Tuesday, November 29, 2011

Tech Talking

Greetings, Hohenfels, welcome to Hohenfels Volks, THE place for our place. Here’s hoping your week is off to a good start and Tuesday didn’t turn in to Monday part 2.

Today we’re going to introduce the concept of “Dynamic Range.” If you remember our introduction to the Zone System, there are 11 zones, 0-10. Ansel Adams considered this the full range, zones 1-9 were the dynamic range, and 2-8 the textural range. Zone 2 is the lowest value that retains discernable texture, and zone 8 is the highest value retaining usable texture, and in both cases the values where detail is preserved and recorded.

When we speak of dynamic range today, this still in some ways holds true. Metering from a gray card, it’s how many stops of exposure above and below middle gray that are usable. For instance, the EOS 7D has about 8 stops. Its range consists of 5 stops below gray before clipping to black or solid noise, and about 3 stops above middle before blowing to white. This means it runs from about zone 1 to zone 8, maybe a little higher. Each camera’s range is different; so don’t use one camera’s range to guess another’s. "Dynamic Range" determines the amount of contrast an image can have and how sharply that gets applied. It also can effect how you change the sides on your exposure triangle, based on your intention.

When you know your camera’s range, you can adjust your exposures appropriately. If you wish to increase middle gray, zone 5, to zone 6, you have to know your limits before the higher zones blow out. Taking 5 to 6 brings zone 7 to 8, and anything starting at or above 8 will be blown to solid, textureless white.

A camera’s range often times is limited by the size of the photocells or photosites. These are the individual receptors on the camera sensor. A larger frame sensor will usually have larger photocells, allowing more light to be received and detail retained. There are millions per most of today’s sensors.

Another way to expand your “Dynamic Range” is to always shoot RAW, as your camera records more information. You can add up to a stop and a half shooting RAW. Shooting automatically and in JPEG mode can cost you that latitude in your exposure. Keep that in mind when shooting in very bright or low light conditions.

Well, that about wraps up our discussion. Try to keep that in mind when you’re out capturing the beauty of Hohenfels, our area, and your holidays. The results will amaze you.

On to other things, I’d like to remind all of you to get your votes in and get working on your photos for this week’s theme, “Morning Moments.” I can’t wait to see what you amaze me with!

Shoot for the love, of photography, your subjects, and your art, it really will show! Get shooting and start posting at the Hohenfels Volks Facebook page. Of course, commenting here is always welcome, too!

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