EF 75-300mm f/4-5.6 III lens Canon's EF 75-300mm f/4-5.6 III is a cheap lens with a long focal length. It doesn't have great image quality nor a great build, but it delivers 4x zoom for a low price and is extremely portable. This 75-300 is not a fast lens. A long lens not only magnifies subjects, but also the effects of the photographer's movement. When hand-holding a lens this long, a fast shutter speed is essential to counteract blur. The 75-300’s small max aperture means raising your ISO will often be necessary to let in enough light to utilize those fast shutter speeds. Especially indoors. The 75-300's max aperture varies according to focal length. It starts at 70mm at f/4 and closes down to f/5.6 at the 300mm end. When exposing manually, you need to be conscious of your focal length because zooming may change your exposure. I suppose some people don't mind variable max aperture lenses; they irritate me. The lenses, that is. This lens is small, light and feels fragile. Its light weight makes it easy to carry around, keep in a bag, and hang around your neck without causing too much strain. At the same time it doesn't feel very strong and I would be careful not to abuse it too much. I didn't own it long enough to see exactly how much punishment it could take.

EOS Digital Rebel XTi w/ EF 75-300mm f/4-5.6 III @ 75mm, f/8, 1/1250 sec., ISO 400

I was never impressed with this lens' image quality. It's not incredibly sharp and I thought it produced average color. Of course it doesn't hold a candle to L zooms like the various 70-200 lenses, but that comparison is unfair since the L zooms are extremely expensive professional-grade gear. A comparison that makes more sense is the EF 70-300 f/4-5.6 IS USM. That lens has a similar focal length range, the same variable max aperture, a USM focus motor and Image Stabilization. It's heavier, feels much more durable, and I think it produces a much better image.

EOS Digital Rebel XTi w/ EF 75-300mm f/4-5.6 III @ 80mm, f/7.1, 1/400 sec., ISO 100

Where does the 75-300mm f/4-5.6 III excel? Telephoto for cheap. The main reason most people buy this is the reason I originally did: 4x zoom to 300mm for only about $200. This is a very affordable lens that will produce decent photos of kids running around outside, animals at the zoo, and such. Being telephoto at all focal lengths, the 75-300 makes it easy to produce background blur. Set the aperture wide open, zoom in and you will be able to achieve singular focus, isolating your subject from most reasonably distant backgrounds. This was one of the least liked lenses I have owned. I bought it in August and sold it four months later for a few reasons:
  1. My shooting style doesn't often necessitate 300mm.
  2. I didn't like the image quality.
  3. I didn't like the variable max aperture.
  4. I do most of my photography in low light, where this lens doesn't excel.
If you want the most zoom for the least amount of money, consider the EF 75-300mm f/4-5.6 III. If you shoot in low light, abuse your gear or are critical of image quality, consider other options.