Nikon has leaked the specifications of the Nikon D300s. This has already sparked off a debate and it is not confirmed by Nikon that these are the specs. You might wonder what sets the Nikon D300s from the Nikon D300. It is the video shooting capability. Comparisons can go on and people already wedded to a camera may not be wanting to upgrade for many subjective reasons. But there are already competitors in the market like the Canon EOS 5D mark II. This model is likely to hit the market in August and the update of Nikon D300 is set to enter the market only in 2010. 
It is clear that Nikon D300s is aimed at those who are planning to buy a D300 and is also a competitor for the Canon EOS 5D Mk II. Some may complain that it does not have as many mega pixels and some complain that it has video capability at all. The performance of a Nikon is always competitive even with a Canon whether it is ISO sensitivity, noise reduction and image processing speed not to talk of the increase in the memory buffer.
Those who are interested can wait for July to pass( for the rumour to become a confirmation).
Specification credits : http://nikonrumours.com/2009/5/28
Image sensor
Image sensor 23.6 x 15.8 mm CMOS sensor
Total pixels 13.1 million
Dust-reduction system Image Sensor Cleaning, Image Dust Off reference data (requires optional Capture NX 2 software)
Storage
Image size (pixels) 4,288 x 2,848 [L], 3,216 x 2,136 [M], 2,144 x 1,424 [S]
File format NEF (RAW): 12 or 14 bit, lossless compressed, compressed, or uncompressed
TIFF (RGB)
JPEG: JPEG-Baseline compliant with fine (approx. 1:4), normal (approx. 1:8) or basic (approx. 1:16) compression (Size priority); Optimal quality compression available
NEF (RAW) + JPEG: Single photograph recorded in both NEF (RAW) and JPEG formats
Picture Control System Can be selected from Standard, Neutral, Vivid, Monochrome; storage for up to nine custom Picture Controls
Media Type I CompactFlash memory cards (UDMA compliant); SD memory cards, SDHC compliant
Dual card slots Either card can be used as the primary card; secondary card can be used for overflow or backup storage, or for separate storage of NEF (RAW) and JPEG images; images can be copied between cards
File system DCF (Design Rule for Camera File System) 2.0, DPOF (Digital Print Order Format), Exif 2.21 (Exchangeable Image File Format for Digital Still Cameras), PictBridge
Viewfinder
Viewfinder Eye-level pentaprism single-lens reflex viewfinder
Frame coverage Approx. 100% horizontal and 100% vertical
Magnification Approx. 0.94 x (50mm f/1.4 lens at infinity; -1.0 m-1)
Eyepoint 19.5 mm (-1.0 m-1)
Diopter adjustment -2 to +1 m-1
Focusing screen Type B BriteView Clear Matte screen Mark II screen with AF area brackets (framing grid can be displayed)
Reflex mirror Quick return
Depth-of-field preview When depth-of-field preview button is pressed, lens aperture is stopped down to value selected by user (A and M modes) or by camera (P and S modes)
Lens aperture Instant return, electronically controlled
Lens
Compatible lenses DX NIKKOR: All functions supported
Type G or D AF NIKKOR: All functions supported (PC Micro-NIKKOR does not support some functions); IX NIKKOR lenses not supported
Other AF NIKKOR: All functions supported except 3D color matrix metering II; lenses for F3AF not supported
AI-P NIKKOR: All functions supported except 3D color matrix metering II
Non-CPU: Can be used in exposure modes A and M; color matrix metering and aperture value display supported if user provides lens data (AI lenses only)
Electronic rangefinder can be used if maximum aperture is f/5.6 or faster
Shutter
Type Electronically-controlled vertical-travel focal-plane shutter
Speed 1/8,000 to 30 s in steps of 1/3, 1/2 or 1 EV, bulb, X250
Flash sync speed X = 1/250 s; synchronizes with shutter at 1/320 s or slower (flash range drops at speeds between 1/250 and 1/320 s)
Release
Release mode S (single frame), CL (continuous low speed), CH (continuous high speed), Q (quiet shutter-release), mark (self-timer), MUP (mirror up)
Frame advance rate With Rechargeable Li-ion Battery EN-EL3e: Approx. 1 to 7 fps (CL), Approx. 7 fps (CH)
With optional Multi-Power Battery Pack MB-D10 and Rechargeable Li-ion Battery EN-EL4a: Approx. 1 to 7 (CL), Approx. 8 fps (CH)*
Self-timer Can be selected from 2, 5, 10 and 20 s duration
Exposure
Metering TTL exposure metering using 1,005-pixel RGB sensor
Metering method Matrix: 3D color matrix metering II (type G and D lenses); color matrix metering II (other CPU lenses); color matrix metering available with non-CPU lenses if user provides lens data
Center-weighted: Weight of 75% given to 8-mm circle in center of frame. Diameter of circle can be changed to 6, 10 or 13-mm, or weighting can be based on average of entire frame (fixed at 8 mm when non-CPU lens is used)
Spot: Meters 3-mm circle (about 2% of frame) centered on selected focus point (on center focus point when non-CPU lens is used)
Range (ISO 100 equivalent, f/1.4 lens, 20°C/68°F)
Matrix or center-weighted metering: 0-20 EV
Spot metering: 2-20 EV
Exposure meter coupling Combined CPU and AI
Exposure modes Programmed auto with flexible program (P); shutter-priority auto (S); aperture priority auto (A); manual (M)
Exposure compensation -5 to +5 EV in increments of 1/3, 1/2 or 1 EV
Exposure bracketing 2 to 9 frames in steps of 1/3, 1/2, 2/3 or 1 EV
Exposure lock Luminosity locked at detected value with AE-L/AF-L button
ISO sensitivity (Recommended Exposure Index)
ISO 200 to 3200 in steps of 1/3, 1/2 or 1 EV; can also be set to approx. 0.3, 0.5, 0.7 or 1 EV (ISO 100 equivalent) below ISO 200 or to approx. 0.3, 0.5, 0.7 or 1 EV (ISO 6400 equivalent) above ISO 3200
Active D-Lighting Can be selected from auto, extra high, high, normal, low or off
ADL bracketing 2 to 5 frames with strength levels varying according to number of frames chosen; for 2 frames, off and a chosen level are applied
Focus
Autofocus Nikon Multi-CAM 3500DX autofocus sensor module with TTL phase detection, fine-tuning, 51 focus points (including 15 cross-type sensors) and AF-assist illuminator (range approx. 0.5 to 3 m/1 ft. 8 in. to 9 ft. 10 in.)
Detection range -1 to +19 EV (ISO 100 equivalent, 20°C /68°F)
Lens servo Autofocus: Single-servo AF (S); continuous-servo AF (C); predictive focus tracking automatically activated according to subject status in single- and continuous-servo AF
Manual (M): Electronic rangefinder supported
Focus point Can be selected from 51 or 11 focus points
AF-area mode Single-point AF, dynamic-area AF, auto-area AF
Focus lock Focus can be locked by pressing shutter-release button halfway (Single-servo AF) or by pressing AE-L/AF-L button
Flash
Built-in flash Manual pop-up with button release and a Guide Number of 17/56 (m/ft., ISO 200, 20 °C/68 °F; GN at ISO 100 equivalent is 12/39)
Flash control TTL: i-TTL balanced fill-flash and standard i-TTL flash for digital SLR using 1,005-pixel RGB sensor are available with built-in flash, Speedlight SB-900, SB-800, SB-600 or SB-400
Auto aperture: Available with Speedlight SB-900 or SB-800 and CPU lens
Non-TTL auto: Supported flash units include Speedlight SB-900, SB-800, SB-28, SB-27 and SB-22S
Range-priority manual: Available with Speedlight SB-900 and SB-800
Flash modes Front curtain sync, slow sync, rear-curtain sync, red-eye reduction, red-eye reduction with slow sync
Flash compensation -3 to +1 EV in increments of 1/3, 1/2 or 1 EV
Flash bracketing 2 to 9 frames in steps of 1/3, 1/2, 2/3 or 1 EV
Flash-ready indicator Lights when built-in flash or flash unit such as Speedlight SB-900, SB-800, SB-600, SB-400, SB-80DX, SB-28DX or SB-50DX is fully charged; blinks after flash is fired at full output
Accessory shoe ISO 518 hot-shoe with sync and data contacts and safety lock
Nikon Creative Lighting System (CLS)
Advanced Wireless Lighting supported with built-in flash, Speedlight SB-900, SB-800 or SU-800 as commander and SB-900, SB-800, SB-600 or SB-R200 as remotes; Auto FP High-Speed Sync and modeling illumination supported with all CLS-compatible flash units except SB-400; Flash Color Information Communication and FV lock supported with all CLS-compatible flash units
Sync terminal ISO 519 sync terminal with locking thread
White balance
White balance Auto (TTL white-balance with main image sensor and 1,005-pixel RGB sensor), Incandescent, Fluorescent (7 options), Direct Sunlight, Flash, Cloudy, Shade, preset manual (able to store up to 5 values) and color temperature setting (2,500K to 10,000K); fine-tuning available for all options
White balance bracketing 2 to 9 frames in steps of 1, 2 or 3
Live View
Modes Tripod, Hand-held,
Autofocus Tripod: Contrast-detect AF anywhere in frame
Hand-held: Phase-detection AF with 51 focus points (including 15 cross-type sensors)
Movie
Frame size (pixels) 1,280 x 720/24 fps, 640 x 424/24 fps, 320 x 216/24 fps
File format AVI
Compression format Motion-JPEG
Autofocus Contrast-detect AF on a desired point within a frame is possible (Tripod mode)
Audio Sound can be recorded via built-in or optional external microphone; sensitivity can be adjusted
Maximum length 5 min (1,280 x 720 pixels), 20 min (640 x 424, 320 x 216 pixels)
Monitor
LCD monitor 3-in., approx. 920k-dot (VGA), low-temperature polysilicon TFT LCD with 170° viewing angle, approx. 100% frame coverage, and brightness adjustment
Playback
Playback function Full-frame and thumbnail (4, 9 or 72 images) playback with playback zoom, movie playback, slide show, histogram display, highlights, auto image rotation, and image comment (up to 36 characters)
Interface
USB Hi-Speed USB
Audio video output Can be selected from NTSC and PAL
HDMI output Type C HDMI connector; camera monitor turns off when HDMI cable is connected
Audio input Stereo mini-pin jack (3.5mm diameter)
10-pin remote terminal Can be used to connect optional remote control, GPS Unit GP-1 or GPS device compliant with NMEA0183 version 2.01 or 3.01 (requires optional GPS Cable MC-35 and cable with D-sub 9-pin connector)
Supported languages
Supported languages Chinese (Simplified and Traditional), Danish, Dutch, English, Finnish, French, German, Italian, Japanese, Korean, Norwegian, Polish, Portuguese, Russian, Spanish, Swedish
Power source
Battery One Rechargeable Li-ion Battery EN-EL3e
Battery pack Optional Multi-Power Battery Pack MB-D10 with one Rechargeable Li-ion Battery EN-EL3e, EN-EL4a/EN-EL4 or eight R6/AA-size alkaline, Ni-MH, lithium or nickel-manganese batteries; Rechargeable Li-ion Battery EN-EL4a/EN-EL4 and R6/AA-size batteries available separately; Battery Chamber Cover BL-3 (available separately) required when using Rechargeable Li-ion Battery EN-EL4a/EN-EL4
AC adapter AC Adapter EH-5a/EH-5 (available separately)
Tripod socket
Tripod socket 1/4 in. (ISO 1222)
Dimensions/Weight
Dimensions (W x H x D) Approx. 147 x 114 x 74 mm/5.8 x 4.5 x 2.9 in.
Weight Approx. 840 g/1 lb. 14 oz. without battery, memory card, body cap or monitor cover
Operating environment
Temperature 0-40°C/32-104°F
Humidity Less than 85% (no condensation)
Accessories
Supplied accessories (may differ by country or area)
Rechargeable Li-ion Battery EN-EL3e, Quick Charger MH-18a, Eyepiece Cap DK-5, Rubber Eyecup DK-23, USB Cable UC-E4, Audio Video Cable EG-D2, Camera Strap AN-DC4, LCD Monitor Cover BM-8, Body Cap BF-1A, Accessory Shoe Cover BS-1, Software Suite CD-ROM
* With a battery other than Rechargeable Li-ion Battery EN-EL4a, the continuous shooting speed may be slower than 8 fps in continuous high speed mode.
