- This topic has 2 replies, 1 voice, and was last updated 9 years, 8 months ago by Anonymous.
- June 5, 2010 at 2:36 AM #48708AnonymousInactive
I’ve owned the Panasonic HMC40 since Dec. of ’09 but recently purchased the HMC150. I’ve been reading some disturbing things about these cams lately concerning quality of resolution. It turns out that footage from the HMC40 outdoes footage from the HMC150 in bright light conditions. They say the footage from the 40 is much sharper than what the 150 can produce. This really concerns me, since I did shell out a ton of money for the 150. I would have thought that a cam with 1/3rd inch CCDs would produce a sharper image than a cam with 1/4th inch 3MOS sensors. Does anyone out there have experience with both cams?
- June 5, 2010 at 4:32 PM #199745
- May 18, 2011 at 2:04 PM #199746AnonymousInactive
With every camera, there are a series of trade-offs.
The HMC40 uses three ~3Mpixel, 1/4″ sensors. Like most sensors, these are 4:3, so in the 16:9 crop, they each deliver a 1920×1080 image. And of course, given the AVCCAM encoding at 1920×1080, there’s no resampling needed, thus, a very sharp image. The downside, of course, is the potential for the Jello Effect (the result of the rolling shutter, not an inherent problem with CMOS, but an issue with the way more CMOS sensors are made
these days), and of course, a relatively small sensor, leading to a lack of low light sensitivity. You get a little of this back because the HMC40’s sensors, being modern CMOS, have a lower noise floor than typical CCDs. But it only goes so far.
The HMC150 uses three 960×540, 1/3″ sensors. The green sensor is offset in both horizontal and vertical dimensions. The image recorded is an interpolation, not unlike the Bayer interpolation done in a single chip camera, so there’s an effective loss of resolution here. On the other hand, each sensor site is much larger than a full raster sensor would have been, and of course, 1/3″ vs. 1/4″. Thus, the fact that the HMC150 is a little softer, but substantially better in low light than the HMC40.
This is probably going away. The CCD has been a fairly mature technology, but it has issues: power (and thus heat), expensive all-analog chip process, smearing. But it mandates a global shutter, which is certainly preferred, particularly for video. CMOS is new enough that the technology is still advancing: noise levels are falling, innovations like backlit sensors get more light gathering in the same chip, etc.
It’s technically possible to build a CMOS chip with global shutter. I suspect one of the main reasons they don’t is simply minimizing the extra circuitry on-chip with the sensors… a problem that’s rapidly vanishing with the move to backlit sensors, where you’re not going to care so much about the size of the other circuity on the chip. I bet global shutter CMOS chips become the next big thing with five years.
- You must be logged in to reply to this topic.