Massive Broadwing Migration

[micpic]

Monday hundreds upon hundreds of Broadwing Hawks came down the Wapsipinicon River Basin. Mixed in were Eagles, Buzzards, Redshouldered, and Coopers Hawks. They started coming through at 8 a.m. with the main force of them coming at noon. Some stragglers were still coming through at 3 P.M. The accompaning photos are not very good quality because they were all taken hand held and the hawks were high and moving fast. A very filthy lens did'nt help either.

Mike

[Steve Foss]

Mike, I love those hawk migrations. The same hawks you're seeing could easily be among the thousands that are moving south along Hawk Ridge in Duluth.

Here are some perspectives that might be helpful about sensor dust and shooting birds in flight. Hope you don't mind, Mike.

Your blemishes on the photographs are not likely from a dirty lens. It looks like sensor dust, which can be hard to see at f5.6 on your 100-400, but you've got the lens stopped down to the max at f39, and the more you stop down the aperture, the more dust particles pop out off that sensor and mar the photograph. At, say, f8, I doubt any of those specks would have become visible in the image.

For birds in flight, f8 is generally plenty. Particularly when shooting them at pretty long range, since depth of focus at any given fstop increases as the distance to your subject increases. The 50D/100-400 at 400mm will produce the sharpest images when shot at f8-f10, so you're killing two birds with one stone (so to speak) by choosing f8. You can also then keep your iso down to about 400 instead of the 1600 you shot these at, which will help overall image quality. Lastly, when shooting darker subjects against a light background like this, you can easily enable and spin your rear dial on the 50D to use exposure compensation. With these, shooting +1 EC (one stop overexposed), would be a good starting point, with further overexposure possibly needed. Your histogram will be your guide to how much EC to use. In your situation, I like to see the sky on the histogram just short of blowing out. That ensures you'll still have data in the sky but the darker bird will be as bright as possible.

Also, using + EC will slow down your shutter speed, so you may have to creep iso up a bit over 400. Just depends on the lighting. With decent handheld panning technique, you should be able to capture good sharp images of BIF at 1/500 to 1/1000. If you use aperture priority mode (Av), set your aperture at f8 and your iso at 400, then simply pan the first bird that comes by and take some pictures, noting shutter speed and exposure. If you use + EC to brighten the dark bird and maintain shutter speeds of 1/500 or better, you're good to go. If it drops below 1/500 bump up to iso 500 or 640 and go from there.

These settings have been my basic settings for BIF for the last five years or so: Av mode, evaluative metering, Ai servo focus with center focus point enabled, iso400, f8 (for an f5.6 max aperture lens), shutter speeds at or faster than 1/500, EC used as needed based on lighting and brightness of sky and bird, and iso negotiable upward if +EC is needed.

Sorry to be long-winded. I've been a hawk fan since boyhood. Easily my favorite class of birds to watch and photograph.

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Steve, thanks for taking the time to show me the ropes. After cleaning my lens and taking more pics, I still notice the spots on the upper left, so a sensor cleaning is indeed in order. I probably paniced seeing all those hawks and was just taking what the camera would let me take, plus the mosquitoes, gnats and no-see-ums were biting the bejesus out of me.

Mike