Fast glass f2.8 is usually much more expensive than it's slower counter-part (f4/f5.6).I'm not sure if this is the right place to ask, or maybe it should be in the techno lounge - but it's about camera lenses so I will try here.
So... my grown up daughter is earning a living (of sorts) where photography is an important element. It's sort of aligned to her job (with horses and horse safety equipment) where she has to produce photos for work as opposed to her life's calling if you get my drift... i.e. she isn't trying to be a commercial photographer by trade.
Anyway - she is building up equipment as she ends up making more from the photo side of her work than the other parts and in true daughter fashion she is tapping up her old dad for a new lens which she will "pay me back for" :lol::cheese::lol:.... oh, sorry - where was I...
Hert camera body is a Canon (I think it's a 6 or a 60?) - she got it last year and it cost about a grand so that positions it.
So she sent me a link for a Canon EF 70-200 zoom lens (f4) with IS which I can find for between 800-950 quid at various places, although apparently the f2.8 version is better (but pricier) and the version without IS is a bit cheaper. She also doesn't mind second hand versus new as long as its working.
I know these are professional items, so am worried that Ebay ones might have been used a *lot* and be on their last legs - but on the other hand, how much can go wrong with a lens?
So - various questions for the cognescenti:
1. Is it a good lens generally?
2. Is Image Stabilization a worthy extra?
3. Why is an f2.8 so much more than an f4?
4. Are there equally good lenses that are better value?
5. I see lots of indie camera shops with a variety of prices - are most indies reputable?
6. Would you buy a 900 quid lens off Ebay for 400 quid with no warranty and unproven history?
7. Are lenses (pro ones like this) fragile enough to worry that a well used year old one could be duff?
As I say - she is earning a living from this, so it's not just hobby kit - and she needs to take photos of horses, horse equipment etc for use in advertizing and manuals with the horses in motion in many cases.
Any info greatly appreciated.
The f number is the size of hole at the back of the lens that lets your light in, oddly enough the smaller the number the bigger the hole f22 is, usually, the smallest.
At a wide open setting, a f2.8 lens will allow you to shoot at a faster shutter speed than a f4 (proper exposure is the size of hole (aperture) times the shutter speed). You want to use a fast shutter you'll need a big hole, the opposite is also true slow speed, small hole.
I've got a big (50-500mm) lens which is f5.6 and ideal for airshows, as it's usually bright outside, but would not be so good for indoor sports (such as horses in an arena) as I'd have to use a much lower shutter speed to get the right exposure and may not be able to "freeze" the action. So most Pros will have f2.8 teles.