Guides · Updated 5 November 2026

Sony A6400 for bird photography: the numbers, worked out

What the Sony A6400 puts on a bird, worked out from its sensor and the lenses people pair with it: pixels across birds from chickadee to heron at 10, 25 and 50 m, how far you can crop and still meet iNaturalist and contest sizes, and how much the wingtips blur in flight.

Pixels on the bird at 10, 25 and 50 m

Pixels across the bird from beak to tail, using the bird lengths in our reach calculator (600 mm: FE 200-600mm G at 600 mm, or the FE 600mm GM · 800 mm: FE 400-800mm G at 800 mm):

“Won't fit” means the bird is longer than the frame is wide at that distance. The sum: the bird's length × focal length ÷ (distance − focal length) gives its size on the sensor, divided by the 3.9 µm pixel pitch. Same lens and distance on other bodies, in pixels per millimetre of sensor: Sony A6400 255, Canon EOS R7 312, Sony A7R VI 278, Sony A7R V 266, Sony A6700 266, Sony A1 II 241, Sony A1 241, Nikon Z8 230, Sony A7 IV 195, Sony A7 V 195, Sony A9 III 169, Canon EOS R6 Mark II 167.

Compare all Sony cameras for bird photography: every Sony body with a guide here, side by side on the same 600 mm lens.

Why the A6400's small pixels matter

On the same lens, reach comes down to how many pixels fit in each millimetre of sensor. The A6400 packs 255 pixels into each millimetre of its 23.5 mm-wide APS-C sensor; the full-frame Canon EOS R6 Mark II has 167. On the same lens, at the same distance, the A6400 puts 1.53 times as many pixels across the bird: 1,507 pixels across an American robin at 25 m with 600 mm, against 986 on the R6 Mark II.

How far you can crop and still meet real sizes

Nearly every size rule counts pixels on the long edge. Here is the smallest share of the A6400's 6,000-pixel width that a horizontal crop can keep for each, and how much of that crop an American robin at 25 m with 600 mm (1,507 px) would fill:

So with this robin you can crop until it fills 50% of the width and still have Audubon's 3,000 pixels. Crop tighter and the file drops below the size; enlarging it to reach the number adds no detail, and the contests that ask for full-size files say so (crop rules and minimum sizes for 11 contests). For the general case, see how much you can crop a bird photo. The rule that always holds: crop from the full-size original, never from a downsized export, and never upscale.

Birds in flight: wingtip blur at 1/2000 and 1/4000

From our shutter-speed calculator, with 600 mm, panning with the bird, wingtips measured mid-stroke where they move fastest:

Wingbeat rates for the osprey and bald eagle are estimates (est.), so treat these as close guides rather than exact figures. Holding the osprey's wingtips within 3 pixels at this distance would take about 1/12800; for the bald eagle, about 1/10000. The wings slow to a stop at the top and bottom of each stroke, which is why a burst catches sharp wingtips that a single frame usually misses.

Try it with your own lens and birds

The reach calculator and the shutter-speed calculator open pre-set to the A6400; change the lens, distance or bird to see your own numbers. Both run in the browser.

BirdFrame for Mac finds every bird in a folder or Photos album and crops each from the full-size original, thousands at once.

Questions

How many pixels does the Sony A6400 put on a bird?

It depends on the lens and the distance. With 600 mm, about 1,507 pixels across an American robin at 25 m and 744 at 50 m; with 800 mm, 2,026 and 996. The sum: the bird's length × focal length ÷ (distance − focal length), divided by the pixel pitch (3.9 µm).

How far can you crop an A6400 photo for iNaturalist or a contest?

A horizontal crop has to keep 34% of the frame's width to fill iNaturalist's 2,048 pixels, 50% for Audubon's 3,000-pixel entries and 58% for Australian Geographic's 3,500-pixel finalist files (2026 rules). Crop from the full-size original and never enlarge a crop to reach a size.

Does the A6400's APS-C sensor give more reach than a full-frame camera?

Yes, against a 24-megapixel full-frame body: the A6400 has 255 pixels per millimetre of sensor and the Canon EOS R6 Mark II 167, so on the same lens and distance the A6400 puts 1.53 times as many pixels across the bird. The 45-megapixel Nikon Z8 has 230, so the A6400's lead over it is 1.11 times.

What shutter speed freezes a bird in flight with the A6400?

With an osprey at about 65 m on 600 mm, wings across two thirds of the frame, the wingtips blur about 17 pixels at 1/2000 and 9 at 1/4000 mid-stroke when you pan with the bird. Holding them within 3 pixels would take about 1/12800, so a burst is what catches the wings sharp near the top or bottom of the stroke. Wingbeat rates for the osprey and bald eagle are estimates.