I had some concerns about the sharpness of my relatively new, still warranted, Canon 300mm f/2.8 lens after taking some bird photos that just weren't as sharp as I wanted. Mostly, I'd used this lens on my Canon 40D to get some extra telephoto punch via the 1.6X crop sensor, but most of my images just weren't as sharp as I'd like. I'm still concerned that the 40D isn't focusing well enough or fast enough in the servo mode on a moving subject (reputed to have some front-focus/back-focus issues) so I tested the lens by shooting across Lake Union in Seattle, using a tripod and +/- IS (which I haven't analyzed yet).
Shown below are small 100% crops of the first 6 shots I've looked at. The bottom line is that when looking at an edge section of the image, the 300mm f/2.8 shot at f/8 easily beats the 100-400 shot at either f/8 or at f/14. The real surprise to me was that the image from the 40D cropped sensor (which appears more telephoto due to the sensor crop factor) actually seems to have more detail than the image from the 5D. That would suggest that the 40D is a great camera/sensor to give you a little more telephoto punch than the 5D (full-frame) sensor. Both cameras were shot with mirror-lock-up and at ISO400, with no IS in either test. Another surprise, the Canon 135mm f/2.0 actually produced pretty sharp pictures with reasonably good edge sharpness (same cropped area) when using a 2x telextender (effective focal length 270 mm) ... shot at f/8.0 (2 stops closed down from maximum aperture).
Here are the shots:
300mm f/2.8L shot at f/8.0
100-400 f/4.5-5.6 shot at f/8.0Canon 5D (at about 280mm focal length)
100-400 f/4.5-5.6 shot at f/14
Canon 5D (at about 280 mm focal length)
(a little sharper than at f/8.0)
Here's the Canon 40D with the 300mm f/2.8 at f/8.0
...and the 40D with the 100-400 shot at f/8.0
...and for comparison, 1st the 5D 135mm f/2.0 with a 2x
teleextender shot at f/8.0
So, for now, it is "back to the drawing board" to figure out why my bird shots weren't as sharp as I'd like. Perhaps I didn't wait long enough for the IS to settle, or perhaps the servo focus was spending too much time trying to catch focus and just not nailing it. Hmmmmm.....
1 comment:
I sent a comment but I think I wasn't signed in properly so here I go again. I'm also having focus issues with a new Nikkor 16-85mm f/3.5-5.6 lens with Vibration Reduction. I wanted the wider angle lens and thought I wanted the VR feature but now not so sure. It is hit or miss - mostly miss - just too soft. I keep going back to my older lenses, which is a real shame given the price of the new one. Please let me know if you find the secret!
Betty
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