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Author Topic: Using the LCC Function in C1  (Read 5536 times)

Mike Guilbault

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Using the LCC Function in C1
« on: December 04, 2015, 09:53:44 pm »

I've just watched a short tutorial about using the LCC function in Capture One Pro.  Is there any advantage to creating a LCC reference image using dSLR's as opposed to medium format or technical cameras?  How exactly would you create the reference image?
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Mike Guilbault

pfigen

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Re: Using the LCC Function in C1
« Reply #1 on: December 04, 2015, 11:25:20 pm »

You want to make the LCC reference image with the same lens, camera and lens parameters i.e. shift and/or tilt that you took the original image with. The LCC is correcting for that lens on that camera with that shift or tilt. There would be no point in using anything other than the same lens, aperture, shift, etc, especially with setups that produce color and density shifts, which the LCC is really great at correcting for.
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Jimmy D Uptain

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Re: Using the LCC Function in C1
« Reply #2 on: December 04, 2015, 11:45:40 pm »

Yup. I have done it with my D800.
I used it on a stitched pano with a tilt-shift lens. The extremes on the shift will make for some nasty vignetting and the LCC does the trick.
Not only does it get the density right, it'll knock out the the dust bunnies as well.
Its not something I use a lot but I know its there if needed.
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Bart_van_der_Wolf

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Re: Using the LCC Function in C1
« Reply #3 on: December 05, 2015, 12:15:33 pm »

I've just watched a short tutorial about using the LCC function in Capture One Pro.  Is there any advantage to creating a LCC reference image using dSLR's as opposed to medium format or technical cameras?  How exactly would you create the reference image?

Hi Mike,

You create an LCC by shooting through a semi-translucent white Acryllic/Perspex or opaline glass sheet held flush to the front of the lens(hood). You can also shoot a uniformly lit surface, e.g. a neutral background for a reproduction.

You use the same lens settings (focusdistance, aperture, tilt/shift) as for the actual subject shot.

You can choose to also remove dust bunnies, and/or take out any unevenness in the effective image exposure due to lens vignetting / color cast / illumination. It's a great utility for leveling the apparent brightness across the image, but severe underexposure will still produce a somewhat different noise structure.

Cheers,
Bart
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Dinarius

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Re: Using the LCC Function in C1
« Reply #4 on: January 04, 2016, 07:44:47 am »

Any recommendations on the exposure for the perspex image with C1?

For Hasselblad's Phocus software's Scene Calibration tool, it is recommended that the exposure be 1-2 stops under.

Thanks.

D.
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Bart_van_der_Wolf

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Re: Using the LCC Function in C1
« Reply #5 on: January 04, 2016, 09:35:26 am »

Any recommendations on the exposure for the perspex image with C1?

For Hasselblad's Phocus software's Scene Calibration tool, it is recommended that the exposure be 1-2 stops under.

Hi,

While it seems not too critical, you generally get the best results if exposure level is 1-2 stops under saturation levels, which means adding the amount of 2 or 1 stops of exposure to an average exposure metering. Do make sure to leave the aperture and (manual) focus (and tilt/shift) itself identical to the aperture and focus settings used when shooting, only adjust exposure time or illumination intensity.

The additional exposure will reduce the relative amount of noise (improve the S/N ratio), so noise should become less of a factor in the calculations. The influence of read-noise is marginalized, and photon shot-noise becomes a lower percentage of the signal level, that's why.

But C1 can handle a wide range of LCC exposure levels (by blurring the noise, especially when higher ISO is used), so it's not too critical. But proper exposure may help a bit, so why not do it the best way we can.

Cheers,
Bart
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mediumcool

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Re: Using the LCC Function in C1
« Reply #6 on: January 04, 2016, 09:58:43 am »

Yup. I have done it with my D800.
I used it on a stitched pano with a tilt-shift lens. The extremes on the shift will make for some nasty vignetting and the LCC does the trick.
Not only does it get the density right, it'll knock out the the dust bunnies as well.

Dust bunnies! Love it!
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Dinarius

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Re: Using the LCC Function in C1
« Reply #7 on: January 04, 2016, 10:41:55 am »

Bart,

Thanks as always.

One other question.....

On the issue of dust removal using the LCC tool; do you not find that a dust removal, that is then applied to an area of texture in an image, can leave a mark on that area?

The online Support guide advises against using Dust removal in LCC unless absolutely necessary.

Thanks.

D.
« Last Edit: January 04, 2016, 10:53:20 am by Dinarius »
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Bart_van_der_Wolf

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Re: Using the LCC Function in C1
« Reply #8 on: January 04, 2016, 12:02:48 pm »

Bart,

Thanks as always.

One other question.....

On the issue of dust removal using the LCC tool; do you not find that a dust removal, that is then applied to an area of texture in an image, can leave a mark on that area?

Not really, unless perhaps it is a very dense dustspot. That could change the noise structure/color due to photon shot noise getting relatively worse at underexposed spots. It of course depends on how it's implemented under-the-hood, but it should improve the image more than it hurts it.

Quote
The online Support guide advises against using Dust removal in LCC unless absolutely necessary.

I wouldn't know how up to date that recommendation is, given the improvements to the processing engine. But I do know that when I need it, I can use it, and it saves me a lot of postprocessing/spotting time and unwelcome surprises.

The need of course also varies with the aperture used. Some subjects I rarely shoot at apertures that show the dust, other subjects need small apertures or are high magnification macros that are impossible to clean the sensor good enough for.

Cheers,
Bart
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Wayne Fox

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Re: Using the LCC Function in C1
« Reply #9 on: January 05, 2016, 12:03:54 am »

You can also shoot a uniformly lit surface, e.g. a neutral background for a reproduction.

Wow.  Never even thought of that ... very cool idea. Some I've found are very problematic, such as pencil sketches or similar media on light papers.  Will be trying it this week.
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Dinarius

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Re: Using the LCC Function in C1
« Reply #10 on: January 05, 2016, 06:23:23 am »

Another question......

If I'm using a lens that has an inbuilt C1 profile, can I still use only the Dust Removal part of the LCC tool, while leaving the selected items in the Lens Correction panel above intact?

Thanks.

D.
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Bart_van_der_Wolf

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Re: Using the LCC Function in C1
« Reply #11 on: January 05, 2016, 10:25:02 am »

Another question......

If I'm using a lens that has an inbuilt C1 profile, can I still use only the Dust Removal part of the LCC tool, while leaving the selected items in the Lens Correction panel above intact?

Haven't tried it myself, but I think that is not a problem. Give it a try.

Cheers,
Bart
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Dinarius

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Re: Using the LCC Function in C1
« Reply #12 on: January 06, 2016, 05:13:21 am »

Here's what I did.......

I took a white perspex shot with my Canon 17-40mm lens - a lens for which C1 9 has an inbuilt profile.

I then ran the LCC with ONLY "Include Dust Removal Information" selected.

In terms of vignetting and colour cast, there was an improvement in the file which I could apply to the actual photograph.

However, and I must be misunderstanding this, the spots were still there in the LCC file.

By "spots" I mean the grey, circular, "liver" spots (almost certainly moisture spots) that are almost always present to some degree on a sensor. Do I take it that these are not removed by LCC, but that only physical dust present on the sensor is removed? (For the record, there was no physical "dust" present on this sensor, only the spots I've described.)

Thanks.

D.

Ps. Does anyone find the Phaseone usage of the terms "spot" and "dust" a bit loose? https://www.phaseone.com/en/Search/Article.aspx?articleid=1340&languageid=1
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Dinarius

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Re: Using the LCC Function in C1
« Reply #13 on: January 08, 2016, 10:10:02 am »

Update:

Have had it confirmed by Support that LCC only removes physical Dust on a sensor, not those "liver" spots I was referring to above.

TBH, I can live with that. The difference LCC makes, even to lenses with built-in C1 profiles, is amazing.

D.
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Paul Ozzello

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Re: Using the LCC Function in C1
« Reply #14 on: January 19, 2022, 03:55:41 am »

This may be a stupid question. Can I make a LCC for film? I'm using a Schneider 72mm SA XL lens on a 617 film camera with a center film and getting a lot of color casts on the corners. Could I shoot an LCC and apply it after scanning?
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