Re: F3 BBC Report
 

The problem is that while Sony refuses to provide specifications (see Juan's video where actually say he can't provide the numbers) they have said that 3.37Mp are "used." That forces assumptions to be made.

But Allan's paper -- if you read it carefully -- works through the process very clearly. Here is my parsing of it:

Figure 1 shows the luma resolution when the camera was in factory default settings for detail enhancement.

The result is not free from spatial aliasing, there [ARE] both horizontal and vertical visible aliasing. The aliasing, is, [UNUSUAL], both first and second order, i.e. frequencies are reversed and then reversed again.

The first alias [IS] centred on 1920 and 1080,

WHICH IMPLIES IT IS FROM THE RECORDED FRAME-SIZE.

while the second aliases are centred on about 1100 pixels and 619 lines, implying that the sensor has dimensions which are related to those numbers, probably 2200x1238.

MY ESTIMATES ARE 2456 AND 1380. HOWEVER, THE VERTICAL ESTIMATE IS TOO HIGH.

THIS IS A 3,389,280 PIXEL FRAME. SONY SPECS 3,370,000 PIXELS.

THIS IS BOTH: THE FRAME THAT RESULTS FROM THE "DOWNSCALE" OF THE PHOTOSITES FRAME AND THE PRE-DEBAYERING FRAME. THIS FRAME , THROUGH DEBAYERING, BECOMES 1920x1080.

The F3 specification [IS] T/11 at ISO800, and since ISO800 corresponds to 0dB gain, this means that the sensitivity is very similar to that of a 3-sensor 2/3-inch sensor,

IN HIS EXPERIENCE, THIS VALUE, IS WHAT HE TYPICALLY SEES FROM 2/3-INCH CHIPS

which in turn implies that the pixels are about 5μm square.

THESE CHIPS, HE STATES, HAVE A TYPICAL SIZE OF 5μm

Given that the sensor is ‘super 35mm’ size, it must be 24x13.5mm. [Not the 23.5x15.6 of an APS-C]

SIMPLE MATH, GIVEN THE DIMENSIONS

For the pixels to be 5μm spaced, the sensor width must be about 4800 pixels, making the sensor approximately 4,800x2,700.

MY ESTIMATES ARE 4912x2760 WHICH MEANS THEY WOULD BE SLIGHTLY SMALLER AT ABOUT 4.784 WITH AN AREA OF 9.568

This fits reasonably well with the estimations in section 1.2.1, and means that the sensor has approximately 12.9 Megapixels, typical of a digital stills camera.

MY ESTIMATE IS 13.56MP.

It also explains why there is little or no coloured aliasing,

and why the red, green and blue signals all have the same resolution and aliasing.

THE LATTER "MAY" BE A GOOD CLUE BECAUSE THERE ARE TWO WAYS A CHIP COULD WORK.

PERHAPS YOU ARE CORRECT, ALTHOUGH THE CHIP HAS A BAYER FILTER, IT MAY NOT BE BEING READ-OUT AS SUCH.

Figure 3 shows the result for setting progressive, again with factory detail settings. There appears to be no difference in resolution between progressive and interlace, a sure sign that the native resolution of the camera does not reach the limits of the 1920x1080 format.

WHICH IS TRUE, GIVEN THE REZ HAS BEEN MEASURED MUCH LESS THAN 1000TVL/ph.


IF you assume the chip is a Sony 16MP chip that is being read-out slightly differently, it is possible for everything Sony has said is true while Allan's measures are valid and his speculations are very good.

I've got to do more digging on the how the increased sensitivity is achieved. Juan seems to imply it is because the photosites are 4X bigger. Of course, the critical question is bigger than WHAT? Did he say?

Sony IMX046 chip is a 1/3.2 type 8MP sensor that has a very tiny 1.4 µm photosite x 2 is 2.8sq x 4 >> 11.2sq >> 5.6 µm

But, HOW the data are read-out could be contributing as well.

Re: F3 BBC Report
 

Sorry for the paraphrase Steve but Juan doesn't "imply" that pixels are four times the size, he flat out says they are. Plus he goes to a lot of trouble to point out the sensor is not from a stills camera, it is a moderate resolution chip purpose built for video.

He says that, and has pictures to make his point even more. He would have to be grossly misinformed (or lying) to be wrong.

I am no expert, I am just repeating what was said.

Re: F3 BBC Report
 

As I mentioned on the FS 100 thread, Alan Roberts' assumption seems to be based on an ISO of 800, which is a rating similar to that of the Alexa and Epic, which do have rather different pixel counts.

Re: F3 BBC Report
 

I said;

"I've got to do more digging on the how the increased sensitivity is achieved. Juan seems to imply it is because the photosites are 4X bigger."

It = the greater light sensitivity.

And, where do I say it IS from a still camera?

Where does Allan say it IS from a still camera?

Re: F3 BBC Report
 

Yes, Alan doesn't say it's a still camera sensor, just his guessimate at the pixels based on his line of thought and a passing comment on that number: "the sensor has approximately 12.9 Megapixels, typical of a digital stills camera".

That figure is roughly the same as a Sony F35 or Panavision Genesis sensor.

If his guessimate is accurate is another matter, but he gave his reasoning behind the figure, which may or may not not apply in practise. However, that's in the nature of these things.

Re: F3 BBC Report
 

You basically say that in the post below, and perhaps other places:
http://www.dvinfo.net/forum/sony-avc...ml#post1639132

Re: F3 BBC Report
 

I'm not trying to start a fight so I'll stay out of this...

Someone did find this about the sensor. It mentions gross pixel count vs effective. It is talking about the FS100 but still they both use the same sensor.

page 4.
http://www.sony.co.uk/res/attachment...7480643259.pdf

Re: F3 BBC Report
 

There is just too much confusion surrounding this sensor to know for sure.

What are "effective pixels?" Why is the pixel count "approx.?" Are "pixels" the same as photosites?

This sensor could be anything, and convincing arguments have been made which run the gamut.

Re: F3 BBC Report
 

Gross pixels Approx. 3,530,000 pixels
Effective pixels of moving pictures in 16:9 Approx. 3,370,000 pixels
Effective pixels of moving pictures in 4:3 Approx. 2,530,000 pixels

While many have assumed pixels are photosites, there are reasons to think this is not true:

Juan say's the image is "grossly" over-sampled. There's nothing grossly over sampeled with 3.37MPixels if the photosite count is only 3.53 million.

PS: from the same PDF:

The sensor also features an optimum number of effective pixels for shooting HD
moving images. At a high 50fps in >>> all-pixel scan mode <<<, this allows images to be
captured with less color aliasing, jaggedness and rolling shutter than DSLR
cameras, while providing the sensitivity to shoot at a minimum illumination of
0.28lux.

Re: F3 BBC Report
 

With regard to sensitivity, I don't think we can draw any meaning full conclusions over pixel size from sensitivity alone. There are far too many other factors that can skew any conclusions, Q-factor, gain settings and noise reduction, microlense size and usage, binning etc etc.

The F3's effective resolution does seem to tie in quite well with what I would expect from a 3.3MP Bayer sensor. If it really was using 4800 x 2700 I would have expected higher measured resolution.

Bottom line: It does produce a good image in the real world.

Re: F3 BBC Report
 

I was at a talk on HD tapeless workflow at the BBC yesterday. Seemly they have a spectrum analyser which all the delivered programmes are put through. Problems are not just caused by the camera codec, but how the post workflow itself is handled.

Apparently, about 60% of delivered programmes have an issue of some sort. The reasons vary from not having the right paperwork to needing to re-shoot material because they used the wrong codec for more than 25% of the programme or post workflow issues. Any variation from the 25% needs to be discussed and to be justified eg the use of archival material.

That's how it stands for HD at the present time. Perhaps they may reduce the quality standards in the future, but the impression was they weren't going to let these standards slip..

Re: F3 BBC Report
 

I'd like to hear more about this...in this context, "spectrum analyzer" is a pretty unscientific term. Not saying I don't believe you, just wary of that term.

I've had a lot of my deliverables go through an outfit in Burbank called DVS, which does QC, encoding and vaulting for a lot of content producers, and the reports I've seen (i.e., the jobs that got rejected) are definitely machine generated with a human running it (human written notes in the comments beside each line item violation).

But nothing that sounded like "spectrum analyzer" that could somehow divine what codecs were used before a master was made.

Re: F3 BBC Report
 

That's the term the BBC guru used. I suspect it's a similar device to the one that I linked to earlier in the thread.

http://www.cnrood.com/PHP/files/vide...nix-PQA500.pdf

There was a mixed range of people at the talk, so I guess it was just a catch all term for a piece of test equipment. They sounded confident about being able to spot non spec video content, which may or may not be the case 100% of the time in practise. Certainly, he said HD programmes have been failed. It could be also be due to issues somewhere else in the chain, because post workflow was also mentioned in connection to this.

Of course, it could just be a virtual transmission chain that pushes the master to the limits, so that the compression errors in the workflow start to show up.