Lens Sizes what do they mean

Joined: 22 Apr 2005 Posts: 23

Hi, AM new to photography. Can anyone help. Have been looking at lenses, what I want to know is what all this 28-800mm f3-f5.6 blah,blah,blah mean. Can someone give me an explanation.

Cheers

Joined: 12 Mar 2005 Posts: 152 Location: Ireland

Well, without getting needlessly technical, the 28-800mm bit (I'd like to see that one) indicates the focal range on a zoom lens - 28mm being the wide-angle end - gets plenty in - and then zooming all the way out to a length that reaches farther into a particular part of the scene, drawing it close.

F3.5-5.6 indicates the maximum aperture (the adjustable hole in the lens that lets light through) at the focal length extremes - f3.5 at 28mm and f5.6 at.. er, 800mm. Fixed wide aperture zoom lenses - "faster" lenses - like f2.8, are more expensive.

:o)

Posted: Sun Jun 26, 2005 3:55 pm

Tip4 did a good job of the basic explaination of the subject but I would suggest getting a copy of John Hedgecoe's book, "The New Manual of Photography".

There are other good books out there as well but I have read this one and think it's very well laid out.

He discusses all aspects of photography in short (2 pages) sections and makes it very easy to understand.

Posted: Sun Jun 26, 2005 9:49 pm

I Second the reccomendation to read Hedgecoe.

In 35mm FILM photography, a 50mm lens is considered a "normal" lens. That is, if you put your camera up to your eye, focuse the image, and then look at the same scene with both eyes, you will see the same scene through the camera, as with the naked eye.

So, a 100mm lens on that camera is like a 2X telescope. Something that appears to be x high to your naked eye, will record on film as 2X high.

A 300 mm lens, a favorite of many sports photographers who shoot on film is the equivalent of a 6X telescope. But, now with digital with its smaller "film" size a 200 mm lens is equivalent in image size to the 300 mm. That is because the digital sensor is smaller, which means it captures a smaller frame of the image projected by the lens onto the film plane. This makes a 200 mm lens SEEM like a 300 mm lens on a 35mm film camera.

This is definitely cool, since it makes some of my exotic lenses even more exotic. For example my 500 mm f5 mirror Nikkor -- this is the older model before the f 8 -- is now the equivalent of a 750 mm f 5.

Joined: 20 Apr 2005 Posts: 238 Location: Outside Boston Ma

Thank you Bill, your explanation helped me.

jamie

Joined: 20 Apr 2005 Posts: 238 Location: Outside Boston Ma

i found this helped too

http://photographycourse.net/exposure.htm

jj