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Author Topic: 23mmHR vs 24mmXL Coverage & Distortion  (Read 9046 times)

Jeffreytotaro

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23mmHR vs 24mmXL Coverage & Distortion
« on: May 28, 2009, 10:34:09 am »

I recently received a copy of the new Rodenstock 23mmHR lens for my Alpa cameras.  I have been using the Schneider 24mmXL Digitar with great success but the added coverage of the 23HR was very tempting so I got one.  Here are some quick and somewhat rough comparisons of image circle coverage and shift capabilities and I choose a subject that would help discern distortion characteristics.  For the image circle comparisons I used the Alpa Max camera and keeping the lens still made four quadrant exposures and put them together in CS4.  I didn't spend much time on LCC corrections so you will see some color shifts.

You will also see 0mm shifts of both lenses and I then posted 5mm upward shifts of both the 23 and 24, and then 10 and 15mm shifts of the 23.  The 24 is out of coverage at 5mm so I didn't do those and the camera will not allow such large shifts of the 24.

24 advantages:
Small, lightweight, very little distortion, $5k, vs $8k for the 23HR

23 Advantages:
Much better coverage, no center filter required, lighter wallet to carry around
[attachment=14069:23vs24_Circle.jpg]
[attachment=14076:23HR_0.jpg]
[attachment=14077:24XL_0.jpg]
[attachment=14078:23HR_5.jpg]
[attachment=14079:24XL_5.jpg]
[attachment=14080:23HR_10.jpg]
[attachment=14081:23HR_15.jpg]

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Jeffrey Totaro
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asf

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #1 on: May 28, 2009, 10:35:36 am »

thank you very much jeffrey, very useful info
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Doug Peterson

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #2 on: May 28, 2009, 10:40:25 am »

Extremely generous of you to share. Very very helpful.

jonstewart

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #3 on: May 28, 2009, 02:27:47 pm »

Thanks for taking the trouble to share
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ThierryH

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #4 on: May 28, 2009, 08:42:04 pm »

Dear Jeffrey,

Thank you for this very interesting test and comparison.

May I know the used f-stop for these shots?

Thanks and best regards,
Thierry

Quote from: Jeffreytotaro
I recently received a copy of the new Rodenstock 23mmHR lens for my Alpa cameras.  I have been using the Schneider 24mmXL Digitar with great success but the added coverage of the 23HR was very tempting so I got one.  Here are some quick and somewhat rough comparisons of image circle coverage and shift capabilities and I choose a subject that would help discern distortion characteristics.  For the image circle comparisons I used the Alpa Max camera and keeping the lens still made four quadrant exposures and put them together in CS4.  I didn't spend much time on LCC corrections so you will see some color shifts.

You will also see 0mm shifts of both lenses and I then posted 5mm upward shifts of both the 23 and 24, and then 10 and 15mm shifts of the 23.  The 24 is out of coverage at 5mm so I didn't do those and the camera will not allow such large shifts of the 24.
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rethmeier

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #5 on: May 28, 2009, 08:49:21 pm »

Useful test.
Interesting to see that both lenses have some form of distortion.The 23 HR to be worse,how that was expected.
Those front on building shots are torture for lens designers.


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Willem Rethmeier
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archivue

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #6 on: May 29, 2009, 03:42:00 am »

Thanks for sharing... i'm dreaming of the same comparison with 40 digaron W and 35XL... it must be similar in a way !
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ThierryH

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #7 on: May 29, 2009, 09:06:24 am »

Jeffrey,

I have another question concerning your test and the way you did it: it seems to me that the difference in terms of angle of view/field is enormous while the focal 24mm vs 23mm isn't such a difference. It almost looks like one was taken with a 23/24mm and the other with almost double the focal length. Could you have an explanation to this huge difference?

Also, I found the distorsion to be quite important, with some noticeable misalignment: could it be that the stitcher did that? There must be an explanation to this distorsion and misalignment.

Thanks and best regards,
Thierry
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alan100

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #8 on: May 29, 2009, 03:50:38 pm »

I have also just tested the 23mm Rodenstock. I haven't time yet to aggregate the data but there is obvious barrelling on the lens. I shot interiors and with vertical lines nearer the lens the problem is more noticeable. I reminds me of the 35mm H1 lens, which isn't surprising since both are retro focal in design. I cannot imagine this will not be present on the 28mm and 40mm HR. It makes them problematic for architectural use. For landscape the quality of image and coverage was exceptional.
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Jeffreytotaro

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #9 on: May 29, 2009, 04:01:12 pm »

Quote from: ThierryH
Jeffrey,

I have another question concerning your test and the way you did it: it seems to me that the difference in terms of angle of view/field is enormous while the focal 24mm vs 23mm isn't such a difference. It almost looks like one was taken with a 23/24mm and the other with almost double the focal length. Could you have an explanation to this huge difference?

Also, I found the distorsion to be quite important, with some noticeable misalignment: could it be that the stitcher did that? There must be an explanation to this distorsion and misalignment.

Thanks and best regards,
Thierry
I used f11 for all exposures, which is my typical setting.  This was not meant to be a rigorous test more a real world test.  To your question about misalignment. If you are referring to the image circle images, CS4 did not stitch these together very well at all.  I'm not sure why.  Again, the purpose was just to show the extent of the circle, not the quality of the image inside it.  From what I have heard, the true focal length of the 24 may be closer to 25mm and that of the 23 closer to 22, so that may account for the difference, but overall the 23 is wider as should be expected.

I have done some tests with PTLens, which has a profile for this lens, and it works quite well, even shifted.  Any of these retro-focal designs will have, a:smaller image circles, and b:much more distortion.  The Schneiders are a symmetrical design which keeps distortion at a minimum but may require a center filter.  There are always compromises in design.  I chose the 23 for the greater coverage and can live with software corrections for one out of my 6 lenses, but I will not be interested in the other lenses in the Rodenstock range due to the distortion characteristics and limited movements.
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Jeffrey Totaro
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ThierryH

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #10 on: May 29, 2009, 07:40:42 pm »

Dear Jeffrey,

Quote from: Jeffreytotaro
test.  To your question about misalignment. If you are referring to the image circle images, CS4 did not stitch these together very well at all.
Yes, that's what I meant

Quote from: Jeffreytotaro
... the Rodenstock range due to the distortion characteristics and limited movements.
According to my tests, the 23 HR from Rodenstock has the same shift characteristics as the other HR type of lenses: the given shift value is VERY conservative and one can go at least 50% more than what is indicated on the paper, WITHOUT noticeable losses. And the other advantage , IMO, is the capability of those Rodenstock lenses (in this case the HR type) to get those shifts already at full open aperture, without need to stop down.

Thanks for your explanations and best regards,
Thierry
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Jeffreytotaro

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #11 on: May 30, 2009, 07:46:21 am »

Quote from: ThierryH
According to my tests, the 23 HR from Rodenstock has the same shift characteristics as the other HR type of lenses: the given shift value is VERY conservative and one can go at least 50% more than what is indicated on the paper, WITHOUT noticeable losses. And the other advantage , IMO, is the capability of those Rodenstock lenses (in this case the HR type) to get those shifts already at full open aperture, without need to stop down.
Hi Thierry:

I don't want to get into a lens debate but the Schnieders have larger image circle in general especially the 35xl and 47xl (which is huge for digital).  If the new 40HR has the same circle as the 23 (based on what you said, I have not looked it up) then I would be disappointed to have only 8-10mm shift before it starts to vignette in a vertical composition.  The HR will likely be sharper edge to edge and hold sharpness better when shifted due to the retro-focal design however.  The Digitars do loose some sharpness at extreme shifts much the way standard 4x5 lenses would.

As you can tell, I have an open mind and will look for the best solution in any given focal length, thats why I chose the 23HR, a fine lens for sure.
Cheers!
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Jeffrey Totaro
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ThierryH

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #12 on: May 30, 2009, 07:57:19 am »

Dear Jeffrey,

we simply discuss, and that's why this forum is here, isn't it?

Quote from: Jeffreytotaro
Hi Thierry:

I don't want to get into a lens debate but the Schnieders have larger image circle in general especially the 35xl and 47xl (which is huge for digital).
Yes BUT: the Schneider lenses HAVE TO BE stopped down, otherwise they have some serious sharpness problems at the edge, not so the Rodenstock.
And as said, like said many times by myself and others (rainer_v, for example): the Rodenstock shifting ways (understand image circle) are given VERY conservatively. In fact the image circle is MUCH bigger than what is indicated in the documentations. And what I said, is that you can go about 50% more than what is indicated.

Quote from: Jeffreytotaro
If the new 40HR has the same circle as the 23 (based on what you said, I have not looked it up) ...
I can't remember having said or written that: did I? If so, then I should take it back, since I honestly don't know the 40 HR, and never had it in my hands, so far.

Quote from: Jeffreytotaro
... then I would be disappointed to have only 8-10mm shift before it starts to vignette in a vertical composition.
You have more than this, at least 13 to 15mm, IF the 40 HR has the same image circle (see above).

Quote from: Jeffreytotaro
The HR will likely be sharper edge to edge and hold sharpness better when shifted due to the retro-focal design however.  The Digitars do loose some sharpness at extreme shifts much the way standard 4x5 lenses would.
Definitively so, and from full open aperture.

Thanks and cheers too,
Thierry
« Last Edit: May 30, 2009, 07:59:59 am by ThierryH »
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rainer_v

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #13 on: May 30, 2009, 09:29:27 am »

the available shifts of the HR lenses are  different for the different lenses.

with a 36x48 sensor u can shift horizontal app. 10mm up, ( diagonal clearly less ...)
with the 28+35HR app 12-13 horizontal,
the 60HR allow 15-18, max 20 shift ( with slightly sharpness loss ).

the 40 i dont know.
hard to know if ts at the side of the 60 or more likely at the side of the 35HR.
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rainer viertlböck
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alan100

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #14 on: May 30, 2009, 04:42:50 pm »

If I could try to summarise this thread on the 23mm lens then it would be so, please correct my errors.
The 23mm lens has a retro focal design that offers;

1. even and consistent coverage that  voids the need for a centre weighted filter.
2.  it will allow camera movements to be used on the new backs ie 50mp plus because of the substantial coverage
3. will still require a gain adjust or equivalent, but should suffer from less colour casting and centrefold as the light is striking the chip at a  less extreme angle
4. there is barrelling on the lens but this can be corrected in photoshop, I have not worked out if this is just barrelling but also "moustache"  similar to the 35mm H1 lens

I'm new to this forum but surely this last point must cause some concern to architectural photographers.
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bryanyc

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« Reply #15 on: May 30, 2009, 06:52:48 pm »

I find this to be an excellent test of the given lenses in a real world architectural use.  It seems to me that the 23 has moustache distortion.  This is a real pain, just like the canon 24 shift.

Which wide lenses, from Rodenstock and Scheider, have the the lowest distortion?  In other words, if you could have only one lens (mainly for architecture) which one would you take?  There is always this compromise between the coverage, useable apertures, rectilinearity and falloff.    

 I have an alpa sw waiting for a digital back and would like to start out with a lens in the 35 - 45 focal length.
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pixjohn

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« Reply #16 on: May 30, 2009, 08:44:14 pm »

The other thing you need to think about is the price difference between the two lenses. I am happy with my 24 so for me it’s an easy answer, but for someone buying a new lens is it enough to pay $3000 more?
« Last Edit: May 30, 2009, 08:44:59 pm by pixjohn »
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rainer_v

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #17 on: May 30, 2009, 10:06:10 pm »

Quote from: bryanyc
I find this to be an excellent test of the given lenses in a real world architectural use.  It seems to me that the 23 has moustache distortion.  This is a real pain, just like the canon 24 shift.

Which wide lenses, from Rodenstock and Scheider, have the the lowest distortion?  In other words, if you could have only one lens (mainly for architecture) which one would you take?  There is always this compromise between the coverage, useable apertures, rectilinearity and falloff.    

 I have an alpa sw waiting for a digital back and would like to start out with a lens in the 35 - 45 focal length.
there is no comparison between the canon 24tse and the 23 HR, cause the canon is nearly unusable for my taste not so the 23Hr which is excellent also in terms of distortion, although not perfect.
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Jeffreytotaro

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #18 on: May 31, 2009, 09:08:03 am »

Quote from: alan100
If I could try to summarise this thread on the 23mm lens then it would be so, please correct my errors.
The 23mm lens has a retro focal design that offers;

1. even and consistent coverage that  voids the need for a centre weighted filter.
2.  it will allow camera movements to be used on the new backs ie 50mp plus because of the substantial coverage
3. will still require a gain adjust or equivalent, but should suffer from less colour casting and centrefold as the light is striking the chip at a  less extreme angle
4. there is barrelling on the lens but this can be corrected in photoshop, I have not worked out if this is just barrelling but also "moustache"  similar to the 35mm H1 lens

I'm new to this forum but surely this last point must cause some concern to architectural photographers.

Yes Alan, that is a good summary.  In regard to the distortion I would say it is definitely a "complex distortion" not equal to simple barrel distortion for instance.  I have not done much correction of this sort of thing in PS since my other lenses do not need it (thats why I shoot Alpa/Schneider or Leica M8), but I have done some quick tests with PTLens software.  This seems (again, to me with little PS distortion experience) to be superior since you can adjust the correction based on how much you shifted the lens.  It takes a few steps to get it done but to me is worth the trouble since there is no other lens that can accomplish the shift range of the 23.  

And to Bryanyc's question about which to pick in the 35-45 range.  I like both the 35 and 47 digitars from Schneider.  The 47 has great coverage.  The 35 can sometimes benefit from a center filter but again has a large image circle than others in that range.  Between the 23 and 24?  If you can afford the 23 then it's a great choice unless weight and size are a consideration.  The 24 is practically invisible without the center filter and the 23 would crack the sidewalk if you dropped it and probably survive the fall too.
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JoeKitchen

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23mmHR vs 24mmXL Coverage & Distortion
« Reply #19 on: July 10, 2009, 04:07:27 pm »

Quote from: rainer_v
there is no comparison between the canon 24tse and the 23 HR, cause the canon is nearly unusable for my taste not so the 23Hr which is excellent also in terms of distortion, although not perfect.

Hello Rainer,

How does the lens preform when you are shooting a subject at an angle and have to deal with stretching of items on the edge?  Is it better in this regard then other super-wide lenses?    Also, does anyone know when Rodenstock plans on releasing the center filters for the HR23 and HR28?  

Joe
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