how to choose a lens

[Greg Oden]

i dont understand what a lens does by just reading the numbers on it. i feel like an idiot. any info or suggestions on where i could get some good literature on it. im just not sure what type of picture or distance each lens is for. if their is a book that is good for beginers that would help as well. im very new to the sport.

 

[JamesDD]

understanding exposure is a great book for beginners...i highly suggest it

 

[tirediron]

Huge topic... here's a quick and dirty: There are two main categories of lenses, prime lenses and zoom lenses. Prime lenses have a fixed focal length, eg 50mm; that is, they cannot change their field of view, and to get more or less area in the picture you have to physically move the camera. Zoom lenses, through a rather more complicated optical process cover a range of focal lengths in one lens, eg 70mm-300.

They can also be subdivided based on their focal length. In the days of film, a 50mm lens was considered a 'normal' lens, that is, it most closely approximated what was seen by the human eye. Because most DSLRs have sensors smaller than a 35mm film negative, there's a magnification factor, and on most DSLRs, a 35mm lens would be considered normal. Anything above 'normal' is generally regarded as a telephoto lens, whether zoom or prime, and anything below is regarded as a wide-angle lens. Those which cover the 'normal' range are sometimes referred to as 'normal' or 'mid-range' zooms.

Therefore, a 70-300mm lens would be a telephoto zoom, and a 12-24mm would be a wide-angle zoom. A 28mm prime lens would be considered wide-angle and a 105mm prime would be considered telephoto. Typically wide angle lenses go as low as about 10mm (VERY wide) and telephotos up to about 400mm (high magnification). T

When you're talking about lenses the focal length or "mm" number is simply an expression of how wide the field of view is for that particular lens. A 10mm can see an area many, many times wider than a telephoto. The other number you'll see is the aperture, usually preceded by an "F". This is a representation how much light the lens will admit, the smaller the number (eg f2.8) the more light the lens will allow to hit the sensor.

There's a great deal more to it, including Depth of Field, hyperfocal distance, as well as many specialty types of lenses, but that gives you an idea. In short, if you want to make objects appear closer to the camera, use a telephoto, or long focal length. If you want to see a large area, than a wide angle or short focal length.

 

[Turnerea]

copy, paste, I hope?

 

[tirediron]

copy, paste, I hope?

Copy, paste what?

 

[lpartain]

"Understanding Exposure" is THE book to have if you don't understand the "numbers" on your lens. I highly recommend it.

Lorin Partain
http://www.partainphotography.com

 

[Overread]

Understanding exposure, some other photography books which focus on areas of your interest and asking on forums will give you an idea of what numbers are used in which cases- though you still won't have any real idea untill you try out a lens of course. If you can find a local photography group or try out some lenses (once you have an idea of the lens you are after) in a local store.
After that there are a few other ways to choose a lens beyond the numbers;

1) Budget - based on your current savings, how long you are willing to save and how much you are willing to invest in the kit

2) Use - a lens should always have a use - something that you want to photograph that you either can't with your current setup or that you want to upgrade the quality of your kit. Always think of lenses as a tool for a job - even if that job is as simple as a walk around lens

 

[Turnerea]

@ tirediron: just hoping that you have that saved somewhere and can paste it whenever the question is posed.


I want to second reading over the book understanding exposure. It doesn't necessarily explain what each exact number is, but it really speaks to the beginner in how to understand the basics of taking the "correct" exposure.

 

[tirediron]

@ tirediron: just hoping that you have that saved somewhere and can paste it whenever the question is posed.

Good point! I'll do that.

 

[Greg Oden]

i will be purchasing the book within the next few days. thx for all the advice. i am very new and i will be having a ton of questions i imagine. i am still trying to figure out what camera i should purchase. but thats my problem i guess. thx.