What do all these numbers & letters mean

[Kyle72]

Hi

Being new to the Dslr scene and still trying to decide what to buy for my first, see my introduction.

Im trying to get my head around what all the letters and numbers mean, could someone if you have time and sorry if the question has already been posted before what do all the numbers and letters mean on the following lens types

thanks
kyle

EF 70-200mm f/2.8 L IS II USM Lens f2.8

EF 70-300mm f/4-5.6 IS USM

AF 18-200mm f/3.5-6.3 XR Di II

[ZedEx]

I suggest go to google and search for these things: lens, apeture, USM (ultrasonic motor)
edit: sorry, re read that and it sounds like i'm being a smartarse, i apologise. There are just some things that can get quite in depth, depending on how much you want to read into it. Start with the basics and work your way up, the definitions of what you have asked won't necessarily make sense at first look

[Kym]

When the f/xx is a lower number = more expensive
When the mm is a bigger number = more expensive

:D

In your above (me not being a Canon shooter)
EF 70-300mm f/4-5.6 IS USM will cost less then the better EF 70-200mm f/2.8 L IS II USM Lens f2.8

Why?

http://www.ausphotography.net.au/forum/showthread.php?t=24359
http://www.ausphotography.net.au/forum/showthread.php?t=24048
http://www.ausphotography.net.au/forum/showthread.php?p=356527

[Xenedis]

Here's some information on some of these designations.

Firstly, EF is the name of Canon's range of electronic focus lenses. AF (in other vendors' products) typically designates auto-focus.

70-200mm is a range of focal lengths from 70mm to 200mm. These particular focal lengths are telephoto focal lengths, which allow you to capture subjects that are further away, or more tightly frame nearer subjects.

L is a Canon-specific designation for its (L)uxury lenses; these are premium-grade lenses which are easily visually identifiable by the presence of a red ring on the barrel. They are expensive, and feature high-quality optical technologies, ultrasonic focus motors, and typically offer wider apertures. More on those latter two features below.

IS is Canon's nomenclature for Image Stabilization (American 'spelling' deliberate). It is a gyroscope-based optical stabilisation system that counters photographer-induced movement, and is especially useful at longer focal lengths.

f/2.8 is an f/stop, which is a ratio used to express the diameter of the lens's aperture (opening). The f/number you see is derived mathematically by dividing the focal length (eg, 200mm) by the actual diameter of the lens's aperture. Therefore, a 200mm f/2.8 lens has an aperture of around 71.4mm.

The lower the f/number, the wider the aperture, and the more light is able to enter the lens. Aperture affects a number of things. Apart from light-gathering ability (which is particularly useful and even necessary when shooting movement in low light, as you need a faster shutter speed to freeze motion), wider apertures decrease the depth of field -- the amount of 'stuff' in focus in front of and behind the point of focus in your image (ie, your subject).

USM is Canon's nomenclature for its ultrasonic focus motor. USM stands for (u)ltra(s)onic (m)otor. This is a fast, silent auto-focus mechanism.

The II designation indicates the second release of a given lens. Canon uses this when it issues a new version of an existing lens, and in some consumer-grade lenses, it has issued versions up to IV (ie, fourth-generation). Apparently other manufacturers adopt a similar practice.

I am not sure what the XR and Di designations indicate, as these are specific to one of the third-party lens manufacturers (either Sigma, Tamron or Tokina; I'm not sure which, as I have no experience with any of them -- I think it's Tamron). A quick Google should tell you, or someone else here can fill in the blanks there.

Hopefully this helps you somewhat.

[Kyle72]

Thank you all for your response and a big thanks to Xenedis, for the description. So what would be a good general lens i should be looking for a telephoto sport lens, and to keep in mind im only a beginner, and not wanting something at a professional level. and what would a good general lens to look at for say portrait or wedding, group type photos.

Thanks again

[RaoulIsidro]

If you have the spare time, it would be good to enroll in a local evening class about basic photography, which is a good foundation.
Or try a correspondence or on line course.
That would help you, and anyone, heaps!
Around the Newcastle area, there may be some on offer...
http://domore.com.au/newcastle-nsw/photography/102097-165

[Fantasyphoto]

Or you could join a camera club such as at Belmont or Maitland.

You will find more details on the FCC regional club page http://www.photographynsw.org.au/pages/club_finder_name.php

[elGrando]

Try the NTP section here its very well written and easy to understand for us noobs.