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Author Topic: Requesting comments on the Rodenstock HR Digaron 40mm  (Read 2446 times)

alan_b

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #20 on: May 18, 2021, 02:14:01 am »

Would you mind to make one for the HR40?

Here you go: Rodenstock 40 HR W at infinity, 10mm rise. (IQ 4150 frame w/ dashed 33x44 lines in red.)

FYI, the free Alpa Corrector PS plugin and a selection of distortion charts is available on their site here:
https://www.alpa.swiss/products/900-100-010-alpa-acam-lens-corrector-plug-in

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alan_b

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #21 on: May 18, 2021, 02:32:19 am »

The second kind of distortion is not perspective distortion.

Yep, it's expected and "correct" in a rectilinear projection.

Quote
It is called anamorphic distortion, volume deformation, or volume anamorphosis.

Is that a commonly accepted term?  I thought it was something DXO made up.

I learned to manually construct perspective drawings in architecture school, back before inexpensive 3D modeling software was widely available.  If the angle of view was too wide, we'd usually find a way to fudge/compress the extreme stretching at the edges so things looked somewhat normal.
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USM

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #22 on: May 18, 2021, 04:23:40 pm »

Here you go: Rodenstock 40 HR W at infinity, 10mm rise. (IQ 4150 frame w/ dashed 33x44 lines in red.)

FYI, the free Alpa Corrector PS plugin and a selection of distortion charts is available on their site here:
https://www.alpa.swiss/products/900-100-010-alpa-acam-lens-corrector-plug-in

Found everything. Thanks again.
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David Eichler

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #23 on: May 23, 2021, 07:38:17 pm »

Volume anamorphosis might be something DxO made up or got from an obscure source, but anamorphic distortion is a widely used term, though most usage of the term relates to anamorphic projection for theater display.

Broadly speaking, perspective distortion might cover this effect, since each part of the film or sensor plane has a slightly different perspective. However, perspective in photography most often relates to the position of the entire sensor or film plane, so I think it is best to limit usage of the term to that kind of perspective, in order to avoid confusion.

Yep, it's expected and "correct" in a rectilinear projection.

Is that a commonly accepted term?  I thought it was something DXO made up.

I learned to manually construct perspective drawings in architecture school, back before inexpensive 3D modeling software was widely available.  If the angle of view was too wide, we'd usually find a way to fudge/compress the extreme stretching at the edges so things looked somewhat normal.
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Analogous

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #24 on: June 06, 2021, 02:36:32 pm »

The Alpa lens correction software still works under the latest photoshop - you just have to remember to click the “load parameters” 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, it’s not as strong as the 32, but it’s still present - with the the 50 you can get away with no post correction for most motives with shifts less than 15mm.


A slight tangent to original topic…

But, how have you been able to get the Alpa Lens Corrector plug-in to work with the latest Photoshop (CC 2021 on Mac)? With it loaded into the plug-ins folder it doesn't show up anywhere that I can see, definitely not appearing under the "automate" menu as Alpa documentation describes. Other plug-ins are all managed through the Creative Cloud application, and there's no way to add outside plug-ins through that.

Doing architectural work with the HR 32 can often reveal noticeable distortion, particularly in straight verticals extending through the frame. Would be extremely helpful to have the Alpa Corrector to adjust for this. Or is there another way to address this distortion without using the Alpa Lens Corrector?
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Analogous

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #25 on: June 06, 2021, 07:32:31 pm »

SOLVED!
It took a little trial and error, but I figured out the issue.
For anyone that's interested, or runs into this problem in the future, there is one very important detail.…

The Alpa Lens Corrector plugin doesn't currently appear to work (doesn't even show up) with the newest universal version of Photoshop CC 2021 designed to work on the Apple M1 chip. It does however still work with older versions.
So, on a newer Apple M1 machine, you'll need to run an older Intel based version of Photoshop (via Rosetta II) to keep using the Alpa plugin.
Hopefully this will change in future updates. But this is the case as of now.
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Rod.Klukas

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Re: Requesting comments on the Rodenstock HR Digaron 40mm
« Reply #26 on: July 20, 2021, 07:57:47 pm »

One thing I have not seen noted, is the 40mm, as many said is a really good lens especially if the central or mustache distortion is corrected. 

I must say though it is a lens that requires a lens shade, as it is quite prone to lens flare.  With a shade no issues, but without, I have seen many users have an issue, including myself.

The issue with the 47mm is that it was not designed with the resolution of the 150mm back in mind either.  Both the 40mm and 50mm will have better resolution than the 47mm and a 150mm back.

Hope this helps.

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Rod Klukas
US Representative Arca-Swiss
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