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Rodenstock apo rodagon D 75mm f4 on a7rii
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PostPosted: Mon Jul 15, 2019 6:01 pm    Post subject: Rodenstock apo rodagon D 75mm f4 on a7rii Reply with quote
I really liked the schneider apo enlarger lenses so I thought I would try their German competitor. Well known for macro of course I thought I'd try that and some other things.






PostPosted: Mon Jul 15, 2019 7:35 pm    Post subject: Reply with quote
Like 1 Like 1 Especially the colors


PostPosted: Tue Jul 16, 2019 5:45 am    Post subject: Re: Rodenstock apo rodagon D 75mm f4 on a7rii Reply with quote
jamaeolus wrote:
I really liked the schneider apo enlarger lenses so I thought I would try their German competitor. Well known for macro of course I thought I'd try that and some other things.






Fairly good results! May I ask how you adapt this 75mm enlarger to your camera? I have a Sony a7ii and for a 50mm enlarger, I mainly use a helicoid of 17-31mm. However, I found it doesn't work for the 75mm and 105mm enlarger. Thanks!


PostPosted: Tue Jul 16, 2019 8:28 am    Post subject: Re: Rodenstock apo rodagon D 75mm f4 on a7rii Reply with quote
vivaldibow wrote:
May I ask how you adapt this 75mm enlarger to your camera? I have a Sony a7ii and for a 50mm enlarger, I mainly use a helicoid of 17-31mm. However, I found it doesn't work for the 75mm and 105mm enlarger. Thanks!


The flange focal distance for this 75mm lens at infinity is 136.7 mm according specifications. If you are using an adapter ring from M39 to M42 and a M42 helicoid adapter you have to add either M39 or M42 macro extension rings to compensate the difference. 136.7 - 45.46 = 91.24 mm; i.e. apprx. 90mm extension plus the M42 helicoid adapter would be fine to focus infinity, even more for close focusing.
The 50mm Apo-Rodagon is fine without additional extension rings and therefore my preferred option. Wink


PostPosted: Tue Jul 16, 2019 1:42 pm    Post subject: Re: Rodenstock apo rodagon D 75mm f4 on a7rii Reply with quote
jamaeolus wrote:
I really liked the schneider apo enlarger lenses so I thought I would try their German competitor. Well known for macro of course I thought I'd try that and some other things. [url=http://forum.mflenses.com/userpix/20197/big_7980_DSC01373_1.jpg]


My first post. Can you remember the taking aperture of the two mountain shots? The one across the lake seems sharp to the edges but the not so the other one. I wonder how sharp the corners are at F11?

I use Rodenstock Rodagon Apo N 50mm and 80mm lenses for landscapes on my A7ii and am very happy with the results.


PostPosted: Tue Jul 16, 2019 2:51 pm    Post subject: Reply with quote
I'm not sure the aperture but I think it was near open. I would note that none of the corners were in focus (I could see that with focus peaking). Infinity began about halfway up the pointy mountain. (Thielsen)


PostPosted: Tue Jul 16, 2019 3:27 pm    Post subject: Reply with quote
tb-a wrote:
The flange focal distance for this 75mm lens at infinity is 136.7 mm according specifications.


Must be a mistake. Rodenstock tells in their documentation it is 65mm for a 75mm lens. Sounds more plausible.
That's easier to realise with extension rings.


PostPosted: Tue Jul 16, 2019 4:39 pm    Post subject: Reply with quote
For the infinity shots I was using a NEX m42 close then 2 stacked short m42 helicals and the shortest Asahi m42 extesnsion tube. It went just past infinity. For the others of course I was using a few to numerous extension tubes.


PostPosted: Tue Jul 16, 2019 8:23 pm    Post subject: Reply with quote
jamaeolus wrote:
I'm not sure the aperture but I think it was near open. I would note that none of the corners were in focus (I could see that with focus peaking). Infinity began about halfway up the pointy mountain. (Thielsen)


OK, thanks. I'd love to see a distant landscape at f8 or f11, if you have one.


PostPosted: Tue Jul 16, 2019 10:39 pm    Post subject: Reply with quote
I'll get one for you. Might be a few days. Watch this space Wink


PostPosted: Wed Jul 17, 2019 4:34 am    Post subject: Re: Rodenstock apo rodagon D 75mm f4 on a7rii Reply with quote
tb_a wrote:
vivaldibow wrote:
May I ask how you adapt this 75mm enlarger to your camera? I have a Sony a7ii and for a 50mm enlarger, I mainly use a helicoid of 17-31mm. However, I found it doesn't work for the 75mm and 105mm enlarger. Thanks!


The flange focal distance for this 75mm lens at infinity is 136.7 mm according specifications. If you are using an adapter ring from M39 to M42 and a M42 helicoid adapter you have to add either M39 or M42 macro extension rings to compensate the difference. 136.7 - 45.46 = 91.24 mm; i.e. apprx. 90mm extension plus the M42 helicoid adapter would be fine to focus infinity, even more for close focusing.
The 50mm Apo-Rodagon is fine without additional extension rings and therefore my preferred option. Wink


Thanks. It looks like my setup doesn't have enough "image distance". That's why extension tubes are needed. May I know what the 45.46mm refers to? Looks like registration distance for some mount?


PostPosted: Wed Jul 17, 2019 5:14 am    Post subject: Reply with quote
45.46mm is Asahiflex, ZM39, M42, and PK cameras mount register.


PostPosted: Wed Jul 17, 2019 5:34 am    Post subject: Reply with quote
visualopsins wrote:
45.46mm is Asahiflex, ZM39, M42, and PK cameras mount register.


Thanks. I just figured it out from this chart. Smile

https://cdn.shopify.com/s/files/1/1415/1308/files/FDX-Adptr-Chrt-2019.pdf


PostPosted: Wed Jul 17, 2019 10:25 am    Post subject: Reply with quote
tb-a wrote:
The flange focal distance for this 75mm lens at infinity is 136.7 mm according specifications.


Minolfan wrote:
Must be a mistake. Rodenstock tells in their documentation it is 65mm for a 75mm lens. Sounds more plausible.
That's easier to realise with extension rings.


Ups, you're right, my failure. According to their list the flange focal distance for the Apo-Rodagon D is not for infinity (opposed to all of their other lenses) but for 1:1 duplicates; i.e. 1:1 macro shooting needs 136.7 mm. Infinity distance is not listed for this special lens.
However, some extension is needed in any case, maybe something like 20 mm.


PostPosted: Wed Jul 17, 2019 12:49 pm    Post subject: Reply with quote
A general rule of thumb I use to pull out the right extension tubes, is that the Flange focal distance at infinity will be around about the same as the focal length. It works more often than not with enlarging lenses.


PostPosted: Sat Jul 20, 2019 6:04 pm    Post subject: Reply with quote
The rule I use for enlarging lenses is the extension for infinity focus equals the focal length minus the camera register distance minus the distance from the mount to the middle of the lens. This usually gets pretty close, within a few mm.

Note that this lens is not an enlarging lens, but a duplication lens, hence the "D" in its name. This means it was not designed to operate at infinity, and as you see in some of the pics it is not so good to the corners there without stopping down.


PostPosted: Sat Jul 20, 2019 6:09 pm    Post subject: Reply with quote
Well those shots don't really have anything in focus at infinity. The rounded mountain (Mt Bailey was taken with the auto stitch so it really doesn't count). I promise I will take it out and test it at infinity with something in frame to judge it by. Even if there IS some degradation in the corners at infinity (we'll see) it is so sharp overall that it likely won't matter.


PostPosted: Sat Jul 20, 2019 7:17 pm    Post subject: Reply with quote
[quote="Ray Parkhurst"

Note that this lens is not an enlarging lens, but a duplication lens, hence the "D" in its name. This means it was not designed to operate at infinity, and as you see in some of the pics it is not so good to the corners there without stopping down.[/quote]

Yes, it is only good for 1:1.


PostPosted: Thu Oct 29, 2020 9:03 pm    Post subject: Reply with quote
So if it is optimized for 1:1 it couldn't be good at any other distance? Let us see.


this is roughly 4 to 1, 'shroom is tiny

here is a 100% crop of same



Optimized for a given ratio doesn't preclude it being "good enough" for other uses.


PostPosted: Fri Oct 30, 2020 4:15 am    Post subject: Reply with quote
jamaeolus wrote:
So if it is optimized for 1:1 it couldn't be good at any other distance? Let us see.
...
Optimized for a given ratio doesn't preclude it being "good enough" for other uses.


"Optimized" just means that it works best for corner sharpness and field flatness at 1:1. I often use the 75ARD1 at 1:4, but I don't expect sharp corners without stopping it down to at least f8 or even f11, and by then the entire image is starting to get a little fuzzy. I also use the lens up to 2:1 or so, and indeed it works pretty well there, at least within the constraints of the f4 aperture.


PostPosted: Fri Oct 30, 2020 11:32 am    Post subject: Reply with quote
Ray Parkhurst wrote:

"Optimized" just means that it works best for corner sharpness and field flatness at 1:1. I often use the 75ARD1 at 1:4, but I don't expect sharp corners without stopping it down to at least f8 or even f11, and by then the entire image is starting to get a little fuzzy. I also use the lens up to 2:1 or so, and indeed it works pretty well there, at least within the constraints of the f4 aperture.


yes, it is not computed for infinity and will not give good results


PostPosted: Fri Oct 30, 2020 4:25 pm    Post subject: Reply with quote
komet wrote:
Ray Parkhurst wrote:

"Optimized" just means that it works best for corner sharpness and field flatness at 1:1. I often use the 75ARD1 at 1:4, but I don't expect sharp corners without stopping it down to at least f8 or even f11, and by then the entire image is starting to get a little fuzzy. I also use the lens up to 2:1 or so, and indeed it works pretty well there, at least within the constraints of the f4 aperture.


yes, it is not computed for infinity

Sure.


komet wrote:
and will not give good results

Not so sure. The Minolta MD 4/100mm Macro, certainly not optimized for infinity, and not a floating element lens, gives excellent infinity results on 24 MP FF, even wide open: No visible lateral CAs, and perfect corner sharpness.

S


PostPosted: Fri Oct 30, 2020 6:04 pm    Post subject: Reply with quote
stevemark wrote:

Not so sure. The Minolta MD 4/100mm Macro, certainly not optimized for infinity, and not a floating element lens, gives excellent infinity results on 24 MP FF, even wide open: No visible lateral CAs, and perfect corner sharpness.


For sure the 75ARD1 does not perform well at infinity wide open. Stop it down and it improves.


PostPosted: Mon Nov 02, 2020 11:10 am    Post subject: Reply with quote
stevemark wrote:

Not so sure. The Minolta MD 4/100mm Macro, certainly not optimized for infinity, and not a floating element lens, gives excellent infinity results on 24 MP FF, even wide open: No visible lateral CAs, and perfect corner sharpness.

S


The Minolta has nothing to do with the Rodenstock, this is a special lens for 1:1.


PostPosted: Mon Nov 02, 2020 1:46 pm    Post subject: Re: Rodenstock apo rodagon D 75mm f4 on a7rii Reply with quote


OK, I know that the design was optimized for a 1:1 magnification, but the amount of LaCA, as can be seen in the pine tree in the foreground at the lower right corner, is surprisingly high for a lens that is said to be apochromatic.
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