Dadzcanoe
I was unable to produce clear photographs with the Sigma 150-600 mounted on a Canon EOS T2i. I initially planned to use the lens to document observations of Bald Eagles nests. I previously relied on a Canon 75-300 with some success, but hoped the Sigma 150-600 would provide more detailed images, especially as spring progressed and foliage made it more challenging to get a good shot. The "reviews" I read before purchasing the lens extolled the virtues of the auto-focus functions. Didnt work well for me at any distance. I tried combinations starting with full auto to complete manual. I tried duplicating the ISO, shutter speed and aperture settings of successful pictures I took with the Canon 75-300 from the same vantage point with the same subject. I tried the lens with and without a tripod and a monopod. I tried manually triggering the shutter and a remote shutter. I tried taking pictures of the dogwood in front of the house, testing with a matrix of auto-focus, image stabilization, focal point settings, etc. No dice. I finally sat in the backyard about 70 feet from the bird feeders at 11:30 AM on a sunny day alternating between the Canon 75-300 and the Sigma 150-600 focusing on the same subjects using auto-focus. The Canon produced the sharper images. I gave up. I returned the camera to the vendor. I did not have the original packing material and they refunded $802 of the $939 purchase price.