Like the rest of the Alpha range, the Alpha 450 feels a little plasticky, despite its comfortable handling and decent finish. The grip is excellent, but the whole thing feels less solid than some of its competitors. The controls are fairly traditional, with a single click wheel; you need to move up to Sony's professional range if you want a second. A couple of buttons along the top are quite hard to reach, including the D-range button which activates the DRO and HDR modes, which you're unlikely to use every day. We would have preferred to be able to use it for something else.
Most of the everyday settings are controlled by the Fn button. Onscreen help is included, but it's a little confusing: there are two columns of settings side by side, but once you've chosen a setting, you go back to the list, and it isn't always clear if you're still adjusting the setting or moving through the options again.
Removing the secondary sensor in the viewfinder means it's now larger, but it's still less comfortable than on some other cameras, like the Canon EOS 500D. The main problem is that you can't move too far away from it: you can't see the whole frame and all of the info without having your eye glued to the viewfinder.
The screen is fixed, unlike the rotating version on the 500 series which was so useful for getting shots at unusual angles. Worse still, it has a measly resolution and use TN technology, making it hard to see unless you're directly in front of it, confirming that it's not designed for lining up shots.
Not focussing on screen has dramatic consequences for the battery life, which was a little stingy on the 500 series: the Alpha 450 easily managed 850 shots in real conditions.
The Alpha 450 is a fast camera, and does everything you ask it do without any lag. The autofocus is fast, even for moving subjects, but the SAM kit lenses are quite loud. A 5 fps burst mode is accompanied by an even faster 'boost burst mode' at 7 fps , but for this latter you can't adjust the focus or the exposure during the burst.
As it uses the same electronic circuitry as the Alpha 550, the Alpha 450 produces unsurprising results. There's not much to say about noise handling up to 1600 ISO; at 3200 ISO, noise is visible without being problematic.
The stabilisation system is quite effective, especially given the size of the sensor. Our portrait test shot of Barbie was sharp at 1/5 s. Sony's system can also tell when you're panning to follow a moving subject, something which we only discovered when we took it out into the field.
The automatic white balancing undershoots a little, especially in cold light conditions like a cloudy day, producing a blue tinge. Under artificial light, the traditional red dominance is more visible, but that generally looks more natural.
This part is easy: the Alpha 450 doesn't do video. At least that keeps things single, given how hit and miss the video mode can be on some SLRs ...