VERY beginner question

[jerseycowboy]

Whenever I discuss photography with my friends, they start talking about their lenses and what lens is good for what shot. This lens is too long, it's not long enough. Not quick enough. etc.

Is there a site or a post that would help me understand the basics on lenses.

For instance, I have the 50mm 1.8. I know the 1.8 is the f-stop, but I don't really understand the 50mm aspect.

And what about an 18-55mm? What exactly does that mean?

I'm not expecting a lesson from you all (though I wouldn't turn it down), but I'm looking for a place that explains it from the lowest level possible.

Thanks!

[FlyingPete]

The 50mm is the focal length of the lens, the focal length is defined as:
The distance from the optical center of the lens to the image sensor when the lens is focused on infinity, usually expressed in millimeters.

Not to be mixed up with the filter diamber on the front also measured in mm.

Bascially the smaller the focal length the wider the field of view, the 50mm is defined as 'normal', whereas the likes for example of 28mm are wide angle, and 100mm is telephoto.

The 18-55mm lens means that it is a 'zoom', whereas the 50mm fixed is defined as a 'prime'. The zoom can move between the two measurements given to vary the focal length, 18mm is the widest the lens can go, and 55mm is the narrowest it can go.

We won't go into how a smaller than 35mm sensor found in most of the digital SLR's effects the field of view on these lenses vs a 35mm sensor, for more info on that read this:
10,000 posts on the X-Factor (http://photography-on-the.net/forum/showthread.php?t=45388)

I almost forgot, the references to the speed of the lens are most often to do with the f stop of apeture of the lens, as you pointed out measure in f/. A lens with a maximum aperture of f/1.8 is considered 'faster' than one with a maximum of f/5.6, the smaller the number the larger 'faster' the aperture.

[michael.luczkow]

http://www.dpreview.com/learn/?/Glossary/Optical/Focal_Length_01.htm
http://www.dpreview.com/learn/

[tim]

When I started getting into photography, I did a digital photographyclass at a local art school, and it was a great introduction. It doesn't even have to be a specially digital course, a film class will be fine for the basics, while they're slaving away in the dark room go take some more photos!

[jerseycowboy]

Thanks for the help everyone. I'll be sure to read through those links this week and try and absorb some of the info. I'm sure more questions will follow.

I'm signed up for a entry to digital photography class, but it's not until April.

[cactusclay]

Here's an easy way to get the idea of what different MM lens do. If you look straight ahead, everything that is in you field of view, including your parifial is equal to about what a 38mm lens would see. Some people would argue this point saying it is supposed to be 50 mm, but that's my story and I'm sticking to it. So, if you pick up a 28 mm lens, then you will be able to see an even wider angle of view, sort of like your eyes had moved back towards your ears. The farther you go towards O mm, the more you see. Going the other way, the angle of view gets narrower and at the same time the image get magnified, like looking through binoculars.

[Belmondo]

Thanks for the help everyone. I'll be sure to read through those links this week and try and absorb some of the info. I'm sure more questions will follow.

I'm signed up for a entry to digital photography class, but it's not until April.

Just stick with us. By April, you'll be able to teach that course. ;)

[rodbunn]

http://www.photo.net/making-photographs/lens

[Persian-Rice]

Just stick with us. By April, you'll be able to teach that course. ;)

Belmondo forgot to mention, you will also be in about $8,000 of debt and be on B&H's Christmas card list. LOL

This is an awsome site for you, http://photonotes.org/articles/beginner-faq/

[jerseycowboy]

I think I might be moving one of my wedding registries to B&H! :lol:

[FlyingPete]

I think I might be moving one of my wedding registries to B&H! :lol:

Yep, you've got the idea :lol:

Wish I had thought of that!