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 Replies: 7 / Views: 2,004 |
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Pillar of the Community
United States
4132 Posts |
I've seen a few Apo-Rodagon-N sale lately... Reading the Rodenstock literature on them suggests they are a step up from the Apo-Rodagon-D, and truly apochromatic (or closer to it, if that means anything). Some of the focal lengths have max apertures of f/2.8 which is interesting to me in terms of avoiding diffraction.
Anybody (Ray?) used one before?
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Pillar of the Community
 United States
4038 Posts |
I tried a 90mm, which was right in line with my 75-105 favorite range for bellows work. It was a nice lens, but not as sharp as the 75ARD1 forward mounted. They list it as having optimum range of 2x...15x, which means .07x...0.5x in forward orientation. So it just comes into its optimum range around Dollar size, but Cents are outside the optimum range. If you want to do 2x...15x you can reverse it, but I'd rather use high NA microscope objectives. In order to get that elusive f2.8, you need to go with the 50mm or 45mm models, which will give you very short working distances if you can get the mag low enough for anything bigger than a Cent. So, bottom line is I cannot recommend them as there are IMO better alternatives for less $$...Ray
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Moderator
United States
23522 Posts |
The Rodagon-D's advantage lies in its' greater suitability to the specific purpose of imaging coins. Rodagon-N lenses are intended for magnifications of 2x and greater; it's out of its' sweet spot at the 0.5x-1x we usually use, wherereas the Rodagon-D lives at that range.
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Moderator
United States
23522 Posts |
Heh. How's that for a simultaneous hit?  |
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Pillar of the Community
United States
4038 Posts |
Good stuff there!
I want to add that I finally found a decent 75 Apo-Rodagon R and tested it out. I can't see any difference physically, optically, or in the results with coins vs the 75ARD1. I think the 75ARR is the same lens as the 75ARD1 just marked differently. The 75ARR is famous for its use in turnkey slide copiers and rated at 1:1...Ray
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Pillar of the Community
 United States
4132 Posts |
Interesting. I guess I'll give them a pass. I wonder if some of these 2x optimized Rodagons might be good for folks working with full-frame sensors...
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Pillar of the Community
United States
4038 Posts |
There is a good discussion of this on Photomacrography forum. Here is the link: http://www.photomacrography.net/for...3&highlight=I posted my opinion on that thread but will repeat here...my tests of both 75ARD1 and 75ARD2 show that the 75ARD1 is sharper even at 2x across the entire APS-C sensor. I did not test FF, but sharpness across the entire APS-C means the central 24mm square of a FF sensor will be sharp. The tests of others on the PM forum show that the 75ARD1 loses sharpness at the corners of a FF sensor, but the 75ARD2 maintains its (lower level) of sharpness across the whole FF. While this is interesting for some types of photography, since coins are round and don't extend into the corners, sharpness there is somewhat irrelevant. So, specifically for coin photography, the 75ARD1 is superior even on FF sensors. BTW, if you really want to try it out, I have a spare 75ARD2 that I am not using... Ray Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Pillar of the Community
United States
4132 Posts |
No, I trust you. :-) You're right that coins' roundness makes them effectively smaller targets for photography.
Did you have a thread somewhere where you recommended microscope objectives? I think that's probably my next step...
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Replies: 7 / Views: 2,004 |
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Posted 12/29/2012 9:07 pm
