Fixed focal length lenses
 

Hi,

I'm new to this forum. Can someone explain to me about fixed focal length lenses please. I've seen wildlife and motorsport photographers using them. Surely though with fixed focal lengths you zoom with your feet so why are they used ?

If you're on a corner of a race track or trying to track the action surely if they aren't in the correct place on that lap they are either going to be too big or too small in the frame ? Similarly with wildlife photography if you're hiding waiting for an animal you can't always tell where it's going to go so you need to be able to zoom in and out.

I can't afford one of these lenses so haven't asked any shops to demonstrate one and was hoping someone could explain to me. Thanks ;)

Hi Eyeayen,

Fixed focal length or "prime" lenses as they are sometimes referred to, on the whole offer superior image quality over a zoom lens, as the optics don't have to cater and correct for both telephoto and wide angle shots. They are generally used for specific purposes, like motorsports and wildlife (200 to 500mm), portraiture (50 to 105mm) and landscapes (18mm and below), depending on the focal length.

Framing the shot is done with the feet as you mention and photographers have to pre-position themselves when shooting things like motorsports. Similarly with wildlife shots. The photographer either sits in a fixed position and waits for the animals to appear in a location that they are known to frequent or will have to stealthily track the animal from a distance.

Primes also tend to be "faster" than zoom lenses too, with the majority of telephoto lenses having a maximum aperture of f/2.8 or f/4. 50mm and below lenses often go down as far as f/1.4 and even f/1.2 on occasions.

Incidentally, one of the best lenses you can own is a 50mm prime for close portraiture and as a general walk about lens. My Nikkor 50mm f/1.8 is probably my favorite lens and it was also the cheapest at £109!

Primes have very little to move about inside of them optically, so because of this simplicity they deliver crisper images with very little distortion, if any at all. Good short zooms can match some primes these days, but if you want the very best image quality then it's a prime all the way (my opinion of course). Most pros shooting motor sports (or any other kind of sport for that matter) will have several prime lenses at various focal lengths to suit the action and these are generally fitted to separate bodies. Oh that we had that kind of facility, but most likely we don't. Amk has said all there is to know about them really, but the better the glass used the dearer they get.

You will learn more about composition using a prime than you will with a zoom, because you have to do it on your feet, as you mentioned in your post.

Prime lenses produce better quality shots and are faster. They are not as versatile as a zoom lens but the quality you get outweighs that. Its may sound weird but my husband just bought a Canon 550d and if he uses my canon 200mm fixed lens he gets a 340mm zoom at f2.8! That is really fast for a lens at that focal length and it outshines my canon 100-400!

Karen

[QUOTE=karenoliver;25084]They are not as versatile as a zoom lens but the quality you get outweighs that.[/QUOTE]

Or, they're more versatile than zooms. Depending on your point of view.

A 50mm f/1.4 can give more versatility with depth of field than a zoom, and more versatility with respect to the amount of light you need to shoot in. Zooming is a lesser issue in comparison to those factors as, as mentioned above, you can often move yourself nearer or further.

Brilliant, thank you to everyone that explained that. Strangely it is what I thought, I just couldn't believe it. Some of the photography I've seen I presumed was done with a zoom but I guess that's why these people are pro's and are completely at one with their subject and their gear !

Great answers - thanks ;)

[QUOTE=karenoliver;25084]Prime lenses produce better quality shots and are faster. They are not as versatile as a zoom lens but the quality you get outweighs that. Its may sound weird but my husband just bought a Canon 550d and if he uses my canon 200mm fixed lens he gets a 340mm zoom at f2.8! That is really fast for a lens at that focal length and it outshines my canon 100-400!

Karen[/QUOTE]

Sorry, your Canon 200mm has the same reach on either your or your husbands camera, the only difference his field of view will be same as using a 340mm lens on your camera. :)

Really? I was convinced if I used his camera with that lens that I would be able to zoom in closer. Oh well :-)

Karen