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Mamiya DM22 strange lines...?

Pemihan

Well-known member
I'm just started shooting with a Cambo WRS with a Mamiya DM22 back (Leaf Aptus II 5) and have seen some strange lines in some of the images.
Any idea whats causing those? I have a feeling it's mostly on shifted images...
 

torger

Active member
Is it in the middle of the image? Then it is the centerfold issue which many digital backs have. I don't remember the exact technical explanation but it is something to do with how the readout of the sensor is being made, there's a little bit of difference in sensitivity on the left and right side so you get a line there.

I have it on my Aptus 75 too, but it is very faint there so only at extreme contrast increase I can see it.

One cannot expect to get rid of it completely, but if it is really obvious then the back may need some recalibration.

When you shift wide angles you lose a little bit of DR and then this line more easily becomes visible. When you use a technical camera a good habit is to always shoot a LCC shot, with this you can cancel out dust spots, vignetting, color casts and the centerfold.
 

Pemihan

Well-known member
Thanks Torger, I thought is was something along those lines.
I did shoot a LCC shot and have tried to correct it in Lightroom but to no avail. The only thing that gets corrected is the lens falloff and color cast - not the line or any of the dust spots.

The back has just come back from service check where they realigned and calibrated the sensor.
 

dougpeterson

Workshop Member
Have you opened the image in Capture One rather than Lightroom?

Please do this and report back the results.

A correctly functioning DM22 raw file exposed within the recommend image circle of any given lens and viewed in Capture One should be absent of any visible lines or centerfold even with aggressive photographic adjustments.
 

Pemihan

Well-known member
Doug, I have checked the image in Capture One and the centerfold is clearly visible there as well. I haven't done a LCC correction yet as I can't get it to work, I think I remember something about needing to shooting compressed files..
 

yaya

Active member
If you shoot compressed and open the files in Capture One you will not see any lines, LCC or not.

Yes you need to shoot compressed if you want to use LCC

If your workflow is based on LR then you can use Leaf Capture or the Leaf Raw Converter to correct the files and save them again so that LR can open them

Your dealer should be able to guide you through this. Otherwise you can contact us via a support case.

BR
Yair
 
This happens very heavily on my P25+ as well. Haven't found out a way to get rid of it other than photoshop. If someone finds a real solution please let me know :)
 

Steve Hendrix

Well-known member
I'm just started shooting with a Cambo WRS with a Mamiya DM22 back (Leaf Aptus II 5) and have seen some strange lines in some of the images.
Any idea whats causing those? I have a feeling it's mostly on shifted images...

Doesn't look like "centerfold" to me. Often there is also a resulting tonal shift on one side or the other.

It looks more like a column error, but as has been said, it is critical that you process the file through Leaf Capture/Capture One if you have been processing this through Adobe, etc.

Same situation for the P25+ user.


Steve Hendrix
Capture Integration
 

Pemihan

Well-known member
Thanks Yair, I'll give it a try...

Steve, What do you mean bu column error, could you please elaborate...

Thanks
Peter
 

Steve Hendrix

Well-known member
Thanks Yair, I'll give it a try...

Steve, What do you mean bu column error, could you please elaborate...

Thanks
Peter

A column error is a pixel/pixels or row of pixels that are aberrant in some manner from the original mapped calibration file that require a new calibration mapping (in most cases). The phenomenon is often indicated by a single line of pixels that run through the image, but lines or rows of lines through images can be attributed to many things as well, especially when shooting tethered, depending on the camera/sync combination.


Steve Hendrix
Capture Integration
 

dougpeterson

Workshop Member
This happens very heavily on my P25+ as well. Haven't found out a way to get rid of it other than photoshop. If someone finds a real solution please let me know :)
That's NOT ok. You should contact your dealer with raw files to figure out what's going on. It's not normal and it can be fixed.
 

Pemihan

Well-known member
Ok, I have been looking closer at a bunch of images and the line is EXACTLY in the center of the images. It's clearly visible in shifted shots and can also be seen in centered shots.

I'll try and take some compressed shots tomorrow and open them up in Capture One and see what happens.

Yair, if it's the center fold issue is that something that Leaf will address?
 

yaya

Active member
If you're on a mac you can open them in Leaf Capture and the line will disappear whether they are compressed or not.

The issue was adressed about 3 years ago with new algorithms in both Capture One and Leaf Capture when applying LCC

Both softwares will do a much better job than LR as far as removing colour cast, light falloff and dust spots
 

torger

Active member
Is there a workaround for uncompressed files? I've have lots of them already, and can't apply LCC in capture one...

I usually use Rawtherapee so that's no big issue, but it would be nice to be able to use Capture One on the side.

My back is on repair so I cannot make tests here right now, but I think the reason I chose to use uncompressed in the first place is because dcraw only supports uncompressed and also Adobe's DNG converter. Has the compressed format specification been released so third-party software can implement it?
 
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dougpeterson

Workshop Member
Is there a workaround for uncompressed files? I've have lots of them already, and can't apply LCC in capture one...

I usually use Rawtherapee so that's no big issue, but it would be nice to be able to use Capture One on the side.

My back is on repair so I cannot make tests here right now, but I think the reason I chose to use uncompressed in the first place is because dcraw only supports uncompressed and also Adobe's DNG converter. Has the compressed format specification been released so third-party software can implement it?
Phase and Leaf have always been happy to provide such info to third parties. It's up to those third parties to provide the implementation.

If you shoot pre-credo Leafs you can opt to shoot compressed (full compatibility with C1) and then use the Leaf Raw Convertor (free, no license required) to convert the compressed files into uncompressed files for full compatibility in software that only supports that format.
 

torger

Active member
Thanks for the tip!

Maybe I'll look into the compressed format later on, I do some coding myself and have contributed with .mos support in RawTherapee. If it's not too much work I'd be glad to add support for the compressed format too. The way it works today for many/most third-party programs with raw support is that it enters the Dave Coffin's dcraw first (which is open source), and the third-party implementors take the code/inspiration from there (which is Dave Coffin's intention). My work in RT was basically parsing some meta data and enabling the dcraw parsing that was already there so it was not too hard. Afaik dcraw does not parse the compressed .mos format though so it will be a tougher one to implement.

Of what I've heard Adobe make indirect use of dcraw too, so if the compressed .mos makes it in there it may appear in the DNG converter too. So if I was Leaf I'd send the specs to Dave Coffin and have him implement it in dcraw.
 

yaya

Active member
There are two main types of compressed .mos files:

1. Shot to CF card or tethered to Capture One

2. Shot tethered into Leaf Capture or resaved in Leaf Capture (with the compressed option checked)

# 1 can be converted into # 2 by either resaving them in Leaf Capture or running them through the Leaf Raw Converter utility (available for Mac OS & Windows)

# 2 are compatible with most 3rd party applications although Iridient Raw Developer can also open # 1
 

torger

Active member
Uhhh... are the file format specs available? Are these complex formats, or is it basically the same as uncompressed with some compression over the sensel data?

The de-facto way to get widespread support for a raw format today is to get it into dcraw, wether you like it or not.

One of my pet hates is camera manufacturer's proprietary file formats and unwillingness to release the specs in public. I hope this is not the case with Leaf.
 

torger

Active member
There are two main types of compressed .mos files:

1. Shot to CF card or tethered to Capture One

2. Shot tethered into Leaf Capture or resaved in Leaf Capture (with the compressed option checked)

# 1 can be converted into # 2 by either resaving them in Leaf Capture or running them through the Leaf Raw Converter utility (available for Mac OS & Windows)

# 2 are compatible with most 3rd party applications although Iridient Raw Developer can also open # 1
Uhhh... I just got my paws on my back which has been away for some time, and did some tests and just realized I've been shooting compressed all the time :eek:. Actually both uncompressed and compressed format are already reverse engineered and out in the open, just tested that it works. My vague memory now tells me that it is Adobe dng converter that only does uncompressed from the Aptus, or at least did.

I assumed the files were uncompressed when LCC did not work in Capture One, but if I had used my brain I'd understand from the file sizes that they were indeed compressed. So that must be some other problem, I'll try figure it out. It's easier to make tests when one actually has the back :)
 
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