In the web there are many tests including authoritative ones , such as those conducted by Photozone . People going to make a purchase very often did not try the lenses they want, otherwise they would not seek here for information about them, so the added value we try to give here is just an analysis of the equipment that is always focused and guided , first and foremost by my experience as it is obvious but most important by limiting the too many variables that incur in the “perfect” choice .
In fact, many scientific tests are likely to make us lose sight of the most important thing: lenses are to be used on the field! Unless one is interested in the tests as such, the photographer only cares that equipment effectively responds to the uses he intended for it. Perfect lenses moreover do not exist and those that border on perfection are very expensive. Canon 24-70 2.8 L II and the Canon 70-200 2.8 IS L II zooms are amazing and certainly the best to accomplish most photographic situations , if we live with the weight and expense ( € 4000 both). However, the perfection for which we are willing to spend that much, is very often "wasted " . The photographer knows the equipment must be assessed on the basis of the uses to which he employs it and almost always chooses different equipment for different tasks . Clearly one of the thing to consider is that many of these do not relate to the quality in the strict sense . Personally, I consider the portability ( size and weight ) and the versatility a highly decisive factor . Then there is the cost , of course.
In another article I compared, using real images, the Canon EF 17-40 f4 L with its bigger brother EF 16-35 2.8 L II. The latter, also belonging to the series L ( Luxury) of Canon has shown as definitely more powerful, but when we look at the actual use, such as landscape photography, where one stop more light is not needed, and we exclude the possible fixes in post-production, especially if you shoot in RAW ( deformation, vignetting, chromatic aberrations ), differences are reduced to very little. Add that the 16-35 costs twice as much , weighs more, and does not solve other photographic situations where I find the prime optics do much better, or prefer the zooms covering most useful focal lengths (24 -70mm ) , and the 16-35, despite being an excellent zoom, is a poor choice .
My workhorse is now the Canon EF 35mm 1.4 L that covers for me the normal focal length (instead of a 24-70). Others will most likely use zoom lenses that cover the range of 24-100 or 28-100 . Obviously we talk about focal lengths on 35mm film or full frame . In the area of APS- c the same focal length is covered by the different specific lenses such as the 18-55 , 17-85 , 15-85 , etc. . On the other hand if we are going to use the the full-frame-specific EF 17-40 on a reduced size sensor or APS -c what we have in our hands is a completely different lens . Used for two years on a EOS 40D , this lens that covers a focal length of about 28-70 was very efficient. In fact, by eliminating the extreme edges of the optics, the small sensor captures a large optical quality out of the Canon 17-40. Even at maximum aperture, F4 , results are more than good , not so on full frame . This certainly contributes to another parameter: versatility of a lens. For those who possess , like me, two bodies, one is full frame camera and the other an APS-c, the EF 17-40 is opened to two very different uses : wide-angle zoom on full frame and standard zoom out of an APS-C . There are certainly more specific zoom wide angles, such as the Sigma 12-24 , but 17mm is definitely a very wide angle of view .
The tests show that at 24mm the 17-40 behaves much better than the Canon EF 24-105 F4 L IS , so very often having optics that cover the same angle of view is not a "waste". If we intend to do a landscape and we own them both, it is clear that we'll mount the 17-40 but for all other uses the 24-105 will prove to be more convenient, even only for the image stabilizer .
Going then by exclusion few optics remain to be so versatile, lightweight and with a great value for money that you can use as a wide angle if designed for full frame. In addition to Sigma 12-24 , there is for example the Tokina AF 16 -28mm f/2.8 AT- X Pro SD FX. The latter seems to perform even better than the corresponding Canon , the 16-35 2.8 L II and costs much less, about 800 euro against the 1300 Canon . But as the latter weighs a lot, and is very big, it also can not mount filters except with a complicated adapter. In landscape photography, despite the miracles of digital, filters are still to be used.
The EF 17-40 mounts comfortable 77mm round filters, more easy and cheap to find than the 82mm filters needed for the 16-35. It has with it, as well as a lower cost, reduced size and weight, while maintaining the build quality of a L lens, professional luxury series . Other low-cost alternatives are definitely the Samyang 14mm, a miracle optical from what we read about, as long as you are willing to give up autofocus (even the AF-assist in manual focus is missing ) and the aperture setting on the camera (and therefore the metering ) . But this is definitely not a problem in landscape photography. As a dedicated lens, I do not think that there are rivals. Even the Canon EF 14mm f/2.8 L USM II which costs about 2000 euro , the top of the top, does not reach the quality of the Samyang .
Back to our 17-40, we said that it is suited to multiple uses, while covering different focal lengths (which are tested and all contribute to the final judgment in laboratory tests ), on the field we are interested only in a specific way. At normal focal lengths, such as 28, 35 and 40, a large part of the standard zooms out there are doing very well, as I said I prefer to use a 35mmm fixed lens, if you make one step back it is fine as a 28mm and even of a 24mm, unless you particularly like this kind of angle of view, which I find not particularly interesting . The 17-40 is better suited, within the full frame, for the range 17-24 , and even more specifically as a wide angle zoom , at around the 20mm, where the classic zooms do not go.
The maximum amplitude of the field, in particular, is the reason for which this kind of objective is used, however, from the tests it seems that the Canon 17mm suffers a lot of loss at the edges. Only at the edges, because the center is sharp at all focal lengths and all useful apertures ( F4 to F11). From F11 all lenses begin to behave the same way in the middle and at the edges and they all lose quality on the whole rectangle due to diffraction. From testing it seems that already at the 20mm Canon 17-40 regains a more homogeneous behaviour, limiting de facto at 20mm the ideal use in the field.
This means that at 20mm we can thus consider another choice, such as the Canon EF 20mm 2.8 USM . This objective is very old , dating back to the early '90s . And is one of the many primes that Canon will have to renew sooner or later, hoping that they do not make it as the 24, 28 and 35 f2, adding the stabilizer and selling it for twice the price! This lens has been long criticized for its salient feature that it is the AF plan that is curved, suitable for use in the field but not with flat subjects such as a wall (typically a subject for test is flat) . This has penalized it. Some consider it even better than 16-35 in landscaping, or with apertures of F8 onwards. We will test it soon and put it in comparison with the 17-40 . The Sigma 20mm 1.8 is not up to the two Canon and despite the low price does not constitute a viable alternative.
The 17-40 , which costs around 600 euro, on his side, with respect to any fixed 20mm, has a greater versatility, it can in fact be used as a all-around zoom on APS-C size (EOS 600D , 60D, 7D). Indeed, even at 20mm mm is very usable since becoming a very interesting 33mm on APS-c. Bur aperture is a limiting factor. The 20mm costs about 400 Euros , which are not few , and has on its side an additional advantage in terms of size and weight. Not that the 17-40 is heavy, but certainly more than the 20 that is really more comfortable.
Back to the EF 17-40, we want to see how it behaves in its more useful scope, let's start by the 17mm. If on APS-C even at F4 we do not notice any loss, by the many shots taken with the EOS 40D I say this with confidence, on the full format actually it starts to degrade a lot, both as for sharpness as for deformation (like all wide-angle lenses). But this 17mm lens is used to make landscapes. Certainly urban landscapes are a different thing , but there a shift lens should be rather used , like the Canon TS- E 17mm f / 4 L. I show here the landscape shots at 17mmm with the use of apertures from F8 to F13 to verify any loss at the edges. In landscape photography, sharpness from edge to edge is important, in other areas it is not.
Photos are moderately worked. Aberrations, vignetting have been corrected, a luminosity curve was applied and a minimum of sharpening during conversion (the standard of Adobe Camera Raw). It is the final picture that interests us as evaluating fact, to understand the limitations of the lens whether they are so prejudicial as to prevent a large print. Obviously a good photographic technique will minimize the defects and allow us an easier and better processing in post-production . Errors of the photographer should not be confused with the limits of the lens.
Crop 100% UP-LEFT:
Crop UP-RIGHT:
Crop 100% LOW-LEFT:
We have NOT presented the extreme angles. These are not always important. Here is another picture:
Crop 100%, top-left (note the "coffee stains" on the sensor of the EOS 1Ds2!)
Crop 100% up-right:
Crop 100% LOW-LEFT:
Then by changing the subject, with a different depth of field, it is clear that high and low acquire different connotations. The angle at the bottom left, the extreme one, after processing retains a lot of detail to my eyes, the aperture is F13. This latter picture is a test, because it has no PDC-related problems, but is photographically less interesting:
CROP 100% UP-LEFT
CROP 100% UP-RIGHT
CROP 100% LOW-LEFT
CROP 100% LOW-RIGHT
I do not know what experience you have with the super-wide-angle images, but to me they seem good enough. I note with disappointment that, probably, my copy loses more on the left side, something that can happen sometimes. There’s a fall in the extreme-corner crops , those on the left have a softening even before the extremes. But I think it's really a small thing.
I do highly recommend the 17-40 for all areas of landscape photography. Among other things, the photographic examples given here show how the optic is able to resist against flare, a characteristic that makes it very attractive for landscape photography. Photographing landscapes having to avoid shooting with front light is like drinking a cappuccino without milk!
©2012 Marco Palladino – All rights reserved
