RE: Prime Lenses

Hi All,

I keep seeing this phrase but I have no idea what it means

What is a prime lens or at least what makes a lens prime ?

Thanks in advance all

Regards
PaulM

A prime lens is one with just one focal length i.e. not a zoom.

A prime lens is a lens that can be divided by itself and 1.

1 what i don't know.



see here for more info.

http://en.wikipedia.org/wiki/Prime_lens

A prime is a non-zoom lens. Like 40mm, 100mm, 21mm, 70mm.

Well the wikipedia article i read says that the original meaning of a prime lens is the first lens used on a camera before any other lenses are added. i.e. you could have a 10-20 mm zoom lens and because it is attached to the camera first then it is the 'prime' lens.

this is especially true if you are using other lenses attached to the prime for macro or telephoto.

So according to this article, a prime lens is not necessarily a fixed focal length lens.

Aj, I thought you meant it was the first lens you put on your camera (or the one that's always on there, so it's your prime lens - for me the 16-45). Having read the article, I see it's slightly different to that, and I'll quote it:

"When the camera lens is used with some other optical device, such as a close-up lens or tele converter, the camera lens itself is properly called the prime lens. That is really all the term "prime lens" means -- whether it's fixed focal length or zoom makes no difference."

If that's true, then I think you can safely say the meaning has evolved since that was the case, and is generally now regarded as meaning a fixed focal length lens.

Interesting though.

Dan

I don't believe all what is writ on Wikipedia.

Everywhere else I have looked:-

Prime Lenses - A prime lens is a lens that has one focal length only.

and this from a printed book
"Prime lenses are lenses that have only a single focal length. These lenses are generally of high quality and low price, compared to their zoom lens counterparts. The most common focal lengths are 28mm, 50mm, 85 and 100mm"

low price? have they ever looked at the top end primes???
The Pentax limited lenses for example cost a small fortune. (they are worth it, but they are expensive)

/remco

It was quoted from an old book.

I don't always believe the web, and it is not unknown for books to be wrong too. . If you look at some of the links further down the wikipedia page, you will see the makers of some lenses have 'variable primes'. These lenses seem to be designed to have additional lenses put on the front.

Daniel, it does say in the lower part of the wiki that the meaning has changed from the original.

Things have just developed from the time when a zoom was a new comcept and there was never a need to describe a lens that had one focal length.

They have come to be known as primes, but in addition I notice that AP has started to describe them as monfocals.

Language does change as requirements change, but the important thing is that we know what each other are talking about.