AF100 successor?

[A. J. deLange]

The original question was as to whether there is a successor in the wind for the AF100. When I bought the camera in the spring it came with a $500 rebate (in the form of a fixed value AMEX 'credit' card - just had another great lunch on Panasonic yesterday). When a manufacturer does this it is a sign that he is trying to clear inventory and one reason they will want to do that is to clear all of an old model out so they can introduce a new one. OTOH while I really like the concept of this camera (especially being able to use every Nikon lens that I've ever owned with it) I don't sense the buzz that I have with some of the other HD cameras. Perhaps that was just the excitement of the early introduction of that technology.

How would they improve the AF100?. Higher resolution could be had at the cost of more aliasing by raising the corner frequency on the antialiasing filter. Higher resolution without more aliasing would require more pixels (more over sampling) followed by digital antialiasing (more processor demand, a new sensor, more power consumption and definitely more $). Certainly pixel for pixel mode in the EVF is something sorely needed. Slower shutter speeds would be nice etc. I don't think the noise performance of this camera is that great. Improving that would require a different (larger) sensor and dramatic redesign - again many more $. Maybe a redesigned DSLR with XLR's on it isn't the shining path it at one time appeared to be.

[Lee Mullen]

Originally Posted by A. J. deLange

The original question was as to whether there is a successor in the wind for the AF100. When I bought the camera in the spring it came with a $500 rebate (in the form of a fixed value AMEX 'credit' card - just had another great lunch on Panasonic yesterday).

Is this only for the US or other countries as well? Ive never heard of it. Seems the ROW gets left out.

[A. J. deLange]

That I don't know. I just checked to see if they are still giving this rebate in the US and they are through the end of September. I've looked at a couple of web sites for sellers of the AG-AF101 and do not see it mentioned. So I guess the answer is that it is Panasonic USA that is offering this.

[David Heath]

Originally Posted by A. J. deLange

How would they improve the AF100?. Higher resolution could be had at the cost of more aliasing by raising the corner frequency on the antialiasing filter.

I doubt it - look at charts for the AF100 (and I suggest Adam Wilts - ProVideo Coalition.com: Camera Log by Adam Wilt | Founder | Pro Cameras, HDV Camera, HD Camera, Sony, Panasonic, JVC, RED, Video Camera Reviews ) and it's pretty clear that fine detail is already getting to the chip well beyond the level where "real" resolution has turned to aliasing.

Look at the horizontal and vertical trumpets - the lines that converge towards the centre are real resolution, the ones that diverge are aliases. The point where they go from convergence to divergence is the real resolution limit, and it's about 650 lpph. But the aliases are strong at around 1200 lpph, and you're even getting second order aliases faintly visible even at around 1750 lpph.

Higher resolution without more aliasing would require more pixels (more over sampling) followed by digital antialiasing (more processor demand, a new sensor, more power consumption and definitely more $).

The problem with the AF100 is not too few pixels, but the wrong number! The F3 has just over 3 megapixels, the C300 about 8 megapixels - both far fewer than the AF100 at around 16 megapixel - yet both the F3 and Canons C300 produce full res 1080 video. It may be thought that the more pixels the better - but it becomes impossible to read and process so many at video framerates. Hence the need to simplify the read out system - only read a fraction of the total. This also explains why the raw sensitivity is so far below what may be expected for this size of sensor. (All that likewise applies to DSLRs.)

Hence what I said earlier - the lower performance is the price paid when a chip designed for stills use is used for video. The easy way to (much) better resolution would be to REDUCE the photosite count, yet be able to use them all. If you are designing the chip specifically for video use, the approach Canon have taken is the obvious way to go, 8 megapixels and direct read.

[A. J. deLange]

The resolution of a sensor with n pixels in the horizontal direction and m in the vertical is n/2 lp horizontally and m/2 lp vertically. Period. If you present such a sensor a strictly band limited image (an impossibility) such that no spatial frequency above n/2 or m/2 are present then you can reproduce that image perfectly (ignoring aperture error). In the real world, of course, images are not strictly band limited by any means. If the image has spatial frequency above m/2 and/or n/2, as the test charts do intentionally, then the sampling theorem is violated and aliasing occurs. To combat aliasing in the real world requires an antialiasing filter i.e. something which blurs the image. MTF limitations in the lens does this to some extent but not sufficiently if good quality glass is used, not stopped down too far etc. So some manufacturers put a blurring filter on the sensor itself. Hardware antialiasing filters are not perfect as the trumpet photos you reference show. Bear in mind when looking at these that they have probably been sampled and resampled many times such that some of that aliasing will be caused by the resampling necessary to make the picture fit your display. Images can be introduced in upsampling regimes as well as down sampling. The fact that you see response at spatial frequencies above the ultimate resolution of the sensor says that energy with spatial frequencies above the fs/2 is reaching the sensor which means that the antialiasing filter is not removing those spatial frequencies. As I noted above hardware solutions are not that effective. The response of a hardware device cannot reproduce the 'boxcar' response the design engineer would love to have.

This said, if a hardware (optical) filter with a higher corner frequency were used, the resolution of the camera would go up. But the aliasing would be worse because the attentuation of frequencies above fs/2 would be less. In the early days of CCD photography the option of removing the antialiasing filter was given by some manufacturers. You decided whether you wanted a sharper picture or more moire. I guess you could argue that more resolution is not an improvement of it introduces more moire but then whether its better or not depends on the spatial frequency distribution of whatever it is you are photographing.

So if an optical antialiasing filter doesn't work, then how do you get a sharper picture without aliasing? The answer is to recognize that an optical filter can only knock the response down so many db/octave and over sample so that the folding frequency occurs at a high enough frequency that the response of the antialiasing filter is sufficiently down at the folding frequency. Oversampling is acheived by increasing the number of sensors on the chip. So now you have more data than you can use. What to do about that? The answer is a digital lowpass filter. These can be made to have much much better performance than optical filters. You can get the sharpness without the moire. But of course there is a cost. All that extra data has to be shuffled off the chip in a frame time and all that data has to be processed. The sharper the filter the more 'taps' it must have and as we are working with a two dimensional image doubling the number of taps requires a filter kernel four times larger. Memory, processor speed, power consumption all go up. All this is, of course, complicated by the necessity to derive R an B channels if it's a Bayer sensor and so on.

Thus increasing the number of pixels on the chip and using digital antialiasing filtering can increase sharpness without increasing moire up to the limits of n/2 by m/2. But at cost and that's why I said it is unlikely that Panasonic would do it.

Reducing the number of photosites and using them all is a nice idea but it's like trying to go faster than the speed of light. Physics won't allow it. Perhaps you can do better than a particular manufacturer is doing and that's what this game is all about but the limits are still there

[David Heath]

Originally Posted by A. J. deLange

The resolution of a sensor with n pixels in the horizontal direction and m in the vertical is n/2 lp horizontally and m/2 lp vertically. Period.

Not so simple, (assuming we're talking about colour, and a Bayer sensor) and the easiest way to illustrate why not is with the example of the C300.

In this case, a Bayer block of 2x2 photosites is treated as a single resolution unit, with values for R,G, and B. To get resolution matching the 1080 system it follows there must be 1920x1080 blocks - so 4x1920x1080 photosites in total. (8,294,400 - we'll call it "8 megapixel") The beauty of the Canon approach is that not only will it give full 1080 resolution for R,G, and B, (so 4:4:4 off the front end) but it will get it with very simple processing - no deBayering etc. Each block corresponds to a single output pixel of the image.

What therefore would be the point of moving up to a sensor with a higher number of photosites? If every photosite is still read, then not only does that impose difficulties in the reading (at videoframerates), but it will give a base raster of GREATER than 1080 resolution - which then needs downconversion down.

In practice, cameras such as DSLRs and the AF100 with high count sensors have to cheat. Their reason for using such sensors is that they are neccessary for high quality stills (for DSLRs), and in the case of the AF100 that the GH2 chip was readily available. In every case, they get round the problems by ignoring a percentage of the photosites. Early DSLRs did it in quite a clumsy fashion which gave considerable colour aliasing, such as the AF100 and GH2 are better in that they employ virtually the same technique as the C300 - reading out blocks of 2x2 as a resolution "unit".

The reason that the performance of the AF100 is so much poorer than the C300 is that it only reads out one block in two horizontally and vertically - so only one in four in total. Consequently, a resolution of a quarter of the total photosite count on both axes. Using the measured figure of 650 from Adams chart, that predicts a total chip count of about 2600 vertically and hence about 4620 horizontally. Multiply them together and you get 12,012,000, say 12 megapixel - as would be expected for such a sensor windowed to 16:9. (Look earlier in the thread and you'll see more exact figures and an explanation of why even the GH2 outperforms the AF100 for resolution.)

If you go the route of deBayering, downconverting etc, then it's possible to get full 1080 res with much less than the 8 megapixels of the C300 - at the expense of complexity, power, hence cost etc. But in that case the minimum necessary is about 3.5 megapixels - exactly as with the F3.

Yes, in this case oversampling may be beneficial for the reasons you mention to do with aliasing (as the Alexa does) - but there is absolutely no point in going even up to 8 megapixel, let alone 12 or above!

Reducing the number of photosites and using them all is a nice idea but it's like trying to go faster than the speed of light. Physics won't allow it. Perhaps you can do better than a particular manufacturer is doing and that's what this game is all about but the limits are still there

The "laws of physics" lower limits are about 3.5 megapixel if you fully deBayer etc, and 8 megapixel for direct read. That's what Sony are doing with the F3 in the former case, and Canon in the latter - and no, I couldn't do any better than those manufacturers. But using substantially more won't bring significant benefits for a 1080 output, and is likely to have the reverse effect. As the results from DSLRs and the AF100 prove.

The block skipping means that whilst about 3 million 2x2 blocks are AVAILABLE, only about a quarter (0.75 million) are USED. Far better to do what Canon do and have about 2.2 million and be able to use them all!! But then you can't make use of an already existing still camera chip......

[Roger Martin]

Rumor has it that the AF1000 or what ever they call it will be announced soon.
NAB 2015 starts April 13th.
New better 4/3 Sensor, Usable 12,800 ISO?

Twice as high as GH4 would trigger my buy button as it is maxed out for indoor poor light at closer to 1600 for me and I need to go higher.
I got rid of my HC-W850 and HC-X1000 because they were not as good as the GH4 in low light.
But I really miss the handling and controls of the X1000.
And I really hate the handling and workflow of my A7s.

[Christopher Young]

This is the only web rumor I've seen re a 101 replacement. Lifted verbatim, make of it what you will.

Chris Young
CYV Productions
Sydney

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Panasonic AF101 Replacement Camcorder Coming on April 13, 2015

Published by dcnadmin on March 10, 2015

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Panasonic will have a press conference on April 13 at the NAB 2015 show in Las Vegas. Panasonic AF101 replacement camcorder expected to be announced the same day.

According to latest rumors, the upcoming MFT camcorder – which is said to be an upgrade of the Panasonic AF101 – will be able to capture 4K videos and feature a newly designed 18-megapixel image sensor.

The camcorder with Micro Four Thirds image sensor to have a high price tag between $3,000 and $4,000, similar to the AG-AF100.

New Panasonic AG-AF 4K MFT camcorder coming on April 13

panasonic-af101-successor-nab-2015

Here are the previously rumored specs of the upcoming AF101 replacement camcorder.

4K video
18MP photo
16+ stops of dynamic range
Improved lowlight capabilities
Improved skintones
Improved highlight rendition
Useable ISO (almost no grain) up to 12,800
The new camera will basically have one of the best stills and videos images/color rendition/dynamic range compared to the competition
The big event for the new camcorders is the National Association of Broadcasters Show 2015, which takes places between April 11th – 16th.

[David Heath]

Originally Posted by Christopher Young

Lifted verbatim, make of it what you will.


Here are the previously rumored specs of the upcoming AF101 replacement camcorder.

4K video
18MP photo
16+ stops of dynamic range
Improved lowlight capabilities
Improved skintones
Improved highlight rendition
Useable ISO (almost no grain) up to 12,800
The new camera will basically have one of the best stills and videos images/color rendition/dynamic range compared to the competition
The big event for the new camcorders is the National Association of Broadcasters Show 2015, which takes places between April 11th – 16th.

If it's 4/3 and 18MP sensor, the photosites must inevitably be quite small, certainly compared with a normal 4K (approx. 8-9 MP) s35 sensor.

In such case I find talk of 16+ DR and "almost no grain" up to ISO12,800 on the highly optimistic side.

It seems quite likely there may be some substance to the basic rumour, but it's most likely to be the basic innards of the GH4 in a more video friendly form factor. The AF100 was, after all, just that using the GH1 innards and GH2 sensor. I think such will be welcomed by many, and sell plenty well enough, but talk of "almost no grain up to ISO12,800" almost certainly an exaggeration in the rumour mill.

[Roger Martin]

I too doubt "usable" ISO 12,800.

I am all for a 4/3 interchangeable lens VideoCam but think that 12 MP or less could be optimized for lowlight performance much easier and with better results.

[Christopher Young]

Like most of the wild rumors that float around prior to any big broadcast show... I believe very little especially specs like these.

But there again who knows. Sometimes revolutions take place. I remember the first time I used a DXC-3000. A CCD camera that never lost it alignment on the tubes. Wow! Those CCDs created a whole new world in cameras. I will never forget sitting on a pavement in London prior to an interview trying to auto align a Sony BVP-3 that had it tubes go out of alignment after a knock.

Maybe there is something special at this year's NAB. We can always hope this year is the next big revolution. I'm a a bit skeptical though I must admit.

Chris Young
CYV Productions
Sydney

[Gary Huff]

Originally Posted by Christopher Young

Sometimes revolutions take place.

Revolutions cannot undo the laws of physics. These specs are ludicrous. Wishful thinking by someone who doesn't know what they're talking about.

[David Heath]

Originally Posted by Christopher Young

Like most of the wild rumors that float around prior to any big broadcast show... I believe very little especially specs like these.

But there again who knows. Sometimes revolutions take place.

As Gary says: Revolutions cannot undo the laws of physics.

And I'm afraid it seems to be an April Fool, or based on one and spread in good faith, anyway. I've been sent this link about an "about to be released GH5" Panasonic GH5: Feature Wishlist - the author apparently didn't originally say it was an April spoof - and a lot of the detail seems very, very similar to the "AF200" rumour above. Eg:

The GH5 tops out at an ISO of 12,800, which is surprisingly clean. In fact, there is barely any difference in image noise between 800 and 12,800 on the GH5. It’s almost unbelievable.

Here are a couple frame grabs at ISO 800 and 12,800:
.........

This is not to say nothing may be coming from Panasonic at NAB - if an AF200 is predicted every year, then eventually you may get lucky! :-) - but I'll put a pretty heavy bet that especially if 4/3 it will NOT be "Useable ISO (almost no grain) up to 12,800"!

[Jack Zhang]

Well... we got one, but it ain't got a removable lens, and it's not part of the AF series.

[Roger Martin]

I went to NAB expecting to see the AF200 in the Panasonic Booth.
Instead, they were exhibiting the AG-DVX200 4K which does not fit my needs.
Across the isle was the JVC booth and the Camcorder I expected the LS300.