Advantages of a 50mm

[swoosta]

I have a Canon 40d with the 17-85 kit lens. I have read a few reviews saying it's a good idea to get a 50mm prime lens, what would be the advantage of this as the focal length is covered in the zoom? (The 50mm is the Canon 1.4)

[ianpinion]

There are infact many advantages to be had having a prime lens.

Firstly, the Canon 50mm is an f/1.4 as you point out, which means that it's widest aperture is 1.4 as against only 4 for your kit lens so it will let a lot more light through the lens on to the camera's sensor. Or to put it another way, if you had two 40ds, but one had the prime lens whilst the other had the kit lens, both lenses opened up to their widest aperture and you shone an equal amount of light through both lenses. The light passing through the prime lens would pass through the lens to the sensor in probably a tenth of the time it would take to pass through the kit lens. This is what we mean when we say a lens has fast glass.

Secondly, you may have heard us discussing how zoom lenses have a sweet spot where at a certain focal length they produce their sharpest images and either side of that the quality suffers. With a prime lens, it has a fixed focal length and it always produces a sharp image from the centre to the virtually the very outer edge no matter what! They are also less likely to produce any distortions that can be commonly found with zoom lenses when shooting in certain condtions.

So the 50mm f1.4 is a great lens for portaits and still life as well as being a good lens for close up work or macro.

[ap4a]

I would agree with the first part of that, and part of the second.

Another benefit of fast primes is that the wider max apertures give greater control over depth of field.

[Forseti]

Originally Posted by ap4a

Another benefit of fast primes is that the wider max apertures give greater control over depth of field.

Indeed, which to someone not used to a 50mm lens (or nifty fifty as it's often referred to), this can take some getting used to especially with the f/1.2 and f/1.4 variants. I've learnt to love my Sigma 50mm f/1.4 as it produces extremely sharp edges, it's exceedingly good in low light with the 7D meaning I can pump up the ISO and obtain a reasonable hand-held aperture speed without recourse to using flash.

Another advantage of a prime lens such as the 50mm is that it encourages you to think about composition more. Gone is the benefit of standing in one place using a zoom - now you have to zoom using your legs.

[ianpinion]

Originally Posted by Forseti

Another advantage of a prime lens such as the 50mm is that it encourages you to think about composition more. Gone is the benefit of standing in one place using a zoom - now you have to zoom using your legs.

I always use my legs to find the best position to take the shot from when composing an image. You can use your legs to move you sideways, forwards, backwards and up or down. What zoom lens will do that?

[chris-p]

As has been previously said there are all sorts of advantages to a fast prime lens, (faster, sharper, more contrast, brighter, more creative control and it makes you think more before you shoot).

My only caveat to it is that 50mm is relatively long on an APS-C sensor although I know a lot of people use them. I'm more of a fan of a 35mm length (if there is a suitable option for Canon cameras) which is closer to a "normal" focal length for APS-C (which is 26.7mm on an EOS 40D).

Depends on what you want to do with it...

[heronfisher]

For practical purposes, you can achieve the same thing with an 18-55, but within limits.

You will not have the range of f stops that you have on the 50mm, thus you limit some of your choices on how you want the photo to look. As for the 50mm being "sharper," you will never notice the difference.

The problem with most of those answering here is that they tend to be a little specish, look at specifications rather than results. They can argue about those things all day, but in the end, when two photographs are produced, one from the 50mm and one from the 18-55, they will not be able to tell the difference. Most today, however, will have software so that they can identify the specifications of the picture and then comment once they have that. BS

What you do, then, is to purchase the lens that you want if you have the money. If you don't have the money, stay with the 18-55 kit lens and do the best that you know how to do.

I would not use a 50mm for portraits, it is not long enough. If I were using a Nikon, I would look for a 70mm or a 75mm. In 35mm, I use a 135 prime lens when I shoot portraits, but then I don't shoot many any more, so I do mylandscape shots with the kit lenses on my digital.