Canon 1D Mark IV is the fifth incarnation of the professional Canon range. With the launch of the Nikon D3s there was much speculation and excitement about this release from Canon. The MKIII was plagued with auto focusing problems and this release from Canon has been highly anticipated.

The Canon 1D Mark IV body has been built out of a light weight magnesium alloy body. Canon has also put a significant amount of time ensuring that the body of Canon 1D Mark IV is weather and dust proof, including a whopping 76 separate environmental gaskets and seals into the design. Included in this design is the integrated cleaning system from the predecessor. The cleaning system uses ultrasonic vibrations to shake lose any small particles on the sensor. If there is a particularly bad issue with dust particles, the Canon 1D Mark IV can map the locations to process removing any distortions automatically or manually using the digital professional software that comes in the box. The dust removal is triggered automatically when powering up the Canon 1D Mark IV, but if you need to stop it, hitting the shutter buttons works. This automatic sensor cleaning can be switched off if you decide to. All of these innovations do make the MK IV a tiny bit heavier than its predecessor.

As with the previous model the Canon 1D Mark IV has been designed, despite its slightly cumbersome weight, to be ergonomic and is equally comfortable to operate in both landscape and portrait modes. This means that the controls and buttons are easily accessible whichever way you are shooting. In fact the biggest difference cosmetically between the MKIII and the MKIV is the fact that there is a small built in microphone grill to complement the high definition video shooting.

The Canon 1D Mark IV boasts a 16.1-megapixel APS-H-sized CMOS sensor with gapless micro lenses. Canon has equipped this beast with dual DIGIC IV processors, which means that the MKIV can certainly keep up with its 10 frames per second shooting in burst mode – it is incredible to see it in action. If you are a sports photographer, you have no choice but to upgrade to this model. However, if your main concentration is landscape or portraiture, perhaps considering the 5D is a better move.

The 3 inch LCD display is beautiful with all 920 000 pixels of clarity and makes reviewing your shots and working in Live View a treat. The images have a native 3:2 aspect ratio and you are looking at resolutions of 4,896 x 3,264 pixels in both JPEG and 14-bit CR2 Raw formats. The noise levels in RAW data from the Canon 1D Mark IV are much improved form its predecessor at the same levels.

As with most of Canon's releases, the MKIV also now includes high definition video capturing mode. The shooting modes for video are as follows:

• 1920x1080@30/25/24
• 1280x720@60/50
• 640x480@60/50

The Canon 1D Mark IV has kept the video capturing very similar to the very popular EOS 7D, and provides for capturing movie clips of up to 4gb. I believe that the range of frame rate options are to ensure that the captured video can match broadcast television formats as well as online video and therefore removing the need to fiddle too much with the output frame rate. Many professional videographers have taken to using these DSLR's as their second video cameras because of the clarity and creativity available to them.

The Canon 1D MKIV movies include audio built in to the updated design, but the quality of sound reproduction is not great. Cleverly though they have included the ability to add an external microphone which negates this issue. There is also, thankfully, an HDMI-out port on the MKIV.

The video capture mode gives you options to control most of the functions manually or automatically. For example you can allow the MKIV to choose the appropriate ISO range automatically while shooting after you have set the aperture. The Canon 1D Mark IV also allows for very limited video editing in camera, but it is fairly simplistic. And, as with the 5D MKII you are able to capture still in video mode by pressing the shutter button which allows the video capture to continue, but captures a still simultaneously.

The focusing remains as with all the other models in the Canon range, manual. And as with most DSLR's with built in high definition video, if you pan too fast with the machine, you get an awful sway in the image.

Canon has also included dual card slots, which, considering the additional video functionality is a fairly clever innovation. The Canon 1D Mark IV can now accommodate both SD and CF cards. However if that was the only reason I was purchasing the camera, the price would certainly make me think twice.

The ISO on the MKIV has been expanded to a low of 50 and a high of an insane 102 400. Yes – you read that right. 102 400. However, having bragged about that the noise at that ISO makes the images look as though they have been taken with a mobile phone camera. So even though you have the functionality, it doesn't mean you should be using it.

Auto focusing – whilst the MKIII was plagued with auto focusing issues Canon has certainly put in place great development and improvements on this aspect. The total number of focusing points stays the same as the MKIII but the cross type points have been boosted to at least 39 from 19. These cross points are high precision and are f2.8 compatible. In addition to this all 45 points are now user selectable.

One of my favourite Canon innovations over the past few years has been Live View. The Canon 1D Mark IV offers live view shooting with some interesting improvements to make this function even more useful. The higher resolution LCD screen and changed focussing capabilities of the MKIV including three auto focusing options make significant sense to this model.

There is now Live Mode auto focus which allows contrast detection without interrupting Live View. The second is Face Detection Live Mode, which detects and focuses on human faces. The third mode is Quick Mode Auto Focus which allows the mirror to drop to allow for Auto Focus to be completed, but it does momentarily disrupt the live view streaming during Auto Focus.  The overlaid grid lines are also present in the MKIV in Live View and there is a great depth of field preview as well.

Overall the Canon 1D Mark IV is an incredible piece of machinery. However, I believe that the price tag attached to it makes it not entirely an obvious choice. The Nikon D3s, the closest competitor to this Digital Camera certainly beat Canon at high ISO shooting, but this camera is great for sport and action photographers who need a versatile body