Canon EOS 1D Mk IV

• Launched: October 2009
• Type: Digital SLR
• Sensor: APS-H, 27.9 x 18.6mm
• Resolution: 16 megapixels
• Lenses: Canon EF (not EF-S)
• Key features: 10fps continuous shooting, full HD movies
• Links: Press release, Product page

Summary: High-speed digital SLR for professionals. It has a unique sensor size mid-way between APS-C and full frame, which puts it at a slight disadvantage to the Nikon D3s, though the Nikon only shoots standard HD movies.

Nikon D3s

• Launched: October 2009
• Type: Digital SLR
• Sensor: Full frame 'FX' format, 36 x 23.9mm
• Resolution: 12.1 megapixels
• Lenses: Nikon F (FX, DX in 'crop' mode)
• Key features: 9fps continuous shooting, high ISO performance; standard HD movies
• Links: Press release, Product page

Summary: Second-generation version of Nikon's original full-frame D-SLR optimised for speed, with a 9fps continuous shooting speed (11fps in 'crop' mode) and a maximum ISO raised to 12800.