ksbuehler's reviews

  • Canon EF 70-200mm f/4L IS USM

    10 out of 10 points and recommended
    sharp, light (compared to f2.8 70-200)

    I use a 20D. This is my favorite lens. Sharp, wide open across the full zoom range. The stabilization system works beautifully. Focus is fast and accurate.

    I also use this lens for macro photography with 1.4x EF II TC, 36+20+12mm Kenko extension tubes (68mm total), tripod ring, monopod, and small quick release head. Corners go a bit soft, but center remains sharp. I order this massive stack as follows: 20D->1.4x->36->20->12->70-200 f/4 IS. The stabilizer seems to help in the configuration, but I haven't done detailed analysis to confirm.

    Using this macro setup at closest focusing distance:
    70mm- 0.75" subject fills the frame
    200mm - 1" subject fills the frame

    The biggest difference between 70 and 200mm macro (using the above setup) is the working distance. At 200mm front of the lens is more than 1 foot from the subject. At 70mm it's just a few inches.

    reviewed January 21st, 2009 (purchased for $980)
  • Canon EF-S 18-55mm f/3.5-5.6 IS

    8 out of 10 points and recommended
    light, cheap, small, good zoom range, stabilization, sharpness
    manual focus not-smooth, [email protected]

    It's light, cheap, and gives great results when used correctly. Good bang for the buck. Image stabilization mainly helps out at 55mm in low lit conditions.

    I've tried using extensions tubes with this lens on my 20D (12mm, 20mm, and 36mm Kenko EF/EF-S tubes).

    12mm tube @ 18mm
    barely useable. ~1 inch working distance. Poor magnification.

    12mm tube @ 55mm
    decent results. ~3inch to 12inch working distance. At closest distance, I can fill the frame with 1.5" subject.

    20mm tube. The working distance drops to 0" at 24mm. 55mm gives a working distance of between about 2" and 8" across the focal range. At closest distance, a 1" subject fills the frame.

    36mm tube. At 55mm the working distance is about 1.5" to 4.5". At closest distance, a 0.75" subject fills the frame.

    reviewed January 21st, 2009 (purchased for $140)
  • Sigma 18-50mm f/2.8-4.5 DC OS HSM

    9 out of 10 points and recommended
    light, inexpensive, 18mm @ f2.8 with stabilization, HSM
    a bit of Chromatic aberration, focal field curvature

    I concentrated my tests on performance at F2.8 and 18mm, as that is what I care about. I have a 45mm TSE 2.8 and 70-200mm F4L IS to cover other focal lengths.

    For the price, this lens is great. I wanted a wide lens for use in low-light without a flash on my Canon 20D. This is the least expensive f2.8 18mm lens on the market with stabilization.

    Weighing only 400g, it is also the lightest stabilized 18mm f2.8 lens on the market. Size and weight are big factors for me. I fly internationally for business quite a bit, and prefer to travel carry-on only. Between dress shoes and business clothes, not much room for my photo gear.

    As a bonus, it uses the same 67mm filters as my 70-200mm f4L IS.

    The 18-50 lens does not rotate or extend during focusing and zooming. Great!

    Build feels pretty solid.

    The HSM is NOT full time manual. I've been pampered by my Canon L lens so this was unexpected. I'll get over it.

    I used a few USAF 1951 test targets to measure resolution performance from f2.8 through f11. Sharpness is nearly as good across the frame at f2.8 as f8.

    Be aware there is noticeable field curvature at f2.8 and 18mm. (I'm talking about the curve of the focal plane, not barrel/pincushion distortion). If you focus on a perfectly flat wall at f2.8 @ 18mm, either the center of the image will be in focus, or the corners, not both. In the real world, a curved focal "plane" is not usually a problem. Most of my shots are not of a perfectly flat object that is perfectly parallel to the sensor plane. I'm not sure how slrgear, or any other site, can account for this in their tests. My method is to step through a few focal distances to check quality of focus in the corners.

    The optical stabilization works well at 18mm. I can shoot at 1/15 with nearly 100% of shots being very sharp. At 1/8, it's more like 30~50% of shots very sharp. It seems to depend even more on how much coffee I've had so YMMV.

    At 18mm, there is chromatic aberration present in the corners at all apertures tested (f2.8 to f11). It appears to be consistent across all corners, indicating that it could easily be removed in s/w. Further, the CA seems fairly consistent across apertures from f2.8 to f11. I have not tested software correction of the CA yet nor have I checked CA performance at other focal lengths.

    There is about 1/2 stop vignetting near the corners at 18mm and f2.8. From reviewing test data for other lenses, this is better than the Canon 17-55 2.8 IS, Canon 16-35 2.8, Sigma 18-50 2.8 EX DC. It is about the same as the Tamron 17-50mm 2.8 XR Di II.

    Macro performance. I put on a 12mm extension tube. Working distance is 0" at 18mm, 1" at 28mm, 2" at 35mm, and 4" at 55mm. The frame width is 1.3" at 18mm, 1.4" at 24mm, 1.5" at 28mm, 1.75" at 35mm, and 2.1" at 55mm. Using Canon 20d, followed by Canon 1.4 II TC, followed by 12mm ring, followed by Sigma 18-50 2.8-4.5 gives a 1" frame width at 55mm. 20d+1.4x+20mm tube+Sigma gives 0.75" frame width at 55mm.

    Next things on this lens to test, not necessarily in this order:
    1) 28mm performance and Optical stabilization performance
    2) optical stabilization in 55mm macro configurations
    3) 45mm performance vs my 45mm TSE

    reviewed September 15th, 2009 (purchased for $300)
  • Canon TS-E 45mm f/2.8

    10 out of 10 points and recommended
    Very sharp. Very nice manual focus control. Amazing focal plane control.
    A bit more Chromatic aberration than I'd like in a lens of this price.

    I bought this lens used from a studio photographer. I shoot on a Canon 7D (1.6x APS-C sensor), making this 45mm lens a 72mm equivalent.

    In my view, this is the best value and most versatile tilt/shift lens on the market for APS-C sensors. The nikon is double the price. The 90mm canon is a bit too long for most uses on an APS-C camera. If I need a longer tilt/shift lens, I use the canon 1.4x teleconverter with the 45mm. The 1st generation canon 24mm is not as good of optics as the 45mm. The 2nd generation canon 24mm is much more expensive, and the larger image circle isn't needed on APS-C cameras.

    I use this lens more often than I expected. Here are some of the ways I use it:

    1) landscape - increase depth of field. Ex: getting both the pebbles on the beach in focus and the mountains in the background
    2) landscape - decrease depth of filed. In "busy" scenes, isolate specific elements of the landscape. Caution should be used to prevent the "miniature" look, unless that is what you are going for.
    3) portrait - control exact focal plane placement to emphasize features. Ex: get only one eye in focus, or only the mouth, etc...
    4) low light photography. This applies to indoor, night-time, or other times when you need to open to f2.8 and still struggle to capture enough light. Controlling the focal plane enables you to get more of what you want into the limited depth-of-fielded dictated by wide apertures.
    5) macro. I use this lens with extension tubes and the 1.4x TC as needed. Depth-of-field is always an issue with macro. More focal plane control can enable a smaller aperture setting, and therefore allow for faster shutter speeds and/or lower ISO settings.

    reviewed January 25th, 2010 (purchased for $900)