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Arca-Swiss R-Series Video Introduction

lance_schad

Workshop Member
Here is a video that explains the operation and features of the Arca-Swiss R series technical camera. It was produced by Rod Klukas from Arca-Swiss.

This is the same camera Jack just evaluated with his IQ Back.

Click To Watch Video


Lance
 

David Klepacki

New member
I am surprised to see that the Schneider 72mm lens cannot reach infinity focus (captured video frame attached below).
 
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RodK

Active member
I am surprised to see that the Schneider 72mm lens cannot reach infinity focus (captured video frame attached below).
This is because infinity has no value and so to make a DOF chart you have to choose a value for infinity and a circle of confusion. These choices vary.
The values calculated therefore do not make sense because 'infinity is infinity correct? Well not always.
The standard for analog or film seems to vary between 20 times the focal length and 200 times the focal length to maybe 10,000 times the focal length for satellite surveillance lenses as they are so far away from a solid object.
Similarly aerial lenses used to use a high number for aerial photography, but were mostly useless on the ground. Never sharp.
So the formula for the lenses we use can say we are not reaching infinity with this near point at the 5.6 stop. And your farthest point is probably not super sharp. And we tell you that. Also the corner quality is not so good either due to refraction. So stopping down 1 or 2 stops is usually your best choice for quality and added DOF, anyway.
Hope this helps,
 

David Klepacki

New member
Thanks for the explanation Rod. I had no idea the Schneider 72mm lens was this poor.

For example, according to this information at F8, the Schneider 43mm lens can give critically sharp focus at infinity (however infinity is defined by Arca-Swiss), but the Schneider 72mm cannot even come close to being sharp at infinity ... even though it has significantly higher magnification due to its longer focal length. Wow, this is awful.

The infinity value for the 72mm lens must be greater than 62.5 meters, which is the farthest depth of field indicated at its F16 setting for infinity focus. The fact that the Schneider 72mm lens can only get to 36.2 meters at its farthest depth of field at F8 is a really poor performing lens. My Mamiya 80mm lens does not behave like this, and gives me very sharp results at F8 for more distant objects when focused at infinity.
 

jlm

Workshop Member
aren't DOF calcs lens quality independent? only depending on aperture, focal length, distance and image size?
 

David Klepacki

New member
aren't DOF calcs lens quality independent? only depending on aperture, focal length, distance and image size?
Technically no. If these were the only things taken into consideration, then the far depth of field should always indicate "infinity", when the lens is focused at infinity. The data here from Arca-Swiss does not indicate this, which implies that they are taking into consideration other factors that limit effective resolution that may be lens quality dependent (e.g., lens MTF, diffraction, etc.), and perhaps introduce an "effective value of infinity" for each lens as well.
 
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yatlee

Member
For thos who use a Phase one back. Do you do 2-shot? Will the one shot cabe offered by Kapture group has a magnetic attachment to the R-lens?
 

Jack

Sr. Administrator
Staff member
The one-shot cable, or any other standard cable will still screw into the mag socket on Arca lenses. I used my one-shot with the 43 test and *really* prefer it over the two shot system --- lot's faster to use.
 

yatlee

Member
Thanks Jack. I have a one-shot cable and love it. Wouldn't it be nice if Keith can modify the other end. So, we have a quick attach and release.

I like Arca rd3m more and more. I currently have 4 Rodenstock HR lens (40mm, 50mm, 70mm & 90mm). How much will it cost to retrofit lenses to R- mount? I probably will do it after I upgrade my back. Anyone has experience on this?
 

yaya

Active member
Technically no. If these were the only things taken into consideration, then the far depth of field should always indicate "infinity", when the lens is focused at infinity. The data here from Arca-Swiss does not indicate this, which implies that they are taking into consideration other factors that limit effective resolution that may be lens quality dependent (e.g., lens MTF, diffraction, etc.), and perhaps introduce an "effective value of infinity" for each lens as well.
David, the 72mm is very popular for aerial applications and I think what matters most to these customers is the f8 performance at infinity

Note that for these applications each lens is mated and calibrated to a specific body+back combo and everything is bolted after calibration.
 

David Klepacki

New member
David, the 72mm is very popular for aerial applications and I think what matters most to these customers is the f8 performance at infinity

Note that for these applications each lens is mated and calibrated to a specific body+back combo and everything is bolted after calibration.
Yair, this is very surprising. According to the Arca-Swiss data on this 72mm lens, they indicate that the "acceptable sharpness" of this lens at infinity focus at F8 does not exceed 36.2 meters (see my above attachment containing the 72mm lens tube above). I just do not see how anyone can take decent aerial photos with such a lens.
 

Jack

Sr. Administrator
Staff member
Thanks Jack. I have a one-shot cable and love it. Wouldn't it be nice if Keith can modify the other end. So, we have a quick attach and release.

I like Arca rd3m more and more. I currently have 4 Rodenstock HR lens (40mm, 50mm, 70mm & 90mm). How much will it cost to retrofit lenses to R- mount? I probably will do it after I upgrade my back. Anyone has experience on this?
I have asked Arca to make the cable magnets available -- I understand they are cable threaded and then basically screwed and glued to basic release cables at the factory. So if we could get some blank magnets, we could easily adapt our one-shot releases the the Arca mag release mount which would indeed be cool!

I do not know how much each lens costs to convert. It's probably best to contact Rod Klukas, RodK from post #3 above, and ask him directly.
 

Steve Hendrix

Well-known member
The cost for mounting existing lenses into the R Bayonet is:

$1,146 for 23mm - 120mm

$1,581 for 135mm - 250mm


Regarding modifying the One Shot to accept a magnetic interface, I would say it will likely need to be stronger than the existing magnetic setup and I believe Arca Swiss is working on strengthening this anyway.


Steve Hendrix
 

RodK

Active member
Thanks for the explanation Rod. I had no idea the Schneider 72mm lens was this poor.

For example, according to this information at F8, the Schneider 43mm lens can give critically sharp focus at infinity (however infinity is defined by Arca-Swiss), but the Schneider 72mm cannot even come close to being sharp at infinity ... even though it has significantly higher magnification due to its longer focal length. Wow, this is awful.

The infinity value for the 72mm lens must be greater than 62.5 meters, which is the farthest depth of field indicated at its F16 setting for infinity focus. The fact that the Schneider 72mm lens can only get to 36.2 meters at its farthest depth of field at F8 is a really poor performing lens. My Mamiya 80mm lens does not behave like this, and gives me very sharp results at F8 for more distant objects when focused at infinity.
David,
We have seen that we have an error and are working to correct. Anyone with a 43mm and/or 72mm will get a corrected drum or sticker for the drum. We are reviewing all the drums.
The data has nothing to do with the quality of a lens. The 72mm is an excellent lens and I own one myself. Schneider has one of my pics on their site as well. See 72mm Apo-Digitar in Copal and click SAMPLE. The 72mm in work otherwise, has always been excellent and no one should have a problem using it for anything, including aerial photography. You were correct in that '0' is infinity and should be infinity at all apertures. The drums will be replaced or new sticker Data labels will be provided as soon as new ones printed. Thanks for bringing to our attention. '0' is indeed infinity for our purposes on all the lenses. Just math error on our chart. mea culpa...
Rod
 
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ddanois

Member
David,

I purchased a 43 when I purchased the Rm3Di. I haven't heard this from my dealer. How do I get a new drum?

Derek
 

David Klepacki

New member
David,
We have seen that we have an error and are working to correct. Anyone with a 43mm and/or 72mm will get a corrected drum or sticker for the drum. We are reviewing all the drums.
Rod
Rod,

This is good news, at least for Schneider. However, I checked my own Rm3d lens tubes for accuracy, and every one of them contain errors. So, in general, the Arca-Swiss lens tube information data must be considered unreliable at this time for all its lenses, and not just this 43/72 one.

Please keep us up to date on how to obtain replacement lens tubes. And, of course, thank you for looking into this.

David
 

RodK

Active member
David,

I purchased a 43 when I purchased the Rm3Di. I haven't heard this from my dealer. How do I get a new drum?

Derek
Derek,
Email me and tell me which lenses you have and I'll get it to you as soon as available. Sorry for problem.
Rod
 

RodK

Active member
To all we will be checking all the R drum data and replacing where needed.
If you are concerned email me and tell me your lenses taht are R mounted and I will replace if needed as soon as available.
Rod
 

Jack

Sr. Administrator
Staff member
To all we will be checking all the R drum data and replacing where needed.
If you are concerned email me and tell me your lenses taht are R mounted and I will replace if needed as soon as available.
Rod
Talk about great customer service -- awesome that A/S is owning up and fixing ASAP!
 
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