Guides · Updated 4 November 2026
Kestrel photography: shutter speed, lens and crop for kestrels in flight
The numbers for photographing an American Kestrel or a Common Kestrel in flight, worked out from published wingspan, flight-speed and wingbeat figures: the shutter speed that freezes the wingtips and the body, how many pixels the spread wings fill with 400, 600 and 800 mm lenses at 10, 25 and 50 m, and how far away the bird can be for a 2,048-pixel image or an A4 print.
Short answer: pan with a kestrel in flight, or catch it hovering, and its body stays put in the frame, so the wingtips set the shutter speed. With the wings across two thirds of the frame on a Canon EOS R7 and 600 mm lens (an American Kestrel about 24 m away, a Common Kestrel about 32 m), 1/2000 leaves the wingtips about 34 px and 32 px of blur mid-stroke, and keeping them sharp on screen (3 px) takes about 1/25600 for either, beyond the 1/8000 top speed of most mechanical shutters. At 1/2000 a 20 fps burst still catches the wingtips within 3 px about once a second (1 frame in 18 for the American Kestrel, 1 in 17 for the Common Kestrel). Held still, the camera needs about 1/32000 to keep either kestrel's body within 3 px as it flies across; when one hovers, its body barely moves, so only the wingtips count. At 25 m with 600 mm, an American Kestrel's wings span 2,301 px on a 24-megapixel full-frame body and a Common Kestrel's 3,123 px.
Shutter speed for kestrels in flight
From our shutter-speed calculator with its default setup: a Canon EOS R7 (32.5 megapixels) and a 600 mm lens. You pan with the bird (or it hovers), so its body stays put in the frame and the blur that's left comes from the wings, each taken to sweep a 100° stroke at the bird's wingbeat rate, fastest mid-stroke. Blur is counted in the photo's own pixels at 100%: up to 3 pixels is sharp on screen, 1 pixel is pixel-sharp. The camera-still column is for a bird crossing in front of a camera that doesn't move, at its cruising speed.
| Canon EOS R7, 600 mm | Wingtip blur at 1/2000, panning | Wingtips sharp on screen (3 px) | Body sharp on screen, camera still (3 px) | Frames with the wingtips within 3 px at 1/2000 |
|---|---|---|---|---|
| American Kestrel: wings across two thirds of the frame, about 24 m | 34 px | 1/25600 | 1/32000 | about 1 in 18 |
| American Kestrel: wings across a third of the frame, about 46 m | 17 px | 1/12800 | 1/16000 | about 1 in 9 |
| Common Kestrel: wings across two thirds of the frame, about 32 m | 32 px | 1/25600 | 1/32000 | about 1 in 17 |
| Common Kestrel: wings across a third of the frame, about 63 m | 16 px | 1/12800 | 1/16000 | about 1 in 8 |
Both kestrels' wingbeat rates and the American Kestrel's cruising speed are estimates (sources below), so treat these as close guides rather than exact figures. Holding the wingtips pixel-sharp (1 px) with the wings across two thirds of the frame would take about 1/68,000 for the American Kestrel and about 1/65,000 for the Common Kestrel. The wings stop for an instant at the top and bottom of each stroke, which is why a burst catches sharp wingtips that a single frame usually misses. Stepping back until the wings span a third of the frame halves the blur; crop in afterwards.
Pixels across the wings with 400, 600 and 800 mm
Pixels across the spread wings at 10, 25 and 50 m, from our reach calculator, on a 24-megapixel full-frame Canon EOS R6 Mark II, a 45.7-megapixel full-frame Nikon Z8 and the 32.5-megapixel APS-C Canon EOS R7:
American Kestrel (0.56 m wingspan)
| Distance | Lens | Canon EOS R6 Mark II | Nikon Z8 | Canon EOS R7 |
|---|---|---|---|---|
| 10 m | 400 mm | 3,900 px | 5,366 px | won't fit |
| 10 m | 600 mm | 5,974 px | 8,220 px | won't fit |
| 10 m | 800 mm | won't fit | won't fit | won't fit |
| 25 m | 400 mm | 1,522 px | 2,094 px | 2,842 px |
| 25 m | 600 mm | 2,301 px | 3,167 px | 4,298 px |
| 25 m | 800 mm | 3,094 px | 4,257 px | 5,778 px |
| 50 m | 400 mm | 755 px | 1,039 px | 1,410 px |
| 50 m | 600 mm | 1,137 px | 1,564 px | 2,123 px |
| 50 m | 800 mm | 1,522 px | 2,094 px | 2,842 px |
Common Kestrel (0.76 m wingspan)
| Distance | Lens | Canon EOS R6 Mark II | Nikon Z8 | Canon EOS R7 |
|---|---|---|---|---|
| 10 m | 400 mm | 5,292 px | 7,282 px | won't fit |
| 10 m | 600 mm | won't fit | won't fit | won't fit |
| 10 m | 800 mm | won't fit | won't fit | won't fit |
| 25 m | 400 mm | 2,065 px | 2,842 px | 3,857 px |
| 25 m | 600 mm | 3,123 px | 4,298 px | 5,833 px |
| 25 m | 800 mm | 4,199 px | 5,778 px | won't fit |
| 50 m | 400 mm | 1,024 px | 1,410 px | 1,913 px |
| 50 m | 600 mm | 1,543 px | 2,123 px | 2,881 px |
| 50 m | 800 mm | 2,065 px | 2,842 px | 3,857 px |
“Won't fit” means the wings are wider than the frame at that distance. The sum: wingspan × focal length ÷ (distance − focal length) gives the wings' size on the sensor, divided by the pixel pitch (5.98 µm on the R6 Mark II, 4.35 µm on the Z8 and 3.20 µm on the R7). Halve the distance and the pixels roughly double.
How far can you crop?
Most size rules count pixels on the long edge. An image 2,048 pixels wide can come from as little as 35% of the R6 Mark II's 6,000-pixel width, 25% of the Z8's 8,256-pixel width and 30% of the R7's 6,960-pixel width. A landscape A4 print at 300 ppi (29.7 × 21 cm) needs 3,508 × 2,480 pixels: 59% of the width and 62% of the height on the R6 Mark II, 43% of the width and 46% of the height on the Z8 and 51% of the width and 54% of the height on the R7.
Framed the way the reach calculator frames a crop, with the wings across half its width, here is how far away the kestrels can be and still give you each size, cut from the full-size original with nothing enlarged:
American Kestrel
| Camera and lens | Image 2,048 px wide | A4 print at 300 ppi |
|---|---|---|
| Canon EOS R6 Mark II, 400 mm | up to 36 m | up to 20 m |
| Canon EOS R6 Mark II, 600 mm | up to 55 m | up to 30 m |
| Canon EOS R6 Mark II, 800 mm | up to 73 m | up to 41 m |
| Nikon Z8, 400 mm | up to 50 m | up to 28 m |
| Nikon Z8, 600 mm | up to 76 m | up to 42 m |
| Nikon Z8, 800 mm | up to 100 m | up to 56 m |
| Canon EOS R7, 400 mm | up to 68 m | up to 37 m |
| Canon EOS R7, 600 mm | up to 100 m | up to 56 m |
| Canon EOS R7, 800 mm | up to 130 m | up to 75 m |
Common Kestrel
| Camera and lens | Image 2,048 px wide | A4 print at 300 ppi |
|---|---|---|
| Canon EOS R6 Mark II, 400 mm | up to 50 m | up to 27 m |
| Canon EOS R6 Mark II, 600 mm | up to 75 m | up to 41 m |
| Canon EOS R6 Mark II, 800 mm | up to 100 m | up to 55 m |
| Nikon Z8, 400 mm | up to 68 m | up to 37 m |
| Nikon Z8, 600 mm | up to 100 m | up to 56 m |
| Nikon Z8, 800 mm | up to 130 m | up to 75 m |
| Canon EOS R7, 400 mm | up to 93 m | up to 51 m |
| Canon EOS R7, 600 mm | up to 130 m | up to 77 m |
| Canon EOS R7, 800 mm | up to 180 m | up to 100 m |
With the American Kestrel's wings across a third of the R7's frame (about 46 m at 600 mm), a crop with the wings across half its width is 4,620 × 3,080 pixels, a 39.1 × 26.1 cm print at 300 ppi. With the Common Kestrel's wings across a third of the R7's frame (about 63 m at 600 mm), a crop with the wings across half its width is 4,562 × 3,041 pixels, a 38.6 × 25.7 cm print at 300 ppi. These distances count pixels only; at long range, heat haze and focus cost detail too. Crop from the full-size original, never from a downsized export, and never enlarge a crop to reach a size (how much you can crop a bird photo).
Try it with your own camera
The shutter-speed calculator opens set to the American Kestrel, and the reach calculator to its wingspan; change the camera, lens or distance to see your own numbers. Guides for the bodies above: Canon EOS R6 Mark II, Nikon Z8 and Canon EOS R7. To see how a crop looks on one of your own photos, try the free online cropper.
BirdFrame for Mac finds every bird in a folder or Photos album and crops each from the full-size original, thousands at once, so a day of bursts doesn't mean cropping by hand.
Sources
American Kestrel: wingspan 0.56 m (All About Birds); cruising speed 11 m/s (est. from the Lesser Kestrel, Bruderer & Boldt 2001 radar data, in Alerstam et al. 2007, Protocol S1); 5.5 wingbeats a second (est. from the size and weight of the Lesser Kestrel, Pennycuick 1996). Common Kestrel: wingspan 0.76 m (RSPB); cruising speed 13 m/s (Pennycuick et al. 2013); 5.2 wingbeats a second (est. from size and weight, Pennycuick 1996).
Camera sensor sizes and pixel counts are the makers' published specifications. Every bird is taken to beat its wings through a 100° stroke (est.; 80–130° depending on speed, Park et al. 2001). Values marked est. are estimates.
Questions
What shutter speed freezes a kestrel in flight?
Pan with a kestrel in flight, or catch it hovering, and its body stays put in the frame, so the wingtips set the shutter speed. With the wings across two thirds of the frame on a Canon EOS R7 and 600 mm lens (an American Kestrel about 24 m away, a Common Kestrel about 32 m), 1/2000 leaves the wingtips about 34 px and 32 px of blur mid-stroke, and keeping them sharp on screen (3 px) takes about 1/25600 for either, beyond the 1/8000 top speed of most mechanical shutters. At 1/2000 a 20 fps burst still catches the wingtips within 3 px about once a second (1 frame in 18 for the American Kestrel, 1 in 17 for the Common Kestrel). Held still, the camera needs about 1/32000 to keep either kestrel's body within 3 px as it flies across; when one hovers, its body barely moves, so only the wingtips count.
How many pixels does a kestrel fill with a 400, 600 or 800 mm lens?
American Kestrel (0.56 m wingspan), at 25 m on a 24-megapixel full-frame body: 1,522 px with 400 mm, 2,301 px with 600 mm and 3,094 px with 800 mm. Common Kestrel (0.76 m wingspan), at 25 m on a 24-megapixel full-frame body: 2,065 px with 400 mm, 3,123 px with 600 mm and 4,199 px with 800 mm. Halve the distance and the pixels roughly double.
How far away can a kestrel be for a 2,048-pixel image or an A4 print?
With the wings across half the crop's width, as the reach calculator frames it, and 600 mm on a 24-megapixel full-frame body: American Kestrel up to about 55 m for a 2,048-pixel-wide image and 30 m for an A4 print at 300 ppi; Common Kestrel up to about 75 m for a 2,048-pixel-wide image and 41 m for an A4 print at 300 ppi. Crop from the full-size original and never enlarge a crop to reach a size.
Crop every bird in one go, at full resolution. BirdFrame finds the birds in a whole album or folder and crops each one from the full-size original. Free for up to 50 photos per run.