G Dan Mitchell Photography

Canon EF 24-70mm f/2.8 L versus Canon EF 24-105mm f/4 L IS

Posted on 06 February 2011

Anyone who spends any time in photography forums discussing Canon lenses has seen this topic come up regularly. (Some might say it comes up almost obsessively!) If you follow this subject you are familiar with posts asking which of these lenses is “best” or claiming that one or the other is great and the other is poor. Rather than re-writing what I have to say about this every time the subject comes up, I thought I’d try to post once here and then link. (A disclaimer: I own and use one of the two lenses but not the other.)

To begin with, a few general thoughts about comparing lenses and other gear:

1. “Best” and “better” are relative rather than absolute concepts – what is “best” must be considered relative to each photographer’s particular needs. Rather than asking “Which is best?” it more often makes sense to ask, “Which is the best fit for me?”
2. When your personal comparison results in a decision that one thing is better than the other for you, it does not necessarily follow that “the other thing” is no good or even deficient in a general way. In many cases both of the compared items are actually excellent.
3. When comparing lenses, “sharpness” is not only a more complex topic than it might seem… but it is also not the only or even necessarily the most important factor. Flexibility, size and weight, cost, functional features, suitability to intended use, and much more can be more significant than small differences in image quality.
4. It is risky to take online forum reports too seriously. For one thing, people are far more likely to post about a perceived problem than about  something that works fine, and when they do post about a problem they can become quite emotional about it. For another, depending upon the particular people who get involved in the discussion, a single incident – sometimes of questionable context – can become inflated into scores or hundreds of posts and become an online meme. (Forums are not without value – just be cautious!)
5. Considering a lens on its own is useful, but photographers also need to consider how a lens fits into the overall set of lenses they use on their camera body or bodies. If you identity a weakness in the performance of one lens, this weakness may be less important if you have another lens that is strong in that area.
6. No lens is perfect. Each has strengths and weaknesses, or what I like to call its personality. While lens A might have a weakness in some aspect of its performance, lens B probably has a weakness in some other area. The strengths of the two lenses may also be somewhat different.

With all of that in mind, I start with the premise that both lenses are quite good and that excellent photographs can be produced with either. In many cases, other reviewers hold the same point of view. While you can certainly find reviewers who will state that one or the other is “better” in a specific or general way, the overall trend it so recognize both as being very fine lenses.

EF 24-70mm f/2.8 L

This lens has a strong reputation as a solid “normal” zoom on full frame Canon cameras. It can reportedly produce fine image quality throughout its focal length range, and the f/2.8 aperture slightly extends its ability to shoot in low light, to deal with moving subjects, and to minimize depth of field (DOF). Resolution is very good for a zoom, though it should be no surprise that the image softens some, especially in the corners, wide open – this is normal. It has an interesting “backwards” design in which the lens extends as it goes wider, which has an effect on lens hood design that many regard as positive. The lens is not small nor is it light. The 24mm wide focal length gets close to the start of the ultra wide range on a full frame camera, though it isn’t particularly wide on a cropped sensor body. The 70mm focal length begins to get into the wide end of the portrait focal length range on full frame, and certainly does “go there” on crop.

EF 24-105mm f/4 IS L

This lens also has a strong reputation as a solid “standard” zoom on full frame Canon bodies. It also produces generally excellent image quality across its range. The addition of image-stabilization (IS) extends the use of the lens by several stops in low light shooting as long as the limiting factor would otherwise be camera stability rather than subject motion. (IS won’t help with moving subjects where shutter speed is the limiting factor.) Resolution is quite good for a zoom, being best in the middle of the range and perhaps being a bit less sharp at 105mm, where it is still quite good. As with the other lens, the 24mm wide focal length borders on ultra wide with a full frame camera, though it is not really very wide at all on cropped sensor bodies. The 105mm focal length at the long end provides more “reach” and goes will into the “portrait” focal length range on full frame, and well beyond on cropped sensor bodies. For its focal length range the lens has a reasonable weight and bulk. Given its larger focal length range, it isn’t surprising that it exhibits more barrel distortion at 24mm and light fall-off (“vignetting”) at f/4.

So, how to decide? Rather than thinking first about the lenses themselves think first about your photography. After all, you aren’t looking for The World’s Best Lens – you are looking for the lens that works best for you. How do you shoot? What subjects do you shoot? In what conditions do you shoot? How would either of these lenses fit into your current collection of equipment or the setup you are gradually acquiring? Here are a couple of hypothetical cases – though both represent real photographic situations:

Scenario 1

This photographer often works indoors in low light and may or may not be able to use flash, often shooting at larger apertures and working handheld. The need here might be to expand the functionality around the “normal” 50mm focal length with a more flexible zoom that still has as large an aperture as possible. The larger aperture permits photography of moving subjects in slightly lower light without a flash, the 24mm wide end lets the photographer work in tight interior situations (among other things), and 70mm is enough to get a bit more reach. This photographer might also use one of the 70-200mm L zooms, and might even have two bodies, one with each lens, making overlapping focal lengths somewhat redundant. While IS might be “nice” on such a lens, expanding its usefulness a bit in some low light situations, this photographer might simply add a flash. It may also be the case that this photographer isn’t too concerned about the weight and bulk of the equipment. The 24-70 f/2.8 sounds like it might be a great choice here.

Scenario 2

This photographer most often works in good light, or with static subjects in lower light, and tends toward using smaller apertures – perhaps this person is an outdoor photographer. The photographer may shoot handheld on occasion, but may also frequently work from a tripod. This photographer’s issue in low light is perhaps more the ability to hand hold the camera than it is to stop action. Or perhaps this photographer pairs large aperture primes with the smaller aperture zoom. The 24mm wide end is useful for some shots here, too, but the 105mm focal length reduces the need to switch lenses as often when a longer focal length is needed – and some photographers might get along with just this lens in some situations. This photographer may pair the lens with one of the 70-200mm zooms, too, but perhaps likes overlapping focal lengths, which also can reduce the need to make lens changes. If our photographer is an outdoor shooter, the smaller/lighter lens with larger focal length coverage may appeal in terms of lightening the load of equipment. The subjects that this photographer shoots rarely reveal the increased vignetting/barrel distortion at 24mm, and when this is an issue a post-processing fix can work. The 24-105 f/4 IS sounds like it might be a great choice here.

These aren’t the only possible scenarios – consider how many others there might be – and these aren’t the only issues. But do notice that once you let go of the sometimes-distracting question concerning which of two good lenses is slightly better in optical terms (e.g. “sharper”) you can see more clearly the other important functional differences between the lenses and consider how they are or are not important to your shooting.

In the end, one talented and skillful photographer might choose the 24-70 as the better lens for his/her work… and another equally talented and skillful photographer might choose the 24-105.

Note for cropped sensor camera photographers

I often see photographers who shoot Canon cropped sensor cameras (and other photographers, too) falling victim to what might be termed “L lust.” They assume that a lens must have a red ring and an embossed letter “L” in order to be good, and they frequently simply dismiss all non-L lenses from consideration. And photographers who are shopping for lenses are often overwhelmed by the “advice” from some “L-caholics” who can’t say anything good about non-L lenses.

L lenses generally are quite fine lenses, both in optical terms and in terms of their robust construction or “build quality.” But this doesn’t mean that L lenses are the only good lenses, nor that the L lens is always preferable to a non-L alternative. One place where this is very true is with several of the Canon EFS lenses that are designed specifically to work on Canon 1.6x cropped sensor cameras. Among these lenses is the EFS 17-55mm f/2.8 IS lens. I mention this because this could well be a better choice than either of the two L lenses discussed above if you are a cropped sensor shooter looking for a very high quality lens that covers the range around the normal focal length range on a cropped sensor body.  It has the IS of the 24-105 and the f/2.8 aperture of the 24-70 in one package, and its focal length range is more ideal for most shooters.

The lenses in this article are available from site sponsor B&H Photo:

• Canon  EF 24-70mm f/2.8L USM Lens
• Canon 24-105mm f/4L IS USM AF Lens
• Canon EF-S 17-55mm f/2.8 IS USM Zoom Lens

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