Polycarbonate bodies

• Nikon offers three models of DSLR with a lighter-weight, less durable polycarbonate body; all three use SD memory cards. The D3000 is Nikon's lowest level DSLR, retailing for $600 with an 18-55 lens. The D5000 is the next step up, retailing for $730, and has a 12-megapixel sensor (as opposed to the 10 on the D3000) and can shoot HD video. The D3000 and D5000 lack an in-body autofocus motor, so the only lenses that will autofocus are ones that have an autofocus motor. The D90 ($1,000) also has a 12-megapixel sensor and can shoot HD video, but has more external control buttons, including two control dials. It also has an in-body autofocus motor, so older Nikon lenses will autofocus on the D90.
  
  

D300S

• Announced in the fall of 2009, the D300S ($1,800) replaced the D300, which has been a popular body for many professional photographers. The 51-point autofocus system is incredibly quick, and the magnesium-alloy body is very durable and weather and dust resistant. The D300S can shoot HD video and shoot seven frames per second. The D300S uses the better quality Compact Flash memory cards, which are much faster than SD cards.
  
  

Full frame

• Nikon offers three models with a full frame sensor. A full frame sensor is the same size as 35 mm film, so there is no cropping of the image when a non-DX lens is used. The bigger pixels of a full frame sensor also equate to less noise. Nikon offers the D700 ($2,700), D3 ($4,000), and D3X ($8,000) full frame bodies. The D700 and D3 are very similar; both sport a 12-megapixel sensor and work well in low light, shooting cleanly up to ISO 6400. The D3 can shoot nine frames per second, the D700 five frames per second, though the addition of the optional MB-D10 battery grip, useful for vertical shooting, increases that speed to eight frames per second. The D3 has the grip feature built in, and also is rated for double the shutter life of the D700. The D3X has a 24.5-megapixel sensor, offering outstanding image quality. Both the D3 and D3X have dual Compact Flash memory card slots.