Does anyone know the max. f.l. one can get to focus on a 4x5 Pacemaker CG or SG? I've never measured it and don't have it where I am right now (but I have a question right now!)

I know the minimum f.l. is different on CG vs. due to the fp shutter.

Thanks

Hi, Murray,

The maximum distance from a likely location of the second principal point of the lens to the film plane on a Pacemaker Crown Graphic is about 12.75" (this is with the front edge of teh front standard carriage just flush with the tips of the fully-extended bed track).

I believe that the focal plane on a Speed Graphic is about 0.75" further back (owing to the presence of the FPS) than that of the CG and thus we might suspect that the maximum focal length for focus at infinity on a PSG would be about 13.50" (343 mm).

Quote:

On 2006-11-14 09:05, Murray@uptowngallery.org wrote: Does anyone know the max. f.l. one can get to focus on a 4x5 Pacemaker CG or SG? I've never measured it and don't have it where I am right now (but I have a question right now!) I know the minimum f.l. is different on CG vs. due to the fp shutter. Thanks

Murray, it depends a bit on the lens and how you set it up. The longest standard issue lens for 4x5 Graphics (with and without FPS) was the 15"/5.6 TeleOptar (also badged TeleRaptar). Remember that telephoto lenses have shorter back focus than normal lenses of the same focal length. Also remember that the rear node of a most, not all, lenses of normal construction is very near the diaphragm. So a longer lens will work front-mounted than in shutter, and you can put a lens in barrel on an extension tube ...

And how close you need to focus makes a difference too.

Good luck, have fun,

Dan

OK, good info.

I was wondering if I'd need a lens box instead of a lens board. (15" nominal (376 mm engraved).

Thanks

According to Graflex Model History, on this site, the Crown max extension is 12 1/2 inches and the Speed is 12 3/4 inches. A 12" (305mm) anyone's will close focus to 25 feet on a Pacemaker Speed.