Sony Alpha A33 Digital Camera Review$649.99
The Sony SLT-A33 records Full HD video (that’s a 1920 × 1080 resolution) using a 60i frame rate. There’s also an option for recording video at a 1440 × 1080 resolution using an alternate compression system (MP4) and a 30p frame rate. We liked what we saw from the A33’s 60i recording, however, and it is pleasing to see this kind of frame rate offered on a DSLR. Most only have 30p or 24p recording options, so having a 60i setting is somewhat refreshing. Of course, we would have appreciated a 24p record mode as well. More on how CamcorderInfo tests motion.
Overall, the A33's motion video looked almost identical to what we saw from the Sony A55V. The A33 showed a bit more fuzzy blur on the RGB color wheel (color bleeding), and the video seemed to pop in and out of focus on occasion. The A33's video was very smooth, however, and artifacting was not a problem.
Because the A55V offers a 60i frame rate (like the A33), its motion video looked very smooth in our testing. The A55V also had little-to-no artifacting in our test and there was less color bleeding and interference than what we saw from the A33. These two Sony models (the A33 and A55V) managed some of the best motion videos we've seen from DSLR cameras—although we are miffed that neither camera offers a 24p frame rate in addition to 60i.
The Pentax K-x had decent motion rendering, but we saw more artifacting in its motion test video than we've come to expect from video-capable DSLRs. The camera does not record Full HD video, but it does record 720p HD using a 24p frame rate (it has a standard def option as well).
Like the Sony models, the Canon DSLRs that record video generally do well on this test (probably because both Canon and Sony have a strong background in video from their camcorder department). The Canon T2i captured motion video that looked as smooth and artifact-free as what we saw from the A33, but the T2i does not include a 60i or 60p frame rate option. Instead, it has a 24p and a 30p record mode (both for recording Full HD).
The A33 produced crisp video in our testing, but its sharpness numbers weren’t quite that of its higher-end cousin, the Sony A55. In all, the A33 managed a horizontal sharpness of 700 lw/ph, but its vertical sharpness was only 600 lw/ph. While these numbers are good, and are also better than most video-capable DSLRs we’ve tested, they are still a bit lower than the sharpness scores we are accustomed to seeing from high-end HD camcorders. Perhaps with a better lens the A33 could improve its results on this test. More on how CamcorderInfo tests video sharpness.
Low Light Sensitivity
The Sony A33 required 17 lux of light to obtain a video image bright enough to register at 50 IRE on our waveform monitor. This score is not great by any means, and it represents a significantly worse score than the Sony A55, but needing 17 lux of light to record a viable image isn’t the worst low light performance we’ve seen. Many mid-range HD camcorders need around this amount of light to hit 50 IRE on our waveform monitor, and we’ve seen plenty of video-capable DSLRs (like the Pentax K-x) that did even worse than the A33 on this test.