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View Full Version : 213 repromaster 11x14 coverage



johnielvis
29-Jun-2011, 20:38
it does NOT cover 11x14 at infinity---even with the trick of tilting the lens to get foreground and backhground in focus---I was hoping I could do that BUT the corners are dark--it LOOKS like it would cover with some machining work though---the vignetting comes from the front lens barrel---although it is only slightly longer than the front lens element to protect the lens glass, the lens sure wants to cover past this. I bought it to use as an enlarging lens but figured...hmmmmmmmmmmm may as well see if it works---got a packard shuttter...what the heck.

SO--some people say it covers, some people say it don't. I say it don't but may with some not-worth-it-to-do machining.

oh well--worth a try---it was cheap to get---and it's still an enlarger user anyways.

it was SHarp all the way to the corners when they got dark---

note only SLIGHT darkness though--this will work for "close" distances.

OH---f45 of course---

eddie
29-Jun-2011, 23:07
Tilting the lens Uses the coverage up fast.

I would try not tilting the lens, focus at something 8-15 feet away and stop way down. I do not know this particular lens but try this anyway.

Lachlan 717
29-Jun-2011, 23:54
Mine covers 7x17 (i.e. bigger image circle).

Slightly dark corners wide open, but gone when stopped down.

YMMV.

johnielvis
30-Jun-2011, 11:15
i thought tilting would increase the coverage--it must, since you're using the image cone cut at an angle---the coverage gets bigger--turns from coverage circle (parallel axis) to an even larger ellipse if I know my conic sections, and I think I do.

If one covers 7x17, the that's the one I want--probably slight different barrel or something--i can see the barrel metal vignetting the aperture in the corners at infinity--it vignettes the aperture at f45 too...so SOME light makes it to the corners, but they are dark an will only be lightened with mine by machining off the excess "shade" metal it looks like.

there are probably many versons of this lens---anyways, this one's for the 8x10 enlarger so no big loss....oh what am I talking about...BIG loss--i was hoping hoping hoping....blah

eddie
30-Jun-2011, 11:26
Tilting front uses IC very fast. Tilting the back helps preserve your IC when some movements are needed.

Arne Croell
30-Jun-2011, 12:44
i thought tilting would increase the coverage--it must, since you're using the image cone cut at an angle---the coverage gets bigger--turns from coverage circle (parallel axis) to an even larger ellipse if I know my conic sections, and I think I do.

If one covers 7x17, the that's the one I want--probably slight different barrel or something--i can see the barrel metal vignetting the aperture in the corners at infinity--it vignettes the aperture at f45 too...so SOME light makes it to the corners, but they are dark an will only be lightened with mine by machining off the excess "shade" metal it looks like.

there are probably many versons of this lens---anyways, this one's for the 8x10 enlarger so no big loss....oh what am I talking about...BIG loss--i was hoping hoping hoping....blah
Yes tilting the lens turns your image circle into an image ellipse in the film plane - however, the center of that ellipse is no longer in the center of the film but above it (if you tilted downward), i.e. your cone projects upward. The second effect eats up your image circle much faster than the first one enlarges it.

Mark Sawyer
30-Jun-2011, 13:19
The increase in area would be very slight at the shallow angles you'd be using, so it wouldn't help much. But you could use the front rise/fall to keep it centered.

There's some misleading information out about the coverage of process lenses, as they're meant to be used around 1:1, and manufacturer claims of coverage are often for that distance.

johnielvis
30-Jun-2011, 17:24
I tilted back then wanted proper allignment of verticals, so I tilted front and dropped the lens---it's the same thing as a tilted back with the camera "pointed down"--so you do get a bit more image area---anyways--the main thing is I got one and it don't -- but there's still claims that it works...so there's gotta be a couple of different designs--probably a slight difference that nobody can tell without looking at them right up next to one another.

like I said--any case--it's going on the enlarger where it belongs.