24-70 f/2.8 lens advice

aztec

aztec

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Shaun
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I need a lens to cover the 24-70 range but cant make up my mind go all out and buy the canon then I think its to exspensive, buy the tamron? then the sigma comes into play and finally the tokina enters the fray :bang: give me a clue. I definately want a fast lens but one I wont regret buying
 
I have the Canon, never regreted it, nice and sharp, not used the others so dont know if they match it though.
 
:help:

Hi I am new in this forum! and in photography as well!!:thinking:

Just being curious, What a fast lens can do?? what possible difference a fast lens can make?? I want to know. It might be a stupid question which everyone may know, but I dont!! plz help!!:shrug:
 
The faster a lens, the more light it lets in and often can make the difference between getting a shot under adverse conditions or not. Downsides are weight and cost. It is not cheap to make large pieces of optical glass and they are also not light. It is much more difficult to make fast lenses that perform well at their maximum aperture and this also adds to the cost.

The larger the maximum aperture of a lens for a given focal length the less depth of field will be available, this can be a good thing if you want to have a blurred background, but in extreme conditions can accentuate poor camera technique and often the lens is blamed for how the photographer has used it.
 
Fast is a word that can be used in two ways when talking about lenses.

The first way is talking about "fast glass" That usually means BIG wide apertures so f1.8, f1.4, f1.2 and even f1!! They are called fast because even in low light you can achieve some fast shutter speeds.

The other, more literal way of using the word is that it focuses and locks the focus quickly. (That's what is meant here in this thread) The speed at which a lens will find focus can affect it's usability in some instances. i.e. They use contrast to find focus and some react more quickly than others.

To answer the OP I've found the Canon is quicker than the Sigma to find focus. It would be my choice. :)
 
AliB said:
Fast is a word that can be used in two ways when talking about lenses.

The first way is talking about "fast glass" That usually means BIG wide apertures so f1.8, f1.4, f1.2 and even f1!! They are called fast because even in low light you can achieve some fast shutter speeds.

The other, more literal way of using the word is that it focuses and locks the focus quickly. (That's what is meant here in this thread) The speed at which a lens will find focus can affect it's usability in some instances. i.e. They use contrast to find focus and some react more quickly than others.

To answer the OP I've found the Canon is quicker than the Sigma to find focus. It would be my choice. :)
Click to expand...

Sorry Ali, I disagree, the lens does not find focus or use contrast to assist it, this is a trait of the camera body and hence why some bodies are reputedly better than others at focussing with the same lens, and whilst one lens may work better than another or be faster focussing due to the use of a different type of motor (USM as opposed to ring for example) the term a fast lens is predominatly meant as a large maximum aperture against it's comparable focal lengths or types.

Hence a 400mm f2.8 is a very fast lens whereas a 50mm f2.8 would be considered slow (even if fast focussing) and a 50mm f1.4 or larger aperture lens would be considered fast regardless of the speed of the motor.
 
mehraj said:
How do I know which one is faster??

Thanks EdBray ...
Click to expand...

The "speed" or how "fast" a lens is is denoted by the amount of light it lets in.
The more light the smaller the FNo. f4 is therefore twice as slow as f2.8.
 
photo plus did comparison test on fast zoom lenses in jan 2009 they picked efs-17-55 as best on test target price £625 with tamron 17-50mm best valve but think i would miss the extra focal lentgh.
 
If the Canon 24-70L is possibly too expensive then think about a slightly older 28-70L...price should be somewhere between the 24-70L and the Sigma.

Bob
 
Another Canon 24-70L user here, I'm sorry to say........and I love it!! Some good advice about looking for the older version though.
 
I've got the Sigma version...hasn't let me down yet :) It was a snip at £249 when I got it from Jessops...still a bargain now after the price rises!
 
I paid £175 for the Sigma version myself and its pretty good.

Tbh you'd be hardpressed to tell the difference by looking at the photos.

Unless you really need USM drive and Weather sealing go for the cheaper ones.

sid
 
The 24-70mm is outstanding, but if you can get a good copy of the 28-75mm it pushes it close.
 
Another vote for the sigma. I couldn't justify the price of the nikon version at the time and to be honest the sigma has not let me down once. It is a he'll of a lot of lens for the money.
 
EdBray said:
Sorry Ali, I disagree, the lens does not find focus or use contrast to assist it, this is a trait of the camera body and hence why some bodies are reputedly better than others at focussing with the same lens, and whilst one lens may work better than another or be faster focussing due to the use of a different type of motor (USM as opposed to ring for example) the term a fast lens is predominatly meant as a large maximum aperture against it's comparable focal lengths or types.

Hence a 400mm f2.8 is a very fast lens whereas a 50mm f2.8 would be considered slow (even if fast focussing) and a 50mm f1.4 or larger aperture lens would be considered fast regardless of the speed of the motor.
Click to expand...

That's one definition of "fast" Ed and one I quite agree with. I'm also adding in the speed of focus which I think you will find on almost any lens review with terms like "Fast to find focus"

Just trying to differentiate the two, unfortunately and, for the reason you stated the time to focus for each lens will be different in different conditions and it's almost impossible to assess. I've had instances where one lens will get the shot while the other just keeps hunting for focus.
 
I have just bought the Nikon 24-70 F2.8. It is a wonderful lens, it is as good if not better then the prime lenses I have got, so will probably sell them. I just wish I could afford the 14-24 F2.8. Regarding third party lenses Tokina are hard to beat. I have the 11-16mm F2.8. It is for DX format so with my D700 it works at 16mm full frame. I have decided to keep it as it is so good, using it as a 16mm full frame lens.
 
icnoble.....I'm thinking about the 24-70mm Nikon, but £1200 is a serious amount of money for one lens. What primes are you comparing it to?
 
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