Canon first approached Live View with the EOS-1D Mark III, the EOS 40D's implementation provides live view of the scene with magnification up to 10x, optional overlays (such as histogram and gridlines) as well as optional 'mirror up' auto-focus, although no contrast-detect auto-focus as seen in the Nikon D300. I was a little annoyed that you have to manually release the AF-ON button to return to live view after auto--focus, surely a better implementation would be to simply return to live view once auto-focus had been locked (as implemented by Olympus and Panasonic).
Live View exposure simulation
You can optionally (via C.Fn IV-7) enable Live View exposure simulation mode where the Live View display will attempt to simulate the brightness of the final exposure. In this mode changes to exposure compensation or exposure (in manual mode) are simulated, but of course this may lead to the image being too dark or too bright to frame correctly.
Live view display modes
Pressing the INFO button while in Live View toggles between the four available display modes, each with differing levels of overlaid information. The final view shown below is the default view with optional 'thirds' gridlines enabled.
|1: Live view with magnification area indicated + status line showing shutter speed, aperture, flash compensation, exposure compensation, frames remaining and ISO sensitivity.||2: Live view with magnification area + status line + brief overlay (simulation mode, battery status, Picture Style, AE lock, flash-ready)|
|3: Live view with magnification area + status line+ overlay + live histogram||4: Live view with magnification area (and nothing else)|
|Optional gridlines overlay|
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. The 40D does appear to be able to go all the way to 1:1 magnification (one pixel on the sensor for one pixel on the LCD) which makes it easy to achieve perfect focus (it's worth noting that while magnified the camera applies higher sharpening than in the final image to assist focusing).
Live view Depth-of-Field preview, reaching the limit
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 wel in our test scene up at F11 but at F22 the reduction in light produced by this very small aperture was beyond the video capability of the Canon sensor. (I personally was a little surprised by this, it does appear that Canon don't boost the Live View signal and so in low light situations you can end up with an image too dark to see).
|Normal Live View||DOF preview button held at F11|
|DOF preview button held at F22|
Live view "silent shooting"
One interesting addition to the EOS 40D's Live View options is "silent shooting" where the noise made at the time of exposure is reduced by delaying (and/or slowing, it's not quite clear) the mirror / shutter return. When Disabled the camera is already quieter than in normal mode (the user manual says continuous shooting isn't available but we were able to use it), in Mode 1 the exposure sequence is slightly quieter and in Mode 2 it's quieter still as the shutter does not 're-cock' itself until the shutter release button is released (hence continuous shooting is not available).
To provide a better idea of just how "silent" these modes are we have provided audio clips of each of the Live View silent shooting modes below. In each recording the sequence of events is the same:
Enter live view -> take a shot -> wait (live view returns) -> continuous shooting -> Leave live view
Live view exposure, silent shooting: Disabled
Live view exposure, silent shooting: Mode 1
Live view exposure, silent shooting: Mode 2*
* In "Mode 2" continuous shooting isn't available and the delay between the exposure
and re-cock of the shutter depends on the photographer.
Live view sequence video clip
The following video clip shows live view in use, the sequence in this video was:
- Lens at infinity
- Press AF-ON button (view goes black) and release once focus is locked
- Magnify to 5x, move magnified area, magnify to 10x
- Return to full size live view
- Depth-of-field (DOF) preview
- Shutter release (take a shot) followed by two second record review
- Enter play mode and magnify image