Prime vs Zoom sharpness

[Dolby]

I've heard there is a difference - but how big is it ? A pixel peeper difference - or one my mother would be able to spot?

Would a 24-70mm L be as sharp as my cheap 28mm prime? It better glass - but it's a zoom ...

 

[bwana]

On newer zoom lenses like the 70-200 mk2? It would take a pixel peeper and even then it would probably be a guess.

 

[hilton]

It's a little bit more complicated.

First up you need to compare L with L. Then you need to remember that certain lenses are sharp wide open whereas your 28mm is certainly not sharp wide open. Then...........you probably need to find a prime that has the same maximum aperture as that of the zoom in question. An example would be the EF 200 f/2.8 and the EF 70-200 f/2.8 II.

 

[koffiejunkie]

It really differs from lens to lens. Fast wide primes often make big compromises. Other times technology simply helps newer lenses. As nice as my 200mm f/2.8 L prime is, the new (and probably the old) 70-200mm f/2.8 L is sharper at every aperture. My 24-105L also wipes the floor with my 30mm f/1.4.

 

[Dolby]

Thanks - so it is quite complex :/

Basically if I get an L lens that covers my current 28mm F2.8 (ie the 24-70mm 2.8) - would there be any reason for keeping the prime lens at all?

 

[koffiejunkie]

Basically if I get an L lens that covers my current 28mm F2.8 (ie the 24-70mm 2.8) - would there be any reason for keeping the prime lens at all?

In terms of sharpness, probably not. But that's not the only thing primes have going for them. The 24-70 f/2.8 weighs almost a kg. Sometimes it's nice to have a light/compact lens when you don't need the zoom. I've found that the difference a prime and a big zoom on my DSLR often makes the difference between being able to take it into a concert or not. I also find that people are more intimidated by a big camera/big lens combo.

 

[hilton]

No because at 28mm the 24-70 will be sharper.

However, the 28mm prime is waaaaaaaaaaay lighter than the 24-70 so this may be a factor. The nice thing about buying the consumer grade Canon lenses is that it gives you a chance to learn that focal range and aperture settings for a relatively low cost investment. You can always sell it on, apportion the loss to your learning curve and then when you do invest in the L lens you sure as dammit know what you need.

 

[bwana]

Thanks - so it is quite complex :/

Basically if I get an L lens that covers my current 28mm F2.8 (ie the 24-70mm 2.8) - would there be any reason for keeping the prime lens at all?

That prime? No, probably not unless you wanted a light weight lens to carry. One of the many reasons why I went for the Sigma 24-70 is that it is smaller and lighter than the canon (it's also sharper and has faster AF) so I don't particularly mind carrying it around all day. Same goes for my 70-200 f/4 that I kept even after I got the new f/2.8, it's just a pleasure to carry.

These days I don't really see a need for anything but the fastest of primes (excluding the longer focal length lenses of course) if you've got the holy trinity (16-35, 24-70, 70-200 f/2.8s) but some people swear by them.

 

[koffiejunkie]

These days I don't really see a need for anything but the fastest of primes (excluding the longer focal length lenses of course) if you've got the holy trinity (16-35, 24-70, 70-200 f/2.8s) but some people swear by them.

I don't have any of those

 

[bwana]

I don't have any of those

Count yourself lucky, I've got nothing to look forward to

 

[koffiejunkie]

So you're not looking forward to the 400mm f/2.8 or 200-400mm f/4?

 

[bwana]

So you're not looking forward to the 400mm f/2.8 or 200-400mm f/4?

Ah, thanks for reminding me about that - my short ranges are well and truly covered though. Hopefully I'll have that 400 in my hands by cricket season.

 

[koffiejunkie]

Ah, thanks for reminding me about that - my short ranges are well and truly covered though. Hopefully I'll have that 400 in my hands by cricket season.

And once you have that, there's still always the Sigma 200-500mm f/2.8 to lust over

 

[bwana]

And once you have that, there's still always the Sigma 200-500mm f/2.8 to lust over

Oddly enough I've got no real interest in that one.

 

[Dolby]

Count yourself lucky, I've got nothing to look forward to

Oh no ... You telling me its downhill from here? Bleh!

I actually like the weighty lens! Think I'll consider getting the 24-70mm L then and selling the 28mm shortly.

Thanks!

 

[hilton]

You have the 7D, do you not think that 24 on the short end may not be wide enough?

 

[MongooseMan]

Oddly enough I've got no real interest in that one.

Why not? You could take photos of the cricket without leaving the house (assuming you find a tripod large enough to mount it on )

 

[bwana]

Why not? You could take photos of the cricket without leaving the house (assuming you find a tripod large enough to mount it on )

I don't do tripods.

 

[Dolby]

You have the 7D, do you not think that 24 on the short end may not be wide enough?

It is a slight concern, yes.

I saw the 17-55mm 2.8 as well - but I need more experience with different scenes in order to work out exactly what I'd prefer in terms of focal length.

 

[koffiejunkie]

Oddly enough I've got no real interest in that one.

Me neither. But it will go nice with my cargo pants