No idea if it'll cover 11x14 (I've read that it covers 8x10) or what it's performance would be if it does cover (for that matter, I have yet to use the lens), but I have a B&L 508mm f5.6 Tele-Anastigmat (some sort of aero mapping lens I believe). Because it's a tele, it needs less bellows draw. There was a seller on ebay who had a few of them for around $35 - some marks on the glass, and the aperture is iffy. And, its a big heavy thing so you either need a robust front standard or a brace.
Dan
I wonder what lens was on my llx14 Empire State originally. The lens hole seems bit small...
Probably a B&L Protar series VII, V ,IV or something like that.Originally Posted by cyrus
*Sigh* too late in the night to be doing math
Last edited by cyrus; 1-Oct-2011 at 21:48. Reason: bad puppy
late it is...but look at my post with the formulae you need and you won't have to keep doing all them calculations...particularly formula #2 for bellows draw
http://www.largeformatphotography.in...ad.php?t=81060
the forumua is s'=(1+M)*f
so knowing focal length f and the magnification you want is EASY to get the bellows draw (including distance to aperture/rear nodal point) you need...this is EXACT if measured to rear nodal point--which is pretty close to aperture in almost all cases and for LONG bellows, the amount your off in any case is tiny compared to the bellows you're drawing (percentage wise).
OH.....for 1:1 type magnifications, all lenses have the same depth of field....in fact, the longer lenses kind of have "more"...more front focus dof....I doubt you notice this with portraits....it's due to the changes in magnificaiton---a shorter lens has it's magnification change faster than a long lens with subject depth....don't bother with all that...just know that depth of field is pretty much independant of focal length at 1:1 regime.
Thanks Johnielvis - the problem I'm having now is finding a darn lens that I can do 1:1 with, but which draws 21" bellows, and which lets me keep the lens out of the subjects face (say, lens about 5 feet away from subject)
If anyone can solve THAT one, I'd be grateful!
Oh, and the lens should be relatively light not a monster, and it should not be rare as hen's teeth and cost about the same as a car.
OTOH I may try to extend the camera - add an extension to the track front and get a longer bellows . . . focusing would require really lloooooooooooong arms
yeah...you need a long camera--you want 60" at 1:1--you need 30 inch lens..... a mangnification of .5 gives you a pretty big field...much larger than head and shoulders so you'lll want to be using beween 1:1 and .5:1 range for 11x14.
you can get longer bellows for your camera or make an extension back--that is the best way---large cardboard box like I said...just use your camera back maybe for starters---huge box (black foam or dark corduroy or something on the inside)...tape the back to one side of the box and the lens to the other side--voila...focus by moving the whole contraption back and forth...you got a portrait camera.
distance to subject is (1 + 1/M)*f....
total distance is (1+M)*f + (1+ 1/M)*f = (2 + M + 1/M)*f
so if you want 60" to subject, you're working with 60" = (1+1/M)*f.....got a 21" lens, this gives 60" = (1+1/M)*21" OR M = .538....this gives you a viewing field of 11"/.538 by 14"/.538 OR 20.4" by 26.0"
the bellows for this is (1 + .538) * 21" = 32" about.....so get a 2 boxes...like 16x16x16 and put them together oblong to get 16x16x32 and you're in business with the 21" lens---special purpose camera--just tape the back on one side of the box and the lensboard on the other side...you'll be surprised how rigid it is...and easy to focus up and back..you'll need a table to put it on to slide it back and forth...but this will probably get more use than anything else you got if you like it....easily portable and you don't care if it gets wrecked (other than the back and lens).
The rear extension box is probably the quick n easy way to go to make this into an 11x14 portrait camera. (I have an old Century 10A studio stand that cranks up and tilts 'n everything.) I think a 10" box to start with, gives me a bellows of 31 inches. Question is how to build the box. I don't have woodworking tools or knowledge & I'd want this to be a permanent thing instead of carboard because I'd hate to put weight on it with a holder containing a sheet of wet glass and watch it collapse & fall off. I'd need at a min. a table saw and one of those thingies that makes wood thinner...oh and a plaid flannel shirt and a beard...
dude--cardboard is amazingly rigid---besides, if you put your wood back on it, that provides the structural support--that and the camera back..it will be just like wood only better because it's lighter--therefore more rigid--i recommend affixing the bottome of the box and the bottom of the camera on a long plank to make them one solid unit.
try a cardboard mockup--you will be AMAZED....12" square tube is amazingly strong and rigid when supported on the ends.
I've built a cardboard 8x10 as a mockup and am still using it...it's THAT good---make sure you put the corrugations axes along the lens axis...
just dont' get it wet--if you do...let it dry and it should be fine..and if affixed to a comon plank, you won't have to worry about wet collapses..the wood is the failsafe.
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