CurtPalme.com Home Theater Forum

[garyfritz]

A friend asked me about calibrating his LCD display. Turns out he's been learning how to do that so he can accurately see what his photographs will look like when he sends them to get printed. I pointed him to Kal's excellent writeup, but as we kept talking, I started to wonder if it's possible to calibrate a *camera*.

When we calibrate our projectors, we calibrate to match the Rec601/Rec709 standards. Why? Because that's what the movie CAMERA (and film developing/etc) system is calibrated for. When our projector matches the standard, it matches the movie-filming process, so what we see matches what the camera saw.

The same thing should apply to digital photography. If the LCD display is properly calibrated, the resulting print matches the display -- presumably because the printing process is equivalently "calibrated." If the camera was calibrated to the same standard, then what the camera sees should match what you see on the display and then on the final print.

Of course, photographers don't always WANT it to match. Sometimes they mess with the white balance for "artistic" effects. But it would be nice to be able to set it to the "right" point to match the display & print.

I know most digital cameras have white-balance controls (sunlight, tungsten, etc), and some also have Kelvin settings. But do any of them let you actually control the 0% - 100% response of R G B so you could calibrate the camera like you can calibrate projectors and displays?

My friend has a Nikon D200. As far as I can tell from online reviews, it doesn't have any projector-like "R G B cutoff/gain" calibration abilities. He says it has the standard white-balance controls and Kelvin controls.

Am I right in assuming that the sunlight/tungsten/etc settings are just pre-set Kelvin temperatures? Or are they arbitrary CIE x/y coords that don't necessarily fall on the color-temperature curve?

Is setting a Kelvin temp of, say, 2700K in the camera equivalent to putting an orange filter on the lens?

I'm a little unsure exactly how the white-balance works in a camera. Let's say I'm shooting by candlelight. That would be a very warm yellowish light. Do I set the white balance to a warm temperature, say 3000-4000K, to match the color temp of the light? Is the intent of doing that to do the kind of "color correction" that our eye-brain system does? (I.e. the same kind of correction that lets you see "proper" colors underwater when you're scuba-diving, even though photographs of the same underwater scene look very blue-green.) So the resulting picture would look like what you see, instead of an excessively-yellowish candle-lit image?

Thanks!
Gary

[Tom.W]

Lots of info here.

http://www.nikonians.org/html/resources/software/Adobe_digital_workflow/index.html

[JustGreg]

I just calibrated mine. A Toshiba PDR-M65. Before I reveal how I did it, I have a back story.

So I forgot it at the wifes relatives over the holidays but unlike NORMAL frigging parents with little kids; they didn't put it up out of the way. SOoooooo, I stopped to pick it up last week, (it's out of the way so couldn't get it sooner) and 'mom' tells me the kids got into it but she took it and hid it.

WHAT A WASTE of GAS! It was all f*ck*** up. The self closing plastic lens protector iris looked like a boxer who'd taken 10 or 20 shots to the eye (partially open for you non violent readers). When I turned it on, the camera is supposed to cycle through an onboard test of focus, zoom, etc., then beep that it's ready.

NOPE! The lens motors whirred madly away while the lens assembly cycled in and out of the body in some weird techno pelvic thrust mating ritual...then just sat there with a red ready light accompanied by beeping that got faster and faster. Every movie I'd ever watched with a bomb in it flashed through my mind. I felt like I should be looking for a wire to cut! (Is it the red or the blue you cut?)

Everything through the viewfinder was out of focus. So armed with absolutely no training or experience, I opened up the body thinking they dropped it with it powered on. I thought I might get lucky and all they did was drop it when the lens protector is open and the lens is extended out of the body in the ready focus position and misaligned the drive motor and lens barrel. Easy fix to realign everything into the neutral position right? NOPE again! 'Somehow' one of the ribbon cables had 3 torn traces. You ever solder repair one of those buggers? I STILL can't focus on anything smaller than a loaf of bread.
I even went so far, (stamp my forehead right now with the IDJIT stamp...better do it backwards to so people can see me coming in their mirrors) as to pay $14.95 for a service manual for it. I figured it was cheaper than a new camera and I liked this one. All it got me was $14.95 poorer. Not ONE useful thing in it as far as lens alignment. A great schematic...if you're into that kind of thing. I was looking for a procedure to align the telephoto, zoom, focus, neutral position, etc.

What's worse than getting no help for my money, when I tried to fix the boxers eye...seven f*cking buhzillion little pieces scattered to the farthest reaches of the galaxy. With the help of a magnet and a lighted work bench magnifier (removed and hand held...what a site to behold), I managed to find them all. THEN like a puzzle out of Raiders of the Lost Ark, I had to figure out the puzzle to fitting the 'eye' back together. I'm sure it's a closely guarded ancient secret known only by a few Tibetan monks. But I got the eyeris (as I came to call it while mumbling over the workbench for hours) to work.

I put it all back together feeling VERY confident that I was victorious, turn it on, NOPE! The lens was still f*cking the body and it wouldn't zoom or focus. PLUS, the menus were like running Vista on an 8088 processor.

OCD to the rescue!!!!! I'll just take apart ANOTHER....10....f*cking....TIMES!!! The 10th time was the charm and led to the following procedure.

I took it outside on Saturday, pulled out the Craftsman 12 HP chipper shredder, fired it up and let it warm up, blasted the throttle, pulled the expensive NiMh batteries out of the 'camera'...and calibrated it.
Anybody in the market for a really nice camera bag and 4 NiMh batteries?

[Tom.W]

A bit crude but effective ! LOL 8)

Reminds me of this scene from Fargo....

http://www.youtube.com/watch?v=mAM57-62IS0&feature=related

[ecrabb]

That's funny, Greg. The story's ending is priceless. Hey, at least it was a camera that wasn't worth much anymore. You'd have been really pissed if it was a brand new $300 camera or something. Lessee... 3 megapixel point/shoot? What would that cost to replace? About what you spent on the service manual?

Gary, here's a good little article on color management:
http://www.outbackphoto.com/color_management/cm_01/essay.html

It's not as easy as it sounds to go from camera, to display, to printer and have them all look the same. You've got different sized color gamuts and completely different color systems (additive in the camera and display and subtractive in the printer). That's where color management comes in.

With color management, we can create a "profile" of the monitor by using a calibrator. The monitor profile tells Photoshop about how the display actually displays images, so it can make adjustments to accurately display what's in the image.

Then, if we have a profile of the printer (again, how does the printer actually reproduce images), then we can also *simulate* on-screen, what the image will look like printed on the printer.

Once we have our display and output device profiled, we can take an image from the camera, adjust it, tweak it, modify it - all the while having a good idea of how it will look printed. Then we can print it and have it come out pretty much like we expected. That's the goal of a color management system - being able to reproduce an image as accurately as possible and exactly as expected.

SC

[garyfritz]

[AnalogRocks]

I'm not sure about calibrating the camera but I've calibrated the monitor to the printer output and got perfect greyscale when priting in full color. Esentially what I see on my CRT screen is what come's out on my Epson printer. I used a spyder to do the calibration.

[AnalogRocks]

I'm not sure about calibrating the camera but I've calibrated the monitor to the printer output and got perfect greyscale when priting in full color. Esentially what I see on my CRT screen is what come's out on my Epson printer. I used a spyder to do the calibration.

[kal]

And that's the actual original reason the Spyder was invented: Photography. Not for HT.

Kal

[kal]

And that's the actual original reason the Spyder was invented: Photography. Not for HT.

Kal

[AnalogRocks]

[AnalogRocks]

[kal]

I got mine when I bought a Canon 30D camera a couple of years ago. It was on sale for $120 (half price) when bought with any better digital camera. The irony is that I didn't start to use it really until the regular price had come down to $70.

Kal

[kal]

I got mine when I bought a Canon 30D camera a couple of years ago. It was on sale for $120 (half price) when bought with any better digital camera. The irony is that I didn't start to use it really until the regular price had come down to $70.

Kal