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View Full Version : Aperture Scale for 150mm Graphic-Kowa or Computar


Old-N-Feeble
3-May-2015, 08:49
Does anyone have this lens in shutter with the correct factory aperture scale? Perhaps any 150mm f/9 non-telephoto scale will work? I believe these only came in Copal or Copal Press shutters but others are of interest too.

If you have one could you please post a scan of the F/scale? If the scale is on the front then just removing the front element and scanning the front of the shutter is fine. Thanks in advance!!
IanG
3-May-2015, 09:11
The scale off any 150mm (non Telephoto) lens will be OK you just don't need the apertures wider than f9. What's more important is what shutter are you using ? Presumably a Copal, the scale is on the side so would need to be removed to scan, I think someone posted one on this forum some time ago.

Ian.
Old-N-Feeble
3-May-2015, 09:25
The scale off any 150mm (non Telephoto) lens will be OK you just don't need the apertures wider than f9. What's more important is what shutter are you using ? Presumably a Copal, the scale is on the side so would need to be removed to scan, I think someone posted one on this forum some time ago.

Ian.

Really? I didn't know any 150 scale will be accurate. That makes mounting my barrel-mount lens into a shutter super-easy. :)

But are you sure that's true??
IanG
3-May-2015, 09:44
The f-stop is related to the focal length and the diameter of the aperture. f-stop = Focal length / diameter

In practice a 150mm lens might actually be nominal in reality it may be slightly longer/shorter say 148 to 152mm but the difference is inconsequential when it comes to the aperture.

I use a 150mm f9 G Claron in an AGI #0 shutter marked for an f4.5 75mm lens, so the actual f-stop is double the one marked,

Ian
Whir-Click
3-May-2015, 10:14
It may be a distinction without much difference in practice, but both the 150 and 210 Graphic Kowa and Kyvytar lenses are mechanically limited to f/9 in barrel and achieve f/6.8 in shutter. My 150 and 210 G-K lenses happily share the same S.K. Grimes engraved 6.8 shutter. Any Copal 1 6.8 aperture scale will work, and a 9 scale will probably be just fine.