Appletonwest Loc: Wisconsin

As a newbie I would like to know or go to a post to explain the numbers (f stops) on top of the lense and how to use them.

rocco_7155 Loc: Connecticut/Louisiana

f-stops represent a fraction that denotes the opening size of the aperture allowing light to be registered on the medium in use (film or digital sensor).
For a good and easy to understand explanation (which is too wordy for here), look at your bookstore or library for Understanding Exposure by Bryan Peterson. In my opinion, it should be on the shelf of every photographer.
Rocco

jerryc41 Loc: Catskill Mts of NY

The smaller the f/number, the more light the lens can let in, and, probably, the more expensive it will be. The smaller the number, the better, all things being equal.

The larger f/numbers represent smaller openings. Makes perfect sense, right?

A zoom lens will have something like 18 24 35 50 etc. These numbers represent the wideangle/telephoto view the lens is giving you. Larger number, more powerful telephoto.

RobertMaxey

Slight correction. On Leica and Hasselblad lenses, the numbers represent the price in US dollars. That is, $182,435.50

Roger Hicks Loc: Aquitaine

Try http://www.rogerandfrances.com/subscription/ps%20basics%20lens%20design.html

This tells you about focal length

"Focal length and magnification

The longer the focal length, the bigger the image will be projected onto the focusing screen, film or image sensor. As the illustration on the left shows, it is a simple linear relationship: a lens with twice the focal length produces an image that is twice the size.

You can work it out with trigonometry if you like, but you can also just draw it with similar triangles, as in the illustration."

and aperture

"At first sight, stop numbers are really confusing. They seem to go backwards -- a bigger opening is a smaller number -- and the numbers appear somewhat arbitrary. Perhaps surprisingly, they are very easy to understand.

They go backwards because they are a written as a fraction of the focal length of the lens. The effective diaphragm aperture of an 'f/2' lens is one-half the focal length, so a 50mm f/2 has an effective aperture of 25mm. Stop it down to f/4, and the effective diaphragm aperture is 12.5mm. With a 100mm lens, f/2 would be 50mm and f/4 would be 25mm. Because the aperture is calculated relative to the focal length, it is called a relative aperture. We will come back in a moment to why this is important."

The illustrations in the link will make these explanations a lot easier to understand.

Cheers,

R.

JimH Loc: Western South Jersey, USA

See my lens/aperture/shutter speed guide noted in my sig. It's a very basic intro.

The only 'number' on a lens I didn't mention is the lens diameter number that's usually found on the ring around the front element. That's important to know when buying filters.

Nikonfan70 Loc: Long Island

F stops are relative openings of the lens. Each number up or down whatever the number is twice as large or small. For example f4 is twice as large as f5.6. This is compensated by shutter speeds which also double or halve. A picture taken at f4 @ 1/400 should have the same exposure as f5.6 @ 1/250.The main differences would be depth of fiels and action stopping.
LOL

Appletonwest Loc: Wisconsin

Have exposure book very Good readlng - he says to set your lens 3ft to infin This is what I was asking about - how dø you use This

JimH Loc: Western South Jersey, USA

I think what the author is talking about there is something called "hyperfocal distance" -it's a fairly complex optics thing that basically says, if you have a small enough aperture, such as f/16 or f/22, and you're doing something with a great deal of depth to it, such as a mountain lake with some flowers about three feet in front of you, and the snow-covered summit about 20 miles away, and you focus about 1/3rd of the way INTO the scene, like on the lake shore, then everything from about three feet away to infinity, will be in focus. This is more a function of the specific lens, and the aperture (you need a really small one) than anything else. It's how those sweeping landscape photographers get everything from here to there in focus.

Google "Hyperfocal distance" and you'll find out more than you ever wanted to know.

sinatraman Loc: Vero Beach Florida, Earth,alpha quaudrant

Clearly you need to get an introduction to photography book and read it. Not to be harsh but f-stops are so fundamental to taking a photograph and not a snapshot. Like any hobby, photography has its own language, fundamentals and concepts. You need to tke some initiative and go to a library or a barnes and noble. look in the photography section. If I was say interested in baking pies as a hobby for example, I would first thing get me a book on intro to baking ang get framiliar with the basics and not just go to a baking website and ask whats a rolling pin? The concept of apeture covers so much that a forum site can not do it justice. This may sound snobish, it is not intended that way. i have no problem helping newbies, but the new photographer has got to be making an effort on their own to learn, and not just expect to be spoon fed the basics.

Rick Clark Loc: Utah USA

Link on Amazon.

http://www.amazon.com/Understanding-Exposure-3rd-Photographs-Camera/dp/0817439390


For sale under $20.00

Nikonfan70 Loc: Long Island

How long have you been doing photography bud?

dirtpusher Loc: tulsa oklahoma

me..about 30 min......

RobertMaxey

Not sure about digital cameras, but all of my lenses let me determine my DOF at a glance using the scale on the lens. No guessing at all.

Try this: http://www.cambridgeincolour.com/tutorials/hyperfocal-distance.htm

Rick Clark Loc: Utah USA

Am I bud?