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CFV50c Images

darr

Well-known member
Hi all,

I'm urgently in need of some advice and guidence with the CFV-50c please.
Today I met with the rep to test the back on my Linhof Techno, but we ran into some problems...

Firstly, we needed up update firmware so we could have on back live view. Check...

Secondly, and here's where the problems lie, we couldn't get the live view to show an anywhere useable image without stopping the lens down to f45 (we had it set to ISO100) and even then things were pretty dodgy. Diffraction and DOF meant we couldn't begin to focus. Plus the frame rate was dog slow...

I was under the impression that one could turn live view on on the back, have the lens wide open for critical focusing when zooming in, and that the back would use its electronic "shutter" to give you a good preview image? Am I right in thinking this?

If so, how do I turn that feature on? Should it be doing this automatically anyway? Without this feature I can't do the tests I was hoping to do and I'd consider the implimentation of live view a real failure...

THanks,

TJV
(1) If using a view/tech camera, make sure your back is setup for Flash Sync:
Menu > Settings > Camera Body > Flash Sync

(2) Set the back's "P" button for the Live View option:
Menu > Settings > Custom Options > P Button > Live View

(3) Press the Nav button to go to area you want to zoom in at 100% and then press the "+" button.

Once setup, pushing the "P" Button at ANY aperture will work for LV.
I do use my shooting aperture for critical focusing.

Hope this helps!
Darr
 

tjv

Active member
Thanks to all that PM'd me with great info!
I managed to shoot some tests and they look brilliant. I will post them later but don't know how to get them to display at true scale. Each time I post anything the forum rescales the file...
In the meantime I'd like to confirm something though...

Let's say the ambient light reading is a 1/60th at f11 and ISO100. If I switch on live view and set my lens to wide open at f4.5, should the preview correct itself so that it's not blowed out and showing radical over exposure? I could only get the preview to display a legible image when stopped down past f11. This was a real bummer and I imagined live view would be more like on a DSLR.
If this is normal, do people use ND filters to focus wide open to achieve perfect focus?
 

tjv

Active member
So, I've been processing the test shots and things look very good.

To give some details of my test, I used my Linhof Techno and Rodenstock 55mm APO Sironar-Digital. I didn't have anything wider on me, but this lens would be my perfect standard lens in a two lens setup. The second lens would be either the 40mm or 32mm HR. I also own a 90mm HR-W, but this focal length doesn't interest me at all on this size sensor. The 55mm held up okay, but falls off relatively quickly past 9mm of movements.

The first series of test I shot was from center in landscape orientation, taking a series of photos in 3mm incraments of back fall. Second series was in portrait orientation, with same series of fall on the back. For both of these, I went upto 18mm of back movment. Lastly, I shot using horizontal lens shift and back fall simultaneously, with 3mm incraments in each direction.

My observation is that things look good at pixel level upto about 12mm of shift in the landscape orientation. Interestingly, I think you can get away with more in portrait orientation. Maybe 15 or 16mm? Even more intersting was that when employing movements in two directions, things looked very good even at 9mm of horizontal shift AND 9mm of back fall. This is actually where I stopped, as it was obvious that I could have hit 12mm of fall on the back with 9mm of horizonal shift and still seen excellent results. That, plus I'd hit the limit of horizontal shift on the front standard of the Techno. (I'd buy the live view shifting back if I end up buying the 50c).

So, does anyone have any tips on the best way to post some screen grabs so they don't look horrible?
 
Interestingly, I think you can get away with more in portrait orientation.
This is consistent with what I found with the IQ250 :) Movements along the longer edge of the Sony CMOS sensor appears to be more resistant with problems.

So, does anyone have any tips on the best way to post some screen grabs so they don't look horrible?
I use skydrive. I upload screenshots to the public folder and click "view original" on an uploaded image, then copy the link and paste it into the forum code with "
". If the image is not too big then getdpi froum would not rescale it.
 

jotloob

Subscriber Member
Using the CFV-50c with a HASSELBLAD or a TECHNICAL CAMERA , I could imagine , that WiFi would be an other great feature .
What are your thoughts and what is your wishlist for future development of the CFV-50c ?
 

tjv

Active member
Good question, Jurgen.
I still can't ascertain if the live view performance – i.e. the preview "exposure" issue I've described. I thought it would self correct to give a useable image for focus check at full aperture – is normal for the back, or we had a setting wrong. If this issue is odd and not how others experience live view, then to be honest there's not much more I'd like to see on a future back other than a larger sensor. It'd have to be tech camera wide friendly, though!
 

tjv

Active member


Hope this displays correctly...
Thumbnails of 50c shift test, as per the file names. Scene calibration shots and matching test shot after appying corrections.
All shot with Techno and Rodenstock 55mm APO Sironar-Digital.

I turned off all correction boxes in Phocus except Scene Calibration and a minus 0.3 exposure, then imported into Lightroom to apply editing in my preferred software. In Lightroom I added very minor clarity and a subtle contrast curve, plus a small amount of sharpening and colour NR.

Will post crops later.
 

tjv

Active member
Have now made 22x29" prints of the 12mm and 15mm shots in both orientations. They very much exceed my expectations....

Can anyone comment on the live view things I've described above? Do you need to stop down to see the image without it blowing out? Do people focus wide open or do you have to focus at you working aperture?
 
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The Live View on the IQ250 is pretty tolerant to virtually any aperture and any light condition (sunny, outdoor, night, interior, with or without centerfilter, etc) just similar as a modern DSLR or mirrorless. I'm not sure why you would need any dynamic range control for the CFV-50C. It sounds a firmware bug or just wrong settings imo.
 

tjv

Active member
Great, thanks for the info Void.
Darr or jlm, can I confirm with you guys on what your live view experience is? Does it sound like a bug to you?
 

darr

Well-known member
I do not have any issues using Live View with my CFV 50c. I can use it at the largest or smallest aperture with no issues. I generally set it at the working aperture whether in the studio or in the outside environment; I do not require the use of a loupe or ND filter to shed ambient light. If your back is not working in this manner, I would say there is something amiss with it.
 

tjv

Active member
Thanks Darr, that's very heartening. Must have been a glitch in the back I used, most likely culpret being a dodgy firwire port used to update firmware...
 

tjv

Active member


Portrait and Landscape oritentation with 18mm fall on back. Linhof Techno with Rodenstock 55mm APO Sironar-Digital.
 

tjv

Active member


Landscape and portrait orientation crops with 15mm back fall. Still the Techno with 55mm APO SD. Thought I'd post one more set with 12mm fall on back, just so people can see what I perceive are the upper limits of movments with this back. In an ideal world I'd have tested the back in more varied lighting conditions and with differing subject matter, but I feel confident I have a good handle on performance from doing this simple set of test shots.
 

tjv

Active member


All 12mm back fall, again with Techno and Rodenstock 55mm APO SD. This lens isn't the sharpest off center, but in print it is acceptable with this much movement. Hope all the above helps a few people make some well informed decisions. For me, I think this back is a real winner. I just wish I didn't encounter the live view issues I did. I have had to send the adaptors back to Linhof Studio so won't have the opportunity to test again for peace of mind.
 

tjv

Active member
Just in case people missed my comments above regarding settings I used to convert the files, I used Phocus to apply only scene calibration and pull exposure by 0.3 stops. I turned off all other boxes, including NR and sharpening. I then imported into LR and applied a +10 clarity, did a very subtle WB adjustment. I added a +10 colour NR adjustment and +35 sharpening with a 1 pixel radius, 25 detail and 2 threshold.
 

arionelli

Member
I'm developing some interest in this back as an upgrade from a P30+.
Questions, from those who have used it with the wides 40if, 40fle or 38mm 9xx, are there any issues here?
Although I have never actually used a Flexbody, how do these two mate together? I can see from data for the Flex' with V lenses on 6x6 film that the 40 won't go far, 50 has +/-5mm, remainder to 250 have +/-10 to 15mm of movements. A non-expert guess is that results may vary compared with Rodie and SK lenses on tech cams (which have been subjected to a healthy dose of scrutiny already) as image circles are probably different, but otoh may be similar if aberrations are primarily an effect of angular change centre to corner.
Thank you for any further sharing of information.
Martin
 
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