Good lens with some shortcomings

Pros:
Telephoto range
4x zoom ratio
Lightweight
Cost

Cons:
Very slow focus
Hard bokeh (depth of field blur)
Rotating front element
Minimum focus distance

This is the least expensive telephoto zoom that Canon makes. For an entry-level telephoto lens it’s not bad, but you may want to consider the other lenses that Canon offers in this focal length range: (street price for new lenses)
EF 75-300mm f/4.0-5.6 III - $150.00
EF 75-300mm f/4.0-5.6 III USM - $180.00
EF 70-300mm f/4-5.6 IS USM - $ 550.00
EF 70-300mm f/4.5-5.6 DO IS USM - $ 1,100.00
The main problem with this lens is the very slow focus system. If you’re used to a DC focus motor on a smaller lens, you will still notice how slow this lens focuses comparatively. If you’re used to an Ultrasonic Motor, this lens is probably not for you. This somewhat limits this lens’s ability to be used in action situations, but for wildlife you probably won’t mind. If you have the aperture stopped down, the background blur (bokeh) is unappealing. The long focal length inherently has a lot of shake, so this lens needs good lighting to keep shutter speeds up, Image Stabilization would of course help. The good news is that the USM version (with the same optics) is only $30 more, well worth it in my mind. If you are serous about using this for sports or low light conditions , you should really consider the 70-300mm IS USM. If you have some serious cash to invest, the Diffractive Optics version is a pro-grade lens.

Bottom line: Yes, it’s the most affordable, but a novice shooter will outgrow its features quickly. There is very little reason not to get the USM version instead, and the only downside to the IS version is cost.

Good value and performance

I recently jumped into the world of DSLR cameras, and I was not very familiar with all the different varieties, features, and functions. After doing some research, I determined that my best bet would be to go with a Canon camera because of the lens variety. Why purchase a $700 camera and be stuck with crappy lenses?

I wanted to have a lens with about the same zoom power as my old digital camera (Sony Cybershot H50) (15x Optical Zoom), so I needed a good telephoto lens - with image stabilization. Canon makes a cheaper 75-300mm lens, but without the image stabilization. This is definitely a noticeable improvement over the latter. I have tried to take images without image stabilization, and it is noticeable, especially considering the added length and weight of this lens on my camera.

I feel that I made the right choice, this lens has exceeded my expectations and does excellent photos. With this lens you will be liberated to take photos of birds, hot air balloons, airplanes, the moon. Anything in the sky will be in your reach!

Auto focus is good, and added benefit when I have to have someone else use my camera. (though I seldom use it) Some reviews have mentioned that the auto focus was slow, but I have found it to be faster than my old point and shoot camera.


Over all, very impressed. This lens provides a good feature set for the price. It's an excellent value if you want to do outdoor photography and do not have the budget for an "L" series lens.

Good Lens For Those On A Budget

PROS
1. Cost (can normally be purchased for under $200)
2. Zoom Range
3. Lightweight

CONS
1. Slow To Focus (as compared to USM)
2. Front Element Rotates

While not the greatest this lens is capable of produces really good photos. This is Canon's lowest priced lens in this zoom range, so expect to give up some of the luxuries with it. My biggest complaint is that is is slow to focus, but then again I normal have one of Canon's USM lenses on my camera (the 28-135mm IS).

When used outside in good light this lens works very well. However, when used inside, or in low light, the images aren't as sharp and clear, due to lens shake (this is where the IS version has the advantage, or if used with a tripod). As long as you are using a faster shutter speed the photos taken with this lens will be fine. If you are going to be using it to shoot birds or wildlife with then this lens isn't a bad choice, and the price can't be beat, but don't plan on using it for shooting portraits.

For the difference in the price I would look at the USM version, though, due to the faster focus. And, if your budget supports it I would recommend the IS version of this lens, as I am sure that would greatly enhanced the photos (as it will compensate for lens shake), especially if you are going to be using it in any low light situations.

I personally do not use this focal length that often, and when I do I use it outside when it is well lighted, so the other features aren't that important to me. Although I wish I had spent the extra and gotten at least the USM version. I can say that if I used it more often then I do now (I have had this lens for about 4 months now, and think I have only used it twice) I would get the IS version.

Canon's "Hidden 'L'" Lens

If you're looking for a quiet, affordable lens with great image quality, effective stabilization, very good resolution, lots of telephoto reach and low distortion all in one package, look no further. At its price point, Canon EF 70-300mm f4-5.6 IS USM simply cannot be beat.

This is the ideal complement for your Canon EF-S 18-55mm IS. Although there's a 15mm gap between the long end of the 18-55 and the short end of the 70-300, I recommend this lens over the EF-S 55-250mm lens which is the 18-55mm lens's standard stablemate. I've owned them both, and the 70-300mm is just a better lens in several regards--more reach, better construction (metal mount versus plastic) and less vignetting, to name a few.

Two days after my 70-300mm lens arrived, I accidentally dropped it on lava bedrock in the Chihuahuan desert. My heart sank when I did it--there was just no way the lens could have survived that kind of blow. But when I picked it up, dusted it off and mounted it on my 40D, the lens worked flawlessly. I'm certainly not suggesting you throw your 70-300mm on the ground...I'm just saying...I don't think the 55-250 would have survived that accident.

This lens works on SLR cameras with full frame sensors as well as crop sensors, so if you're planning a future upgrade to, say, an EOS 5D, the 70-300mm comes along nicely in the transition.

I'm giving the lens a Good rating rather than Excellent for a couple of reasons. First, it's not as dust-resistant as I'd like. This is probably only a potential issue in a very dry, windy climate like the one where I live. Also, at full zoom, images are a little soft even at optimum apertures. However, they sharpen nicely with Canon's Digital Photo Professional software, Photoshop or any good post-editing program.

Overall, I'm VERY satisfied with the quality of images the lens produces.

The lens extends a LOT during zoom, and the front element rotates, making it a little bit of a hassle when using a circular polarizing filter.

But for sheer image quality, portability, contrast, reach and resolution, I soundly endorse Canon EF 70-300mm f4-5.6 IS USM. It's a keeper!

If you just bought your camera and need a good cheap zoom lens, this is it!

One of the most affordable lenses made by Canon, this Telephoto offers 5 things an aspiring photographer on a budget needs...

-a lens made by Canon - just for that warm fuzzy feeling
-unbelievable low price for a for a Canon lens nevermind a telephoto!
-a telephoto zoom to 300mm
-USM III which is a quicker, quieter motor for auto-focus
-size/weight ratio (small and light compared to its white bodied professional brother lenses)

On the downside, this is not a professional photographer's lens! Don't panic! If you are a pro or expecting heavy use out of this lens, here's why you don't want it and will pay a ransom for a better lens...

-made of plastic not metal, obviously cheaper and less durable.
-F/4.0 as the largest F-stop. This could limit the landscape-ability of some images to say the least.

So, if you have already spent more than you wanted on the camera but need (and you do) a zoom lens (and don't forget about getting a tripod) then this zoom belongs in your kitbag!