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Hasselblad CFV II 50C and LCC?

nameBrandon

Active member
Hey all..! I was discussing this with @jng via email and he had a good idea of posting this on the forum to get some wider input and to have the discussion available to others for reference / posterity.

I know the CFV II 50c has only been out a few months, but I'm curious if anyone has any experience with large format lenses and technical cameras, and the need for reference LCC images to correct vignette / color cast? I believe this is the same 33x44 Sony sensor that was in the IQ350 (and perhaps IQ250?), so I'm wondering if it's a legitimate approach to use feedback from that back as a corollary with the CFV II 50c?

I've recently ordered a Cambo technical camera and picked up an SK 35XL so I was starting to do research on if I was going to need to do a fair amount of work with LCC reference shots at different movement amounts, etc.. or if this would be mostly OK without. I did not get the center filter (still looking for one), so that was my primary reason for looking into this.

Has anyone seen any documented results from the CFV II 50c and large format lenses with view/tech cameras?

I'll happily add my 35XL test results as soon as the fine folks over at CI deliver the Cambo..!
 

tcdeveau

Well-known member
Yeah I’m using the CFVII 50c with a tech cam/large format lenses - specifically an Alpa 12 plus, 40 HR, and 70 HR.

It uses the same IMX161 FSI 50mp 33x44mm sensor in all the other 50mp CMOS backs, so any observations with those backs should generally apply to the CFVII 50c as well. The only other back I have experience with is the H5D-50c, and in my experience, the CFVII 50c behaves the same on the tech cam with movements. I know Fuji did some optimization of the micro lenses on the sensor for the GFX, but I think the sensor hardware in the P1 and Hasselblad backs should be the same.

My understanding with the 35mm XL is you are going to need to do LCC correction with movements. It’s fairly straightforward though IMHO: take shot with movements, repeat with LCC, create LCC profile in phocus with LCC shot, apply LCC profile to image that needs correction. Hasselblad has a tutorial on the software aspect on YouTube: https://m.youtube.com/watch?v=b7iggTakk-M . It’s an older video but still applies.

I can post some examples at some point, maybe this weekend.
 

nameBrandon

Active member
Yeah I’m using the CFVII 50c with a tech cam/large format lenses - specifically an Alpa 12 plus, 40 HR, and 70 HR.

It uses the same IMX161 FSI 50mp 33x44mm sensor in all the other 50mp CMOS backs, so any observations with those backs should generally apply to the CFVII 50c as well. The only other back I have experience with is the H5D-50c, and in my experience, the CFVII 50c behaves the same on the tech cam with movements. I know Fuji did some optimization of the micro lenses on the sensor for the GFX, but I think the sensor hardware in the P1 and Hasselblad backs should be the same.

My understanding with the 35mm XL is you are going to need to do LCC correction with movements. It’s fairly straightforward though IMHO: take shot with movements, repeat with LCC, create LCC profile in phocus with LCC shot, apply LCC profile to image that needs correction. Hasselblad has a tutorial on the software aspect on YouTube: https://m.youtube.com/watch?v=b7iggTakk-M . It’s an older video but still applies.

I can post some examples at some point, maybe this weekend.
Thanks! Would love to see any sample / example images.

One thing I'm interested in testing is just how effective software LCC correction is across CaptureOne, Phocus (scene calibration) and Lightroom (flat field). I know C1 and Hasselblad raw files don't play nice together, but I'm assuming if I convert to .DNG then C1 will play nice. If one goes by the amount of discussion on the forums it seems as if C1 is the best for this kind of correction, but I'm not sure if that's an artifact of Phase DB's being more prevalent (and thus discussed more).
 

tcdeveau

Well-known member
Thanks! Would love to see any sample / example images.

One thing I'm interested in testing is just how effective software LCC correction is across CaptureOne, Phocus (scene calibration) and Lightroom (flat field). I know C1 and Hasselblad raw files don't play nice together, but I'm assuming if I convert to .DNG then C1 will play nice. If one goes by the amount of discussion on the forums it seems as if C1 is the best for this kind of correction, but I'm not sure if that's an artifact of Phase DB's being more prevalent (and thus discussed more).
There are probably at least some differences in quality, but some of the discussion here I imagine has to do with the prevalence of P1 backs and the presence of P1 dealers. I'm not a pixel peeper, don't care much for comparisons, and my own philosophy is to use the camera-specific raw converter. I'd be surprised if the differences between C1 and Phocus are day/night regarding LCCs but I have Hasselblad gear (which C1 doesn't natively support) and my Phocus/LR/Photoshop workflow works fine for me....except I'm not currently happy with Photoshops stitching algorithms and need to find an alternative.

P1 backs traditionally have been more tech cam friendly than Hasselblad IMHO. None of the Hasselblad H backs have an integrated power source, so use on tech/view cams requires additional hardware (external battery pack/power source) and cables. PITA in the field compared to P1 backs. With recent backs, the H6D100c launch also didn't go particularly smooth and left a lot of users frustrated. My understanding is that heat can also be an issue with use of the H6D100c back on a tech cam. The future of the H system is also unclear currently. I've read statements that say they're committed to it and that a new H should come at some point, but who knows.

The CFV backs have an integrated power source (battery that hangs off the bottom of the back) but not too many people are using them on tech cams (there may be 2-3 users here?). The CFV50c, while having live view, doesn't have great live view. It also lacks an electronic shutter.

The CFVII 50c is a great step in the right direction for today's tech cam usage compared to previous Hasselblad backs since it has: an integrated power source (battery sits inside the back, like P1); great live view; and an electronic shutter (so you don't have to rely on copal shutters, which are now discontinued).

I'll post some examples when I can for interested people to play with. Busy week for me and it might be a few days.
 

SrMphoto

Active member
Thanks! Would love to see any sample / example images.

One thing I'm interested in testing is just how effective software LCC correction is across CaptureOne, Phocus (scene calibration) and Lightroom (flat field). I know C1 and Hasselblad raw files don't play nice together, but I'm assuming if I convert to .DNG then C1 will play nice. If one goes by the amount of discussion on the forums it seems as if C1 is the best for this kind of correction, but I'm not sure if that's an artifact of Phase DB's being more prevalent (and thus discussed more).
If you convert Hasselblad file to DNG using Adobe's DNG Converter, C1 will not accept it. The only way that you can make C1 read a Hasselblad file is by manipulating the EXIF information or by demosaicing it before importring to C1 (e.g., TIFF).
 

anyone

Well-known member
I'd step away from the idea to shoot a library of LCC shots. In practice, it's not a big issue to shoot a LCC right after the exposure (with the exception of long expousres), and you also get dust correction with it. That means: 3 minutes less clone stamping vs 20 seconds of LCC.

The CF can be still bought new, I did that a little while ago.
 

nameBrandon

Active member
I'd step away from the idea to shoot a library of LCC shots. In practice, it's not a big issue to shoot a LCC right after the exposure (with the exception of long expousres), and you also get dust correction with it. That means: 3 minutes less clone stamping vs 20 seconds of LCC.

The CF can be still bought new, I did that a little while ago.
Fair enough, I did pick up the CI LCC "card" with the camera, so shooting the images in the field shouldn't be that much additional effort.

I would love a link to anyone selling a new CF one if you happen across it!
 

anyone

Well-known member
I just had a look in my files, the company is 'Greiner Photo', www.greiner-photo.com , it costed EUR 300.

Edit: Don't bother with their rather dysfunctional German website, contact them straight away.

Edit #2: Maybe you also first want to try out how your back harmonizes with the lens before making that investment. I recall some reports that there were issues with the CMOS backs and this lens.
 

jng

Well-known member
I'd step away from the idea to shoot a library of LCC shots. In practice, it's not a big issue to shoot a LCC right after the exposure (with the exception of long expousres), and you also get dust correction with it. That means: 3 minutes less clone stamping vs 20 seconds of LCC...
Agreed! I routinely grab an LCC frame at the same time but also keep a library of LCC files in case I'm unable (or forget) to do so and later wish to make the correction.

Does the LCC correction in Phocus also remove dust bunnies? I take LCC frames even when lens cast is not an issue so that I can remove dust spots using the LCC correction tool in C1 (although this does not work so well with lenses with non-rounded aperture blades like the 5-bladed Hasselblad/Zeiss V system lenses).

John
 

nameBrandon

Active member
If you convert Hasselblad file to DNG using Adobe's DNG Converter, C1 will not accept it. The only way that you can make C1 read a Hasselblad file is by manipulating the EXIF information or by demosaicing it before importring to C1 (e.g., TIFF).
You've got to be kidding me.. they went that far to prevent Hasselblad files from coming in? Sheesh.. Talk about petty.
 

Godfrey

Well-known member
You've got to be kidding me.. they went that far to prevent Hasselblad files from coming in? Sheesh.. Talk about petty.
I don't know much about the Phase One vs Hasselblad wars, but C1 isn't the only DNG supporting app that won't read various DNG files.

The DNG file specification includes a camera calibration profile requirement ... At least two vendors of raw converters with DNG file compatibility that I ran into in the past would not process DNG files rendered from native raw files by Adobe DNG Converter unless they already had camera calibration profiles for the specific native raw file that had been converted. I can only guess that they felt the result wouldn't be up to their quality requirements for their raw processor unless they generated the CCP themselves.

Silly stuff: As someone looking for a 'universal' raw file standard that I could throw into any raw processor and some kind of results with, it seemed like a contradiction in terms that I couldn't use the DNG files unless I could already use the native raw files in those processors.

G
 

nameBrandon

Active member
I don't know much about the Phase One vs Hasselblad wars, but C1 isn't the only DNG supporting app that won't read various DNG files.

The DNG file specification includes a camera calibration profile requirement ... At least two vendors of raw converters with DNG file compatibility that I ran into in the past would not process DNG files rendered from native raw files by Adobe DNG Converter unless they already had camera calibration profiles for the specific native raw file that had been converted. I can only guess that they felt the result wouldn't be up to their quality requirements for their raw processor unless they generated the CCP themselves.

Silly stuff: As someone looking for a 'universal' raw file standard that I could throw into any raw processor and some kind of results with, it seemed like a contradiction in terms that I couldn't use the DNG files unless I could already use the native raw files in those processors.

G
Yeah, that's a shame. DNG had (and still has, I guess) a lot of promise.

The Phase One vs Hasselblad thing isn't even a DNG thing though, amazingly. C1 actively prevents Hasselblad files from coming in, and I had thought it just prevented the Hasselblad raw format by not being able to read it.. but it appears (per SrMphoto) Capture One is actually looking at the EXIF info and either using a white list / black list of EXIF values and rejecting the files. We know the sensor isn't a special snowflake like the X-trans or something, it's widely used, even by Phase. There shouldn't be any technical reason they couldn't allow the files to be imported.

I guess they see the ability to use C1 with a given camera / back as a competitive advantage. Perhaps it is... but I would love to see what their revenue breakdowns are, software vs hardware. I have to think with the all of the mirrorless / dslr users out there in addition to MF, they have to be making more from C1 than the cameras. I guess I have a hard time imaging a lot of people / companies prioritizing purchasing decisions on the software they want to use with the camera, rather than the camera itself. I have no doubt that there are those out there who are heavily workflow dependent on C1, but for Phase to actually reinforce that dependency by software limitations is amazing to me.
 

anyone

Well-known member
When I was in the market for a 'new' (in my case always used) digital back, Phocus was one minor reason keeping me away from CFV backs. Disclaimer: I never used Phocus, and I do like the C1 workflow.

In the end, but that's just my humble opinion, the raw converter that is best integrated with the files/hardware is the one that I would use, coming from the thought that you can only lose if you start to convert files. Only the first few steps of an imaging workflow happen in the converter in any case, the rest is done in PS that is universal.

That's not a statement commenting on the P1 software strategy, but purely from an image quality viewpoint.
 

tcdeveau

Well-known member
You've got to be kidding me.. they went that far to prevent Hasselblad files from coming in? Sheesh.. Talk about petty.
They view Hasselblad as a competitor since Hasselblad is still making/selling cameras with a 40x54mm sensor. Hasselblad can't be selling too many H6D-100c's these days, and it appears P1 isn't going to make a 33x44mm mirrorless system, so I'd open up C1 to the X1D/CFVII if were P1. May as well bring in some extra revenue from software licenses.

I also wouldn't be surprised if the agreement between Fuji and P1 regarding GFX access to C1 also explicitly locks out Hasselblad cameras with 33x44mm sensors (since they compete with the GFX).

Not sure it's petty so much as "just business". Shrug.
 

mristuccia

Active member
Can't tell by personal experience, but owning the Mk1 version of the CFV-50c I did some research before buying a Cambo technical camera to match it with.
From what I've understood, the lenses with symmetrical schemas don't fit well with this sensor, so most of the Schneider lenses are not going to give great results with it.
The Rodenstock ones, or any other "retro-focus" lens, will probably give better results.

That's the reason why even Hasselblad discourages the use of this back with the SWC (the 38mm Biogon having a symmetrical schema, too close to the sensor).

As for me, I've bought a custom Cambo adapter and keep using my Hasselblad V lenses with it and the CFV-50c back. Until now I never needed an LCC with this combination.
If one day my pocket will allow it, I'll buy a Rodie 23mm HR.

Best,
marco
 

nameBrandon

Active member
Can't tell by personal experience, but owning the Mk1 version of the CFV-50c I did some research before buying a Cambo technical camera to match it with.
From what I've understood, the lenses with symmetrical schemas don't fit well with this sensor, so most of the Schneider lenses are not going to give great results with it.
The Rodenstock ones, or any other "retro-focus" lens, will probably give better results.

That's the reason why even Hasselblad discourages the use of this back with the SWC (the 38mm Biogon having a symmetrical schema, too close to the sensor).

As for me, I've bought a custom Cambo adapter and keep using my Hasselblad V lenses with it and the CFV-50c back. Until now I never needed an LCC with this combination.
If one day my pocket will allow it, I'll buy a Rodie 23mm HR.

Best,
marco
That's good info, Marco, thanks! I've actually purchased the Hasselblad V adapter board (with shutter mechanism) for my Cambo as well. I'm curious what V-series lenses you primarily use with that setup? 40mm? 50mm? I have a 50mm CF FLE, and had concerns that on the 33x44 sensor the 50mm was going to be too long (unless I’m reversing the crop factor math..). Cambo should be in on Monday and hopefully I can get some testing in next week.
 

jng

Well-known member
The Hasselblad/Zeiss 40/4 CFE IF is a terrific lens (not to be confused with the 40/4 FLE or earlier versions). This is perhaps the sharpest lens in the V system lineup although it shows quite a bit more distortion compared to the 38 Biogon, which as Marco notes above struggles somewhat in the corners with these sensors (although others here use it with great results). I previously used the 40 IF on my Flexbody + IQ160 and found the image circle large enough to allow for at least 10mm shifts. I don't know how well it will play on the smaller 33x44 CMOS sensor but my hunch is that with its retrofocus design, it should do fine (I think that Marco uses this lens?). I reluctantly sold mine a few years ago when I moved to the Cambo and picked up the Rodie 40HR. Good copies are out there; they are not cheap except perhaps when compared to the Rodie... :ROTFL:

John
 

nameBrandon

Active member
Okie dokie.. quick test since everything arrived a bit ago. I didn't get the LCC tool in yet, and just shot a wall nearby, which was slightly window lit, so definitely not a 100% solid LCC capture on this, but just wanted to see results at 0 shift. There is definitely color cast happening here.. I did shoot at a variety of movement settings but will wait until can get a clean LCC image before sharing any image results.. my gut feeling though is 10mm in any direction is probably going to be the limit with this 35XL and CFVii.

These were all fixed in Phocus using scene calibration, except for the final one for comparison, which was done in LR flat field. The image is not evenly lit, the brighter side of the image was closer to a window, so it's expected that one side (to there right of the flowers) is brighter and the other sider darker.. again, not a great test, but I wanted to play with the new toy. :)

all at f/11, iso 100.. 1 second exposure.

Interesting to note the RAW conversion difference as far as colors go between Phocus and LR. I want to say Phocus is more accurate as far as the actual wall color but it's honestly hard to tell. It was a significant enough difference that I went back and checked WB settings and they are the same values. I may have to start looking at raws in both Phocus and LR if the color is this different..

Uncorrected LCC frame



Corrected LCC frame (Phocus Scene Calibration)



Sample shot - uncorrected




Sample shot - Corrected / Phocus SC



Sample shot - Corrected / LR FF

 
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mristuccia

Active member
That's good info, Marco, thanks! I've actually purchased the Hasselblad V adapter board (with shutter mechanism) for my Cambo as well. I'm curious what V-series lenses you primarily use with that setup? 40mm? 50mm? I have a 50mm CF FLE, and had concerns that on the 33x44 sensor the 50mm was going to be too long (unless I’m reversing the crop factor math..). Cambo should be in on Monday and hopefully I can get some testing in next week.
With my Cambo WDS I mainly use the 40 IF, the 60 and the 80.
If I remember well, with the 60 and the 80 I'm able to shift up to 18-20mm without problems. With the 40 IF I usually stop shifting at 13-15mm.
As John (Jng) already stated, the 40 IF is a terrific lens, in terms of sharpness (super), weight (a lot) and distortion (significant). :)

As for the RAW developer, I mostly use Lightroom with the "Enhanced details" algorithm, or LR with the Iridient RAW developer integration. Both of them give me more details than the standard LR demosaicing algo.

I've posted some stuff in the "Technical Camera Images" thread.
 

tcdeveau

Well-known member
Here are some test files people can play around with if they want....

https://drive.google.com/drive/folders/1s3nRR7HuPv6cCVPgB0JbF2AXKMfbQCq0?usp=sharing

CFVII, Alpa 12 Plus, 40 HR, and 70HR. There's a series of -15mm, 0, +15mm shift (no rise/fall) and -15mm, 0, 15mm (+5mm rise...or -5mm? can't remember) for each lens. Electronic shutter used on the back, each lens was maybe at f8? Remote used with the back for capture. Body leveled according to spirit levels on the 12 Plus.

The corresponding LCC frame for each shot is the filename of the original shot +3....so if the original capture was xxx1.fff, the corresponding LCC shot is xxx4.fff.

I think for whatever reason I did 15mm and not 20mm but it could be 20mm too. Would be nice if we could enter the data manually via the back.

Not a scientific test or anything and the light was changing pretty fast. Have not tried to do any shimming or anything with the back yet to make sure infinity focus is spot on either (each lens was at infinity).

Feel free to post your results in this thread or elsewhere on GetDPI, just please credit me for the capture if you do. Please ask for permission if you post them anywhere else :)

Anyway...have fun :cool:
-Todd
 
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