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Author Topic: Hasselblad SWC with a Digital Back  (Read 17030 times)
John R Smith
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« Reply #20 on: July 31, 2011, 12:19:50 PM »
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Just to set the record straight -

My CFV back uses the Kodak KAF-39000 sensor, which according to the spec sheet has an active image size of 49.0 x 36.8 mm. The pixel size is 6.8 um. It does not have microlenses. Interestingly, there are two grades available - standard, and engineering grade.

I think that with the SWC a sensor using microlenses would be very bad news. The rear element of the Biogon is very, very close to the sensor plane - actually, I'm amazed that it works as well as it does. The light rays at the edge of the sensor must be coming in at a very low angle.

Another interesting thing which really we only become aware of when we put these old lenses on a digital back, is that just like the Distagons and in fact most of the old Zeiss glass, the Biogon is optimised for the far field. It does close focus (down to 12 inches) but close shots are OK but not stunning. When you get out to 30 feet plus, the lens comes on song and you go "Wow" as the detail snaps in. Which is just what you want for architectural stuff and church interiors, of course. For close work stick to the 120mm S-Planar.

John
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rolad
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« Reply #21 on: July 31, 2011, 01:13:03 PM »
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Rob, Ronald, John
you are right of course - i meant to write "36*48mm approx" in my question, not 24*36...

john,
thanks again for your input!
so your opinion would be that the swc biogon ought to be basically unusable with sensors with micro lenses?

you also mention that the biogon is optimized for the far field.
short of me starting to try to get hold of one with a back and testing myself:
could you give some indication as to what kind of IQ difference ld have to be expected between i.e. 3-6 and 30 ft?

thanks
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eronald
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« Reply #22 on: July 31, 2011, 02:25:28 PM »
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Just to set the record straight -

My CFV back uses the Kodak KAF-39000 sensor, which according to the spec sheet has an active image size of 49.0 x 36.8 mm. The pixel size is 6.8 um. It does not have microlenses. Interestingly, there are two grades available - standard, and engineering grade.

I think that with the SWC a sensor using microlenses would be very bad news. The rear element of the Biogon is very, very close to the sensor plane - actually, I'm amazed that it works as well as it does. The light rays at the edge of the sensor must be coming in at a very low angle.

Another interesting thing which really we only become aware of when we put these old lenses on a digital back, is that just like the Distagons and in fact most of the old Zeiss glass, the Biogon is optimised for the far field. It does close focus (down to 12 inches) but close shots are OK but not stunning. When you get out to 30 feet plus, the lens comes on song and you go "Wow" as the detail snaps in. Which is just what you want for architectural stuff and church interiors, of course. For close work stick to the 120mm S-Planar.

John

I think engineering grade is a with some image defects. No problem for doing electronics.

Edmund
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John R Smith
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« Reply #23 on: August 01, 2011, 02:23:03 AM »
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john,
thanks again for your input!
so your opinion would be that the swc biogon ought to be basically unusable with sensors with micro lenses?

you also mention that the biogon is optimized for the far field.
short of me starting to try to get hold of one with a back and testing myself:
could you give some indication as to what kind of IQ difference ld have to be expected between i.e. 3-6 and 30 ft?

Roald

I have no microlens back to try out, so I am just guessing. I could well be wrong. Almost all of the Zeiss lenses of the period are optimised for the far field (Zeiss say so themselves, in their spec sheets and MTF charts). The exception is the 120mm S-Planar, which has astonishing MTF and zero distortion in the near field. I also believe, but have no solid data to back it up, that the 80mm Planar (of which I have two examples) is optimised somewhere in the middle, because it works very well close-up but is a little soft at infinity (compared with the 100mm Planar).

I have only done a little bit of testing with the SWC, but to my eyes shots taken at around 4 to 6 feet from the subject have not got the “bite” that I would have hoped for. Mind you, the 50mm and 60mm Distagons are even worse close-up. Later on, Zeiss fitted the 40 and 50mm Distagons with floating elements (FLE versions) so that the lens could be adjusted for close work, which demonstrates that they were well aware of the problem. This is a very relative thing, however – the image quality from the 38mm is still very good by most standards close up. What you seem to lose is some of the micro-contrast that separates the detail out and gives the picture a real edge.

Once you put a digital back on any of these old cameras, you see stuff that you would never have noticed with film.

John
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KLaban
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« Reply #24 on: August 01, 2011, 03:26:30 AM »
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I also believe, but have no solid data to back it up, that the 80mm Planar (of which I have two examples) is optimised somewhere in the middle, because it works very well close-up but is a little soft at infinity

John, that's also been my experience.

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John R Smith
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« Reply #25 on: August 01, 2011, 04:04:27 AM »
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John, that's also been my experience.

Keith, thanks for that supporting evidence!

John
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« Reply #26 on: August 01, 2011, 05:55:04 AM »
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Keith, thanks for that supporting evidence!

John

Seen this with the 60mm Distagon but not with the 80mm so I'd look at sensor position/ alignment
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« Reply #27 on: August 01, 2011, 06:22:07 AM »
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Seen this with the 60mm Distagon but not with the 80mm so I'd look at sensor position/ alignment

My experience was with film and on several bodies.

I can also confirm that, as one would expect, the FLE versions of the 50mm showed significant improvement at close focus.
« Last Edit: August 01, 2011, 06:27:51 AM by KLaban » Logged

John R Smith
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« Reply #28 on: August 01, 2011, 07:49:36 AM »
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Seen this with the 60mm Distagon but not with the 80mm so I'd look at sensor position/ alignment

Well, sensor position and alignment for me is what I believe the Americans call a "crap shoot". I have three 500 C/M bodies, all getting on for forty years old and in varying states of wear, and now the SWC as well, also nearly forty. None of them have been serviced or collimated or whatever it is you are supposed to do. I am quite sure that when I swap around between these with various equally elderly lenses that the idea of 10 micron tolerances between the sensor plane and the lens or whatever is just laughable. Nonetheless, my shots are mostly in focus and when it does go wrong it always seems to be down to human error. The only thing I have done (and always do with a "new" body) is to very gently adjust the lower magazine "hooks" so that the CFV back is really a very snug fit. No slop.

We should also remember that the 38mm Biogon was first introduced with the Hasselblad SWA in 1954, and should be judged in that context with the film technology of the day. The lens remained in production with the SWC, SWC/M and later 903 and 905 unchanged in design, just in a revised package. That a nearly 60 year old design still works well with digital is a real tribute to its quality.

John
« Last Edit: August 01, 2011, 08:11:54 AM by John R Smith » Logged

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Rob C
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« Reply #29 on: August 02, 2011, 12:03:37 PM »
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Well, sensor position and alignment for me is what I believe the Americans call a "crap shoot". I have three 500 C/M bodies, all getting on for forty years old and in varying states of wear, and now the SWC as well, also nearly forty. None of them have been serviced or collimated or whatever it is you are supposed to do. I am quite sure that when I swap around between these with various equally elderly lenses that the idea of 10 micron tolerances between the sensor plane and the lens or whatever is just laughable. Nonetheless, my shots are mostly in focus and when it does go wrong it always seems to be down to human error. The only thing I have done (and always do with a "new" body) is to very gently adjust the lower magazine "hooks" so that the CFV back is really a very snug fit. No slop.

John


That's an opinion I see as being based on reality; I wonder if it's possible to steer some of the other threads towards the same attitude... I suggest it applies way beyond the confines of 500 Series photography!

The curse of the new. Opens entirely fresh Pandora Boxes, copiously stuffed with clouds of misinformation and opinion made fact.

Rob C
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TH_Alpa
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« Reply #30 on: August 02, 2011, 12:20:02 PM »
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Rob,

There may always be misinformation and opinion made facts. Also, issues bothering some may not be of importance for others. In any case, I can assure that the sensor position, the precision of the different parts of a system is something to consider carefully and it can lead to surprises, the more with the newest back generations. It is actually not that much the problem of getting focus, much more of getting it at the right place.

Best regards
Thierry


Opens entirely fresh Pandora Boxes, copiously stuffed with clouds of misinformation and opinion made fact.

Rob C
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Nick-T
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« Reply #31 on: August 02, 2011, 02:57:43 PM »
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It's a wonderful thing that these old beauties can keep on doing their thing in this digital age.



At the launch of the H4D I was lucky enough to shoot a few test frames with a CFV back on one of the Apollo cameras (obviously not one of the ones that went to the moon), it worked just fine.
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rogerxnz
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« Reply #32 on: August 17, 2011, 07:08:01 PM »
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I have read that the tripod plate of the SWC prevents Leaf digital backs (and, possibly, other makes as well) from being attached in landscape orientation because the battery pack occupies the same space.

Would someone confirm or deny this, please.

Options include (1) removing the tripod plate (and the released nuts from inside the body) and adding a metal block, threaded to attach to a tripod, which allows room for the battery and (2) cutting off the rear of the tripod plate which extends into the space required for the battery.

Any other options?
Roger
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Roger Hayman
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« Reply #33 on: August 18, 2011, 05:19:11 AM »
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I have seen the plate unscrewed (very tight) and it works fine but it is just simpler to rotate the camera from Port. to Land. and leave the plate in position.
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rogerxnz
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« Reply #34 on: August 18, 2011, 05:11:00 PM »
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Thank you, ced. That is an option, I agree, but you then lose the assistance of the bubble level!

I guess I could always use a level app on my iPhone!
Roger
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Roger Hayman
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« Reply #35 on: August 23, 2011, 06:06:33 AM »
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Couple of helpful notes:

If you do need to get service on V-system (500 series, et all) US cleaning and tune up is $99 per body at NJ Service Center
Although I have not personally tested; the digital backs with a microlens should not be compromised on the SWC as the imaging plane is the same as the lens plane - not the case if swing or tilt that introduce different plane angles.

John
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« Reply #36 on: August 23, 2011, 12:45:51 PM »
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I think there may have been a modification at one time, to put some sort of spacer between the body and the mounting foot to lower it. A good repair shop could possible make something like that.
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Lulumi
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« Reply #37 on: August 27, 2011, 01:04:48 AM »
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Hi guys
I took some pictures about SWC vs CFE40IF last year.
Digitalback:P65+
CFE40IF is better than SWC.(esp. corner)



CFE40IF
Central

http://omwdca.bay.livefilestore.com/y1paej0bX8G_l8ZblvisXTu5wI3OmZ84mdH-7xqxW5eNof1Z-Ubkbbk_Nos5isM5NG-CgrYTQmpYrZDQ3MYWmxRWsvAvU24Gl23/CFE40IF_c.jpg
Corner

http://omwdca.bay.livefilestore.com/y1pdx0ca0ckDAEmiYwYEyafaCFw1oep460nmPuv4wPAqkjHIowDMdYFnYg6660EY9h5V3zbWZKFWO-wVZ6ABiYdbTnQ1cce91mT/CFE40IF_p.jpg

SWC
Central

http://egryhq.bay.livefilestore.com/y1pZKevNedFRGDxL_G4Oq4d5-ARz8zHMJb366qG3yUXQkdLM2u2fLzpi98S7Lgh8QaK4tD_vsTKE9ExISjIagAaUtoJ9X2-zqSk/905SWC_c_1.jpg

Corner

http://egryhq.bay.livefilestore.com/y1p9boDIlRByWuwdLmXe2qLM2IHu53RO_me2hZ9gq7EQyRY_FMq1wAfF4UmHLFb4wE-g8RZgp8FkWuNbjGvmNJmHNcPkG-LXQC5/905SWC_p_1.jpg

The other lens :
http://www.hasselbladfans.net/viewthread.php?tid=959&extra=page%3D1&page=1
« Last Edit: August 27, 2011, 01:10:27 AM by Lulumi » Logged
John R Smith
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Still crazy, after all these years


« Reply #38 on: August 27, 2011, 02:58:51 AM »
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Lu

Thanks for that useful and interesting comparison. I am sure that you are correct, and I would have expected that the retrofocus 40mm FLE would work better on a digital back than the SWC. It is a far more modern design, of course. It is interesting to see how the corners on the SWC continue to improve up to f22, whereas the 40mm is definitely losing IQ by then due to diffraction.

I thought about the 40mm myself (and purchasing one used it would have been cheaper than the SWC), but combined with the 500 C/M and the CFV back the whole package is a lot heavier than the SWC and back. And I needed something (relatively) compact and light as a walk-around camera.

I'm having a lot of fun with the SWC - here are a couple of recent shots.

John
« Last Edit: August 27, 2011, 06:14:51 AM by John R Smith » Logged

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neilwatson
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« Reply #39 on: August 30, 2011, 09:19:51 PM »
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Very interesting information on the performance of the SWC.  Looks really good considering the lens is an old classic design.

I found out that my SWC needs to go back to Hasselblad to have the bottom plate modified.  Looks like it's worth paying for this to be done.

Do you have any problems with the positioning of the battery with the L plate on the cfv39.  Does this make the camera harder to hold or ok?

Do you mostly use the SWC on a tripod or you find you can hand hold?  I was worried about accurate focus. Do you find this to be a problem?  Any tips to share here.

Thanks

Neil
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