It’s not just the HD33’s design that’s different to the HD83, inevitably; there’s also divergence where key specs are concerned. For although both models, as indicated, have full HD native resolutions, the HD33’s contrast is quoted at 10,000:1 versus the HD83’s 50,000:1, while the HD33’s brightness is quoted at 1800 ANSI Lumens versus the HD83’s 1600 ANSI Lumens.
Such measurements tend to bear little relation to real-world performance, of course, but they are useful here to the extent that they suggest a fairly hefty shift with the HD33 towards brightness at the expense of black level response and contrast.
This wouldn’t normally count as a particularly promising trait if you’re a movie fan. But where 3D projection is concerned, if there’s one lesson we’ve learned from the HD83 it’s that brightness is crucial. Especially if you’re also working with the somewhat limited sort of contrast levels usually associated with the more affordable end of the projector market.
The HD33’s connections are more than acceptable for its money, including as they do a pair of 3D-friendly v1.4 HDMIs, a component video input, a composite video input, and even 12V trigger and RS-232 control ports to aid system integration.
Plus there’s the DIN port now familiar from the HD83, to which you have to attach Optoma’s external 3D transmitter. This transmitter is shipped free with the projector - along with a single pair of Optoma’s latest 3D glasses - and is unusual in that it delivers its sync information to the glasses using RF rather than IR technology. This proves to be a pretty brilliant move, as the sync signal didn’t lose connection with the glasses even once during our tests.
Setting the HD33 up immediately exposes a pretty large if probably predictable shortcoming: no vertical image shifting. This predictably makes getting the image in the right place on your screen quite difficult without using keystone correction (something we would never recommend that you do given that this is essentially ‘distorting’ the native image resolution).
The HD33 does offer a degree of optical zoom via a simple circle around the lens, but it’s fairly limited, which again could create an installation issue or two.
The HD33’s bland but functional onscreen menus contain more picture set up features than anticipated. Particularly surprising is the appearance of Optoma’s PureEngine controls, with separate processing elements aimed at boosting colours, sharpness/detail, and motion reproduction.
There’s also greyscale management via a white balance control, and adjustments for the projector’s gamma, colour temperature and colour space settings. This is all very satisfactory on such an aggressively priced 3D projector.
As noted earlier, our experience with the HD83 meant we didn’t really expect much from its far cheaper sibling. But we couldn’t have been more wrong, as it happens - at least where 3D is concerned.
Within just moments of settling in to watch a series of our favourite 3D test scenes, it was obvious that the HD33 isn’t just as good as the HD83 with 3D, it’s actually better. A lot better.
The straightforward reason for this is that its brightness/contrast balance is much more suited to reproducing active 3D images, with the extra emphasis on brightness allowing the image to retain detail and, thus, depth in dark scenes, despite the dimming effect of the glasses. With the HD83 by comparison, dark scenes routinely seemed almost completely devoid of shadow detail, and thus flat and unconvincing.