23mmHR vs 24mmXL Coverage and Distortion

[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.

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

 

[jeffreytotaro]

The 10 and 15mm shifts of the 23HR....

 

[Jack]

Nice comparison, thanks for posting!

If you send that 23HR 0 shift shot to thomas Niemann at PTLens, he will build you a correction profile

 

[jeffreytotaro]

Thanks Jack! I was hoping I would find some correction ideas. I guess I could send various shift amounts and he correct for each?

 

[Guy Mancuso]

Just the no center filter alone would make me lean to the 23mm. Okay a much lighter wallet too
But the ability to shift more makes up for it

 

[Jack]

I think you can move the center point for corrections in his software already, so probably not necessary, but ask him.

 

[jeffreytotaro]

Hi Jack:

I can't seem to find his email on the site. Can you PM me his address?
Thanks!

 

[Jack]

Hi Jeffrey:

Yes, his site is a bit spartan and not intuitive to navigate. Here is the site link, navigate initially on the side bar. Note especially the section on shift lenses as he explains how to do the capture so he can profile it: http://epaperpress.com/ptlens/index.html

Here is his contact form on the site's feedback link, click here and navigate to "feedback": http://epaperpress.com/whoami/index.html

FWIW, his software is excellent and works as stand-alone or as a CS plug-in, and now works on both Mac and PC. A bargain at $25.

 

[jeffreytotaro]

Thanks Jack!

 

[Don Libby]

Hi Jeffrey

Great post!

I saw the very same thing with my Schneider 24mmXL Digitar lens while I was testing it. It appears the 24 can not be shifted without causing even the slightest of vignette [found out the hard way thinking I was set at zero movements].

Never been a huge fan of having to use a centerfilter however at a $3000 difference I think I can get used to it.

Just thinking out loud here - I'm wondering if the centerfilter is the cause of some of the vignette problems; would a different filter - one that attaches directly to the lens without the 1/2 inch collar add the ability to shift at least out to maybe 5mm?

I may have missed it but which back are you using? Very glad to see others testing and posting.

Here's my sample of 10mm with the 24mm

I think they're both good lens after you find their limitations and quarks. Have any more tests to share?

Don

 

[jeffreytotaro]

Hi Don:

I saw your earlier post about the 24. Yes I think the center filter does vignette a bit but it's such a big difference without for exposure.

 

[Jack]

Don,

You might want to try using the 2A CF designed for the 38XL mounted via a 52>67 step ring. I bet that would work pretty darn well and alleviate the vignette...

PS note on optical design: Optical design is always an exercise in tradeoffs. The common at odds tradeoff is falloff versus distortion; correct for falloff and distortion increases but you usually gain some coverage (IC/CoI), correct distortions and falloff increases while IC decreases. IMO, it appears the design of the 23 favors landscape type captures and the 24 design favors architectural captures...

Cheers,

 

[Don Libby]

Hi Don:

I saw your earlier post about the 24. Yes I think the center filter does vignette a bit but it's such a big difference without for exposure.

I agree the IQ without the centerfilter just ... sucks (to use a highly technical term).

Don,

You might want to try using the 2A CF designed for the 38XL mounted via a 52>67 step ring. I bet that would work pretty darn well and alleviate the vignette...

I need more time with the lens/filer combo before I go that route. We're headed to Sedona in June and plan to put this lens through its paces and really see just how good it is. Right now I feel I can live without movements on the lens but am willing to wait till I do an actual landscape shot (vs the testing I'm doing around here). The other side of the coin is that I doubt the lens will support that much of a movement and as is I get the coverage I like.

PS note on optical design: Optical design is always an exercise in tradeoffs. The common at odds tradeoff is falloff versus distortion; correct for falloff and distortion increases but you usually gain some coverage (IC/CoI), correct distortions and falloff increases while IC decreases. IMO, it appears the design of the 23 favors landscape type captures and the 24 design favors architectural captures...

Cheers,

I agree - but then again I'm noted for doing things differently:ROTFL:

 

[ericstaud]

There is still a fair amount of falloff in the 23 HR. The top of the building should be the same value or brighter than the middle of the building, but instead it's at least 1/2 stop darker. It looks easy enough to manually correct in Photoshop, but using a filter on that kind of shot would save you some time down the road.

 

[Don Libby]

Jeffrey

My intent is not to hijack your post however it did make me want to review my original test images.

What I found is that the 24mm requires a lot more attention to detail making absolutely certain that no movements occurred between shoots. These two image are from a series I took for a layered focal image later in CS4. The first image does not show vignetting while the second does. Same settings on both image however it appears I had a slight movement change between images. There are actually two images taken before that show no distortion however there's two in-between afterwards that show a slight increase. I've decided to double check the camera to ensure the movement adjusters are secured.

No more images - I promise!

Don

 

[arashm]

Jeffrey
Thank you so much for posting these.
these images are of great help.
am

 

[carbonmetrictree]

I'm also very happy with my 23HR. It might just be me, but it seems that Rodenstock's new Digaron series' glass is sharper than the older Sironar versions. I just had my 28HR replaced with a Digaron and the files are incredibly sharp, even when comparing the images with the same lens from a friend. I was a bit afraid that I wouldn't have gotten my money's worth considering the 1mm difference, but the image circle and sharpness made me smile when I first opened up a few test shots a month ago.

Thanks for the test, Jeffrey! I've been itching to see the differences between the lenses side by side.

Here's a shot that I absolutely needed the 23HR in an abandoned coal refinery. I was able to shift 6mm each way vertically to get all of the pipes to create a stronger composition.

 

[Don Libby]

I'm also very happy with my 23HR. It might just be me, but it seems that Rodenstock's new Digaron series' glass is sharper than the older Sironar versions. I just had my 28HR replaced with a Digaron and the files are incredibly sharp, even when comparing the images with the same lens from a friend. I was a bit afraid that I wouldn't have gotten my money's worth considering the 1mm difference, but the image circle and sharpness made me smile when I first opened up a few test shots a month ago.

Thanks for the test, Jeffrey! I've been itching to see the differences between the lenses side by side.

Here's a shot that I absolutely needed the 23HR in an abandoned coal refinery. I was able to shift 6mm each way vertically to get all of the pipes to create a stronger composition.

Nice image - I like the yellow against the b&w.