Aperature location effect on Focus

[Emile J Schwarz]

I have a Kowa 480f5.3 and a noname 360f4 barrel lens' mounted on lensboards for a Calumet C1. I have never shot the camera or lens as both lens have no shutter or aperature. Last week I found out that 4"sewer pipe caps work great as lens ca ps. Sense then I have bought a shutter on Ebay; I can mount it on a "lens cap" a nd plan to use it both as a shutter and as aperature control. The shutter has a "30 mm throat", giving me a f16 or f11 wide open shooting aperature. Both lens' are about 4.5" long. I would like tofocus the lens wide open (without the lensca p/shutter) and then use the slideon shutter/aperature to shoot. Will the slideon shutter/aperature cause any focus shift?

[Pete Andrews]

Sounds like you've got hold of a couple of photocopier lenses there.

The only right place for an aperture is at the optical centre of the lens. Putting an aperture in front of, or behind a lens can cause barrel or pincushion distortion, as well as limiting the field-of-view. There'll probably be a focus shift too.By all means try it, but I wouldn't expect too much by way of image quality from those lenses with that arrangement.