Fast Lenses?

[PhoenixF2B]

Hi all,

I know this must be a VERY novice question, but I am wondering what is meant by a lens being "fast". These are not video lenses, but what makes a lens fast?

Also I just purchased the Letus35 Extreme and am looking for some recommendations for some good lenses.

Thank you.

[ifownlee41nite@mac.com]

The term fast refers to the aperture of a lens. The lower the number the more light (faster) is alllowed in. That higher the number the less light (slower) is allowed in.

These aperture size is measured in a term called f-stops.

There are alot more experienced persons on this forum who can help you with such a question, but I believe the answer I provided should point you into the right direction.

Try a search for this topic and you'll be surprized by the amount of existing threads on the subject.

I recommend Nikkon between a 1.2 and a 1.8 fstop.

[PhoenixF2B]

oh ok, I think I understand what you are saying. I wasn't sure if it was something like that or a physical moving part or some other element of the lens. That makes sense though. Thank you for the response :)

[THoff]

The term fast refers to the shutter speed of a lens.A lens has no shutter.

What the speed is relative to is the lens aperture -- the larger the aperture (and the smaller the F-stop number), the faster the lens is.

[ifownlee41nite@mac.com]

What the speed is relative to is the lens aperture -- the larger the aperture (and the smaller the F-stop number), the faster the lens is.

Thanks THoff,

My mistake. Was thinking aperture but wrote shutter:Drogar-Kriz(DBG):

[SeanEmer]

this is as good a place as any to clear something up that I've been wondering:

I know that a 'fast' lens has a wider aperture, but does this mean that prime lenses don't have a variable aperture at all? That doesn't make much sense to me. I was never big into still photography, so am I right in assuming that a 'fast' lens has a small range of low fstops? And then would a slow lens have a higher range fo fstops? Sorry for the noobie question / thread hijack.

[THoff]

No, this is referring to the maximum aperture size, the lenses can always be stopped down to reduce the amount of light entering.

Prime lenses are simply lenses with a fixed focal length.

[SeanEmer]

ok, I knew about fixed focal length but thanks for clearing everything else up for me! I'll get a hang of this yet.