An 8x10 Revelationgreenspun.com : LUSENET : Large format photography : One Thread
I have recently started using an 8x10, and have only one lens for it (a 12" Commercial Ektar). It's great for general use, and since my camera has 31" of bellows draw, I can use it at 1:1 and a little beyond.
The tulips have been popping up here in Charleston these past weeks, and I wanted to do some close-ups. I nicked one out of the yard and got ready to shoot. Problem: you need to go well past 1:1 to fill an 8x10 negative with a 4" tulip. Not enough bellows. So what to do?
Turns out that I already had the lens I needed, in the form of my trusty 150mm Caltar, a lens that covers 4x5 at infinity. If you're smarter than me (and I pray that you are), you already see where I'm going.
The coverage of any lens INCREASES as you move it farther from the film plane. The circle of light coming out of the lens is really a cone. Move the film farther from the lens and you slice through a fatter part of the cone.
Turns out that the 150mm easily covers 8x10 at the magnification I was using. Exactly how much extension you need to make any given lens cover a given format will have to be determined by experiment. We could do it with trigonometry, but how much fun would that be?
Most lenses are optimized for use when the distance to the film is less than the distance to the subject. Anyone tried turning their lens around backward when going past 1:1? I guess you have to drill a hole in your lensboard so you can trip the shutter.
All of this is blindingly obvious to some of you, so just chuckle and move on. Everyone else, give it a try sometime!
I'm a little smarter today that I was yesterday, so now I get to take Sunday off. Next week's point to ponder: why do I keep my eyes tightly closed when I'm loading film holders in the darkroom? Hmmm.
-- Kevin Bourque (email@example.com), March 03, 2001
Haha! I keep my eyes closed too!
-- Paul Palka (firstname.lastname@example.org), March 03, 2001.
It's like dieting - the calories of the double fudge brownie don't count if you eat it with your eyes closed.
-- Sean yates (email@example.com), March 03, 2001.
"why do I keep my eyes tightly closed when I'm loading film holders in the darkroom? "
Cuz when you try do it with your eyes open, you get a hand-"eye" dissconnect - since your eyes are open, you expect to "see" what your hands are doing - , and it makes it harder to do. I do the same thing with a changing bag also :-)
-- sheldon hambrick (firstname.lastname@example.org), March 03, 2001.
Kevin: You may get all the shaprness you need with the Caltar without turning it around. An enlarging lens also works great at close distances as a camera lens. If you have a 135 or 150mm enlarging lens, give it a try. As for keeping your eyes closed while load film, I have caught myself doing it. Also, I find I keep my reading glasses on in the dark alot. I guess the reading glasses helps me not see anything close up.
-- Doug Paramore (email@example.com), March 04, 2001.
Eyes closed in the dark????......me too!! Weird isn't it! I've even found myself closing my eyes when using a changing tent...in daylight!! Paul
-- paul owen (firstname.lastname@example.org), March 04, 2001.
Just so long as you open them to focus.......
-- Sean yates (email@example.com), March 04, 2001.
Next week's point to ponder: why do I keep my eyes tightly closed when I'm loading film holders in the darkroom?---
I keep my eyes open but i don't look down. although sometimes there are some cool static discharges tearing the tape on roll film. ever watch someone using a changing bag or tent? they get that hilarious "cat in the litter box" expression!
-- Erik Gould (firstname.lastname@example.org), March 04, 2001.
Hmmmm...seems Kubrick was on to something when he made EYES WIDE SHUT...............
-- Wayne Campbell (email@example.com), March 04, 2001.
Aha! So its not only me who sees those damned static discharges from roll film - spooked the heck out of me the first time I saw it.
To answer Kevin's question about turning a lens backward, yes, I've used lenses this way. I use an enlarging lens which I screw into a Copal 1 with an adapter. When going greater than life size, the lens is better used turned around. You can get adapters made - Steve Grimes should be able to help you with that. I cobbled together the following set-up. I have a Canon FD reversing ring which was just the right fit for my Nikon enlarging lens. I drilled a hole through a Canon cap, put the adapter through the hole and screwed it into the Copal 1 and put the reversing ring on the cap and screwed the lens onto the reversing ring. Good luck. DJ.
-- N Dhananjay (firstname.lastname@example.org), March 05, 2001.
I don't close my eyes while I load film, but I have noticed the light discharge from pulling the tape off the 120 film before. It's neat looking!
-- Jason Janik (email@example.com), March 06, 2001.