profiling cameras

There is a better way Jack, but more on that in a few weeks.  

Michael

[Jonathan Wienke]

If you're using Adobe Camera RAW, you can optimize the calibration settings for your camera by following the procedure outlined here. While not the same as a true custom profile, it will make a very significant improvement in the accuracy of the colors you get from ACR.

[hovis]

A Color Checker doesn't cost all that much, and I think you'll be surprised at the difference it makes.

It's something I would definately like to own, maybe I'm being a cheapskate or maybe I'm looking in the wrong places but £50/$100 seems a lot for a piece of card. Does anyone know of any cheaper alternatives or should I just suck-it-up?

[Lisa Nikodym]

You folks have a valid point. Here's my game plan. Next week I have vacation. I am going to read Fraser ("Camera Raw with PSCS" or "Color Management"? I have both.) and absorb this technique. I'll order the color checker and when it arrives have a calibration event. I am quite open to improvement. Everything I learn here has helped.

I figure I'll have this all accomplished in a few weeks. I'll ask questions if I need to, OK?

I'm off to the Alps in a couple of days (happy happy!) and won't be back for a couple of weeks, but I'm happy to answer anything I can when I get back if you get started before then.  Using the instructions and script from Jonathan's web site was relatively simple, though, so I don't imagine you'll have any problems there (at least I didn't) - if you have any questions beyond Jonathan's instructions, he's much more likely to be able to answer them than me (but I can try if he's not around).

Lisa
 :cool:

[Lisa Nikodym]

there is something i dont get. if we profile our cameras, then what's the use of the WhiBal? i mean, after all, isn't that WhiBal that gives correct color? what's the point of using a WhiBal when you'll leave the White Balance as As Shot anyways?

White Balance has only one (in camera) or two (in ACR) parameters you can adjust.  ACR's camera calibration has a bunch more (I don't have it in front of me right now, but it's something more like eight). One or two helps get closer to "right" (for some definition of right), but it isn't enough to cover all bases, color-wise.  Ideally, you should use calibration to get a reasonable baseline image where the colors don't look "wrong" in some ill-defined way, then you can use white balance to adjust them to your taste.

Lisa

[Lisa Nikodym]

Where in the world will I find a neutral location to take the test shots? Don't you need a predictable light source?

All I did was to pick a bright sunny day when the sun was high, lay a white sheet out on my deck (to have neutral-colored surroundings), put the color checker in the middle of the sheet, and stand over it with the camera pointing down at it (without getting any shadows on it).  It's true that not all images are taken under sunny conditions, but that's the most common for me, so that's what I went with for my calibration.  Maybe not rocket science, but it worked OK for me. :cool:

Lisa

[boku]

For a comprehensive explanation, check out this link: http://www.photoshopforphotographers.com/p...ad/movie-10.pdf

Here is the setup I used. Grey seamless background, (2) 400WS Studio Stobes with softboxes at 45 degrees to the color checker plaque. The exposure that worked was f/11, stobes at 1/4 power.


The RAW file, before the profile creation, rendered as follows:


The Gretag-Macbeth reference file (from Jonathan's website) for comparison:


The script gave me the following results. I ignored everything BEFORE Shadow Tint, per Jonathans recommendation.

[hovis]

Is it possible to custom profile your camera? I have a Rebel.

[Jack Flesher]

I can wait...

But I've tried the mask if that's where you're going... It works, but is not an ideal solution when the corners are significantly off -- at least IMO.  

However FWIW, I have found a capture method that generates a nearly perfect capture -- right now I am within 2 points (rgb 8-bit) across all of the corners and center and I think I have the solution to knock that down to 1 or 0.  And even if I can't knock that back to 0, I feel 2 points is probably close enough for the mask

[Jonathan Wienke]

But what I don't understand is, in the course of landscape photography, are we objective to that extent? I don't know about you folks, but I rather enjoy interpretive color and tone adjustment to bring out a mood or my impression of the original rather than a rigid reading of the original. I feel more like creating than recording. I contemplate this from the very start, even before I set up the shot. For me, it is about what can I do with this raw scene to render it that way I imagine.

Given that subjective approach, what would I get out of camera profiling?

Simple. Your color adjustments will be "creative" tweaks done to accommodate your creative vision, rather than frustrating and usually time-consuming attempts to "fix" what the camera failed to get right in the first place. If the color is dead-on accurate to the original subject, then bumping up saturation to taste is simple and easy. But if the blues have a magenta cast and the greens are too yellow out of camera, you have to waste time dealing with that before increasing saturation will yield the desired result. And if you ever photograph people, you'll appreciate the value of good skin tones straight out-of-camera, even if they're just family snapshots.

[boku]

Bob, I'd like to encourage you to at least give ACR calibration a try. A Color Checker doesn't cost all that much, and I think you'll be surprised at the difference it makes.

Yeah - I bought Fraser's books and never read them. I really need to.

[paulbk]

A worthwhile read by Bruce Fraser,  (find in PhotoshopNews.com)
raw 3.1 professional custom profiles for highend digital cameras

[hovis]

Just an aside

Is it possible to set the tonal range for a specific image manually by doing a test shot of your subject with a colour checker in it, and taking the dropper and sampling the neutral grey square to give you a reading of exactly where your midtone should lie on the histogram? I wasn't sure if this would give you an accurate reading as its relationship with the light source would affect its tone, am I right in thinking this or would it be close enough if the colour checker was facing the camera directly?

I guess that calibration would eliminate the need for this but I'm just curious; when photographing my drawings I have to take a guess where to put the grey point on the histogram so I'd like to make it a more consistant process.

[Jonathan Wienke]

That's more or less what I did, but I put the Color Checker on an easel. Put the easel in the middle of a reasonably large sheet of neutral cloth or paper facing direct sun on a clear day and you'll get an emininently useful calibration shot.

I have one in preparation, but it might be a month or two till it's done. Other priorities I'm afraid.

Michael

Yes it is, but the software and hardware needed to do so properly costs as much as your camera. Less expensive systems simply don't do the job well enough.

I'll have a review and a look at what this is all about next month.

Michael

[hovis]

Hi Jack

I hope you'll share your methods once you're happy with them. I use my camera to photograph my artwork, which includes drawings. They are irritating things to light and without fail end up with a subtle shadow passing across the drawing. Though not that noticeable on screen it's very clear in the print. I've developed a method in photoshop to remove it and I can produce an extremely good reproduction with a uniform tone to the paper of the drawing, it would always be nice though to get the picture perfect in the first place.

[Jonathan Wienke]

Bob, I'd like to encourage you to at least give ACR calibration a try. A Color Checker doesn't cost all that much, and I think you'll be surprised at the difference it makes.

[boku]

But what I don't understand is, in the course of landscape photography, are we objective to that extent? I don't know about you folks, but I rather enjoy interpretive color and tone adjustment to bring out a mood or my impression of the original rather than a rigid reading of the original. I feel more like creating than recording. I contemplate this from the very start, even before I set up the shot. For me, it is about what can I do with this raw scene to render it that way I imagine.

Given that subjective approach, what would I get out of camera profiling?

Bob, remember that thread of mine awhile back where I was asking for a technical critique and you said that the colors looked "muddy" compared with my earlier film work?  Well, the single biggest factor (by far) in getting rid of that muddiness was doing the camera calibration thing in ACR that Jonathan suggested.  It's hard to color correct (either to what's accurate or to what you want) when things just don't look quite right, but you're not sure why.

Bob, I'd like to encourage you to at least give ACR calibration a try. A Color Checker doesn't cost all that much, and I think you'll be surprised at the difference it makes.

I second the motion!

Lisa

Lisa,

You folks have a valid point. Here's my game plan. Next week I have vacation. I am going to read Fraser ("Camera Raw with PSCS" or "Color Management"? I have both.) and absorb this technique. I'll order the color checker and when it arrives have a calibration event. I am quite open to improvement. Everything I learn here has helped.

I figure I'll have this all accomplished in a few weeks. I'll ask questions if I need to, OK?

[Jonathan Wienke]

Bob, I'll be happy to answer any questions about ACR calibration that don't involve focusing "beyond infinty".