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Author Topic: Requesting comments on the Rodenstock HR Digaron 40mm  (Read 2444 times)

jam275

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Requesting comments on the Rodenstock HR Digaron 40mm
« on: May 05, 2021, 10:27:47 am »

I was wondering if anyone would share their experience using the Rodenstock 40mm Digaron.  I currently shoot with an Alpa STC using a PhaseOne IQ4 150.  I have a Schneider 47mm Apo Digitar that I use along with Rodenstock 90m and 23mm Alpagons.  The Schneider lens is great in terms of size and image circle, but I can tell it's not as sharp as the Rodenstocks that I have.  I was thinking of purchasing the 40mm lens to take its place (or maybe the 50mm if people recommend it). 

I've read some posts about the retrofocus design of the Rodenstock compared to the symmetric design of the Schneider and how it causes more "moustache" distortion.  I was wonder how big a deal this is.  I've seen some photos posted by other members with the 40mm and they look quite good.  Do the lens profiles in CaptureOne help correct this distortion?

I shoot both landscape and architectural photography.  Thanks in advance for any insight you can provide.

John
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dkaufman

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #1 on: May 05, 2021, 11:25:15 am »

The Rodenstock 40mm is one of their best lenses. It is sharp almost to the edge of the image circle although there is a hard stop that produces a bit of a geometric pattern as you approach the image circle. I also have the Schneider 47mm lens and use both plus five other lenses on an Arca Swiss M-Line Two with various digital backs, now an IQ4 150. The problem with the 40mm lens is its 90mm image circle size which is much smaller than the 47mm lens' 113mm image circle. If you are using movements you have to decide between the two lenses based on the degree of movement and whether or not you are stitching. The 47mm starts smearing as you approach about two-thirds of the way towards the edge of the image circle, at the image edges with more than about 10-15 mm of horizontal movement, but the 40mm is limited to about 15mm movement in both directions with the IQ4150 in a horizontal (landscape) orientation, and less with camera rise (back fall). Without movements my 47mm lens is very sharp, but of a different quality than the Rodenstock. The Rodenstock has a nicer rendering quality, less clinical looking.

As for distortion, there are several ways to correct. One possibility is using Capture One software's distortion  correction, which includes a panel to input your movements. Another possibility is Alpa's lens correction software which is excellent but only runs under 32 bit versions of Photoshop (CS6). I believe a third way may be DxO software but I have never used it. If you use movements or stitching you definitely need software correction for architectural subjects. It's possible but very difficult to fully correct the Rod 40mm distortion without software assistance.

David Kaufman  www.davidkaufmanphotography.com
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Paul2660

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #2 on: May 05, 2021, 07:31:22 pm »

To me the problem with both the 32mm and 40mm Rodenstocks, is retrofocus distortion.  Objects towards the edge of the frame elongate and flatten.  Very easy to see with car tires, trash cans, telephone poles, net anything with "known" dimensions.  The 32mm I have is worse than my 40mm, but both lenses exhibit it to some degree.  This is not correctable in C1, LR, or any other software I have tried.  If you shift the lenses, especially the 32mm, you will see if even more as you have pushed the limit of the optical design by moving to the edge of the IC.

40mm is much lighter, does not need a CF for best capture, as the 32mm does.  Both have 90mm IC's as I recall.  Both will show a hard vignetting as you hit the edge of the image circle, due to the IC indicator placed in the lens by Rodenstock.  The Schneider lenses will not show the hard vignette, only a slight much more manageable one. 

Rodenstock may have worked on the issue of the retrofocus distortion with newer copies, my lenses date back to 2016 and 2015. 

Paul
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Paul Caldwell
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epines

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #3 on: May 06, 2021, 12:04:11 pm »

It's a great lens. Sharp to the edge of the image circle, as others have mentioned. Nicely sharp even wide open at f/4 (but of course improves with stopping down). The moustache distortion is pretty insignificant, in my opinion. Not a big deal, even when shooting straight on to the front of a building. You'll notice it, but it's correctable.

ben730

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #4 on: May 12, 2021, 12:23:51 pm »

To me the problem with both the 32mm and 40mm Rodenstocks, is retrofocus distortion.  Objects towards the edge of the frame elongate and flatten. 

Paul
I have seen the mustache distortion of the 32 mm.
But I never saw a "retrofocus distortion" towards the edge of the frame.
I thought wide angles always distort (elongate and flatten) in the edges, also the Schneiders.
It's perspectival distortion.
Regards,
Ben
 

Paul2660

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #5 on: May 12, 2021, 03:16:19 pm »

Ben

I think from what I have seen the Schneiderís being a symmetrical design do not have same issue. I have tested my Schneider 35 against the Rodenstock 32 and 40mm and the edges look much better none of the flattening I see with the Rodenstocks. The 35 Schneider however canít be shifted very much if any on a 3100 or IQ4 so I mainly use the Rodenstocks.

My 40mm shows the issue a bit more than the 32. And past 12mm of right or left shift the problem gets much worse.


Both lenses are very sharp however so I canít complain.

Paul
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Paul Caldwell
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ben730

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #6 on: May 12, 2021, 03:56:01 pm »

Thanks for your reply Paul.
Could you please post an example with the 35 digitar against the 32 HR.

I sold my 35 digitar long time ago and only have the 32 HR.
I compared it with the Fuji GF 30, but there is no difference concerning flattening.
I had the 28 Superdigitar and the 28 HR at the same time
and could not see any difference in distortion except the mustache.

Thanks,
Ben

chrismuc

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #7 on: May 12, 2021, 11:24:20 pm »

You might see two kind of wide angle distortions:
1. Linear distortion of focal length vs. angle. The retrofocus lenses mostly have second order distortion, that means wave-/mustache shape. The Rodenstock presumably has stronger distortion than the symmetrical Schneider.
2. Perspective distortion of wide angle lenses towards the edge or corner of the image (every circle becomes oval). That effect is unavoidable and only depends on the field of view of the lens with a particular sensor size.
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adammork

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #8 on: May 13, 2021, 04:26:26 am »

Another possibility is Alpa's lens correction software which is excellent but only runs under 32 bit versions of Photoshop (CS6).

David Kaufman  www.davidkaufmanphotography.com

The Alpa lens correction software still works under the latest photoshop - you just have to remember to click the ďload parametersĒ each time, before pressing preview or apply - even if it seems that they are loaded already - then it works - at least on our systems.

Fantastic lens, my favourite wide - kind of small and super sharp - only drawback is that for architectural work you have to deal with the distortion, itís not as strong as the 32, but itís still present - with the the 50 you can get away with no post correction for most motives with shifts less than 15mm.
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USM

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #9 on: May 13, 2021, 08:56:21 am »

Would it be possible to get a image showing the different distortions of the Rodenstock and Schneider?
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adammork

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #10 on: May 13, 2021, 10:43:16 am »

I had the full line of Schneiders, now I have the Rodenstocks - simply put, you do not need to apply any corrections to the Schneiders - if you like straight lines you are forced to do it with the Rodenstocks 23, 32, 40 and to a certain degree with the 50 as well.
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Pforster

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #11 on: May 13, 2021, 11:05:41 am »

For my Alpa STC I have the Schneider 60, 90 & 120 but the Rodenstock 40mm is my go to lens every time.
Maybe Iím not as critical as others, or because I take almost exclusively landscapes, but the distortion has never been a problem at all for me and I donít feel the need to make any corrections.
With the IQ4 150 (and the ability to crop to a mere 50mpx) it serves as a brilliant all rounder and I rarely use the SK 60 now.
Just my experience but I hope it helps.
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Paul.

alan_b

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #12 on: May 13, 2021, 05:24:15 pm »

Would it be possible to get a image showing the different distortions of the Rodenstock and Schneider?

Here are Rodie 32 (orange) vs SK 35 (blue) distortions over a reference grid (gray), centered and with 10mm rise on a landscape format IQ 4150 frame.  Distortion values are from Alpa's Lens Corrector (inverted for this illustration).
« Last Edit: May 13, 2021, 05:32:08 pm by alan_b »
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Gigi

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #13 on: May 13, 2021, 09:38:06 pm »

Have the Schneider 43, which is rumored to be a later (better) lens than the 47. From examples, the 40 has a very good look, but its bigger and more delicate than the Schneiders. Might consider the 43, and then shift/stich as needed?
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Geoff

USM

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #14 on: May 14, 2021, 05:40:50 am »

Here are Rodie 32 (orange) vs SK 35 (blue) distortions over a reference grid (gray), centered and with 10mm rise on a landscape format IQ 4150 frame.  Distortion values are from Alpa's Lens Corrector (inverted for this illustration).

Great! Thanks! Do you also have a Rodie HR 35 vs SK 35 comparison?
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alan_b

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #15 on: May 14, 2021, 12:54:51 pm »

Great! Thanks! Do you also have a Rodie HR 35 vs SK 35 comparison?

Sure: Rodenstock HR35 (red) vs SK 35 (blue), 10mm rise. Dashed line is 33x44mm frame.
« Last Edit: May 14, 2021, 02:37:21 pm by alan_b »
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USM

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #16 on: May 15, 2021, 07:56:10 am »

Thanks again!
So I can also compare the HR 32 with the HR 35.
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USM

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #17 on: May 15, 2021, 08:44:09 am »

Would you mind to make one for the HR40?
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David Eichler

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #18 on: May 16, 2021, 02:39:43 pm »

To me the problem with both the 32mm and 40mm Rodenstocks, is retrofocus distortion.  Objects towards the edge of the frame elongate and flatten.  Very easy to see with car tires, trash cans, telephone poles, net anything with "known" dimensions.  The 32mm I have is worse than my 40mm, but both lenses exhibit it to some degree.  This is not correctable in C1, LR, or any other software I have tried.  If you shift the lenses, especially the 32mm, you will see if even more as you have pushed the limit of the optical design by moving to the edge of the IC.

40mm is much lighter, does not need a CF for best capture, as the 32mm does.  Both have 90mm IC's as I recall.  Both will show a hard vignetting as you hit the edge of the image circle, due to the IC indicator placed in the lens by Rodenstock.  The Schneider lenses will not show the hard vignette, only a slight much more manageable one. 

Rodenstock may have worked on the issue of the retrofocus distortion with newer copies, my lenses date back to 2016 and 2015. 

Paul
So, retrofocus wideangle lenses exhibit greater anamorphic distortion than lenses of symmetrical design?
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David Eichler

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #19 on: May 16, 2021, 02:42:47 pm »

You might see two kind of wide angle distortions:
1. Linear distortion of focal length vs. angle. The retrofocus lenses mostly have second order distortion, that means wave-/mustache shape. The Rodenstock presumably has stronger distortion than the symmetrical Schneider.
2. Perspective distortion of wide angle lenses towards the edge or corner of the image (every circle becomes oval). That effect is unavoidable and only depends on the field of view of the lens with a particular sensor size.


The second kind of distortion is not perspective distortion. It is called anamorphic distortion, volume deformation, or volume anamorphosis.
« Last Edit: May 16, 2021, 02:45:48 pm by David Eichler »
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