Live View displays and operation

The A550 becomes the first DSLR since Olympus's innovative, if esoteric, Evolt E-330 to offer two distinct live view modes. The first - as seen in many other Alpha models - uses a tiny secondary sensor to give a (relatively low-resolution) preview, allowing the use of the conventional DSLR phase-detection AF sensor to give rapid auto focusing (phase detection requires the main mirror to be down, so can't be used by other live view DSLRs unless the mirror is flipped down and up again before each shot).

New for the A550 is the catchily-named 'MF CHECK LV' mode, which - like all other SLR live view systems - lets you flip the mirror and use the main sensor for live view. This produces a higher quality preview (and one with less cropping of the frame), but there's no autofocus (as the name implies). Apart from the face detection and autofocus aspects the on-screen display is the same in both modes.

No overlay Some settings, with exposure scale
With full shooting settings Live histogram

MF Check Live View

This is the live view method used in all other current DSLRs - using the main sensor to give a high-resolution preview. Unlike other makers, Sony does not attempt to offer AF in this mode (no bad thing, since the only interchangeable lens cameras to do this at all well so far have been the Micro Four Thirds designs for which the whole system has been designed around contrast-detection AF). Instead, as the name implies, this mode is used for the fine scale confirmation of manual focus, and with the ability to zoom in to 14x, it's actually pretty good at it too.

No overlay Some settings (no exposure scale)
With full shooting settings Magnified MF Check live view

Smart teleconverter frustrations

We weren't convinced by the usefulness of the smart teleconverter button on the A350 but were deeply entertained by the frequency with which it would prompt the response 'Invalid Operation.' This has been partially rectified with the A550 - not by automatically switching you into a mode in which you can use the feature, but by giving longer descriptions of why it's not currently accessible. Again, it can only be used while shooting JPEGs in secondary-sensor live view mode which, delightfully, means that if you have the misfortune to start off in main sensor (MF Check) live view mode, you can potentially hit three different error messages before you get to the function you're trying to use.

The only reason I'm devoting so much space to what might seem trivial quirk is because of the jarring effect of being given warning messages. Nothing separates you from the shooting experience quite like the camera locking-up and telling you that it can't do what you're asking of it.

If you are shooting raw files using the optical viewfinder (which doesn't seem an unreasonable thing to do as a keen DSLR user), and you try using the MF Check live view then you find yourself at the eye of the perfect storm - three error messages away from being able to use the Smart Teleconverter. The first press of the teleconverter button will tell you that you have to exit MF Check live view
But, having done this, pressing the Teleconverter button again won't yet yield that zoom-by-cropping effect you're after. No, this time it'll tell you that you have to be in live view mode.
Finally, you'll be reminded that you can't use the digital teleconverter while shooting RAW images. And, while it's unlikely that you'll ever go through this whole sequence, it does show that just how easy it is to accidentally lock the camera up, while it tries to educate you about the futility of trying to use the Smart Teleconverter.

Overall handling comments

Handling is, of course, a very personal thing, but having used every digital SLR ever made I feel as qualified as anyone to comment on how well the A550 feels to use as a camera. The good news is that the physical design is a lot more conventional than, say, the Alpha 380 and its sister products, so the grip actually helps, rather than hindering stable handling and easy operation. The overall ergonomics are good, if not great, and are a lot better in live view mode than when using the optical finder.

Button placement is, typically for a mid-range Sony SLR (except the excellent Alpha 700), a bit awkward, particularly if you regularly use the more advanced functions, many of which are seemingly made unnecessarily long-winded to avoid accidental changes. In much the same way my car's auto transmission won't let me select reverse gear when I'm hurtling forwards at 50 mph the implication seems to be that your roaming thumbs will accidentally go changing things you shouldn't be messing with.

This is partly explained by Sony's reiteration (when first showing us these cameras) that they're trying to make DSLRs that are more user-friendly for compact camera upgraders (hence the emphasis on Live View operation and the pointlessly prominent 'digital teleconverter' button).

The biggest problems I found are that the position of the ISO button awkward, and the on/off lever is too near to the mode dial (so it's pretty easy to turn it off when you mean to change exposure), but to be fair all of this this is nit-picking, and anyone who buys and regularly uses the A550 will soon get used to the control layout and lack of redundancy.

All that said, operationally the A550 is a big improvement over the A380 - with a greater degree of direct control, a much more hand-shaped hand grip and, despite the comments above, a far better button layout. Essentially it's a lot like the A350 (which it appears to be an evolution of) and allows easy manual selection of the AF point. It's still nowhere near as well-equipped with photographic features as some of its competitors (especially at its current price point) - there's no program shift, the buttons can't be customized as much as we'd like and the Function menu is more long-winded than the Alpha 700's direct access info panel - but it's not unpleasant to use by any stretch of the imagination.

The viewfinder has also been improved over the other Sony live view DSLRs, though the A550 is still generally more pleasant to use in its main (secondary-sensor) live view mode than as a conventional DSLR. The new exposure display is a really nice idea but one that's been poorly implemented - it doesn't help to give a clearer understanding of aperture/shutter speed pairs or of the role of exposure compensation - and is more likely to confuse than educate the first-time DLSR user.

Another improvement over the A350 is the decision to devote the two most easily-reached buttons to exposure compensation and AEL, rather than the less useful Smart Teleconverter option. It still feels like a user interface with a fair number of quirks (which was always likely to be the case on a camera with three distinct modes of operation: Live view/OVF/MF Check Live View). Although every effort has been made to make behavior consistent across all three modes, the inevitable inconsistencies remain - for example the Smart Teleconverter button is used to magnify the main live view mode but it's the AEL button if you're in MF Check live view.