G-Claron performance at 1:1

[Greg Davis]

……..

[Ken Lee]

If you plan to shoot 8x10, a 150mm lens isn't really the best solution. A 150mm lens will cover 8x10, but you're going out to the extremes of coverage. A longer lens will have a larger image circle, and you'll be using the sweet-spot or center. If you're set on using a G-Claron, the consider a 210/240mm/305mm/355mm length.

[Dan Fromm]

Ken, I'm with you, but note that Schneider claims a 150 will cover 378 mm at f/22 and 1:1. Less at larger apertures, of course.

Greg, the way to beat cos(theta)^4 is to use a longer focal length, greater working distance, and smaller angle.

[vinny]

I use a 305 g claron for close work on 8x10. Very good. I wouldn't go any shorter than that either.

[Graham Patterson]

Unless I am missing something with the chart, the X axis is in half-angle degrees, so 25 degrees is 50% at f9, 70% at f22 assuming something around a 50 degree angle of view. At 1:1 the angle should be smaller and with less fall off.

Now an 8x10 at 150mm from the subject will make lighting and metering something of a challenge, so I'd prefer something a little longer as well.

[Dan Fromm]

Graham, at 1:1, 300 mm (2f) from the subject to the lens' front node, which is more or less at the diaphragm. Small lens, tapered bellows (?), but possibly still a problem.