Pre-PMA 2008: We've had a little more time to really dig around in the new features of Canon's latest baby DSLR, the 450D (Digital Rebel XSi). Many of its new features have been passed down from the semi-pro-level EOS 40D, meaning the 450D promises to put a lot of power in your hand for a very reasonable sum. Here are some further details about the features it offers over the 400D / XTi.

Canon 450D / XSi: What's new and changed

In our brief hands-on look at the Canon 450D we highlighted the new features the 450D offers over the 400D. We've now had a bit more of a look through them so that we can bring you some more details and respond to the questions we're seeing asked.

12 megapixel CMOS sensor
The 450D features a new, 12.4 megapixel sensor. It has 12.2 million effective pixels. Further down the line, the A/D converter is capable of relaying 14 bit information to the camera's image processor or as a 14-bit RAW file. This should, in theory at least, offer smoother gradation steps in the final images.

SD / SDHC Card
This is also the first entry-level Canon DSLR to use the Secure Digital format. It's a popular format with the compact digital camera owners Canon will be hoping to lure into DSLR ownership. SDHC is now available in similar sizes and speeds to the CF format used by the 300D, 350D and 400D.

Larger viewfinder
A big step forwards for Canon's entry-level DSLR is the larger viewfinder. It's unlikely to be as bright as the ones found in Canon's XXD models because it uses mirrors, rather than a glass prism but in terms of magnification (size), it's almost on a par with the 30D which was a considerably more expensive camera. It's unusual to see viewfinder specs mentioned when comparing DSLRs but they can make a really big difference to usability.

Live view
The 450D becomes the latest DSLR to include a live view mode. [Here are the options you get]. It includes a slow but potentially very accurate contrast detection AF method, which can be made the default for Live view. [Using this custom function]. It also offers an optional live histogram to help with exposure and an' Exposure Simulation' indicator to confirm when the view on the screen represents the brightness of the final image.

Spot metering
A regular criticism of Canon's Rebel range has always been the lack of a spot metering mode. Spot metering is a tool that many photographers find invaluable, particularly when setting manual exposures in difficult-to-capture high contrast scenes. Previously only available on XXD-level cameras, we're delighted to see spot metering appear on the 450D (central 4% of the frame).

Multi-shot self-timer mode
The 450D gains the ability to take multiple shots each time the self-timer is used. If you're trying to appear in a group shot and don't want to have to keep running back to the camera, it could prove a really useful feature.

3" LCD
One of the most obvious external differences between the 450D and its predecessor is the inclusion of a huge 3 inch LCD screen. It's got the same number of pixels as the one on the 400D (which means it's actually lower resolution), but, considering it doubles as the camera's settings screen, the extra size should be useful.

Verification data
The 450D adds the "original decision data" option that cropped up on the 40D. This appends a piece of data in the image file, based on certain aspects of the original image. This data would no longer correspond if the image were changed, allowing users to prove the veracity of an image. (Which requires the OSK-E3 security kit)

Auto Lighting Optimizer
A feature that is starting to appear on the majority of DSLRs being announced is something along the lines of Canon's 'Auto Lighting Optimizer.' This processes photos after they've been taken to try to correct contrast and brightness to optimize the image.

Highlight Tone Priority
Another feature that has made its way down from the 40D is 'Highlight Tone Priority' which alters the way that the camera meters a scene. This means it captures and retains more information in the bright areas of the image at the risk of more noise in the shadows.

High ISO noise reduction
Another feature trickling down from the 40D is the option to add an extra level of noise reduction when shooting at the camera's highest sensitivity settings. Comes at the expense of continuous shooting speed so has been made optional.

14-bit A/D converter
The 450D's DIGIC III processor handles the sensor's data in 14-bit. Whether this makes any difference away from the spec-sheet is something we'll see when we get the chance to conduct more extensive testing.

Improved 9-point AF system
Although we've not had a chance to test the changes, Canon is claiming the AF system has been revised in the XSi / 450D. Certainly the AF chip appears to be different to the one we showed in the 400D review.

Larger, higher capacity, battery
The 450D departs from its predecessors by using a new battery. The new, larger, LP-E5 battery has a capacity of 1080mAh, rather than 720mAh. This will be particularly useful given the greater power demands that live view brings.
My Menu
Another feature inherited from its older brother, the 40D, is My Menu. This lets users group their most-used menu items into a personal list, for easy access. It's a feature we found surprisingly useful.
Revised user interface
The status display has been freshened-up and is slightly easier to read. There are now four color schemes available. The 450D also gains the ability to show Speedlight settings on the screen for people working with external Canon flashguns.
ISO in viewfinder
As well as making the viewfinder larger, Canon has found room to fit additional information into the viewfinder information bar. This, along with the sensibly-placed ISO button, gives you fewer reasons to have to take the camera away from your eye when shooting, which we applaud.
New battery grip
Along with the restyled body comes a new battery grip. The BG-E5 gives the option of taking two LP-E5 batteries or 6 AA batteries, using a different slot-in insert. The grip fills the re-shaped battery bay which means these are instead of, not in addition to the normal battery and older grips are incompatible.