Panasonic AG-AF100 series

[Don Miller]

I calculate the diagonal of a 16:9 crop of the AF100 sensor at 19.8mm, or .75 inches.
(The diagonal of a 16:9 crop of the 5DII is 41mm, for comparison.)

[Brian Drysdale]

The same article mentions imaging area of 17.3 mm × 13.0 mm, so that seems like a starting point for comparisions.

2/3 is 8.80mm x 6.6mm, 1/3 is 4.8mm x 3.6mm, Standard 16mm 10.26mm by 7.49 mm.

However, don't take the 2/3 sensor sizes as fixed, the 16:9 sensors are different, for one Sony camera it's 9.58 mm x 5.39 mm. Yet another example: the SI 2k is 10.24x5.76mm @ 2k.

[Don Miller]

I shouldn't have said "AF100" sensor. I took the size off wikipedia, which may not reflect the full 4/3 standard. As pointed out the logical chip may be 16:9 with a 22.5mm diagonal (if the 4/3 standard allows any shape with a 22.5mm image circle)

So it seems 35mmish is "in the ball park" for the AF100, and otherwise we're just guessing.

[David Heath]

Originally Posted by Dan Brockett

IIf you think about it, Panasonic is damned if they do include P2/AVCINTRA 4:2:2 (it's too expensive, I hate P2 cards, waaah) and damned if they don't (SD cards are flimsy, cheap and unreliable, it only has 4:2:0 color space, waaah).

Damned if you do - damned if you don't. A tough one. An innovative manufacturer may therefore try to think of a third way as an alternative to either of those two. One which will be praised by it's customers, is technically easily implemented, and which is cost effective.

So what about AVC-Intra 100 to Compact Flash cards? You simply don't need P2 to record 100Mbs video these days. The nanoFlash is living proof that a 100Mbs video bitstream can be reliably recorded to fairly basic spec Compact Flash. The new Canon has gone for Compact Flash - why does the Panasonic choice have to be either (expensive) P2, or SDHC - why can't the Panasonic camera record AVC-Intra 100 to CF?

Or would that have their marketing people giving the loudest "waaah!"?

[John Wiley]

Originally Posted by Don Miller

Are we sure 4/3 is an actual measurement? Arri also list 16:9 sensors

4/3rds is an actual measurement, but it is not a ASPECT RATIO. 4/3 is not the same as 4:3. Nothing in the standard dictates that it has to use any particular aspect ratio.

I calculate the diagonal of a 16:9 crop of the AF100 sensor at 19.8mm, or .75 inches.

But there is no crop - at least not one that reduces the size of the diagonal. Early reports from Jan Crittenden said the sensor was based on that from the GH1. While the GH1 sensor uses cropping in every aspect ratio, this is because the sensor is larger than it needs to be so that it can accommodate a 4:3, 16:9 and 3:2 image all with a diagonal of 22.5mm. So it is exactly the same as though you are pulling the 16:9 image from a 16:9 sensor.

[Francesco Marano]

a draw to illustrate the size

http://www.dvinfo.net/forum/attachme...0&d=1272467528
bye

[Brett Sherman]

Originally Posted by David Heath

So what about AVC-Intra 100 to Compact Flash cards? You simply don't need P2 to record 100Mbs video these days. The nanoFlash is living proof that a 100Mbs video bitstream can be reliably recorded to fairly basic spec Compact Flash. The new Canon has gone for Compact Flash - why does the Panasonic choice have to be either (expensive) P2, or SDHC - why can't the Panasonic camera record AVC-Intra 100 to CF?

I think by the time this camera actually gets released SDXC will be the new standard or at least the wave of the future. CF currently enjoys the highest transfer rate now, but not for much longer.

[David Heath]

Originally Posted by Brett Sherman

I think by the time this camera actually gets released SDXC will be the new standard or at least the wave of the future. CF currently enjoys the highest transfer rate now, but not for much longer.

Quite possible - the point is that making the native codec AVC-Intra 100 *does not* technically neccessitate the use and expense of P2. At the moment, CF would be the strongest candidate but yes, it's conceivable that in a years time with SDXC it would be possible to reliably use those cards.

What's technically possible, and what is marketing strategy, are two wholly different things and it wouldn't surprise me if for the latter reason Panasonic were keen to keep AVC-Intra linked to P2 and AVCCAM linked to SDHC. It just needs to be absolutely clear that technically a 100Mbs stream like AVC-Intra can be reliably recorded to far cheaper media than P2.

For their higher range products, P2 will no doubt still make more sense than SDXC would. For a sub-$10,000 camera like this, AVC-Intra to CF or SDXC would be far and away the best compromise.

[Don Miller]

Here are some size comparisons compiled for Red
Some of these may be wrong, but it gives a rough comparison to 4/3

2/3" - 3072 x 1620 - 3K
10.1x 5.35mm MX
native 16:9 aspect ratio, approx 11.5mm diagonal,
3.3 micron pixels, approx: 5 mpx, 3.75 FOV crop factor.

R1 - 4520 x 2540 - 4K
24.4 x 13.7mm Mysterium
native 16:9 aspect ratio, approx 28mm diagonal,
5.4 micron pixels, approx: 12mpx, 1.5 FOV crop factor (APS-C).

S35 - 5120 x 2700 - 5K
30x15mm MX
native 16:9 aspect ratio, approx 33.5mm diagonal,
5.4 micron pixels, approx: 14mpx, 1.25 FOV crop factor (APS-H).

FF35 - 6000 x 4000 - 6k
36x24mm Monstro
native 3:2 aspect ratio, approx 43mm diagonal,
6 micron pixels, approx: 24mpx, 0 crop factor (FF DSLR).

645 - 9334 x 7000 - 9k
56 x 42mm Monstro
native 4:3 aspect ratio, approx 70mm diagonal,
approx: 65 mpx, 0.6 crop factor (MF).

617 - 28000 x 9334 - 28k
168 x 56mm Monstro
native 3:1 aspect ratio, approx 177mm diagonal,
approx: 261 mpx, 0.25 crop factor (MF).


Crop Factor refers to Field of View (FOV) crop factor, or Focal Length Multiplier (FLM), referenced to Full-Frame 35mm.

APS-C (Canon1.6, Nikon1.5): Canon Betacam, 550D, Nikon D300s, D90.
APS-H (Canon 1.3 crop): Canon 1D MkIV.
FF DSLR: Canon 1Ds MkIII and 5D. Nikon D3s/x and D700.
MF (Medium Format): various Hasselblad, Leaf, Mamiya, Pentax, Phase One.

[Don Miller]

Originally Posted by Brett Sherman

I think by the time this camera actually gets released SDXC will be the new standard or at least the wave of the future. CF currently enjoys the highest transfer rate now, but not for much longer.

Anything but proprietary storage. There's little benefit to the small SD size in a camera like this.

[Lawrence Bansbach]

Originally Posted by David Heath

Quite possible - the point is that making the native codec AVC-Intra 100 *does not* technically neccessitate the use and expense of P2. At the moment, CF would be the strongest candidate but yes, it's conceivable that in a years time with SDXC it would be possible to reliably use those cards.

AVC Intra 100's data rate is 100 megabits -- or 12.5 megabytes -- per second. Panasonic's E-series P2 cards can reach 1.2 Gbps, or 150 MBps. SDXC cards following the SD 3.0 specification were scheduled to reach 104 MBps (UHS104) last year, and SD 4.0 specifies a maximum transfer speed of 300 MBps. So, on speed alone, SDXC should easily handle AVC Intra 100, and probably AVC Ultra (200 Mbps). Reliability is, of course, another matter.

[Don Miller]

UDMA CF is necessary with Canon CF to reliably do 35mb/s.

I've been looking at GH1 movies and I have to say the color is nice. Seems very well controlled, especially skin tones. Canon can get a little pink or go too dull at times(with Caucasians). That chip with a proper video anti-aliasing filter should be very nice in the AF100. Especially if the chip is read faster.

I wouldn't want to buy 4/3 lenses, but it doesn't sound like that will be necessary.

[David Heath]

Originally Posted by Don Miller

UDMA CF is necessary with Canon CF to reliably do 35mb/s.

I think you are confusing MegaBITS with MegaBYTES. The data rate of the EX is 35Mbs(bits), the Canon camera will be 50Mbs (MegaBITS/s). UDMA CF is rated up to 45 MBs (MegaBYTES/s) or no less than 360Mbs - 10x the 35Mbs data rate you refer to.

Something like Sandisk Extreme III (much cheaper) is rated to 30MBs - or 240Mbs. That's still nearly 7x the speed of the 35Mbs codec, and about 5x the speed of the 50Mbs codec (as used by the new Canon).

Now I take the figures with somewhat of a pinch of salt, and ones which need a big safety margin to be allowed. But in real world usage that speed of card is approved with the nanoFlash for the 100Mbs datarate - so about 2-2.5x seems to be an adequate safety margin.

And if the card can record 100Mbs reliably in the nanoFlash, there is no reason why it shouldn't do the same for AVC-Intra 100 in a Panasonic camera. As far as reliability goes, Compact Flash is relied upon by the vast majority of the professional digital stills photo industry. The only failures I've heard of first hand was someone who bought a very cheap, unbranded card - needless to say, he sticks to decent brands now, with no further trouble.

[Don Miller]

The point I was trying to make was that the speed rating alone didn't matter for avoiding buffer overrun. The card needed to be UDMA.
I do wonder if more than 50 mb/s is necessary. I am curious if current CF cards can really do sustained 100 mb/s.

[David Heath]

Originally Posted by Don Miller

I am curious if current CF cards can really do sustained 100 mb/s.

Don, I don't think there's any doubt about it, and that's relatively cheap cards at that. Higher spec ones will reliably record much higher bit rates still. As far as the 35Mbs rate goes, many people are reliably recording that to pretty low spec SDHC via an adaptor in an EX.

Still not convinced? Just take a look at the relevant Convergent Design website page - Media | nanoFlash | Video Recorders and Converters . You can't just take any cheap unbranded card and hope for the best, but that reference gives a range of cards qualified by CV for given bitrates - all the way up to 280Mbs!

The nanoFlash has been in use for quite a while now - if CF usage for recording sustained 100Mbs was a problem, we'd have heard a lot about it by now.