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RichS
Joined: 18 Oct 2001 Posts: 1468 Location: South of Rochester, NY
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Posted: Tue Feb 04, 2003 9:14 pm Post subject: |
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Okay, just for Les... I got it! And I'm glad I did. What a nice, interesting lens in an old Compur shutter... But it does lead to a few questions which I hope you can answer (or anyone else, the "just for Les" part is over )
This lens has two elements which could be front or rear. One is marked 32cm and 15.3cm. The other is marked 22cm. As I got it, the 15.3-32 is on the front and 22 in rear.
With both elements screwed in, it's as wide as it gets, so obviously 15.3. With either element alone, apparently the 32 or 22 as marked.
But, which elements should be in front when both are used? A quick check didn't seem to make any difference but I didn't loupe it either...
With one element alone, does it go in the front or rear, or does it make a difference? I've heard about other convertables where the single element should be in the rear. Is this always the case?
And one note about 8x10 coverage... The 22 & 32 configuration is fine. Nice & bright with a large image circle. But with both elements mounted for the 15.3cm, it only get's about a 10 inch circle. Not quite 8x10...
But still a really nice lens that will also work just fine on my GVII, so I'm happy...
Rich...
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Les
Joined: 09 May 2001 Posts: 2682 Location: Detroit, MI
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Posted: Wed Feb 05, 2003 2:34 am Post subject: |
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the theory goes that you want to block out as much extraneous light as possible. The fewer odd rays to bounce around inside the glass the better. Which is why the first lenses, and the way Ansel used combinable lenses is to put the glass in the back. This also makes it easier to put a strong yellow filter to cut down on color fringing in the front.
And yet I've seen B&L pamphlets that suggest the single element in front.
As to which element goes in back, I may be mistaken, but I think I remember that the planets align and world peace reins when the longer element is in the rear, but honestly, in the field when your going to go out on that stinking boulder in the middle of the river, you put the one you think your going to use in the back, and put the other one on so you can see the short version and descide without having to fumble with lens cells above granite in a trout stream more than necessary. |
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RichS
Joined: 18 Oct 2001 Posts: 1468 Location: South of Rochester, NY
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Posted: Wed Feb 05, 2003 3:56 am Post subject: |
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Ahh, yes, the filter in the front. I remember hearing about that too. I'll have to work on a font filter for this lens. Luckily, both elements are the same size...
If I read nothing about these, I would probably use the front element. It seems to make sense by keeping the dirt out of the shutter if nothing else. Plus, you can see what lens is on... But there must be a reason for popular opinion on convertables...
Hmmm... Can't wait for the planetary alighnment! I was never one for rules anyway, but it seemed like there should be a recommended way of doing it? Wonder what the chances of ever finding an original Meyer instruction sheet?...
No doubt, I'll be playing a bit with this lens and trying different combinations. First thing I'm trying tomorrow is to see what happens when I take off the rear element of one of the elements (yeah, that came out clear). When cleaning it, I noticed that both elements have a rear lens that almost looks like it's supposed to unscrew. Of course I did for the cleaning. But now I have to see what the lens will do without one of them...
This lens was worth it just for the curiosity and playing. If it takes decent photos, I'll wind up very happy. On the down side, it does have a very slight haze. On the up side, most of that haze is due to the coatings. This may be the first lens that's worthwhile to look into a proffesional cleaning?
Now if I only had some film, and film holders....
Thanks!
Rich...
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