on-line, and was surprised since I had thought that Kenko used the diopter system of labeling.
 

ic-racer

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Ok I see them now.

 
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ic-racer

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Topcon also had a "0" for the 100 and 135mm telephoto lenses. Maybe, like the Minolta, a fraction of one.
 

reddesert

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xkaes said:
I'd do that if I could, but as I mentioned, I don't have the lens -- "Here it is. I don't have it, but it's obviously not a No.10".

I just ran across it on-line, and was surprised since I had thought that Kenko used the diopter system of labeling.
Click to expand...

You did say that in the opening line and I missed it entirely.

As various accessory makers have been around for a really long time (Kenko, Tiffen, and so on), perhaps not unusual if they've gone through multiple systems of naming. Smaller things like accessories are often less well documented, as no one devoted a lot of attention to them. (I just found a Nikor plastic film tank ... surely an obscurity, virtually un-googleable.)
 
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xkaes

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