According to NorthLight Images, there are a few Canon EOS 1D MkIV in real test now. Their features would be:
- 1.3 crop
- Images ~16MP
- ISO 50-26500
- 8MP sRAW1 format providing images that seem to best 1D3 files in detail
- Very clean images at ISO 3200. 6400/12800 take further processing very well
- Slightly faster FPS than 1D3 in real life shooting
- AF greatly improved and very good in low light (actual comment was ‘Nikon fast’ 😉
- Liveview AF – not up to fast sports use, but very usable otherwise
- Video as with 5D2
- Screen as per 5D2
- Ergonomic improvements with grips – some buttons moved
- Feels faster and more responsive in nearly all aspects of real use.
Of course, this may be right or not. Canon may change the name and feature set, or not.