I have recently bought a 50 mm prime lens for my Canon EOS 400D. I was advised that it was the one lens that I absolutely must have and that, compared to other lenses, it was ridculously cheap at less than £90. The amount I paid was even less since I had an Amazon gift voucher in recognition of some pictures I took at work for the website (is this my first paid comission :-)).
‘So what is a prime lens’ I hear you cry in a harsh panting whisper… Basically, a prime lens is not a zoom lens so you do not have a variable focal length. It does not contain any of the expensive internal mechanics of a zoom lens (motors, etc) and therefore provides excellent optical quality. On a zoom lens you can vary the focal length (eg 70-300 mm) but the construction is complex and you lose some optical quality. Still with me? In a nutshell, because of its fixed focal length (i.e. 50 mm), with a prime lens if you want to take a close up you have to move your sorry ass closer to the subject – with a zoom lens the camera would move the subject closer for you.
Prime lenses are particularly good for portrait photography and the lens I have bought allows you to have a very large aperture (i.e. lets in more light). This means that at the largest aperture (f1.8) you can limit the depth of field so that the subject stays in focus whilst the background and foreground are blurred. The larger the aperture (or the smaller the f-stop number) the narrower the depth of field. Which is why for portrait photography this lens is a good choice.
I’ve been experimenting with the lens this weekend and am amazed at how my portraits have improved. Now most of the pictures have been of the kids and as I have said before I don’t really want to use images of them on this blog and the greater world wide web. However, I think that this image is suitably non-descript as it is mostly all about reflection rather than the subject. My daughter was doodling in the garden and I took this picture with the new lens. I think it works pretty well and the reflective service of the table give it an interesting angle. Next week I am taking some portraits at work and hopefully this lens will help to improve my portrait photography. Some volunteers have come forward to act as my guinea pigs for my portraiture experiments so we’ll see how things develop (ba doom and indeed tish, develop… geddit)