Review: Canon 300mm F4 IS L Lens (& 1.4x converter)

Whenever I go out to shoot wildlife, this is the lens that will be attached to my camera 95% of the time and it is absolutely cracking for what I need. A 300mm lens is not the longest lens for wildlife, and at F4 it is certainly not the fastest you can buy, but personally, I wouldn't swap it for anything, and here's why:

Weight

A baby swallow being fed on the wing by a parent

After I graduated from Glasgow University the first time around, and before I even had my own DSLR, I spent a summer working for a company offering wildlife boat tours in the Firth of Lorne, near Oban. The guy I was working for had just bought a 2nd hand Canon 1D MkII N and a 300mm F2.8 IS L lens and was more than happy to let me use it while we were out running the trips, which was great, but that early experience with that kit taught me two important things: firstly, if you're going to shoot wildlife at sea, you're pretty much going to have to handhold your camera to compensate for the swell. Secondly, handholding a setup that weighs over 3kg for long periods of time on a boat is going to screw your back up pretty quickly. I'll admit I'm not the strongest person in the world (though I'm pretty fit from diving), but holding that amount of weight in front of you while you wait for a shot really takes it out on your shoulders! So, as much as I might like to own a 300mm F2.8 or one of the longer super-telephoto lenses, the weight of them means they're just not practical for me. I'm sure they're amazing, but until it becomes practicable for me to use a tripod (or someone develops some kind of helium-balloon support), I will be sticking to the 300mm F4 which by contrast weighs in at just over 1kg. So it's still not what you'd call light, but it's certainly usable.

Cost & Flexibility

Fast shutter speeds get the most out of telephoto lenses

Another major consideration for me was the cost of the lens and how flexible it would be. Essentially, I wanted the best possible telephoto lens I could afford for the best price (under £1000), so it effectively came down to a choice between the Canon 300mm F4 IS L, 400mm F5.6 L and the 100-400mm F4.5-5.6 IS L. At the time when I was buying the lens (about 8 years ago), I was pretty sold on the idea of image stabilisation, so that was a factor which nudged me away from the 400mm. Between the 300mm prime and the zoom, it largely came down to reviews of the image quality, and the prime lens seemed to come out on top. Finally, the 300mm F4 is the only lens of the choices that is compatible with the 1.4x teleconverter without losing autofocus (on EOS bodies at least) which nudges the zoom up to 420mm with minimal loss of image quality at the cost of one f-stop.

In the end I got lucky with ebay and managed to find an excellent 2nd hand copy for just under £600 which was a bit of a bargain and sealed the deal! 

Image Quality

Stabilisation allows you to use a lower shutter speed for still  subjects or easier tracking for fast ones

At the end of the day this was really the most important thing and I haven't been disappointed. This is a great lens for wildlife, but as with all telephoto lenses it really needs a fast shutter speed to get the most out of it. I'm also glad it has IS as this makes a very noticeable difference when hand-holding the camera - if you switch it on and off you can actually see the difference it makes through the viewfinder! Even if it will never slow down your subject, it removes enough wobbliness to make tracking fast animals even easier, and if you use it on stationary or slow moving subjects it will apparently compensate for four-stops worth less light than without.

A mackerel chasing a sandeel out of the sea at Tjarno, Sweden.

Other than that, the lens is silent, focuses incredibly quickly and accurately and has been absolutely reliable no matter what I've thrown at it (which is a lot). It is is cosmetically rather more battered and scuffed than it was when it was delivered, thanks to hundreds of hours spent on fishing boats, research, boats and RIBs but despite everything it's still as good as it's ever been, which says a lot about how Canon build and seal their L lenses!

This is still a crop from the original - 300mm lenses (even with the converter) are still quite short for wildlife

Adding the Canon 1.4x teleconverter costs you one stop, reducing the maximum aperture to F5.6, so you lose a bit of speed and you don't get quite the same knife-edge depth of field that you can get on wider aperture lenses. Saying that, it still produces excellent separation between the subject and the background and is certainly a lens to consider if the points raised here are important to you.

A gull taking off at dawn

Prime lenses in general tend to be higher quality than zoom lenses, but choosing a prime does mean that you have no choice in terms of the focal length you get, and if you want to use something else, you will need to physically change lenses. For me, this has never really posed much of an issue, but I tend to shoot animals and birds that congregate in groups so it's relatively easy to choose an appropriate subject. And regardless, 90% of the time the problem will be that you can't get as close as you would like to a subject anyway, so I've very rarely found myself wishing I had a shorter lens attached to my camera! Still, if that is something that you think you might need, then something like the 100-400mm zoom might be a better option.


Conclusions
Honestly? I love this lens. With the 1.4x converter attached it produces excellent quality images and provides a decent amount of zoom for photographing wildlife. It's also relatively affordable and extremely lightweight compared to the super-telephotos you can buy, without compromising on build quality or reliability. I can't honestly say how this configuration compares to the 100-400mm zoom or the 400 F5.6 prime lenses as I've never used them myself, but I believe it would be hard to go too far wrong with any of them.