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 Replies: 12 / Views: 2,641 |
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Pillar of the Community
United States
4038 Posts |
There are several versions of Apo Rodagon-D lenses:
120mm (120ARD): a relatively rare but good performing and possibly truly apochromatic lens that can cover large formats
75mm f4.5 1:2 (75ARD2): a strong performer that while not truly apochromatic, is a very well-corrected achromat with a wide coverage. Is an excellent lens for coins on FF sensors as it performs well from 1:4 up to 1:1 when mounted normally
75mm f4 1:1 (75ARD1): a top performer for smaller sensors. Not truly apochromatic, but has better center sharpness than the 75ARD2 so better suited for full coin imaging on APS-C.
The 75ARD1 was used in several high-end scanners due to its enviable property of being very sharp at maximum aperture. As those scanners are being retired the lenses are removed and make their way onto the used lens market. For scanner use there was a version of the lens built without variable aperture, since there is no real need in a fixed-purpose application to go for the expense of a variable aperture, and the lens performs well wide-open. This fixed-aperture version has the same optics as the variable version but can often be had at a big discount.
The fixed aperture is limiting in that you can't stop-down for improved depth of field. This makes critical focusing more important to ensure good focus on all levels of the coin, or in some cases may require you to do focus stacking. Because of this, the fixed aperture lens is recommended for more advanced users who are looking for best image quality and are OK with taking more time to get it.
From now on I plan to be specific and call out the two version separately...75ARD1F for fixed, and 75ARD1V for variable aperture.
Edited by rmpsrpms
05/07/2016 09:14 am
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Pillar of the Community
United States
1314 Posts |
Thanks Ray. I've been putting off the purchase of a Rodagon D lens, simply because of the cost. But when the opportunity arises, I will now be able to make the appropriate choice.
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Pillar of the Community
United States
627 Posts |
I noticed there are three used 75ARD1F lenses available on ebay now for $136 each BIN, or $98 starting auction price. The seller is solidscapeguru, and the auctions end in 20 hours or so. Just do a search for "APO Rodagon 75" and you should be able to easily find them. That's a pretty nice deal if you are okay with using a fixed aperture version of the lens. I believe I paid around $250-300 for each of my 75ARD1V lenses in mint condition (I bought a 2nd because I knew I loved the lens and wanted to make sure I covered my bases for the future). |
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Pillar of the Community
 United States
4038 Posts |
solidscapeguru is the only source I know of for the 75ARD1F. All the ones I have are from him.
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Pillar of the Community
United States
1298 Posts |
Would this lens be Ok for dollars? Thanks.
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Pillar of the Community
United States
4038 Posts |
The 75ARD1F/V has great central sharpness but the corners start to degrade at lower (and higher) magnifications. It was optimized for around 1:1. That said, coins are round and flat so are the easiest objects to image from an optical perspective. They don't tax the lens at the corners, since they have not corners (well, most don't). So you can get away with using this lens at 1:2 or even 1:3 and it will still be a good performer. Dollars on APS-C require around 1:3. That said, the fixed aperture won't let you optimize depth of field, so you will end up having to critically-focus your shots and make sure the coin is very flat vs the sensor, unless you want to focus stack. What the variable aperture lens does for you is to give better depth of field at the expense of sharpness, but for magnifications around 1:3 this is not a bad tradeoff. At 1:3, the effective aperture is f5.2, which is still within the DLA of most cameras. If you stop down a 75ARD1V to f5.6, the effective aperture is f6.8, which is right on the edge of DLA for 18MP cameras. For the Canon XS, you can stop down to f8 and still not be diffraction limited, but the depth of field will be much better than at f4.
So bottom line, you may not want to use the 75ARD1F for Dollars since its higher resolution will have not benefit at the lower magnification, and the reduced depth of field will create more work (harder focusing, or need to focus stack) than you would have to go through if you had a variable-aperture lens.
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Pillar of the Community
United States
1298 Posts |
Thanks Ray for the informative review. Saved me $$$. Hamm.
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Pillar of the Community
United States
949 Posts |
Quote:
There are several versions of Apo Rodagon-D lenses:
Ray, I recently purchased an Apo Rodagon-N lens, thinking it was the Apo-Rodagon you had been discussing and illustrating on this list. What is the difference between your D and my N? Can I use the N for coins, or is it for more 3D objects like bugs? Edited by lrbguy
05/15/2016 4:37 pm
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Pillar of the Community
United States
4038 Posts |
Apo Rodagon-N is Rodenstock's top enlarging lens line. Like most enlarging lenses, the ARN's are optimized for from 2:1 to 20:1 enlarging ratios. This means they are best as a taking lens up to 1:2 magnification. Beyond 1:2, the ARD's take over up to 2:1 magnification. If you're shooting mostly around 1:2 (ie Dollars) then the ARN will do very well. If you push it up to 1:1 or higher, the ARN will have a little image degradation, though I suspect it will still be a strong performer.
What focal length did you buy?
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Pillar of the Community
United States
949 Posts |
In view of what you are saying I wish it had been a 105. It is a 75.
Thank you for the response. Since the vast majority of ancients have flan sizes well below the size of a dollar (down to 6 mm) it looks like I'm still in the market for a 75ARD1.
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Pillar of the Community
United States
4038 Posts |
I've never seen a 75ARN, and didn't think they made them. I've only heard of 45/50/80/90/105/150mm versions. Are you sure it's actually a 75mm Apo Rodagon N? Could it be a Rodagon R?
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Pillar of the Community
United States
949 Posts |
Quote:
I've never seen a 75ARN, and didn't think they made them. I know the feeling. It isn't listed on their website roster of lens types either. But here it is:   Since it isn't on the charts, I am not 100% sure of the specs. But the shape of the lens is wrong for a duplicating (75ARD1). Don't know about the 75ARD2. Perhaps? |
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Pillar of the Community
United States
4038 Posts |
There are a lot of lenses made by Rodenstock that I can't find listed. The Scitex lenses, and some versions of the Magnagon, so I'm not surprised at this one. I just thought the ARN series was mainstream enough that they had all of them documented. May have been a special build, like the Scitex lenses. It does look like any of the ARN ARD ARR series, so nothing too weird there. My guess is it's probably closest to the 75ARD2, but it's tough to say without testing it.
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Replies: 12 / Views: 2,641 |
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Posted 05/07/2016 9:00 pm
