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Old Jul 6, 2009, 11:52 AM   #1
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Default Canon 24-70 2.8 vs 24-105 f4

If you were looking at these two lenses, and you could only purchase one of them, I imagine there are certain circumstances that would cause you to choose a over b, and other circumstances that you'd choose b over a.

One has an advantage of have fstop. The other has a bit further reach with a zoom of 105 rather 70mm.

Is one a sharper lens than the other?

In what application does the 24-70 make more sense and in what application does the 24-105 make more sense?

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Old Jul 6, 2009, 12:06 PM   #2
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I'm a 24-105 user and like it a lot, for me having the reach is much more important than the f stop gain. When shooting a social event being able to get tighter is helpful and using the long end I can still get a shallow enough dof.

I find even in a lot of church situations there is enough light that again the f2.8 is not essential as the B&G are not generally moving much so with the IS all is fine.

As for sharpness I think the 24-105 is a little better than the 24-70 but the daddy for sharpness at the moment is the Sigma 24-70 f2.8 HSM.

This weekends wedding was shot with the 24-105, so a few low res shots are here http://forums.steves-digicams.com/pe...tml#post982112
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Old Jul 6, 2009, 2:47 PM   #3
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The best place to compare sharpness is the interactive blur charts on slrgear.
http://www.slrgear.com/reviews/showp...uct/145/cat/11
http://www.slrgear.com/reviews/showp...uct/143/cat/11


DOF [email protected] is about the same or a little less than DOF [email protected] At the wide end you probably don't care as much about a wide aperture anyway.

The 24-105 has 3 stop equivalent IS.

The 24-105 has slightly more distortion and vignetting (as you would expect from the extra zoom range), but it cleans up easily in software if that bothers you. CA is very similar, flare is handled equally well by the L coatings and lens elements.

The 24-105 is cheaper and lighter!

All of the above to me make it a very simple choice - the 24-105 is a far better lens in most respects. The only caveat is if you like shooting at wide angles and wide apertures.

Of course I would only use them on a FF body because 24 on a crop simply ain't wide enough! And to top it all off you can get the 24-105 in a kit with the 5DMkII at a splendid discount. It's a tremendous combination and (though expensive) incredibly good value for money.

On a crop I would much rather go with the 17-55 IS f2.8 - you get the f2.8 and the IS too, as well as incredible sharpness.
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Old Jul 7, 2009, 12:14 PM   #4
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Quote:
Originally Posted by peripatetic View Post
On a crop I would much rather go with the 17-55 IS f2.8 - you get the f2.8 and the IS too, as well as incredible sharpness.
FP is in the same boat as us with the 5D mkII so he will be fine starting at 24mm.
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Old Jul 8, 2009, 2:42 AM   #5
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Ah yes. I remember now. :-)
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Old Jul 8, 2009, 8:14 AM   #6
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Quote:
Originally Posted by Mark1616 View Post
As for sharpness I think the 24-105 is a little better than the 24-70 but the daddy for sharpness at the moment is the Sigma 24-70 f2.8 HSM.
If you got to have an L the 24-105 is the way to go and it'll give you more reach... Their older 24-70 f/2.8 really needs to be upgraded as compared to the Nikon and Sony counterparts (which is probably why the 24-105 was recently released)

IMO you'll be better off staying with your Sigma HSM like Mark suggested:
http://forums.dpreview.com/forums/re...ssage=30995912
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Old Jul 8, 2009, 8:28 AM   #7
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The blur charts at slrgear.com tell an interesting story.

At f4 the 24-105 is very good at 35 and 50mm. Good at 24 and 105 and quite soft at 70. (Where it is often compared to the 24-70 to its great disadvantage).

At f5.6 and above it is excellent at all focal lengths except 70mm, where it is frankly never very good.
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Old Jul 9, 2009, 10:54 PM   #8
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The EF 24-70 f/2.8 L was never really good @70mm, especially @ f/2.8. Photozone data have already shown this, the above links only reconfirmed it against the Sigma (and Nikon's):

-> According to theses MTF's from the threads the 24-70 f/2.8 L need to be stopped down to f/8 in order to better the other brands



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Old Jul 10, 2009, 2:34 AM   #9
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Absolutely.

Sometimes though I wonder whether we give enough credit to the lens designers at Canon (and other companies too). I think they very often don't optimise for sharpness and instead will look for a pleasing rendering. I imagine they might have thought as follows...

24-70, well that's 4 focal lengths:
Wide - 24 - landscape mainly - optimise sharpness at f8-f16
Normal - 35 & 50 - all round - optimise drawing and sharpness at f2.8 - f16
Short tele - 70 - portrait mainly - optimise drawing at f2.8, not sharpness, only needs to be sharp at f8 or so for studio work with flash.

People focus (sic) too much on sharpness as the only good measure of a lens. I think it's far more important that the lens draw in a way that you find pleasing. Sometimes this means for example that you don't want to get rid of all residual spherical chromatic abberation because it can make your bokeh nice. It can mean that you don't want to get rid of all barrel distortion especially if you anticipate that a wide angle lens is going to be used for shooting people. e.g 35mm L. Sometimes you want a lens that is going to draw nicer and give better colour and contrast at the expense of fine detail. And of course sometimes you want a lens that isn't going to cost you $5,000, and weigh 5kg. :-)

When testers find that sharpness at a particular aperture isn't all that great or that there is some distortion they report it as an "aha - caught them out" moment. When really the lens designers knew all those things. It's all about a balance of compromises.

If anyone at Canon is listening I would like to put in a big vote for some slower, smaller and cheaper L primes:

How about a 28mm f2.8 L, 35mm f2 L, 50mm f2L, 85mm f2 L?

Usable wide open, no more than 350g, and about half the price of current fast L primes please. :-)

Last edited by peripatetic; Jul 10, 2009 at 2:36 AM.
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Old Jul 10, 2009, 8:31 AM   #10
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I absolutely agree with Perapatetic. It's the difference between laboratory and real life. Sharpness is only 1 of many characteristics. It's important but you should never judge a lens based solely upon 1 thing (i.e. sharpness at a specific focal length and specific aperture) without considering the other factors as well.

The 24-70 is still a primary photo-journalism tool. It's extremely well built/durable and sealed. Having said that - I agree, it is due for an upgrade.
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