BobDiaz
12-21-2005, 08:48 PM
More Speculation on Native CCD Resolution
IMPORTANT: This is just pure speculation on my part. Do NOT take this as 100% fact.
If I remember correctly, the Sony Z1's CCDs were 960h x 1080v interlaced or 960x540 per field. About 0.49MP per field. A Full 1920x1080 image with BOTH fields is 1.98MP.
Canon newest camera uses CCDs that are 1440h x 1080v interlaced or 1440x540 per field. About 0.74MP PER FIELD. Yes, Canon does de-interlace the fields, but the source information is still 0.74MP per field.
JVC is 1280h x 720v progressive, but due to excessive heat generated by high clock speeds, needed 2 A/D (Analog to Digital) converters per CCD. This worked out OK, but runs the risk of the Split Screen Effect. JVC's CCDs are about 0.88MP per frame. Which is exactly how much information is required in a 1280x720 frame.
This tells me that if a camera uses 0.74MP, a single A/D Converter is required per CCD. After all, Canon did it, BUT if the count reaches 0.88MP, 2 A/D Converters are required.
While I can't be sure of the exact resolution on the Panasonic, to me it seems that something close to 0.74MP is likely to be the native resolution of the CCDs. (There are several combinations of HxV resolutions that make sense, so I can't be sure which they chose.) By using spatial offset with the CCDs, this comes close to a total resolution of around 1.48MP.
Before someone cries that this is short of the 1.98MP for a 1080 frame, remember NO ONE produces a Under $10,000 or 1/3" CCD camera that DOES produce a full 1.98MP.
You could argue that Canon's de-interlacing produces 0.74MP x 2 = 1.48MP. OK, but remember the image is recorded as 4:2:0, MPEG-II and isn't any higher in pixel count than Panasonic. With Canon, you may gain some in horizontal resolution, but you loose in vertical color resolution. This is where a calculator will NOT decide which looks better, only side by side images of the same thing will solve this argument.
As I look closely at the detail in the HVX-200 sample images, the 45 degree diagonal detail seems as sharp as the vertical and horizontal detail. This STRONGLY tells me that the camera CAN NOT have 0.49MP CCDs. If it did, diagonal detail would suffer. The evidence suggests that the CCDs are around 0.74MP, but remember, that is only a GUESS on my part.
What I do know for a fact is that when several of the images are printed on 4"x6" photo paper (cropped), they appear VERY SHARP. Whatever the real pixel count of the CCDs is, it produces very good results.
Bob Diaz
:thumbup:
IMPORTANT: This is just pure speculation on my part. Do NOT take this as 100% fact.
If I remember correctly, the Sony Z1's CCDs were 960h x 1080v interlaced or 960x540 per field. About 0.49MP per field. A Full 1920x1080 image with BOTH fields is 1.98MP.
Canon newest camera uses CCDs that are 1440h x 1080v interlaced or 1440x540 per field. About 0.74MP PER FIELD. Yes, Canon does de-interlace the fields, but the source information is still 0.74MP per field.
JVC is 1280h x 720v progressive, but due to excessive heat generated by high clock speeds, needed 2 A/D (Analog to Digital) converters per CCD. This worked out OK, but runs the risk of the Split Screen Effect. JVC's CCDs are about 0.88MP per frame. Which is exactly how much information is required in a 1280x720 frame.
This tells me that if a camera uses 0.74MP, a single A/D Converter is required per CCD. After all, Canon did it, BUT if the count reaches 0.88MP, 2 A/D Converters are required.
While I can't be sure of the exact resolution on the Panasonic, to me it seems that something close to 0.74MP is likely to be the native resolution of the CCDs. (There are several combinations of HxV resolutions that make sense, so I can't be sure which they chose.) By using spatial offset with the CCDs, this comes close to a total resolution of around 1.48MP.
Before someone cries that this is short of the 1.98MP for a 1080 frame, remember NO ONE produces a Under $10,000 or 1/3" CCD camera that DOES produce a full 1.98MP.
You could argue that Canon's de-interlacing produces 0.74MP x 2 = 1.48MP. OK, but remember the image is recorded as 4:2:0, MPEG-II and isn't any higher in pixel count than Panasonic. With Canon, you may gain some in horizontal resolution, but you loose in vertical color resolution. This is where a calculator will NOT decide which looks better, only side by side images of the same thing will solve this argument.
As I look closely at the detail in the HVX-200 sample images, the 45 degree diagonal detail seems as sharp as the vertical and horizontal detail. This STRONGLY tells me that the camera CAN NOT have 0.49MP CCDs. If it did, diagonal detail would suffer. The evidence suggests that the CCDs are around 0.74MP, but remember, that is only a GUESS on my part.
What I do know for a fact is that when several of the images are printed on 4"x6" photo paper (cropped), they appear VERY SHARP. Whatever the real pixel count of the CCDs is, it produces very good results.
Bob Diaz
:thumbup: