Rodagon 50mm f/2.8 APO-N, APO and non-APO; data sheets anyone?

[sandermarijn]

I know that all these lenses are excellent and that you are unlikely to spot any differences in print at all between them. But being somewhat of a greedy sucker I have come to own all three above lenses (they were free or downright cheap).

Frankly I don't go beyond 13x in 135, and I only print b&w, so it's probably for those reasons that I can't see any differences in prints from the three lenses. Out of curiosity I decided to look up the data sheets to check what the differences should be. The only thing I found was this data sheet on the Rodenstock site:

http://www.rodenstock-photo.com/medi...3-62__8230.pdf

The older 'APO non-N' isn't in there as neither is the 'current' non-APO (the Rogonar-s data are mistakenly listed twice).

Does anybody know the way to the data on these missing lenses? No big deal, just curiosity.

Interestingly BTW, in the above file the 4-element Rogonar-s and the APO-Rodagon-N seem awfully close in performance, at 10x enlargement and stopped down to f/5.6. Particularly the graphs for longitudinal chromatic aberration are suprisingly alike. Maybe the real differences only show up at 15x and beyond?

Thanks for any links/data.

Sander

[sepiareverb]

Give Rodenstock a call. I called them here in the US and got the most remarkable fellow on the line. Really went out of his way to answer my questions, then apologized that he couldn't send me the piece I was after as they were out of stock. I've not had phone help like that since I called Kodak in the early 90's.

[sandermarijn]

I was hoping for someone to have these data sheets lying around somewhere. I don't have too much faith in myself calling Rodenstock Germany about a product they likely stopped producing quite some time ago. Would I get laughed at? Nah, but I might laugh at myself, which is worse.

[PKM-25]

I have the non-N version of the 50 2.8 Apo-Rodagon, I have found several posts by HP Marketing rep Bob Salomon saying that the N versions are better in optical design and have multi-coating where as the older non-N versions do not. I only print in black and white and I doubt I would go over 20 x 24 in 35mm, has anyone seen a big enough difference to go with the N over the non-N version?

[sandermarijn]

I have both those lenses. Never seen a difference, that is up to 12x16"/30x40cm and stopped down to f/8 or so. Not that surprising really if you look at the available data sheets. A Rogonar stopped down would probably also be able to compete.

Beyond 13x I have little experience. Differences may show up there, I don't know. I once made a 50x70cm colour print (from 35mm Gold 200), using a Rodagon 50mm f/4, and it looked GREAT- certainly not the lens as a limiting factor.

[PKM-25]

I'll pick up the N along with the 50 2.8 G mural lens and 80mm F/4 Apo-N and sell the non-N Apo 50. The price the seller wants is right and I will have pretty much the perfect stable other than the missing mural lens for medium format.

[sandermarijn]

APUG'er john_s from down under has been so kind to provide me with the data missing from the Rodenstock pdf available online. Thanks a lot John.

From these figures (see below) it is clear that stopped down (f/5.6) and at moderate enlargement (10x) there will be no discernible difference between the regular Rodagon 50mm f/2.8 and the Apo-N version. No surprises there then. It's what most people see in practice as well.

If anything, at f/5.6 & 10x, the Apo-N is actually slightly (slightly) 'worse' (i.e. lower MTF) in the very centre of the image, and also has a bit more distortion. Not that anybody will be able notice, but still interesting to see how good the regular 50 Rodagon really is. Who needs an APO?

Obviously the Apo-N is all about wide-open performance. Maybe it's also better at larger magnifications, but then for the 20x range Rodenstock have a dedicated lens series (Rodagon-G) that will best both these Rodagons.





Anybody willing to trade their regular for my Apo-N?