Phase One - LCC and Dark Frame - Best practices?

[peterm10]

Hi.  I am new to using my IQ3 100 and Cambo tech cam, and I am wondering how people approach dark frames and LCCs from a practical perspective?  I am not shooting super long or night exposures. 

LCC: As an example, I wanted to set up a library of user presets of LCCs.  I set up my gear outside on a sunny day, shot at f/8 with infinity focus on my Rodenstock at 0 shift, and then +/- 5, 10, 15 up and down, at about 2 stops brighter than normal using the LCC plate, and then created LCCs in Capture One for each one.  Then I saved each LCC as a user preset which I can apply when shooting with those shifts in similar conditions at f/8.  Is this correct?  (I'm not using tilt/swing).  Am I supposed to do this again for different f stops in different lighting conditions?   

Or do you do a LCC everytime you shoot for each different f stops, shifts, etc.?  And you record each time you shift and how much on a notepad or phone or something for later reference?  Do you find you need a LCC when not shifting at all?

Dark Frames: Which setting do you use and why? I have been shooting at less than a second, so I have been keeping it set to "off" or "never" although it still records a dark frame automatically at the start of each session or when I change shutter speed settings.

Thanks!

Peter

[Paul2660]

3100 will require a dark frame as I recall on any image taken at longer than 1 second.  You really can't get around that.  Back will ask for 1 each time, and you need to take it immediately after the previous exposure.  The dark frame recorded is then applied to the previous image in the back, you do anything in post.

For LCC work, you are correctly both light fall off (from shifting or rise/fall) and color cast.  As the light will vary odds are each time (unless you are in a studio) I think you will still be forced to take at least 1 set of LCC frames for each scene shot.  The bigger issue with 3100 and tech lenses is color cast correction and the color cast will vary as the light changes (again for outdoor work). 

I tended to keep one series for each scene I shot with the 3100, so each time I moved, I took another set of LCC frames. 

Over time in the 2 years I owned the 3100, I still took the LCC frames on each trip, but as my library of LCC corrections grew in C1, I did try to use one I already had created first.  This worked very well on Light fall off corrections, but only about 50% of the time on color cast.  Issues with a red tint to blue sky most often required a LCC taken on the day of the shoot to get the best correction.  I did name my LCC frames by lens, aperture and amount of movement so I would have a frame of reference. C1 does a good job with the LCC library, and you can create a separate folder for each shoot if you want, (note it's a bit less transparent with a Mac, than a windows machine, the creation of new folders).

Paul C

Paul C

[douglevy]

FWIW though - if you want to use the LCC for lens dust, you need to do one for every F-stop.

[peterm10]

Thanks both.  I am leaving the dust removal box unchecked in C1 (I read it slightly slows things down), and just trying to keep my sensor clean (having one lens helps)...

Peter

[BFD]

Hi.  I am new to using my IQ3 100 and Cambo tech cam, and I am wondering how people approach dark frames and LCCs from a practical perspective?  I am not shooting super long or night exposures. 

LCC: As an example, I wanted to set up a library of user presets of LCCs.  I set up my gear outside on a sunny day, shot at f/8 with infinity focus on my Rodenstock at 0 shift, and then +/- 5, 10, 15 up and down, at about 2 stops brighter than normal using the LCC plate, and then created LCCs in Capture One for each one.  Then I saved each LCC as a user preset which I can apply when shooting with those shifts in similar conditions at f/8.  Is this correct?  (I'm not using tilt/swing).  Am I supposed to do this again for different f stops in different lighting conditions?   

Or do you do a LCC everytime you shoot for each different f stops, shifts, etc.?  And you record each time you shift and how much on a notepad or phone or something for later reference?  Do you find you need a LCC when not shifting at all?

Dark Frames: Which setting do you use and why? I have been shooting at less than a second, so I have been keeping it set to "off" or "never" although it still records a dark frame automatically at the start of each session or when I change shutter speed settings.

Thanks!

Peter

Keeping a set of preset LCCs will not work unless you do one for every F stop and focal length—pretty much impossible. Vignetting and color shift change at different F stops and focal length. Also, then you would need LCCs for each lens shift value.

[ben730]

If you work with such an expensive and great system I strongly recommend to make always an LCC exposure and a dark frame.
If you don't do it, it's a kind of extravagance...

My 2 cents,...
Ben

[peterm10]

Yup, I started making LCCs each time I go out and shoot since I can see the benefit... here's a follow up question: if I apply the LCC to the corresponding photos in C1 and am happy with the results, do I really need to hold onto the LCCs or can I just delete them (note none of this is for paying client projects)?  I don't want to clutter up my files with LCCs from each time I go out and shoot.

Thanks for the replies.

[ben730]

Convert your Raw file with the LCC and all the other adjustments in C1 to a .EIP. Then you "bake" the LCC profile and everything else into the file.
But as far as I know, only C1 can open .eip files.

Regards,
Ben

[ericstaud]

Yup, I started making LCCs each time I go out and shoot since I can see the benefit... here's a follow up question: if I apply the LCC to the corresponding photos in C1 and am happy with the results, do I really need to hold onto the LCCs or can I just delete them (note none of this is for paying client projects)?  I don't want to clutter up my files with LCCs from each time I go out and shoot.

Thanks for the replies.

If you don't like the LCC clutter, then move them to a subfolder within the folder of RAW files. Don't throw them away. It could make it impossible to process today's RAW files in several years. We don't know what software you'll be using in 10 years time.

When I shot tech cameras years ago I shot a LCC after each setup, usually turning the camera toward the main lightsource. This way I could use the capture for Lens Cast, Lightfalloff, Dust, and color balance.

[MichaelEzra]

Try free, automatic, painless and excellent Flat Field correction with RawTherapee.
All you need is to shoot a single set of reference flat field images with each lens, at desired apertures.
Point RawTherapee setting to directory where the flat fields are stored and it will do the magic, automatically.

• Manual: http://rawpedia.rawtherapee.com/Flat-Field
• RT: http://rawtherapee.com
• ART (Another RawTherapee) is great and easy to use: https://bitbucket.org/agriggio/art/wiki/Home