Point of Comparison

This morning, I went up to Conowingo. Fellow Canon-shooter Mark kindly volunteered to let me shoot one of his long lenses, just to verify that the lens is what’s at issue. Here are the results:

First up, we have the Canon 70-200 f/2.8L IS with the 2X converter.

Canon 70-200 f/2.8L IS + 2X converter on Canon 40D, ISO640, 400mm, f/8.0 1/800sec.

Canon 70-200mm f/2.8L IS + 2X, cropped so Heron height is 1/3 of the image height

Next up is the Canon 500mm f/4 L IS + 1.4X converter on the 40D.

Canon 500mm f/4 L IS + 1.4X converter, ISO640, f/8 1/1250

Canon 500mm f/4 L IS + 1.4X, cropped so that Heron is 1/3 image height.

Finally, for fun, we have the Canon 70-300mm f/4.5-5.6 IS USM on a Canon Rebel XTi, hand-held:

Canon 70-300mm f/4.5-5.6 IS USM on Canon Rebel XTi, ISO400, f/8 1/1000

Canon 70-300mm f/4.5-5.6 IS USM on Rebel XTi, cropped so that the Heron is 1/3 image height

I tried to keep everything as “equal” as possible for these test shots. The bird is on the west end of the island at Conowingo Dam, and the shooting position is from the parking lot fence line to the south. Unfortunately, the distance is not recordedin the EXIF data. Canon do not feel that this information is useful to the photographer. However, I’d guess that the range is at least 800 feet — probably more. The lighting conditions were pretty near equal, and I’ve applied minimal processing in Lightroom, with the exception of applying camera-like RAW-to-JPEG conversion in Adobe Lightroom 2.1.

As expected, the 500mm+1.4X lens combination produced the best image quality. For $6100, it had darned well better! In subjective viewing, the 70-300 on the XTi produced the second sharpest image and the 70-200 with the 2X brought up the rear, from an IQ standpoint (100% blowup on a calibrated Dell FP1907 monitor).

For those into the numbers, here are the MTF charts from Canon for the three lenses (teleconverters not included):

Canon 70-200mm f/2.8 L IS at 200mm

Canon 500mm f/4L IS

Canon EF 70-300 f/4-5.6 IS USM at 300mm

Again, these charts don’t take into account the teleconverters on the 70-200 or the 500. Taken at face value, the 500 is obviously the clear winner. But, based on measurements I’ve seen on other independent test sites, the 70-200 f/2.8 simply doesn’t live up to Canon’s data. Additionally, on other sites, the 70-200 f/4L IS is far superior to the f/2.8 model. Yet Canon’s MTF chart is nearly identical for these two lenses at 200mm in the “key” indicators.

Today’s exercise also pointed to at least one other item I’m going to need, in addition to a better choice of lens, if I’m going to continue with the hard-core bird shots — a better camera support system. My tripod is basically fine, if not a tad short, but the head is just not the right kind. Instead of the “ball” head that is great for landscapes and portraits, I really need one of the Wimberley-style gimbal heads, as they allow much better control of movement when tracking wild birds.

So, as I said the other day — wrong tools for the job.