I've just upgraded this winter from my Canon EOS A2 to a Canon 20D (digital)
I've been doing some air to air recently, and swapped back and forth between lenses using my 28-105mm and the stock 18-55mm.
I believe for closly parked aircraft, such as air shows, I'll probably need to use the 18-55mm in order to get the whole plane in. I think the 28- will magnify too much in digital.
I also have the 75-300mm IS which was my big lens, but have now purchased the 100-400mm IS L lens. It broke within the first couple of times I used it and had to have it repaired. This is basically used for ground to air/runway shots. You can see a few of my pictures at:
http://www.napanet.net/~arbeau/usaah/update.htm that were taken from the ground with the 100-400mm (The PT-20, Stearman, and Piper Clipper)
All lens' are Canon. I had some Sigma lenses which I used with my older Rebel and A2, but had some disappointing results. I've stuck with Canon glass ever since.
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Roger Cain
www.sfahistory.org
http://groups.yahoo.com/group/Stearman/
We must limit politicians to two terms:
one in office and one in jail.