Canon EF 17-40mm f/4 L
Introduction:
Though we generally use prime lenses for the reasons you can read on this site, if you need a lot of focal lengths your bag is going to get very heavy, this is where zooms come in. When you look at the area covered by different focal lengths, you can see that the big differences are at the wider ends. The difference between 17 and 21mm is significant, but modern technology enables 17-40 with f/4, this becomes a very universal lens.
With telephoto zooms, you're usually going to be shooting at the long end nearly all the time and even then still cropping, at the wide angle end the subject matter will generally be framed to be "as is", as a small difference makes a big change you'll be looking to frame things correctly; think also about distortion handling, though here there is very little.
What the above all means is a wide angle zoom lens is a very useful piece of kit and therefore is the obvious addition to your primes.
We've had, used, exchanged and become familiar with several wide zooms and after lots of indecision internal discussions and hours of use, this is the lens which has finally ticked all the boxes along with the EF16-35 f/2.8. Below is some background, some application summaries and some explanation of how and why we have reached this point.
If you like lots of specifications, click this link - Canon 17-40mm f/4 L II Full Specifications.
How wide and how narrow?
If ever there was a seemingly simple question, this would seem to be it, however "what is this lens used for"? There are so many different applications and each will have different demands.
Here is an overlay showing 16, 17, 21, 24, 28 & 35mm FOV's on one image. With 28mm Chris is only partially in the shot, even 21mm gives a restricted composition, so 16 / 17mm is often necessary.
There are far more attributes which influence the use of a wide angle lens. With many subjects suited to this focal length range, there is however a shorter list of attributes the lens needs to have to meet these goals.
First, plans of what you'll use it for may be very precise when thinking about it, but inevitibly a wide angle zoom will be a goto lens for many many unforseen opportunities, so it needs as much flexibility as possible.
As a brainstorm, focal range, focus breathing, edge sharpness, distortion, flare, autofocus speed, weight, filter size, constant maximum aperture & colour fringing come immediately to mind; then add sensor resolution for overall quality.
17mm is very wide, do you need this wide? I believe yes, sometimes you just need to get it all in, beyond this is fisheye - (this is specialised so not included here). The trade off's are then in the longer end, 28 / 35 / 40, matched to aperture.
Where it delivers:
This full image is at 17mm the crop box is 40mm. From the perspective of composition this is a completely different result, having the flexibility to capture both ends at full resolution is a highly desirable feature, cropping this severely in post can have severe quality implications. An alternative is to carry more lenses of course, there are advantages and dissadvantages to this that I don't need to list here.
Broaden this the same way, when you're looking at a subject, be it a landscape, indoor or street scene, having too limited a fov is a blocker, usually no good way around it, hence the 17mm end is in our eyes the most important.
A good example of the lens' flexibility is here, the subjects being the two boats, that's clear. The variations of how these are presented includes the perspective of the boats where moving closer at the wider zoom range accentuates the shape of the boats themselves in a way standing back would not. Additionally the distance to and the scale of the background can be controlled.
This photo was on the R7 body making the zoom range 27 to 64mm; the image here is at 27 effective, The balance including the horizon, distant hills, and scale of the boats with respect to the water leaves a huge amount of scope for a photographer to get the best composition, allowing it to fit in with the available conditions.
With this lens' range a single lens could and does deliver huge flexibility, often turning a missed opportunity into a great shot.
We are not able to control everything when travelling, especially when hiking and the weight and flexibility of you bag plays a part. The 16-35mm f/2.8 is bigger and heavier than this lens, for landscapes the lightweight 17-40mm has every advantage which is why we have it. The 16-35 has the edge in sharpness and low light, but the extra reach and lightweight of the 17-40 is more often the winner.
Lens Optical Quality:
This along with useability, is the most important area for serious photography and the designers have a myriad of parameters and variables to overcome before ending up with an optimum, quality vs value solution.
There is a very strong tendency for pixel peeping to take over all decisions and optical evaluations. certainly watching online reviews you'd sometimes think this is the most critical element! It is a part of the measurement process but if you have to pixel peep to see it, it's only a small part.
The lens you use will also influence colours, barrel and pin cushion distortion, haze and a myriad or points, not directly sharpness. Some of these such as vignetting is very easy to remove when editing in such a way that it doesn't change the picture itself. Chromatic aberration can also be relatively easily handled. If you start having to play too much with colours themselves however you are literally changing the nature of the scene as it will be viewed. Maybe this is ok for some photo genres but not all and certainly not to the excess often seen. Having a lens which reliably and in a trustworthy way maintains colour saturation "as you see it" does vary between lenses.
With a Canon "L" series lens you would expect that the clarity and colour delivered via the lens coatings etc. will be of a high order and this lens is no exception. Colour balance, flare control, contrast and true to reality tests are passed with flying colours, (pardon the pun).
With all this taken into account, this lens is a solid performer and with it's handling advantages is often the winner. The only areas where it falls behind it's big sister the 16-35 is in low light performance including street-scene etc, and where absolute sharpness is a priority, this means printed over 40" / 1m prints, how often will you do that?
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Rainbow from a windy boat crossing on Mull
Colour, contrast and zero flare - handheld
Handling, Carrying:
There is a lot of quality flexibility packed into a compact, lightweight body. This 17-40mm f/4 to carry, use and hold is up at the top, there is the f/4 trade-off and some ruggedness differences compared to the 16-35, more below.
The lens barrel itself is a very comfortable size with well dimensioned and damped control rings giving a good feel. It is not large and comfortable for all hands.
When focussing the front of the lens extends a little but does not rotate. 77mm filters are an optimum and common size, so less likely to need duplication in your bag. CPL's can be used but at 17mm any lens will struggle, simple physics. However the results are still great without any colour issues you're going to have a problem with.
The autofocus of this lens is rapid, quiet and precise. For landscapes and street scene for example it is much faster than your eye can follow.
The zoom range means this lens does fit into the "general purpose lens" category, so inevitably you'll be carrying it mounted a lot of the time. This lens does not feel either big or heavy and is exceptionally comfortable for such a zoom range with the output quality it delivers. You'll want a top quality filter and the hood fitted to protect the front objective, even with the lens hood on it's not far inside.
Decision Options:
Once you have decided you need a wide angle zoom, the decision doesn't get easier. To illustrate the options available and the types of decisions you need to address, this summary explains our criteria and choices. All here are good, and different at the same time.
a) Canon EF17-40mm f/4L:
Pros:
• Wide zoom range.
• Very good image quality.
• Autofocus fast & quiet.
• Lightweight.
• Low relative price.
Cons:
• f/4 (though constant).
• Sharp but not as sharp as below:
b) Sigma 14-24mm f/2.8 DG HSM Art:
Pros:
• Very wide 14mm
• Weather-sealed.
• Compact quality.
• Sharpest image quality.
Cons:
• Limited to 24mm
• Expensive
• Exposed front element
c) Canon EF16-35 f/2.8L II:
Pros:
• Focal length flexibility.
• Excellent image quality.
• Very useful zoom range.
Cons:
• Only f/2.8.
• Heavier and bulkier.
• High cost
Final Decision
If you're looking for a lens in this category, a summary of points written here will help with your decision. These are specific lenses for general applications but with twists, they to our eyes are not direct rivals as are not quite like for like.
Focal Length & Aperture:
The first point to raise and they are all different, all cover 17 to 24mm, but ranging from 14 to 40mm. Each in their own way are very strong and highly recommendable but they are not direct competitors for differing reasons. f/2.8 has clear advantages but so does the weight and size saving of the f/4, most of the time we're above f/4 for this type of lens.
The extra wide FOV or 14mm can be very useful the Canon's don't do it.
Image quality:
We have used the two Canon L series lenses here extensively and of the two, the f/2.8 has the edge, but most of the time you'll struggle to see any difference, let's consider them equal. The Sigma we haven't used but all tests suggest it is potentially the sharpest one here, reviews show very low distortion and the highest sharpness, which is why we have included it here. There have been astigmatism quality concerns but Sigma will correct them.
Design and Build Quality:
These are all top quality, but even though the 17-40 f/4 is an 'L' lens, it lags behind the other two in having plastic body parts throughout, but it is substantially lighter and has a 77mm filter thread which is less expensive and more standard than the 82mm of the 16-35. The 16-35 and Sigma have no real issues here.
All three are weather sealed.
Handling:
All three have big control rings the right way around and feel very good.
The 17-40L is light clean, very portable without flaws.
The 16-35 doesn't have any flaws to mention here, everything works as it should it's large but fully manageable.
The Sigma is in third place here as the 14mm means the lens protrudes out the front so you cannot fit filters and the lens hood must always be in place, there are obvious extra handling considerations and care actions to take.
Conclusion:
This is difficult without a clear winner or clear loser, just advantages and disadvantages:
17-40 f/4L - lightweight, compact, very sharp, very good zoom range - we have one.
16-35 f/2.8L - Overall just ahead here with 2.8 throughout - we have one.
14-24 f/2.8 DG - Excellent option when you need a little wider - not the reach though.
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Thank you, we hope this has helped.
Footnote:
This will be expanded upon from time to time, there is a lot more practical information we'd like to share and guides for more general use.
If you have any questions or would like some open clear specific feedback, just ask us here Contact Us.