lens attachment

[David Woods]

I know this is a silly question, but how do you attach a Petzval lens to a lensboard, as they do not use shutters?

thanks

[Brian Stein]

Nice way:
have flange for lens. Attach flange with screws (usually three) to lens board, screw in lens. (like http://www.largeformatphotography.info/forum/showthread.php?t=32981)

Interchangeable way:
use a lens chuck / iris holder (like http://www.largeformatphotography.info/forum/showthread.php?t=56571).

Dodgy way:
have no flange. Drill tight hole in lens board, stuff lens in with duct tape or using thread cut into lens, do not point too far down. (or even epoxy in =-0 )

hope this helps

[Andrew]

there's another dodgy way to mount a lens without its original flange:

the brass barrel almost always has a wider area just in front of the screw thread that would normally attach to the flange.
if you cut a snug hole in a wooden board you can then use a few screws with wide heads set close in to the lens so that the heads clamp down on the brass.
just be sure to use some something like some felt as a washer to stop the screws digging into the brass.

the attachment shows a large~ish petzval screwed onto a homemade graflex board (made from a sheet of aluminium sandwiched between two pieces of MDF).
the screw heads and felt washers should be easy to make out.
this mounting method is VERY solid and I have no worries about the lens ever falling off the camera but it can be removed easily enough, and the lens isn't damaged.
.

[Brian Stein]

Neat.
off topic what is the recipe for your diy graphic lens board. the bend in the originals always put me off trying home made.

[David Woods]

Thanks Brian ands Andrew, I will actually be using a Graphlex board, sounds easy enough

[Andrew]

ahhh... the diy graflex board.

I start with a sheet of 1.6mm alunimium from the local hardware store and cut it to the dimensions of the graflex board. That sits as a flat sheet in the front standard and it makes a remarkably good light seal as is [so long as you've been very careful to keep it dead flat] I used 1.6mm because that's what was in stock and I was just lucky that it's very close to perfect on my camera.

Rather than trying to bend the aluminium to match the original boards, I cut a piece of MDF to the dimensions of the inner aperture of the standard and glue that to the back of the board. At that stage it looks and fits rather like a mutant version of my deardorff boards in the 'dorff. I like to think that the MDF gives the aluminium some support and makes it less likely to get bent out of shape.

if I was mounting a lens in shutter I'd probably just cut a hole and leave the outer face of the aluminuim alone but with the large brass lens I've added a sheet of MDF on the front so that there's more substance for those lens securing screws to bite into. And there's some small screws from the back into the front bit of MDF to make sure it stays put because it's a heavy lens.

does that make sense? if not I can post some picture

[Brian Stein]

perfect sense. thanks

[Frank Petronio]

One of those pipe clamp bands that uses a ratcheting screw drive will also work to keep your lens from falling out of the lensboard without a flange.

[Fotoguy20d]

I've done the pipe clamp method, front and back of the board, using a strip of silicone rubber sponge (the reddish stuff to some MIL spec I can't remember off top of my head). I've also done a variant of Andrew's method on smaller lenses using two half moons of wood, with slots for the screws so the wood will slide snug against the lens body. I've also just wrapped a bandana or silicone sponge around the narrow part of the lens (usually, removing one of the elements until the lens is in the board) and jamming it into a board with 3" diameter hole which I cut just for that purpose. With lens centered for balance, it's okay in a pinch, but I once had a heavy gundlach petzval slide out the back (I suppose fortunate it wasn't the front) and shatter the GG (fortunately, the fresnel was undamaged).

Dan

[David Woods]

I was wondering what I would use as a flange, a hose clamp makes perfect sense, thank you all for the advise.

Now the hard choice, picking a lens.