I wouldn't call it garbage by any means, but when I compare it to 70-200mm L with a 2X Teleconverter on my 1D MK III, it is harder to get a sharp image, the IS is not as effective. Of course, I have only had it a week, and the weather is so bad that whenever the sun peeks out for 5 minutes, I shoot birds near or at our feeder out the front window, so sharpness is affected. I'd say that unless I pay careful attention to how still I hold it, and brace myself, I get lots of blurred images.


These were taken thru the window at 400mm this morning, the best of probably 25-30 images. Many were spoiled due to the birds hopping around, and the rest due to clouds passing over, or just not as good a pose by the bird. The icy wind was gusting as well. Iconsidering that I returnthe lens, since I use it only at 400mm and get something else, maybe a 300mm F:/2.8 IS, or just use my 70-200mm f4 IS with a TC. i've had the 400mm 5.6, and the lack of IS made thongs difficult at slower shutter speeds.














Here is the 70-200mm f4 with 2X.