Nikon D3s vs Sony Alpha 900 — Which Is Better?

The Nikon D3s and the Sony Alpha 900 are full-frame DSLRs from neighbouring generations, with the D3s arriving in 2009 and the Alpha 900 in 2008. Each has an optical pentaprism viewfinder, so both frame shots through traditional DSLR glass. Their lens systems differ: the D3s uses the Nikon F FX mount, while the Alpha 900 uses the Sony Alpha mount, and lenses do not interchange between them.

The Alpha 900 is the lighter and more compact body, measuring 156 x 117 x 82 mm and weighing 895 g, so it takes less space in a camera bag. The D3s is larger at 160 x 157 x 88 mm and heavier at 1240 g.

The Alpha 900 is the stronger choice when detail matters most, because its 24.6 megapixel sensor carries roughly twice the pixels of the D3s's 12.1 megapixel sensor. Landscape and studio photographers gain more room to crop a distant subject or make large prints. Both use full-frame CMOS sensors with a base sensitivity of 200 ISO.

The D3s leads for moving subjects. It offers 11 frames per second against 5, and 51 autofocus points against 9, which helps track erratic motion. Its standard range reaches 12800 ISO, while the Alpha 900 stops at 3200 ISO, and expanded settings stretch to 102400 and 6400 ISO respectively. The Alpha 900 adds in-body stabilisation, steadying handheld shots with any mounted lens.

Neither camera records video, so moving-image work with either body is limited to stills sequences. The D3s offers one tool the Alpha 900 lacks: built-in timelapse support, useful for capturing changing light such as sunsets or star trails as a series of frames for later assembly.

The Alpha 900 has a flip screen for low-angle and overhead shooting, a control the fixed screen on the D3s cannot match. The D3s answers with live view, letting you compose on the 3-inch LCD for tripod work such as precise product or macro framing.

Both bodies are weather sealed and support external flash units, and neither offers GPS, Wi-Fi or Bluetooth. Their screens are both 3-inch LCDs with dot counts nearly identical at about 921000, a 600-dot difference that is imperceptible on the rear panel.

The D3s holds the far larger rated battery life, at 4200 shots against 880 for the Alpha 900. For long days of shooting away from a charger, that rating favours the Nikon and its EN-EL4a battery.

Both cameras take dual memory cards. The D3s accepts CompactFlash Type I with UDMA, while the Alpha 900 accepts CompactFlash Type I or II plus Memory Stick Duo cards, giving Sony shooters a second card format. Neither body charges over USB, so spare batteries matter for both.