ID This Brass Lens

[Fotoguy20d]

Then I probably don't have the #2. Mine covers 8x10 at around 150' focus distance at f32 (from experience) and I thought it was longer. I also have a WP Manhattan optical RR to compare with.

[Steven Tribe]

#3 paraplanat has efl of 27cm and covers 8x10" and up to 11x13" at small stops. My list doesn't have any larger!

[Fotoguy20d]

Steven,

I believe you gave me a copy of that sheet back when I got the paraplanat (which I've only used once or twice). I'll need to look at the lens again and see which one it is.

I'll take some photos of this mystery lens - not that I really believe it would be so (since the barrel is engraved for the aperture scale), but maybe the aperture was added later using the waterhouse slot. The glass measures around 32mm diameter so at f8, that's around 10" focal length.

Dan

[goamules]

... but maybe the aperture was added later using the waterhouse slot. The glass measures around 32mm diameter so at f8, that's around 10" focal length.

The lens looks factory made with an iris to me. Unknow maker, there were probably hundreds of shops cranking these out, and most aren't named that I've seen. I've seen dozens just like yours, but none are marked with how made them, and all have slightly different engraving and such.

As far as the speed, you're saying the glass is about 32mm or 1.25 inch. You said it's a 10 inch focal length, so 10/1.25 = F8. How were you measuring the iris before when you said it's only 7/8 inch? You are supposed to look into the front glass, and measure the apparent size of what you see of the iris circle.

[Fotoguy20d]

Garrett,

That's the problem. When I look from the front, the iris is clearly smaller (maybe an 1/8" around) than the glass. And my perception is that the lens is dimmer than an f8 RR. Now that the hurricane has passed, I'm going to play with the lens and see how it compares.

Dan

[Fotoguy20d]

Here are two shots with this lens on 8x10 paper. First is at f8, the second at f32. Coverage is just shy of 8x10 at f8 (interesting how it swirls a bit) but coming in nicely by f32. I suppose Garrett is right and its just a no-name Aplanat, around 10 1/2" FL, covering 8x10 stopped down. I can live with that. It's a pity I blew the exposure on these - at f32, on the GG, the number above the door on the house across the street was nice and sharp.

Dan

[Ole Tjugen]

Rodenstock managed to get all the way to Serie L in Aplanats, so that's one of about a hundred possibilities.