The Mark IV's live view system is essentially a second-generation implementation - Canon has given a little more thought to how the camera is going to be used and has created subtly different modes for stills and movie shooting. The whole thing still seems a bit tacked-on, but that's understandable since it's a feature that uses the LCD on a camera that has evolved to be used with your eye to the viewfinder.
For tripod-based studio work the stills mode is very good, allowing accurate manual focus and automatically increasing the brightness of the preview for work under modeling lights. You can also opt for exposure simulation mode (now in the main menu system rather than the custom menus), to let you preview the image brightness. This can be combined with luminance or separate RGB live histograms to give a precise indication of exposure.
Live view stills mode
Pressing the INFO button while in Live View toggles between the four available display modes, each with differing levels of overlaid information. Two styles of grid lines are available, as are a choice of luminance or RGB histograms.
|1: Just the contrast detection ('AF Live' mode) AF area visible. In phase detection ('AF Quick') mode, the AF point is shown as a small dark gray square with a landscape orientation white box showing the area for magnification.||2: Shooting information: Shutter Speed, Aperture, Exposure Comp, frames remaining, ISO and battery level are shown.|
|3: Additional information about shooting mode plus White Balance, Picture Style, file format, Auto Lighting Optimizer and AF type.||4: Full information plus live histogram. The choice between luminance and RGB histograms is made in the settings menu.|
|Also in the settings menu is the option to show one of two composition grids.||Here is the view with the thirds grid.|
|Many of the mode buttons bring up settings overlays, such as this one for ISO.||The AF/Drive button brings up this screen from which you can select AF point, AF mode and Drive mode.|
Live view movie mode
The movie shooting version of view view is very much like the one for stills shooting, with a choice over how much information is displayed. However, the perception that live view had been bolted on to a viewfinder-centric design is only reinforced by the way movie mode has been applied.
Movies can only be shot if you've set live view up to act in movie mode, making it impossible to quickly shoot a movie if you're in the wrong mode - oddly, this is rectified on the (slightly older) EOS 7D through the provision of a live view mode switch and dedicated movie record button. You can configure the FEL button to start both live view and movie recording but again you have to have movie record live view enabled.
|1: As with stills mode there's a 'no info' option though now there are overlaid 16:9 bars to show the active shooting area.||2: As per the stills mode: Shutter Speed, Aperture, Exposure Comp, frames remaining, ISO and battery level are shown.|
|3: Full shooting information including resolution and frame rate. (No histogram option, though).||Frame size and rate cannot be changed when in video live view itself - they're in the settings menu|
Live view magnification
Just as in playback mode you can magnify live view by pressing the enlarge button (or back out again with reduce). While magnified you can use the multi-controller to move around the live image.
Live view Depth-of-Field preview
One very useful feature in Live View is of course depth-of-field (DOF) preview, when the DOF preview button is pressed the camera stops the lens down to the selected (or metered) aperture which provides you with an accurate representation of the depth-of-field of the final image. As you can see from the images below this worked well in our test scene at F11 (though in very low light and with very small apertures you will see the image getting darker). Note that unless you have live view exposure simulation turned off the screen will go very dark when the lens is closed down significantly using depth of field preview.
|Normal Live View||DOF preview button held at F11|
Overall handling comments
It hardly makes sense to discuss the 1D Mark IV's handling as it's so obvious a product of careful refinement and extensive feedback. As a stills camera, it's supremely comfortable and easy to use quickly. Furthermore, 16 of its 62 custom functions are dedicated to fine-tuning the behavior of individual functions and buttons to ensure the camera works the way you'd like it to.
The only aspect of the camera's physical design that might present any real problem is that some shooters have found it's possible to accidentally press the second AF-ON button, on the portrait orientation grip, while shooting. Interestingly some of us experienced the same problem with Nikon's D3S (so it's clearly something quite hard to avoid from a design perspective). These secondary controls can be disabled if you find it is something that affects you but it's worth being aware of, especially if you've got it set to act as AF-Stop.
The other two issues that affected us were the sheer complexity of the camera's customization and its awkwardness as a movie shooting device. The complexity issue is addressed in greater depth in the AF section of the review - the AF setup is simply the most prominent example of a system that you'll get more out of if you learn about it in some depth first. Our concerns about movie mode stem from the fact that this shape of camera has evolved for a very different purpose and not one that envisaged anyone trying to hold the camera away from their body to use the LCD for composition. It's a big, heavy device designed to be held to the eye and that means holding it away from you, especially if you want to manually focus, is extremely cumbersome.
Ultimately, though, neither of these issues is a major problem (and only a sub-set of the users will be trying to shoot video) and, if anything, are only so apparent because the main shooting experience is so intuitive and well arranged.