Well the title is not strictly true for most people and myself when we talk about a 50mm lens. Often the first lens anyone buys is the one that comes with the DSLR. You can buy DSLR’s without a lens, but when its your first DSLR, hardly anyone will do that.

One of the most common tips I give to anyone who is going to or has just bought a DSLR is to buy a 50mm lens. Regardless of the camera manufacturer, they will most likely have a reasonably priced 50mm prime lens available. Prime you say, whats that? It basically means the lens does not have a zoom, the focal length is fixed, any zooming you want to do, you do using your feet, which can be problematic when shooting indoors or in a confined space, but as with most things, there are benefits and drawbacks, the lack of zoom some people consider a drawback, others consider it an advantage, but either way we’ll be discussing the many benefits of a 50mm prime lens below.

Cost

So you’re wondering how much a 50mm Prime lens will cost. At the time of writing a Canon 50mm f1.8 prime lens could be bought for $119 at BHPhotoVideo.com. For most people this is what I’d recommend. Of course Canon at least offers three 50mm prime lenses, the 50mm f1.8 ($119), 50mm f1.4 ($379) and the 50mm f1.2 ($1418). So whats the difference? The main differences are speed, f1.8 versus f1.4 versus f1.2, autofocus speed, low light handling, build quality; the f1.8 version is commonly referred to as the plastic fantastic for a couple of reasons… its plastic and its fantastic! There are other differences also such as color rendition, lens flare handing etc, but once you get to the point of wanting to know about those things, I suspect the job of this article will be fulfilled!

What do I use? I have both the f1.8 version and the f1.4 version and use the f1.4 version. This is the only Canon lens that I own which is not from their professional lens lineup (designated by the red ring as seen on the f1.2 version in the picture above). I thought about buying the f1.2 version, but never have because the focus speed of the f1.4 version is actually faster than the f1.2 version, and for taking shots of the kids, focus speed is important!

Advantages

So far I’ve told you the lens doesn’t zoom and its made of plastic, so you’re probably wondering why bother when you have a zoom lens that came with the camera?

Most kit lenses are inherently slow, typically f3.5 at their widest focal length to f5.6 or f6.3 at their longest focal length. This is the disadvantage of that kit lens, they are cheap and zoom, so in the world of swings and roundabouts, you have to give up speed. Typically of the three – zoom, speed and price, you can get two, i.e. speed and zoom equates to high price, speed and lower price equates to no zoom, zoom and low price equates to slow lens.

So lets take a look at one of the shots I took yesterday. Using photoshop, I try to show what the photo may have looked like shot with a slower zoom lens, i.e under exposed, in reality it would probably have also been blurred and the background would have been more in focus thus isolating the subject less, but this should give you an idea of the difference a fast cheap prime could make…

Direction of Lightsource

One other thing you’ll notice about the shot above, is that my son’s face is well lit. Typically a persons eye will be drawn to the brightest part of an image, so for shots of our children, we’d like that to be their face. So even with a fast lens I try to ensure that the subject is facing window light when indoors. Not only will this allow me a fast shutter speed at the correct exposure for their face, but it will also ensure there is more light hitting their eyes, if you want to see color and definition in the eyes, this is the key, you can see from the photo (the brighter one) above that my sons eyes are blue and nice and white, I haven’t messed around with brightening his eyes in photoshop or sharpened them separately, this is how they where shot in the camera. If he had been facing away from the window, I could have still gotten his face correctly exposed, but his eyes wouldn’t have been as nice and bright and alive as they are above.

In Summary

For cost to the speed of the lens, the 50mm cannot be beat and with a little practice, nice sharp photos can be attained in almost any indoor situation without a flash. So make the small investment, you won’t regret it, then we’ll move on to depth of field an isolating your subject.

Caveat

One thing to note is that I shoot with a ‘full frame’ camera, this means its sensor is the same size as a 35mm film frame. Most consumer seniors are smaller than this and thus a 50mm lens on a typical consumer DSLR will have a crop factor. This means the effective length of a 50mm prime lens on a Canon will be approx 80mm, for a Nikon approx 75mm. The net effect of this, its that the lens will seem like it has a longer focal length than on my camera, and thus you’d have to take a few steps back to frame the shot above in the same way as I did. On the plus side, if you’ve seen photos of people taken with a wide angle lens, you’ll know they have big noses in those photos and if you’ve seen photos of people with a telephoto lens (long focal length), you’ll know that people look skinnier than they really are, well 80mm is about the correct focal length to have no such distortions, whether than it something you want or not is another question!