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Author Topic: Questions about making LCC profiles  (Read 341 times)

Ellis Vener

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Questions about making LCC profiles
« on: December 27, 2018, 10:27:34 AM »

I have been doing some reading up on these and have some more in-depth questions.

1) Are they necessary only for wide angle lenses or will my workflow benefit from making an LCC for all of my lenses?

2) With zoom lenses is it sufficient to make one only at the extremes of the lens' focal length range?

3) With each lens, do they need to be made for each aperture setting (at full stops, not incremental stops)

4) With shift and tilt/shift lenses or Technical cameras with shifting movements,  do you make an LCC profile at the extremes along with the neutral position, and at each aperture at each position?

5) Can any translucent but opaque material be used or is it worth spending $60.00  on the Mamiya Leaf 100 x 100mm Lens Cast Calibration Diffuser  or $20.00 on the CI Pocket LCC from Capture Integration (https://www.digitalback.com/product/pocket-lcc/)
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BartvanderWolf

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Re: Questions about making LCC profiles
« Reply #1 on: December 27, 2018, 11:37:11 AM »

I have been doing some reading up on these and have some more in-depth questions.

1) Are they necessary only for wide angle lenses or will my workflow benefit from making an LCC for all of my lenses?

Hi Ellis,

LCCs will allow correcting for Light Fall-off (which every lens has to varying degrees) and/or Vignetting, and that changes with aperture, especially when used with wider apertures. It also allows removing dust shadows and smears. And it also allows correcting for Color Casts due to sensor technology and ray-angles. So all lenses can benefit, although wider angle lenses tend to benefit most.

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2) With zoom lenses is it sufficient to make one only at the extremes of the lens' focal length range?

No, you need to use the exact same settings as for an actual image, even the same focus distance if you want the best results. That's why these LCCs are usually shot at the same time as the actual shots. If you take multiple images with the same settings (Focal length/Aperture/Focus distance/Shift/Tilt), then only 1 LCC is necessary for the whole sequence. The only risk is that dust moves between shots, but Light Fall-off/Vignetting and Color Cast will be constant, and can be corrected with a single LCC (taken first or last or in between shot with the same settings).

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3) With each lens, do they need to be made for each aperture setting (at full stops, not incremental stops)

The actual shot's aperture and focal settings. So it's not worth your time to prepare for all possible scenarios (and for other shooting distances than infinity focus).

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4) With shift and tilt/shift lenses or Technical cameras with shifting movements,  do you make an LCC profile at the extremes along with the neutral position, and at each aperture at each position?

No, just the setting for the actual shot(s).

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5) Can any translucent but opaque material be used or is it worth spending $60.00  on the Mamiya Leaf 100 x 100mm Lens Cast Calibration Diffuser  or $20.00 on the CI Pocket LCC from Capture Integration (https://www.digitalback.com/product/pocket-lcc/)

In principle, any material can be used, as long as it is not excessively thick (which might attenuate oblique rays more than perpendicular rays). So piece of opal glass held flush to the lens or lens hood is fine, or white diffuse translucent Acrylic/Perspex is fine. Vignetting can even be corrected if you aim at a diffusely lit uniform structureless surface. This can even help with balancing a Repro lighting setup.

Cheers,
Bart

P.S. you'll get the best results if the exposure time for the LCC is a couple of stops longer than for the actual shots, especially when you meter through the lens. You'd aim for an unclipped, somewhat exposed to the right histogram for the LCC, because that gives the best Signal/Noise ratio, especially for the areas (corners) that require the most signal boosting.
« Last Edit: December 27, 2018, 11:47:30 AM by BartvanderWolf »
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Ellis Vener

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Re: Questions about making LCC profiles
« Reply #2 on: December 27, 2018, 03:03:29 PM »

That you for the detailed explanations and clarifications Bart! Coming over  to C1 Pro from Lightroom and ACR is interesting. It reminds me of when I changed from using a Texas Instruments calculator to an HP and had to learn "Reverse Polish Notation." import protocol, although in CaptureOne's case it is more like Reverse Danish Notation.

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nemtom

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Re: Questions about making LCC profiles
« Reply #3 on: December 27, 2018, 03:29:40 PM »

That you for the detailed explanations and clarifications Bart! Coming over  to C1 Pro from Lightroom and ACR is interesting. It reminds me of when I changed from using a Texas Instruments calculator to an HP and had to learn "Reverse Polish Notation." import protocol, although in CaptureOne's case it is more like Reverse Danish Notation.

RPN is superior over infix notation, as there is no need for parentheses for operators with fixed number of operands... :)
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alan_b

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Re: Questions about making LCC profiles
« Reply #4 on: December 27, 2018, 05:06:26 PM »

5) Can any translucent but opaque material be used or is it worth spending $60.00  on the Mamiya Leaf 100 x 100mm Lens Cast Calibration Diffuser  or $20.00 on the CI Pocket LCC from Capture Integration (https://www.digitalback.com/product/pocket-lcc/)

I've been using translucent white acrylic from TAP Plastics for a few years with good results - no affiliation other than a customer.

Description copied from my last invoice:
Acrylic Sheets Color (Cut-to-Size) - Sign Lighting White 40%
1/8 inches Thick, 5 inches Wide, 6 inches Long

It was $20 shipped for 4 pieces this size.
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