apo-ronar

[terry_5379]

would a rodenstock 240mm f9 apo-ronar be better for enlarging 8x10 negatives than the rodenstock rodagon 240mm f5.6.

[N Dhananjay]

The Apo-Ronar is a process lens optimised for performance near 1:1 ratios. The Rodagon is an enlarging lens optimised for performance in the usual enlargement ratio. That is, a 50mm Rodagon meant for enlarging 35mm might be optimised for around 6-10X (i.e., to make 5x7 or 8x10 emlargements). A 240mm might be optimised for around 4X or so. So, technically, using an enlarging lens might yield better results. However, keep in mind that with large formats, even with the process lens you are not using the lens too much out of its sweet spot range. And the dialyte design is reputed to hold its corrections prety well over a wide range of magnification ratios as evidenced in the fact that many people use Ronars as taking lenses at near infinity distances. So, my own guess would be that you would be hard pressed to tell a difference at reasonable enlargement ratios. Variaions in results are more likely to result from variations in quality control or condition of the lens. Cheers, DJ

[Bob Salomon]

would a rodenstock 240mm f9 apo-ronar be better for enlarging 8x10 negatives than the rodenstock rodagon 240mm f5.6.
No. Among other problems using a process lens it is designed to perform optimally only at f22 and at 1:1. The Rodagon performs optimally over a wide range of apertures and is optimized to enlarge the original not make a 1:1 copy which is better as a contact print.