A few months ago, I asked a question on this forum about the picture taking qualities of the Componon (not Componon-S) 150 mm f/5.6 lens as a taking lens, including whether it was convertible as the Componon-S (very similar to a Symmar) is.
I can now report that I'm pretty happy with the results of using the rear group of the Componon by itself. I haven't measured precisely, but have reason to believe the focal length is similar to the 265 mm f/12.5 I've been quoted for the Componon-S rear group; using a 2.5 stop compensation from the whole-lens aperture scale, I've gotten good exposures and image size consistent with a 265 mm focal length. Detail and sharpness over the 4x5 field looks good, to my eye, at least in prints up to 8x10 (I don't have the space to process larger prints, nor paper to print on, nor the enlarger column height to crop at much higher magnification from 4x5), as well as in 2400 ppi scans. I've (so far) only shot at around f/22; using a monorail, there's little incentive to sacrifice DOF for shutter speed. Once I get my bellows translucency issues corrected, I'll likely experiment with smaller openings -- I should be able to stop down as far as f/107, though I'd surely be trading off resolution for DOF well before then.
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