camera calibration and gray cards. do I need it?

Canon EF 24-70mm f/2.8L USM

06/20/2007 04:33:10 AM · #1

hello dear everyone!

i've been studying "Skin" by Lee Varis for some weeks already.
great book
he is talking about camera and lens calibration, colorchecker, grey cards and all those things.
he says i should calibrate any new camera and lens

another wonderful book "the art of photographing women" by Kevin Ames has also much info on color lab numbers and grey cards.

do you use all this?

i've always been correcting colors simply according to how i want them to look like:)
i always thought i see if there's too much yellow/red/whatever. i know it is not a very scientific approach:)
my "raw workflow" has been limited to exposure compensation adjustments so far...

tell me please, how do you process your raw images?
do you really take all the steps described in my books?
for me it looks like it will take ages to go through all of them.

i just want to learn it.
thank you!!

Svetlana

Makka

Canon EOS-5D Mark II

06/20/2007 04:46:13 AM · #2

I don't use a grey card in the studio at all, though that's more me being slack as I know I can adjust it in Rawshooter during post. I know our Bowens lights give off at 5600k so I should set my camera to that setting. The auto white balance tends to fluctuate a bit in regards to what it thinks is correct. The only time I've used a grey card was whilst shooting indoor roller skating because the lighting was crap. But that was with my 300D not the 30D. But, I believe you also need to have a calibrated monitor if you want to get a better adjustment during post.

Hope all this made sense!!

Canon EF 24-70mm f/2.8L USM

06/20/2007 04:53:12 AM · #3

thank you Neil!
i keep reading about the cards and lab numbers everywhere but no one seems to use it in reality:)
it's probably the same as with professional fashion photograpers who say keep it simple! one light is enough! - and then use huge crews with lots of boxes and lamps.
:)

Makka

Canon EOS-5D Mark II

06/20/2007 05:26:18 AM · #4

Originally posted by silverfoxx:

Too true. I guess if I was shooting film it would be more important to me. But as I said before, I'm probably just lazy and technology makes me even lazier as I know that if it's out, I can always adjust it later.

06/20/2007 01:35:51 PM · #5

Originally posted by silverfoxx:

i always thought i see if there's too much yellow/red/whatever. i know it is not a very scientific approach:)
my "raw workflow" has been limited to exposure compensation adjustments so far...

Gray cards help you get the color correct quickly, especially if you're under artificial light (other than strobes).

A white/gray/black card makes setting levels easy--set the white level to white...

Once you have the color corrected for the grey card, you can copy those corrections to other images. Give it a try, grey cards are not all that expensive, and they are easy to use.

BTW, if you go by what you see, I hope you have a calibrated monitor.

Canon EF 24-70mm f/2.8L USM

06/20/2007 02:43:38 PM · #6

Originally posted by hankk:

BTW, if you go by what you see, I hope you have a calibrated monitor.

i hope so too :/

:)
but the light changes all the time! i use mostly window light and it's changing, and i use some reflectors, a softbox, an umbrella and combine them all with lots of ordinary yellow home lamps
can there be any universal setting for this grey card?

violinist123

Canon EOS-6D

06/20/2007 02:46:57 PM · #7

Please cahnge nothing about what you do... Your images are perfect.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/20/2007 09:58:38 PM · #8

Originally posted by silverfoxx:

Originally posted by hankk:

BTW, if you go by what you see, I hope you have a calibrated monitor.

i hope so too :/

:)
but the light changes all the time! i use mostly window light and it's changing, and i use some reflectors, a softbox, an umbrella and combine them all with lots of ordinary yellow home lamps
can there be any universal setting for this grey card?

Ok, you've got mixed lighting. The window light will be different colors at different times of the day (and changes depending on cloud conditions). Also, south facing windows get direct sun, north facing windows don't (in the northern hemisphere) so the direction of the window affects the color. The regular yellow home lamps are probably tungsten.

The worst conditions you will have are when the sunlight is most blue (highest color temperature, when its cloudy...) If you have someone lit on the left by the window and on the right by the tungsten lamp, the right side will be too orange, or the left side will be too blue. You will have a tough time correcting this in photoshop. On the other hand, you can use the two colors to get some great effects becasue we humans perceive orange as warm, and blue as cold.

A flash will have a color temperature closer to daylight. The chart on //www.sizes.com/units/color_temperature.htm gives some color temperatures.

A reflector is cheaper than a flash, especially if you make your own out of cardboard covered with tin (aluminum) foil, or white paper. Its a good way to try things out. Either block the light from the window and use the lamps and reflectors, or turn off the inside lights and use only window light and reflectors.

Message edited by author 2007-06-20 22:01:03.

GeneralE

Canon PowerShot S3 IS

06/20/2007 10:03:56 PM · #9

Originally posted by hankk:

If you have someone lit on the left by the window and on the right by the tungsten lamp, the right side will be too orange, or the left side will be too blue. You will have a tough time correcting this in photoshop.

I'd try with a vertically divided gradient masks, through which I'd try color-correcting the two sides separately with the effects blending in the middle.

06/21/2007 03:42:51 AM · #10

thank you!!

sure, i know about the colors, and i have flashes too.
i just like mixing different lights
i will try to use this miz in a more creative way so i won't need to correct the colos, but instead use them for my compositions.
i have ideas, always have:) i just need to experiment more with this mix
oh, how much i need a model...

06/21/2007 11:53:24 AM · #11

Originally posted by GeneralE:

Originally posted by hankk:
If you have someone lit on the left by the window and on the right by the tungsten lamp, the right side will be too orange, or the left side will be too blue. You will have a tough time correcting this in photoshop.

I'd try with a vertically divided gradient masks, through which I'd try color-correcting the two sides separately with the effects blending in the middle.

Hi General,

Had a similar problem with flash and fluorescent. A vertically divided gradient mask may not always work on people because different parts of the body will be at different angles, and reflect different light.

For example, the left sides of the left and right arms may reflect more daylight and the right sides may reflect more tungsten. It can get messy.

But I think silverfox'es idea of using the light creatively is better. There are a lot of well done portraits using one color of light on DPC.

Message edited by author 2007-06-21 11:55:18.

06/21/2007 11:58:49 AM · #12

Originally posted by silverfoxx:

Can't wait to see what you do with gels on your flash (or room lights).

Nikon AF-S DX Zoom Nikkor 17-55mm f/2.8G IF-ED

06/21/2007 12:05:49 PM · #13

Originally posted by hankk:

Can't wait to see what you do with gels on your flash (or room lights).

:( i don't know where to get them!
i used paper and fabric over my softbox, but they only reduse the light, don't color it. and i can stick some paper to the softbox, but i probably need some tripods for gels, right? i saw it on pictures

oh, what if i use some filters on my lns to change the color? will it give the same effect as gels? i'll try :)

Message edited by author 2007-06-21 12:19:36.

justamistere

Nikon D3s

06/21/2007 12:35:41 PM · #14

My Nikon SB-800 strobes came with some small gell samples to snap over the flash. I work at a large printing business. We have C/Y/M/K rolls of gell, that can be cut into any size. Some only have a portion of them with an image. Look for a company that uses a Kodak proofing machine, that's what these films are used for.

SamDoe1

Canon EOS-350D Rebel XT

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

06/21/2007 12:38:30 PM · #15

Originally posted by silverfoxx:

I'm sure you can find them all over, pretty common thing. If you put a color filter over your lens, you get the same color all over, which tends to not look so good. With gels, you can put color where you want it and mix it up too (different gels on different strobe units). It also allows you to use the natural lights and colors in addition to what you add with the gels.