Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: acg on March 31, 2011, 11:47:18 pm
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I am new to MF digital backs. I just got an Alpa 12 TC with a Leaf Aptus 75, with a Schneider digitar 35mm f/5.6 XL. The photos from that are very sharp. However, when shooting a white wall indoor, the colors became very chaotic, with hints/cast of green / purple here and there.
Any suggestions on how to handle the color cast?
Thanks!
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Both the Leaf and Phaseone software have lens calibration built in to remove lens cast. You need to shoot the white plexi disc that came with the back or just use a piece of white plexi. You do need to shoot it at the same movements and f stop the image was shot at. I believe he Leaf website should have all the directions.
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Thanks for the reply. It seems I will need to connect my camera to my computer to do the calibration. Unfortunately my computer does not have a firewire port. I am going to find an adapter to connect these two and try it out.
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Thanks for the reply. It seems I will need to connect my camera to my computer to do the calibration. Unfortunately my computer does not have a firewire port. I am going to find an adapter to connect these two and try it out.
No need for a computer.
Set the back's compression to "Lossless"
Shoot with a White diffuser filter (or a piece of white perspex) as John suggested. It is important to do one whenever you change aperture and to compensate by adding 2 stops of exposure time.
I'm assuming that no firewire port means it's a PC, so you have to use Capture One Pro:
Select the white image and in the lens tool tab, select Analyse from the LCC drop-menu, save it let's say with the f-stop number. Then select all the images that you've taken with the same aperture and apply this correction by selecting it from the same drop-menu
You can opt to apply fall off correction as well at the same time
Note that this function does not exist in Lightroom/ ACR so if you use these you will have to do the correction in Photoshop, which si time consuming and probably not as good.
Enjoy your new back!
Yair
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Thanks Yair!
I am using a MacBook air actually. (I know it is not that fast, but useable to me.)
So I am using leaf capture v11. The menu has a "camera" item, and there is a "create lense calibration file" under it. However it is disabled.
Any suggestions on how to use LC to correct the colors? Thanks a lot!
No need for a computer.
Set the back's compression to "Lossless"
Shoot with a White diffuser filter (or a piece of white perspex) as John suggested. It is important to do one whenever you change aperture and to compensate by adding 2 stops of exposure time.
I'm assuming that no firewire port means it's a PC, so you have to use Capture One Pro:
Select the white image and in the lens tool tab, select Analyse from the LCC drop-menu, save it let's say with the f-stop number. Then select all the images that you've taken with the same aperture and apply this correction by selecting it from the same drop-menu
You can opt to apply fall off correction as well at the same time
Note that this function does not exist in Lightroom/ ACR so if you use these you will have to do the correction in Photoshop, which si time consuming and probably not as good.
Enjoy your new back!
Yair
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I am new to MF digital backs. I just got an Alpa 12 TC with a Leaf Aptus 75, with a Schneider digitar 35mm f/5.6 XL. The photos from that are very sharp. However, when shooting a white wall indoor, the colors became very chaotic, with hints/cast of green / purple here and there.
Any suggestions on how to handle the color cast?
Thanks!
Back to basics...
How is the wall lit?
Have you set the White balance?
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Thanks Yair!
I am using a MacBook air actually. (I know it is not that fast, but useable to me.)
So I am using leaf capture v11. The menu has a "camera" item, and there is a "create lense calibration file" under it. However it is disabled.
Any suggestions on how to use LC to correct the colors? Thanks a lot!
In the Process tab, select "mos" as the output format, then click "settings"
Check the box that says "lens calibration", select First or Last for the order of the images and the amount of falloff correction you would like to apply (I normally start fairly low, say 10-15%)
You can also check the "Save Compressed" box to save space (this is a lossless compression)
Set the destination folder, I always choose the same folder where the originals are so that I can see before/ after. The corrected file will carry the same name as the original with an "_1" at the end.
More about it in the Leaf Capture help menu: Select Help>Leaf Capture Help and once the HTML file opens, select search and type in "Lens"
Note that the corrected files are basically new raw files, you can then use them in any 3rd party software, archive them etc.
I also suggest that you register on our website so that in the future you can contact us directly for support: Support site link (http://www.phaseone.com/en/SupportMain/ContactSupport.aspx)
Hope this helps
yair
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Yair,
Sure that wasnt a typo? Lossless or compressed??
Other reasons LCC could be grey:
- You are running capture one express rather than capture one pro.
- the firmware of the aptus 75 is far out of date
If you bought from a dealer try should be there to help you through all these questions
Doug
Captureintegration.com
From iphone
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Yair,
Sure that wasnt a typo? Lossless or compressed??
(http://img848.imageshack.us/img848/6718/lossless.jpg)
Uploaded with ImageShack.us (http://imageshack.us)
Other reasons LCC could be grey:
- You are running capture one express rather than capture one pro.
- the firmware of the aptus 75 is far out of date
I think he meant in the software; It is greyed out if the back is not connected as this feature is for tethered work:
(http://i52.tinypic.com/10qfiw0.jpg)
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You can also use Rawtherapee as illustrated here:
http://www.luminous-landscape.com/forum/index.php?topic=50990.0
Works perfectly on any camera/lens as long as raw file format is supported (which is likely the case).
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You can also use Rawtherapee as illustrated here:
http://www.luminous-landscape.com/forum/index.php?topic=50990.0
Works perfectly on any camera/lens as long as raw file format is supported (which is likely the case).
Interesting Michael but I'm guessing that the typical Mac user will not want to delve into coding and compiling software when there is a tried and tested solution offered by the manufacturer
Cheers
yair
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There is a distribution of the compiled (and portable - no installation required) RawTherapee hosted at http://www.rawtherapee.com/releases_head/
as well as here: http://rawtherapee.com/forum/viewtopic.php?t=1910 (always go to the last page of the frequently updated thread)
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Back to basics...
How is the wall lit?
Have you set the White balance?
The wall was lit with fluorescent, not well lit. I used the wall for grey WB picker. Before and after the WB setting, the color casts were very visible.
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Thanks Yair! I will try it tonight when I get home.
In the Process tab, select "mos" as the output format, then click "settings"
Check the box that says "lens calibration", select First or Last for the order of the images and the amount of falloff correction you would like to apply (I normally start fairly low, say 10-15%)
You can also check the "Save Compressed" box to save space (this is a lossless compression)
Set the destination folder, I always choose the same folder where the originals are so that I can see before/ after. The corrected file will carry the same name as the original with an "_1" at the end.
More about it in the Leaf Capture help menu: Select Help>Leaf Capture Help and once the HTML file opens, select search and type in "Lens"
Note that the corrected files are basically new raw files, you can then use them in any 3rd party software, archive them etc.
I also suggest that you register on our website so that in the future you can contact us directly for support: Support site link (http://www.phaseone.com/en/SupportMain/ContactSupport.aspx)
Hope this helps
yair
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(http://img848.imageshack.us/img848/6718/lossless.jpg)
Uploaded with ImageShack.us (http://imageshack.us)
I think he meant in the software; It is greyed out if the back is not connected as this feature is for tethered work:
(http://i52.tinypic.com/10qfiw0.jpg)
That is the case. I guessed it was greyed out because the back was not connected.
BTW, is there a way to update the firmware on an Aptus 75?
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BTW, is there a way to update the firmware on an Aptus 75?
If it's an old/ used back then Leaf Capture 11.2.4 (http://www.leaf-photography.com/downloads_1124.html) will provide the latest firmware for it
If it is a newly refurbished back then 11.4.5 (http://www.leaf-photography.com/downloads_1145.html) might update it (depending on what you already have there)
Either way you need a FireWire connection to a Mac. Your dealer (http://www.leaf-photography.com/dealers.asp) should be able to help you if you do not have access to FireWire
Yair
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The wall was lit with fluorescent, not well lit. I used the wall for grey WB picker. Before and after the WB setting, the color casts were very visible.
There used to be a theory that conventional fluorescent light lacks green, and is bound to cause a colour cast... if you want to calibrate anything, it would be the last light source to choose, white balanced or not.
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There used to be a theory that conventional fluorescent light lacks green, and is bound to cause a colour cast... if you want to calibrate anything, it would be the last light source to choose, white balanced or not.
The colour cast here is a result of using the wide angle, non-retrofocal lens and the type of light source has little or nothing to do with it. That's why you need to use a diffuser filter, WB can be done afterwards
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You can also use Rawtherapee as illustrated here:
http://www.luminous-landscape.com/forum/index.php?topic=50990.0
Works perfectly on any camera/lens as long as raw file format is supported (which is likely the case).
That is quite impressive!
The first image of "Before" is pretty much what I have now. :)
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There is a distribution of the compiled (and portable - no installation required) RawTherapee hosted at http://www.rawtherapee.com/releases_head/
as well as here: http://rawtherapee.com/forum/viewtopic.php?t=1910 (always go to the last page of the frequently updated thread)
Is there a version to try on 10.6.X?
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Is there a version to try on 10.6.X?
I am a using Win7, but one of the main RawTherapee developers is using Mac (actually Emil wrote flat field correction on the mac:) )
Try one of these:
http://www.rawtherapee.com/releases_head/mac/
You should try the auto selection of the flat fields, just store them in a single folder and point to it using preferences.
Lens cast is fixed then with a simple checkbox selection (Flat Field auto select).
If flat field with exact aperture is not found, it will select the closest match for camera/lens/aperture combo.
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I am a using Win7, but one of the main RawTherapee developers is using Mac (actually Emil wrote flat field correction on the mac:) )
Try one of these:
http://www.rawtherapee.com/releases_head/mac/
You should try the auto selection of the flat fields, just store them in a single folder and point to it using preferences.
Lens cast is fixed then with a simple checkbox selection (Flat Field auto select).
If flat field with exact aperture is not found, it will select the closest match for camera/lens/aperture combo.
No dice:-( both builds crash at launch...
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I'll see if there is a tested recent build for your version of OSX.
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Yair, Do you have some recommendations on the diffuser filter? I could not figure out which one to buy. Many thanks!
No need for a computer.
Set the back's compression to "Lossless"
Shoot with a White diffuser filter (or a piece of white perspex) as John suggested. It is important to do one whenever you change aperture and to compensate by adding 2 stops of exposure time.
I'm assuming that no firewire port means it's a PC, so you have to use Capture One Pro:
Select the white image and in the lens tool tab, select Analyse from the LCC drop-menu, save it let's say with the f-stop number. Then select all the images that you've taken with the same aperture and apply this correction by selecting it from the same drop-menu
You can opt to apply fall off correction as well at the same time
Note that this function does not exist in Lightroom/ ACR so if you use these you will have to do the correction in Photoshop, which si time consuming and probably not as good.
Enjoy your new back!
Yair
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I'll see if there is a tested recent build for your version of OSX.
We make a 100x100mm one, you can get it through your local dealer
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http://www.captureintegration.com/store/leaf-accessories/
In addition to the manufacturer solutions I can also selflishly suggest our own LCC panel which is provided with a strap to hang on your camera and a little sleeve to keep it clean.
At the end of the day it's just a white piece of plexiglass thick enough to ensure full diffusion but not too thick to lose excessive light. But I like ours best :-).
Doug Peterson,
Head of Technical Services
CaptureIntegration.com
Phase One, Leaf, Mamiya Dealer and more
(while traveling)
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i use the Leaf disc but have also used 2 plain white plexi doubled and held it against the lens.
I also point a light source directly at the disc. Do a search on LL and you will find lots of posts about lens correction.
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http://www.captureintegration.com/store/leaf-accessories/
In addition to the manufacturer solutions I can also selflishly suggest our own LCC panel which is provided with a strap to hang on your camera and a little sleeve to keep it clean.
At the end of the day it's just a white piece of plexiglass thick enough to ensure full diffusion but not too thick to lose excessive light. But I like ours best :-).
Doug Peterson,
Head of Technical Services
CaptureIntegration.com
Phase One, Leaf, Mamiya Dealer and more
(while traveling)
Thanks! That looks very neat indeed.
I ended up ordering an ExpoCap after some reading on LL as pixjohn suggested. I only have 1 Alpa lens for now and a 52mm ExpoCap seems convenient.
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Thanks! That looks very neat indeed.
I ended up ordering an ExpoCap after some reading on LL as pixjohn suggested. I only have 1 Alpa lens for now and a 52mm ExpoCap seems convenient.
Their site doesn't state the thickness of the expocap. A good diffuser will require approx. 2 stops of compensation. Just remember to do it by changing the shutter speed and NOT the aperture!
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Their site doesn't state the thickness of the expocap. A good diffuser will require approx. 2 stops of compensation. Just remember to do it by changing the shutter speed and NOT the aperture!
Thanks! I will report back when I can try it out. I am not sure if it will work out or not, but my D700 has a 35F2D that can use the ExpoCap if it does not work out for LCC.
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I'll see if there is a tested recent build for your version of OSX.
Michael, on Windows 7, I've never been able to install properlly Rawtherapee (previous versions also). In fact it works but the all folder is always located in the desktop and not where it should be. I don't really understand why but it's like the instalation is corrupted. So yes, I can run it from the desktop folder but this is not normal. Any idea?
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Michael, on Windows 7, I've never been able to install properlly Rawtherapee (previous versions also). In fact it works but the all folder is always located in the desktop and not where it should be. I don't really understand why but it's like the instalation is corrupted. So yes, I can run it from the desktop folder but this is not normal. Any idea?
Hi Fred,
Here is a link to RawTherapee package (just compiled it on Win7) which does not require an install:
http://timelessme.com/temp/Postings/rt-win32-3.1A-b8ebac4184d4.zip - 12.8 MB
Unzip it to any directory you like and run rt.exe from there (create a shortcut, if this is more convenient).
Let me know how t works for you.
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Nope. It crashes all the time at launch. Very weired. Thanks for the help anyway.
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Nope. It crashes all the time at launch. Very weired. Thanks for the help anyway.
This might be compiled for a non-generic CPU, sorry about that. I'll see what I can do.
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This might be compiled for a non-generic CPU, sorry about that. I'll see what I can do.
Hi Michael,
I tried it, and your compilation works fine for me. I'm on Win7 Ultimate, with an Intel Xeon processor, and an nVidia graphics card.
Maybe Fred's hardware is non-generic?
Cheers,
Bart
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It is. It's something else. I know it because it worked for me in the past although I thought the installation not very orthodox, but it worked. I'm sure it is something stupid and easy as often.
If I find I post.
Cheers.
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Thanks, Bart.
Actually, I compiled this rt.exe on Athlon-64 but for a generic CPU target.
However, I do find this particular build unstable on my other i5 machine.
The problem could be that I've packaged here shared libraries from another build,
as my local process for packaging builds for distribution is not yet tuned,
and these libraries may be in conflict with the rt.exe executable on a specific platform.
Fred, great to hear that it is working for you now. I am curious if you get a chance to use the flat field feature, how would it work for you.
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Oh Michael, I'm sorry. It does not. It freezed again when I thought I got it. Nice try anyway.