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Sigma 17-50mm F2.8 EX DC OS HSM

Review Date: Nov 29, 2010 Recommend? | Price paid: Not Indicated


Follow up to my previous review - lens was overhauled and "re-programed" at Sigma service regarding back focus when used in dark with (Canon) external flash`s assist beam. Although Sigma`s Customer Service is by far the best one I have ever dealt with, along with Pentax many years ago (listen Canon ?) lens came back exactly the same. In the mean time I tested my friend`s lens and it has the same problem. I am suspecting that Sigma did some mistake in the lens software or simply ran on Canon`s AF booby trap :-). After all, it challenges seriously Canon`s EF-S flagship 17-55 2.8 IS at almost half the price.
I spoke with Sigma service technicians and it will go in again - seems they are intrigued with the problem. Anyhow, I would appreciate if any actual Sigma/Canon owner could test this lens and post the comment here.
The procedure would be to put on external flash, take some cereal box or anything square with clear lettering in very dark space and
take a couple of pictures. Flash assist beam will engage and "help" the lens to focus - or to miss, remain to be seen. F stop should be around F 3.5 or 4 enough to allow some DOF but not too much to affect the result. All original Canon lenses passed this test with ease and even Sigma does AF almost perfectly without IR beam - weird, at best!

Sigma 17-50mm F2.8 EX DC OS HSM

Review Date: Oct 15, 2010 Recommend? yes | Price paid: $850.00 | Rating: 8 

Pros: Very sharp, very good build quality, right size and price, great warranty
Extreme corners not sharp and distorted at any F. stop, AF unreliable in low light, focusing ring rotates and no full time MF.

This lens replaced my long time workhorse, Canon 17-40L whose AF module bite the dust I did not want to ditch 400$ to repair it.
It is quite a different beast, very sharp and with excellent contrast. I do not care much for OS (or IS for Canon users) in this focal range, and to be honest I do not see much of the difference
compared to non-IS 17-40. Steady hands I guess...anyhow, I have chosen this version over old 18-50 2.8 EX because of HSM focus motor and totally new optical construction - and boy is it better! Took over 4.000 field images in the past two months and had some mixed impressions. As long as there is enough light for the camera/lens to focus without flash or camera assist beam this little guy delivers great results, at ANY F stop but in particular from f. 3.5 and up. But, as soon as you bring it into dim interior (most wedding reception halls) it shows its other nature. All of a sudden, despite giving focus confirmation in the viewfinder, AF is all over the place and most often way back from the focus plane.
As soon as there is some extra light or light level in the room goes up for any reason - AF is bang-on again. Just for the reference, this seems to be exactly the same on three camera bodies. I will take it to Sigma for check-up and see if this improves, if not, this alone makes it unworkable for professional use.
Other than that I really like it, very sharp, there is a bit more corner distortion than with 17-40L ( do NOT put people`s faces nowhere near edges of the frame) but than again not quite a fair comparison since 17-40 takes its sweet spot on a cropped sensor. Will post update after Sigma check-up...

Canon EF 17-40mm f/4L USM

Review Date: Aug 8, 2010 Recommend? no | Price paid: Not Indicated | Rating: 7 

Pros: Build quality, size and handling, price
Overall image quality, AF issues

I had this lens for 5 years on 20,40 and 7D and it was real love-hate relationship. I took close to 100.000 images in almost every imaginable situation, photo journalism, weddings and landscape work. After 5 years, mechanically it was exactly the same as on the first day when I got it (O.K. I take care of my stuff) which tells the story of the build quality. Unfortunately, image quality vise it was the different story: nothing special to complain about but nothing to be particularly excited about either.
Sharpness is so-so wide open and it gets better just marginally when stopped-down. In fact, in real life I could hardly even say the difference if the lens was stopped down to about F.8 or used wide open. After F. 9.0 diffraction clearly brings IQ down so do not expect miracles with extreme stopping down.
Fine details of relatively distant objects (trees, branches and leafs for instance) are just a dream for this lens unless they are geometric forms. Colors and contrast are fine but again lack of sharpness gives a dull impression to the images. Image post processing is a must and it in fact improves the story quite a bit.
Recently (well, maybe year ago) my sample developed weird AF behaviour, throwing AF at the back, in particular at 17-20mm setting. Mechanical check showed everything was perfectly fit inside the lens. Body problems are excluded as it acted same on three different calibrated cameras. It was still able to find right focus point, but using it for serious work was at the end pure gambling. I spoke with a couple Canon trained technicians and they all confirmed that this particular lens was prone to AF problems. Again, I am working pro and use my gear on the daily basis, it does not mean that occasional users or all lens samples will end up like this. To cut it short, maintenance for "L" lenses in Canada is now costly business since July 1st 2010 as 300$ flat fee (plus taxes and shipping of course) has been introduced just to open repair order. So, it would came to about 50% of the new lens price just to calibrate 5 years old product! Some of my colleagues had similar issues and after calibrating the lens problem would came back after 6-12 months, depending on use.
That plus overall mediocre optical performance urged me to get rid (yes, get rid) of the long time work horse and look for other options. New 17-40? No way, things are going forward and I have found myself ordering new Sigma 17-50 2.8 EX with Optical stabilizer for a couple of dollars less than new 17-40L and with 10 years warranty. Tried it briefly and liked it a lot, time will tell...
But I already miss handling and build quality of 17-40 , can not say the same for IQ.

Canon EOS 7D

Review Date: Nov 16, 2009 Recommend? yes | Price paid: Not Indicated | Rating: 8 

Pros: Excellent build quality, great controls layout, very good AF (improvement over 40/50D) a bunch of features, fantastic viewfinder, very fast and responsive, very good noise levels up to ISO 1600.
Too many pixels for APS-C, diffraction issues, some digital artifacts (default noise reduction?) on JPEGs, too much noise dandruff over ISO 1600. N.

So, as an owner of two 40Ds I skipped 50D, mainly for megapixel race reasons which plagued otherwise very good camera. Waiting and waiting for something as good as 40D when it comes to IQ but with better AF (notably servo mode) and more robust/protected body, a bit faster - here we are, 7D! Must note, I do not care much about video anyway. Since I burned my self a few times before I decided to test new camera thoroughly before buying. So, I borrowed one from a good friend and turned it upside-down for two weeks and about 2-3000 shots. To make a long story short, why on Earth 18MP on APS-C? As we could see from issues on 50D, there are a PHYSICAL limits to APS-C sensor pixel density which affect the IQ. Canon did fantastic job in maintaining IQ and noise levels on 7D same or slightly better to their 10/15MP cameras, but that is it. No significant improvement in that field. So, compared with my 40D and regarding my needs ( as a wedding photographer I print quite often 24x36inch) I do not see any single reason to upgrade when it comes to image quality. Period. On a bright sunny day I have to shoot at ISO 100 and F9-11 to save highlights and 7D clearly suffers from diffraction. Let alone that my 17-40 was badly struggling to cope with 7D`s high density sensor, camera shake is very critical and focus has to be spot-on. This camera needs the best (and latest) lenses that Canon has in its line up, plus a few new ones to replace the aging favorites like 17-40/4.0L. Of course, I would kill for 7D`s robust build, body sealing, improved AF and fantastic speed - but at the end it is all about the image quality, right? I could only imagine how good it would be if Canon decided to work on 12MP APS-C sensor and implemented 7Ds technology on it. I wanted to love this camera so much, but at the end of the day I decided to stick with my old-timers and, I will not jump to Nikon camp.