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Canon 24-70mm f/2.8L review
written by Fred Miranda

NOTE: The JPEG samples presented on this review are 100% crops of full images. There was NO image editing performed to any of the below crops. I only resized and sharpened thumbnail examples to better represent what the crops are showing.
All full size images were 16-bit Tiffs converted from RAW files. The parameters used were: No sharpening and matrix 5. All images were shot with a Canon EOS 1D.
It may be difficult for you to judge performance from the compressed JPEG samples posted here. Keep in mind that my opinion and conclusions are based on full size Tiff files viewed at 100% magnification.

Introduction

The image quality gap between high quality zoom lenses and their respective prime equivalents became even smaller, with the introduction of the Canon 28-70L zoom lens a few years ago. In the hands of an experienced photographer, this lens is capable of providing great image quality and therefore has rapidly become the number one choice in the standard zoom range. Is it really possible to have one high quality lens that replaces three primes and still provides similar image quality?

Hypothetically, if that were the case, the newly released 24-70m f/2.8L would offer a fantastic benefit to the professional photographer. It would be like having a 24mm f/2.8L, 28mm f/2.8L, 35mm f/2.8L, 50mm f/2.8L and 70mm f/2.8L all in one lens. In this review, I will be comparing the new 24-70L with the 28-70 f/2.8L and the highly appraised 50mm f/1.4 prime.


Click below for full specifications on these lenses straight from Canon's site:


Below is a quick GIF animation that demonstrates what 4 extra millimeters add to the wide-angle range. If you apply the 1D multiplier, you are looking at a 31.2mm versus 36.4mm. (Refresh the page if you don't see the animation)


 

 


 

Physical comparison: 24-70L vs. 28-70L

 

Quality glass and zoom range add weight to the design of the lens. For this reason, both lenses are bulky and heavy. They are also equipped with an equally bulky lens hood. It's worth noting that the new 24-70L is heavier and longer than its predecessor. Contrary to what you would expect, both of these lenses are longest at the wide-angle end and shortest at 70mm. Zooming towards the wide-angle end, I noticed the front element moving up into the front of the hood, since it is mounted on a non-moving portion of the lens. Cutouts in the hood prevent it from vignette at the wide end. If you zoom back to 70mm, the lens retracts, resulting in a nice, deep hood at the long end. It's a fantastic design.

The previous 28-70 f/2.8L contains a lot of plastic, but has a solid feel. The lens also weighs less than its size suggests. The new 24-70 f/2.8L build quality is similar to the 16-35mm f/2.8L with less plastic and much better dust/moisture sealing. It features a rubber lens mount gasket made for rain and a dust-proof seal when used with the Canon 1V, 1D or 1Ds.

As you can see from the above picture, the new 24-70L is almost a 1/2 inch taller. However, both lenses weight about the same with the 24-70L being about 70g heavier. The new 24-70L is even longer when fully extended at 24mm. See below:

 

 

The included 24-70L lens hood (EW-83F) is slightly longer than the 28-70L's (EW-83BII). I was surprised that the EW-83BII hood was not wider to prevent flare at the new 24mm end. Even using the lens hood with both lenses, I saw some flare in pictures taken with the 24-70L at 28mm that were not seen in the 28-70L's. Here is an example of what I found:



AF comparison

The same inner focusing system with USM was used in both lenses. Canon claims that the new 24-70L is equipped with a new processing unit that makes the AF faster than the 28-70L's. Upon first glance, the 24-70L AF speed seems identical to the 28-70L's. I could not detect any significant improvement in speed.

A wonderful and very welcome 24-70L feature is its closest focusing distance. The new zoom's minimal focusing distance is now 0.38m/1.25 ft against 0.5m/1.60 ft. This translates to greater macro capabilities.


Optical quality

In theory, the newly designed 24-70L f/2.8L, should have superior optical quality when compared to its predecessor.
Although sharing the same number of elements, the new 24-70L has two aspherical lenses and one UD glass as opposed to only one aspherical glass on the 28-70L. See the graphical representation of their design below:

24-70mm f/2.8L
28-70mm f/2.8L
sd

 

Let's see how this translates into real world images. I will start by comparing the 24-70L with the 50mm f/1.4 @ 50mm. All shots were taken in manual mode to ensure identical exposure.

24-70L vs. 50mm f/1.4 @50mm f/2.8 and f/4

 

24-70 @ 50mm f/2.8
 
24-70 @ 50mm f/4
 
50mm f/1.4 @ f/2.8
 
50mm f/1.4 @ f/4
 

 

As you can see from the above 100% crops, the 50mm prime has an edge over the 24-70L in terms of sharpness and contrast at f/2.8 and f/4 apertures. The above results were just what I expected, with the zoom lens lagging a little bit behind the prime. At f/8 the crops are very similar and therefore not shown here.


 

 

24-70 @ 50mm - f/2.8 - 1/500s
50mm f/1.4 - f/2.8 - 1/500s

Again, the 50mm f/1.4 prime provides better contrast and sharpness when compared to the new 24-70L. All 24-70L shots were slightly warmer whereas the images from the prime were more neutral.

 


Now, let's add the 28-70L to the comparison. I will be showing crops from the 35-70mm range since most of the 28mm samples from the 24-70L showed signs of flare and therefore could not be compared. It's worth noting that even with flare, the 24-70L images at 28mm f/2.8 were slightly sharper than the 28-70L's.

@35mm f/2.8

24-70 @ 35mm - f/2.8 - 1/500s (center)
28-70 @ 35mm - f/2.8 - 1/500s (center)

24-70 @ 35mm - f/2.8 - 1/500s (edge)
28-70 @ 35mm - f/2.8 - 1/500s (edge)

@ 35mm f/2.8, the 24-70L performed better than the 28-70L in both center and edge portions of the frame. Both focusing points were dead on at the same location. Notice the warmer colors from the 24-70L samples.

 

@35mm f/5.6

24-70 @ 35mm - f/5.6 - 1/125s
28-70 @ 35mm - f/5.6 - 1/125s


@ 35mm f/5.6 both lens provided images with very similar contrast and sharpness. The crops from the 24-70L however, were warmer and a bit sharper.

 

@50mm f/2.8

24-70 @ 50mm - f/2.8 - 1/500s (center)
28-70 @ 50mm - f/2.8 - 1/500s (center)

24-70 @ 50mm - f/2.8 - 1/500s (edge)
28-70 @ 50mm - f/2.8 - 1/500s (edge)

@ 50mm f/2.8 both lens provided images with very similar contrast and sharpness. The crops from the 24-70L were warmer and a bit sharper, especially on the edges.

 

More tests:

 

 

@50mm f/2.8

24-70L @ 50mm - f/2.8 - 1/500s (center)
28-70L @ 50mm - f/2.8 - 1/500s (center)
50mm f/1.4 @ 50mm- f/2.8 - 1/500s (center)

The 24-70L and 28-70L crops @50mm wide-open look pretty identical to me. The 50mm f/1.4 seems crisper and has better contrast than both L zooms. Keep in mind that the 50mm f/1.4 performs even better at f/4. Now, let's see how the zooms performed at 50mm f/4:

@50mm f/4

24-70L @ 50mm - f/4 - 1/60s (center)
28-70L @ 50mm - f/4 - 1/60s (center)

The image quality between the 24-70L and 28-70L @ 50mm f/4 seems identical.

How about at 70mm? Here's how these lenses compared, when wide-open:

@70mm f/2.8

24-70L @ 70mm - f/2.8 - 1/125s
28-70L @ 70mm - f/2.8 - 1/125s

It may seem repetitive, but as you may have noticed, the differences are very small - if any. I give the edge to the 24-70L @70mm wide-open. It's safe to conclude that optically, the 24-70L and the 28-70L are very similar when shooting at 70mm wide-open. Here is another sample at 70mm f/2.8:

 

24-70L @ 70mm - f/2.8 - 1/30s
28-70L @ 70mm - f/2.8 - 1/30s

Very similar performance @70mm wide-open

 

@70mm f/8

24-70L @ 70mm - f/8 - 1/15s
28-70L @ 70mm - f/8 - 1/15s

 

Same as above. At f/8 I couldn't distinguish the difference between images from both lenses. They also provide identical performance when stepped down.


 

Conclusion

If image quality is more important than lens flexibility, I would still highly recommend shooting with primes lenses. To me the difference is noticeable and we should not be surprised by it.

For the landscape photographer who believes that every little detail counts, primes are still the way to go. The same is not true for photojournalism where getting the picture is more important than the small image quality edge. The differences between the 28-70L and 24-70L in the 50-70mm range are marginal and make their images virtually indistinguishable. However, from my tests, the new 24-70L has the image quality edge in the 28-35mm range when shooting wide-open.

The extra four millimeters in the wide angle range provide even greater flexibility but makes the lens more prone to flare. The lens hood should be used with both lenses at all times. From my preliminary test shots, I ended up with more flare in shots from the 24-70L than the 28-70L. This could be attributed to the almost identical lens hood design and extra wide angle range.

So, should we still keep our 24mm, 35mm and 50 primes? If you have them, keep them!
Should I trade my 28-70L for the new 24-70L? That is a difficult question to answer. If you need the extra range, I'd say go for it. However optical performance is similar with both lenses, especially at the 50-70mm range. The 24-70L is optically better wide-open at the wide angle range.

The new 24-70L provides great image quality suitable to professional standards. However, if you are thinking of replacing your 28-70L or dumping your prime collection, think again. You may already have all you need.