I found my copy of this lens unacceptable...Soft wide open. The imaging stabilizing was very clunky as well (IS) -- I use to use these lenses back when I was shooting news and they were always decent...

I've shot with a 30D for about 7 years and recently switched to a 7D. All my digital SLR experience has been with these APS-C cameras. I purchased the 300mm IS f4L as a way to get a little more magnification than the 70-200mm IS f4L that I already had.

Fast auto-focus; Superior build quality; image stabilization; size and weight; close-up capability; case tripod mount & built-in lens shade

Semi-sharp images, i.s; noise (clunking

Yes, I would recommend this to a friend

Consistent Output; Durable; Easily Interchangeable; Quick Focus; Strong Construction

Heavy

I bought this lens to use on a series of adventure cruises to the high Arctic and Scottish Islands. I was torn between this and the 100-400 L zoom. This lens was lighter and had a constant aperture.

Lightweight; Rugged

Very sharp pictures - if your OK with no zoom, It is a great lens for a decent price. I would highly recommend.

Shoots sharp images; very quiet IS; great colour and contrast; 2X teleconverter; which provides plenty of manual focussing

No zoom

I use this lens for birds in flight photography and nighttime owl photography. It has really impressed me as compared to my Canon 400 f/5.6L lens. 90% of the time I use the 300 mm with a Canon 1.4X III extender. I love the combination for wildlife photography. Fast focusing and super sharp images.

I bought this lens after a lot of thought and spent a lot of time looking around and found one on Amazon "used" and got one at a very good price which I couldn't ignore! The lens was as new and came with a UV filter. I am absolutely delighted with the lens and has exceeded my expectations.

I purchased this lens for my wildlife shots after looking what Canon had available. It is lightweight extremely sharp and very affordable. when you are walking around for hours taking shots it can be handheld without too much problem.

Superior build quality; Super-sharp images; Fast auto-focus

I can say nothing bad about it, colour, sharpness, bokeh. If you have a need for the distance, it is well worth considering. I use it for closeup shots as well as racing and simply love to use it. It's not overly heavy, I hand hold and use a monopod.

With a closest focusing distance of 1. 5m/4. 9ft, you can get in as close to the subject as possible in that unique way only possible with a macro lens. The image stabilizer also functions when using the extender ef1. 4xii and extender ef2xii to provide that elusive 600mm shooting capability.