What is the use of a prime ?

says it all in the title ?

A prime lens is a single focal length. In terms of design it could have a larger open aperture, to assist with low light photography. It could be made very compact, to reduce the weight and bulk carried. It could be higher optical quality than a zoom, to facilitate the production of very loarge images.

Or a combination of these features, mixed to suit the purpose of a particular lens.

Zooms can also be a compromise, in accepting that image quality may be reduced slightly (or otherwise) to achieve the zoom range. Then there is the complexity of moving more than one element simultaneously and the subsequent mechanical wear that takes place.

Bernard

The short answer is to take good photographs.

The best prime lenses are better than the best zoom lenses, as well as being smaller, lighter, etc.

I happen to believe that they encourage better composition - by making it less easy, and forcing the photographer to think more. This view is disputed in certain quarters, but those quarters may safely be ignored.

G

Zooms are a compromise indeed. I have both primes and zooms. If I only had to keep one type though it would be a zoom. I happen to have two stunning copies of the 16-45 and 55-300.

Primes enable lower apertures and are much lighter. They are designed to work at one focal length so of course should be better on image quality.

Zooms have to work well across a whole range. Generally, the bigger the range the more compromises have to be made.

I absolubtly agree with this... My FA50 1.4 is currently my most used lens and while I own a very good 'normal' zoom it's all primes that are on my 'want list'...
When I use primes I generally take better pictures.

I agree too, primes make you stop and think about your shot far more than you do with a a zoom.

My Super Takumar 50/1.4 connects me to my personal photographic history

Pete

I'm hoping this is true as I've just bought the DA15mm for this very reason, just received it and initial impressions are very positive.

I think it's useful to probably have a combination of both primes and zooms as both offer distinct benefits in different situations

Simon

I'm another prime lens fan

It's a bit like using a tripod. Tripods not only improve the quality of the image by reducing shake, they also have the same effect as primes in terms of forcing more care to be taken over composition.

Using longer primes for portraits (e.g. 135mm plus) also forces more working distance between the photographer and the subject - this can be beneficial when shooting people who are a little camera shy.

Regards
David

I second the comments here - particularly that using primes encourages you to think more about composition. I actually find that when using primes I tend to think about the *whole* process of image capture more seriously, not just composition.

The availability of compact, really high quality primes sucked me into Pentax in the first place. Nothing available elsewhere quite like the Ltd lenses - just a joy to use

As has already been said

Faster
Smaller
Less distortion - on the whole
simpler, Better optics (they only have one focal length)
Make you work harder
Sharper? - Probably, even now.
Make you think more about a focal length for the shot.
As for focal length, it makes you learn more about focal lengths
Even "budget" primes are superb. (eg 35mm F2.4, FA 50mm F1.7)

On the other side - zooms
More convenient
Pretty good IQ (dependent on the lens)
You can keep your feet in the same position.
You don't have to keep changing lenses

Personally, I use both, but apart from my DA*50-135, I get the most joy from the images I take with my primes.

Yeah the DA*50-135 seems to be the zoom that breaks the prime theory... Could be one for the wishlist...

I need to think like 'davidstorm' did above and get myself a longer prime... Macro would be nice too... Hmmmm... FA100-2.8? Wonder how it handles portraits...(?)

I like the 12-24 as a landscape lens for the sheer convenience of the zoom range (otherwise I think I'd be forever swapping between 15 and 21) and 50-135 as an event lens. Primes for everything else.