Wednesday, December 30, 2009

LotR 2007 cont. - a word about color temperature

Last entry, I briefly mentioned that color issue - the white balance problem with the Sunday daytime competitions. That was pure slop on my part, and not the fault of the camera. But it highlighted the next piece of the puzzle. I went back and tried my best to correct the color on the Showcase competion (100-200 photos) but was severely limited because I was shooting JPG to save memory. That turns out to be a major mistake that my photographer friends have been warning me about for a long time. The main issue I had was that there wasn't an easy way for me to process a large group of photos.

Honestly, I don't understand white balance as well as I should. All I know is that different types of light get recorded differently. Most indoor lighting will be around 2800-3200 K, while outdoor lighting will often be 5500-6500 K. Shooting outdoors with an indoor setting will make your images too blue, while shooting indoors with outdoor settings will make your images too yellow (I'll show an example of that here). If you want to know more, I suggest reading the Wikipedia entry on color temperature

Let me first start by saying the Sunday afternoon competitions were insanely hard to shoot. I wasn't really happy with any of my Sunday afternoon shots, but this is just for discussion. This shot shows two big issues:

  • Differences in color temperature. There are tungsten lights inside, which are actually pretty dim. Plus, there is some pretty powerful daylight coming in from both sides. There's the sky outside the windows in the photo, and obviously the sun coming in from the doors behind me.

  • Differences in light. In the corner of the room, it's pretty dark. But the people in the lower right corner are getting hit directly by the sun. you can see it's actually blowing out (overexposed).

I was shooting JPG, so I couldn't manipulate it too much afterwards, but today, I would have shot it a stop or two down to avoid the overexposure, knowing that I could rescue the dark areas from a RAW image later.

I'm still not really sure what to do about the color temperature. I think I would still just play with it in Lightroom until I found one that was okay.

But to give an example of how much manipulation goes on...

This is what I started with - I set the wrong color temperature when shooting. Probably all photos taken that afternoon started out looking like this - way way too yellow and a little dark.

Here is my first attempt to fix the color, but I think it turned out a little bit too pink.

A few days after that, it just bothered me so much that I decided to try to neutralize the pink a little bit. I think it actually wound up adding a little more green to fix it. Actually, you can see in the mirror that one wall shifted blue showing I may have gone a little too far. But that's not the biggest part of the shot. If I was really trying to refine this one photo, I would consider taking it into photoshop with a few different color settings and mixing it differently in different sections.

The things to consider were:

  • What should be white? The back wall? Teni's shoes?

  • How white should it be? The back wall probably wasn't really white, but more a beige, very very slightly warmer. Also, there is colored light in the room, whether it's bouncing off the floor and stage

  • What should the skin tones be? Try to pick something reasonable. Remember despite the crayola "flesh" colored crayon, everyone isn't the same. Check everyone. If worst comes to worst, you can use photoshop to fix people individually, but you can probably find a setting that looks right for everyone, knowing that everyone's skin tones can wind up different.

The thing is, making these adjustments is very hard with a JPG because the image gets the color temperature baked in. Though it doesn't even record the color temperature in the metadata in the image. With a RAW image, the color temperature is just a setting recorded to tell the software how to process the RAW data. But (I think) the RAW data is really the same whatever the color temperature is set to. After all, it's the same light that's hitting the CMOS sensor. The processing happens when it's turned into a JPG.

The bottom line:

Always shoot RAW.

The problems with RAW (and why they shouldn't concern you) are:

  • The files are huge. A big high quality JPG may be around 2 or 3 MB. A RAW file is about 12 MB. Let's say you have a 1 GB Compact Flash card. You're looking at over 300 JPG images or less than 90 RAW images. That's a tough decision... in 2007. But today(2009), a new SanDisk Extreme III 32 GB Compact Flash card sells for $149 from Amazon's featured merchants. Now, 32 GB is a lot. That's enough for me to shoot a 4 day swing event without having to delete any photos (though you should delete the crappy ones). A 8GB Extreme III Compact Flash is selling for $50, and that's good for a whole day at a dance camp. And you can probably even find cheaper ones if you start exploring ebay and craig's list.

  • They take a lot of disk space. Again, disk space is getting really cheap too. Today, quickly scanning Amazon again shows a 2 TB hard drive sells for under $200.

  • Sometimes older operating systems (Windows XP) have trouble understanding what RAW is. I'm pretty sure XP and Windows 7 can handle them just fine, and now I'm using a Mac and OS X handles it great. But really, you should use Lightroom or something to process and view the images. Lightroom sells for something like $300 retail. But go take or teach a class or something and the educational price is $100.

So I'll revise that to say:

Always shoot RAW.

Get a 32 GB memory card, or several 8 GB ones.

Get a huge hard drive

Get Adobe Lightroom - I think some people also really like aperture, but I've never tried it myself.

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