Wednesday, August 4, 2010

Manual mode with auto-ISO

It actually works fairly well... I spent a week at AirVenture learning about new airplanes, light sport aircraft, and doing a lot of photography.  I took over 3400 photos, and have to now sort them.

I ended up using the manual mode of the camera with auto-iso in raw mode the last day I was there.  I did most of my ground to air shooting that day.  While you have to be careful to watch the exposure in case you over expose (my usual problem) having the Canon 7D handle the ISO worked surprising well. 

And the reason?  When you take photos of aircraft, you want to have the shutter speed slow enough so that the prop is not stopped still. That gives you a sense of motion.  For a slight blur, you can go as high as 1/800 of a second. I tend to shoot someplace around 1/400 of a second.  A tripod works well, or an image-stabilized lens. Since I have never been very good at panning with a tripod, I use the 100-400 IS lens from Canon. I suppose a gimble head would work well.

If you want to have the full arc of the prop, you need to drop down to 1/80 or less when the engine is at full RPM. Needless to say, 1/80 is very slow for a 400 mm lens. The P-51 shot was taken at 300 mm, 1/80 second, f.16, iso 100.  Handheld but braced.

If you want to practice this, see if you can attend a seminar by one of the professionals. I went to listen to Paul Bowen, a very entertaining and enlightening speaker.