Focal Length

Going bird hunting this weekend, so I got myself a big gun. The Canon 70-200mm f/2.

I also got the 2x tube (or whatever it is called) to get as close to the birds as I can.

So how close is close?

All photos were done on a Canon 7D, which uses a 1.6x crop sensor so the photos should be 1.6x more zoom than if it was shot on a full frame camera.

I snapped some shots at different focal lengths to see. My target for these sample photos was a construction crain, specifically the driver control box. Here are the results (click for larger image).

Construction Crain @ 15mm
Construction Crain @ 50mm
Construction Crain @ 50mm
Construction Crain @ 70mm
Construction Crain @ 200mm
Construction Crain @ 200mm
Construction Crain @ 360mm

I’ve always thought 200 x 2 would be 400, but apparently not. With the 2x adapter on the 70-200mm lens the EXIF data is reporting the final shot is actually taken with a focal length of 360mm.