The Nikon D300s and Canon 7D compared

The Nikon D300s is a digital camera aimed at semi-professionals or serious amateurs, while the Canon EOS 7D is specifically targeted at professional photographers and semi-pros. Both are in a similar league and carry a similar price tag. However, even some ardent Nikon enthusiasts will admit that the Canon 7D has the edge, with its 18 megapixel CMOS sensor that offers superb resolution. By contrast, the Nikon D300s has a 12.3 megapixel CMOS image sensor.
Both these cameras are digital single lens reflex cameras – also called DSLRs – which have interchangeable lenses. And both are good!

What the Nikon D300s has to offer
Launched in July 2009, the Nikon D300s camera was heralded as the best semi-professional digital SLR camera of its time. It boasts some of the best features of previous digital Nikon cameras, including the virtual horizon from the D3, movies that were made possible by the D90, and the "quiet" drive mode launched on the D5000. But there is so much more, including an autofocus (AF) function that allows you to detect contrast while in movie mode. No other Nikon digital camera prior to the D300s was able to do this.
This camera has a non-latched memory card opening that was launched with the D700, but with both CF and SD slots which offers amazing flexibility. The idea is that you use one card after the other, for instance writing backups to the second card after saving the photo files; saving RAW files to one and JPEGs to the other; using one for stills and the other for videos, and so on.
Like the D700 which came before, it also has a multi-controller with a separate button in the centre that you use to start recording movies in live view. This is, in any case, now a standard feature of Nikon digital cameras.
The settings display screen of the Nikon D300s is better than the older D300 (which was launched in 2007). Like most other DSLRs of this era, the screen is interactive and so most of the shoot settings can be changed really quickly. It also more lighting options than the old D300.

What the Canon 7D has to offer
The Canon EOS 7D's 18 MP sensor  (which Canon calls its "Intelligent View finder" ) is one of the best things about it, largely due to the new technology it represents. It offers 1.0X magnification and 100% coverage which its predecessor, the EOS 50D didn't offer (that model has only 0.95X magnification and 95% coverage). But this isn't its only great feature.
Launched in 2009, several months after the Nikon D300s, Canon's 7D introduced a new, improved auto-focus system that has a dedicated dual DIGIC 4 processor as well as a different shutter mechanism that enables an unbelievably good 8 fps (frames per second) burst mode. There are lots of rave reviews about this feature.
It also has a then "new" metering system with a 63-zone dual-layer system that gives the user focus and color information to ensure accurate exposure of pictures even when the lighting is difficult or bad. Its built-in flash gun may also be used to control external flash guns.

What the Nikon D300s and the Canon 7D have in common
For starters, both these cameras are dust and weather resistant. In spite of their megapixel differences, both cameras have image sensors that deliver stunning resolution. These sensors are also both what the industry terms "self cleaning". Their LCD (liquid crystal display) screens are also the same size – 3 inches – and both offer 100% viewfinder accuracy and 920,000 dots.
Both have the ability to record outstanding high definition (HD) movies or videos.
Other features are similar, but promoted in different ways by the respective manufacturers.

How the Nikon D300s and the Canon 7D differ
Megapixels probably top this list. The Nikon scores 12.3 alongside the Canon's 18 MP. 
Next comes the fact that the Nikon D300s offers a 720p HD video. Prepared to be excited by the 1080p HD video offered by the Canon 7D – and it works with manual controls. In fact the high definition video feature is one of this camera's major selling points.
The Canon has high sensitivity (ISO 12800 – ideal for low light situations where you don't want to use flash) and offers speeds of up to 6400. The Nikon's ISO range is only 200-3200, although it can be extended up to the equivalent of ISO 6400 and down to the equivalent of ISO 100.
The Canon is manufactured with a 19-AF system (all cross-type with the centre point offering f/2.8 and f/5.6 sensors), while the Nikon boasts 51 AF points with 3D tracking.
With the Canon you can shoot 18 MP 14-bit images as 8 fps as standard, in a burst of up to 126 large JPEGs. The Nikon, on the other hand, allows 7 fps continuous shooting, although you can upgrade to 8 fps if you use the optional MB-D10 battery pack.
If you haven't decided which brand you prefer, the choice between these two cameras is not going to be an easy one.