l2oBiN
16-Nov-2012, 07:31
Having both the Fujinon A 240/9 and the Rodenstock Apo Ronar 240/9, I mounted them on an 8x10 to compare the coverage wide open (f/9). Since the Ebony Lens Tables (http://www.ebonycamera.com/articles/lenses.html) state the covering power of the Fujinon and Ronar are 336mm and 212mm respectively, I was expecting the Ronar to evidently lack coverage on 8x10 and the Fujinon to just cover the format. However, it appears that both the Ronar and Fujinon cover 8x10 with room to spare, with the Ronar running out of coverage first resulting from sufficient shift movement.
I am a little perplexed at this apparent inconsistency on the GG and I am wondering the reasons for these observations? Perhaps the apparent coverage could be attributed to circle of illumination rather than acceptable circle of resolving-covering power? As a side note, would the acceptable circle of resolving-covering power increase with stopping down of the aperture?
The following are the details of the Rodenstock Apo Ronar 240/9.
All black Copal 1 shutter with a Rodentock quality seal. It is labelled "Rodenstock Apo-Ronar sinar 1:9 f=240mm" serial number 10 325 9xx (MF date 1981-84 (http://www.ground-glass.net/large-format/rodenstock-lenses-age)). It does not have a "MC" sign on it and this is confirmed by single "yellow-ish" coating. Glass reflections are same on front and back cells and consist of B-S-S-B (B=big; S=small) reflections per cell.
I am a little perplexed at this apparent inconsistency on the GG and I am wondering the reasons for these observations? Perhaps the apparent coverage could be attributed to circle of illumination rather than acceptable circle of resolving-covering power? As a side note, would the acceptable circle of resolving-covering power increase with stopping down of the aperture?
The following are the details of the Rodenstock Apo Ronar 240/9.
All black Copal 1 shutter with a Rodentock quality seal. It is labelled "Rodenstock Apo-Ronar sinar 1:9 f=240mm" serial number 10 325 9xx (MF date 1981-84 (http://www.ground-glass.net/large-format/rodenstock-lenses-age)). It does not have a "MC" sign on it and this is confirmed by single "yellow-ish" coating. Glass reflections are same on front and back cells and consist of B-S-S-B (B=big; S=small) reflections per cell.