Mini-Review, Canon EF-S 10-22

Scott_QuierScott_Quier Registered Users Posts: 6,524 Major grins
edited April 9, 2006 in Cameras
This is a re-write of the "mini-review". On first submission, Andy asked if dgrin could use it in the "Reviews You Can Use" section. I demured as I was less than pleased with the lack of completeness of the post - I thought I didn't provide enough information to be really useful.

I'm posting this thread for a couple of reasons:
  • I just got the lens and WOW!
  • I've read a lot of posts here saying how wonderful this lens is, but only in one did I find any images to support that position. I thought adding the detail that follows might help someone.
As you will note from my signature, I don't have any "professional grade" glass. I have read that some hold the opinion that this lens is, in fact, "L" grade glass but that Canon didn't put the red ring on the lens because it is an EF-S lens - something about "L" glass should support full-frame sensors. Looking in from the outside, I really can't talk to that, just thought I would throw that in the mix.





All the above having been said, let me say this is the sharpest lens I have ever shot with and has convinced me that all future purchases will be "L" glass (I'll just have to save my pennies a little longer than I'm used to). I sure wish I had read and paid heed to some of Andy's (and others) comments before I did the "get glass, sell glass, replace glass, repeat". It goes like something this:
"Put your $$ into the glass. Get the best you can, even if you have to wait a bit. You will not regret your decision."
OK, onto the (maybe) useful information. Oh, I forgot to mention:
  • All images were captured using the Canon 20D, tripod mounted, but with out the use of a shutter release cable. I figured, at these shutter speeds, the cable release would not be needed.
  • All images are as "straight from the camera" as possible. I shot the images in raw, imported them into PS CS2, via ACR, changed mode to 8-bit, and saved them as maximum resolution/quality JPG files.
  • All images were shot at 10mm. Results were only better at long focal lengths, so I chose to make this shorter by concentrating only on the "worst case scenario".
  • You can grab a copy of exif by clicking on the image.
  • Where it makes sense, a link to the "original" JPG is also provided.
Because of all the technical difficulties in engineering a wide lens (I'm taking that on faith, I don't have the math background to support this contention) these lenses typically have problems in three areas: flare, contrast loss (under certain circumstances), and Chromatic Aberration (CA). I look at each of these problems, one at a time.

Flare
Point the camera/lens at a point source of light that is brighter than the rest of the image, and you typically get a ghost of that light source at some point on a line defined by the bright light and the center of the lens, but on the "other side" of the center.

This first image is my attempt to create flare at sunset. I think you will agree, there is little, if any, flare to be seen.

#1
67017122-M.jpg
Original

OK, that didn't work. Let's try a much more gruelling test. This was taken at about 10:50AM with the sun just out of the frame. Looking in the upper left corner, you can see some evidence of flare. I have other examples user similar harsh conditions, but this is good enough to demonstrate that this lens is not perfect.

#2
67017133-M.jpg
Original

But, when you shade the lens (like you're supposed to), all those problems seem to go away!
#3
67017142-M.jpg
Original

Contrast
What happens, typically, when you have bright light shining on the front lens element and you are shooting something that is shaded or, at least, darker? Contrast usually suffers. I'm not going to re-post the images here, just scroll up a bit and take a look at images #2 and #3. You can see a slight difference in contast between these. You can, of course, magnify the situation by increasing the difference in light levels between the bright light and the shadows.

CA
Purple Fringe - you can observe this best in images where you have a very bright region next to a very dark region. CA is also, usually, most pronounced at the corners (because these areas are further from the axis of the lens where all the math seems to work so much better). The images below are examples of what is possible under very extreme conditions.

This image is a "whole picture" example of the scene used to for this purpose. Thre is some image distortion here, but, hey, give the lens a break. This is at 10mm with the camera tilted at about 30 degrees from level. There is no way to avoid the distortion given the situation. It's the nature of the beast. This image was taken at f/3.5

#4
67017092-M.jpg
Original

This is a 100% crop from near the center of the above image. This shows that there is little, if any, CA near the center - which one would expect.
#5
67017114-M.jpg

Here is a 100% crop from the upper left corner of the above image
#6
67017115-M.jpg

This is the same region of the scene, taken at f/5.6
#7
67017117-M.jpg

At f/8.0
#8
67017119-M.jpg

And, finally, at f/16
#9
67017121-M.jpg

Conclusions
  • Flare is very well controlled, especially for a lens as wide as this. If you practice appropriate technique to avoid this problem (like use a lens hood and/or shade the lens) you will probably never see this "problem".
  • Loss of contrast due to light bouncing around inside the lens in an uncontrolled manner is nearly unnoticable. Again, good technique will virtually eliminate this.
  • CA - yeah it's there. You can easily find it if you pixel-peep a bit (or enlarge unprocessed images for printing). If, on the other hand, you shoot RAW and adjust for the CA in ACR (or other similar RAW converter) you can greatly reduce or eliminate this artifact from your image.
  • As an aside, the last series of image would seem to support that the sweet spot, aperature wise, is somewhere in the range of 5.6 to 8. By 16, things in the corners start to get a little fuzzy. The "fuzzy-ness" could have been caused by camera shake as the shutter speed at f/16 was only 1/25 sec.
Do I like the lens? Does a bear live in the woods? Oh, yeah, I really love the lens and am looking forward to the time when my JOB allows me to get out and do camera type things. (I'm not out photographing now because I kind of committed to Andy that I would get this together and I like to meet my obligations).

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