It’s not often that an affordable lower mid-range TV causes us to emit an involuntary ‘wow’ as soon as we start watching it. But that’s exactly what happened with the Sony 40W605B – despite the fact that we kicked off our tests in brutally tough fashion, with our infamously tough-to-handle Harry Potter and the Deathly Hallows Part 2 and Casino Royale test Blu-rays.

The main key to the 40W605B’s success is its black level response. For us TV picture quality begins with how well a set can deliver a deep, natural, unforced black colour; without this foundation any TV’s pictures will struggle to convince. So it’s a huge boon to find the 40W605B delivering comfortably the best black level we’ve ever seen at its level of the market.

This no doubt sounds like hyperbole to the more cynical among you. But honestly the 40W605B’s ability to deliver intensely dark sequences like the start of Chapter 12 on the last Harry Potter film disc with scarcely a trace of the usual LCD grey mist issue is incredible for its money – and it’s made all the more remarkable by the fact that it’s achieved without so much as a hint of backlight inconsistency/clouding, even in the image’s corners.

What’s more, while it would be true to say that pictures aren’t the brightest around once the TV is delivering its optimum black level performance, the black level on show is remarkably natural. By which we mean that there’s strong evidence of shadow detailing in dark areas, proving that much of the black level excellence is coming natively from the panel at the TV’s heart rather than just being created by ‘crushing’ light out of the image.

Also, there’s pretty much zero distracting interference from the machinations of the dynamic contrast system. In other words, so long as you leave the dynamic contrast mode on its lowest setting it boosts contrast without creating the sort of brightness jumps and shifts associated with many less able dynamic contrast systems.

How Sony has managed to get such a brilliant contrast performance from an LED lighting system with no local dimming is beyond us. But we’re sure as hell not complaining.

Brilliant black levels usually lead to superior colours, and so it proves with the 40W605B. As well as looking startlingly bold and richly saturated, especially with high quality HD content, colours are also both remarkably natural in tone and possessed of levels of tonal finesse and blend subtlety you just don’t expect to see at the 40W605Bs price point.

The 40W605B also delivers all the Blu-ray HD detailing we love so much with the utmost precision, and without suffering moiré noise or over-egging the sharpness to the point where grain starts to look too dominant or edges start to look stressy.

Actually the out-of-the-box balance the Cinema 1 settings strikes between sharpness and grain is really quite beautifully judged, and joins with the focus on black level, stability and only using image processing sparingly in persuading us that Sony’s engineers genuinely care about picture quality at home rather than just wanting to set up images so that they look eye-catching in a shop.

The excellent image clarity dips a little versus the 50W829 when there’s extensive motion in the frame. But not by the factor of four you might expect given the ‘200Hz’ vs ‘800Hz’ difference between the two sets’ motion processing features, and not enough to become a serious distraction or spoil the overall impression of outstanding sharpness.

The only negative things we can find to say about the 40W605B’s outstanding picture quality are that standard definition pictures look a bit soft (strange given the presence of the X-Reality Pro processing) and that the black level response drops off a touch if you have to watch from an angle of more than around 35 degrees. But even this happens to a lesser extent than we see with the majority of LCD TVs.