Sony FDR-AX100

[Bruce Dempsey]

If the shutter speed was set to 1/40sec instead of 1/60sec would that not remove the jerky?

[Ron Evans]

NO. Its how many exposures are taken of the motion. The more exposures in a period of time ( per second ) the smoother the motion. Faster shutter gives sharper image, slower shutter give more motion blur but not judder removal. A really slow shutter and slow frame rate will give a juddery blurred image !!! Fast shutter and slow frame rate will give really sharp juddery image. One needs to have shutter appropriate for the frame rate.

Ron Evans

[Ken Ross]

Ron, remember, this was for my own enjoyment, not a paid project for others to view. So 30p, frame rate doubled, might be OK. :)

I too am looking forward to 60p, but I really want to dip in to a small 4K cam now.

[Ron Evans]

I am sure it will work fine for you just keep movements slow and smooth or let things happen in front of the camera. I have even considered this myself for my application which is a fixed camera, wide angle for later cropping but think I will wait for 60P since I already have the FDR-AX1. If you really need 60P for an application it will shoot that way in HD anyway.

Ron Evans

[Ken Ross]

Thanks Ron. Good or bad, I'll let you know the outcome.

[Cliff Totten]

Let's toss around this AS100 codec for a minute.

3840×2160 @ 30P using only 60Mbp/s?

If we compare this to 24Mbp/s (which we know can be fairly robust) at 1920x1080, mathematically this "seems" to be an H.264 "downgrade" in motion handling and durability.

So, pound for pound, 4K at 60Mbp/s would equal 15Mbp/s in 1080. (if you think of 4K in HD quadrants)

XAVC-S has something extra thrown into the mix. It runs at the very highest H.264 "5.2" level profile.

What about AVCHD? It's set at high profile but only 4.0 so it uses a lower H.264 toolset.

So here is the technical question for anybody out there that might know: Does the increased XAVC-S H.264 5.2 profile justify the lower bitrate used in 60Mbp/s 4K at 30p? Does the additional tools and calculations cover that bitrate loss?

Can XAVC-S provide at least an equal amount of motion handling at 4K, 29.97p running at 60Mbp/s as 1080 does at 24Mbp/s in 29.97p?....because it uses a deeper tool set?

Can anybody with a Handycam AX1 shoot 10 seconds of a scene with a modest amount of movement and upload it somewhere for people to test?

This new AX100 60Mbp/s only bitrate might be the biggest question about the overall image quality of this new little camera.

At $2,000 I find it hard not to make it my first jump into 4K. For a full manual camera, there is not much to lose and pretty much forces me to get into 4k sooner than I originally planned. (I'll prolly buy a "pro" 4K camera next year but start "playing" with this one in 2 months)

CT

[Ken Ross]

I've asked the same thing on another forum, but I don't think anyone knew the answer. Perhaps people don't have enough experience with this new format?

I guess I'll be getting the answer in March when mine comes in. :)

[David Heath]

Originally Posted by Cliff Totten

Let's toss around this AS100 codec for a minute.

3840×2160 @ 30P using only 60Mbp/s?

If we compare this to 24Mbp/s (which we know can be fairly robust) at 1920x1080, mathematically this "seems" to be an H.264 "downgrade" in motion handling and durability.

So, pound for pound, 4K at 60Mbp/s would equal 15Mbp/s in 1080. (if you think of 4K in HD quadrants)

There's something you're missing if you make that comparison. If a level of compression gives an element of artifacting which is just visible in an HD picture, then in a quadrant of a 4K image, the chances are it won't be. Any artefact will be a lot smaller as a fraction of the whole picture.

Expressed in another way, it's possible to use higher compression ratios as resolutions increase with no increase in the visibility of artifacting. The other thing to bear in mind is that the 24Mbs figure for AVC-HD is a max bitrate - the average will be lower. Do we know what the 60Mbs quoted relates to? Maximum, average, what?

Taking all that together with the fact that XAVC does indeed use more tricks of the H264 toolkit than AVC-HD, then whilst I can't pretend to know exactly by how much this will allow the bitrate to be decreased from the initially expected 4x24Mbs, I fully expect equivalent quality will be obtained with considerably less than 96Mbs.

So will 60Mbs be adequate? We'll see, but I doubt the figure was just plucked out of thin air without any testing. For now I'm prepared to believe the camera wouldn't have the spec if Sony didn't have good reason to think it would be.

And let's not forget we are talking about a consumer badged camera - not an F55. What is adequate for one may not be at all adequate for the latter. The codec and 60Mbs bitrate is likely a good compromise for a 4K camera in this class.

[Ron Evans]

The FDR-AX1 will shoot 30p at 60Mbps and 100Mbps so is this like AVCHD at 24Mbps( 21Mbps ave ) and 17Mbps of the consumer cameras? I have not tried the difference on my FDR-AX1 as I shoot 60P so far. I have sent back to Sony for a backfocus check at the moment so will try when I get it back from service.

Ron Evans

[Dave Blackhurst]

Cliff and Ken -

I think we're all "barking up the same tree" here - this is a "cheap" entry into 4K, something we all know is coming, but probably aren't "ready" for! I've put off a computer upgrade simply because I suspect I'll need even more oomph for 4K...cheap is relative, by the time you include the other probable "upgrades"! CPU, video card, bigger faster drives and memory, 4K monitor/TV...

That 30P does make me nervous, as I don't like the results from 24p typically, and strongly prefer 60p. Will motion be captured in an acceptable way or not... that is the question, and we'll have to wait and see!

In some ways this starts to add some shine to the "ugly stepsister" CX900 - unless that "4K" feature is a total bust, most will buy the AX100, meaning the CX900 might be discounted rather quickly and aggressively, and it should have great 1080 60p... hmmm.

I still think the AX100 is going to be a good "toes in the water" camera for 4K, and likely "good enough" for most users and viewers - sure it may not be "perfect", but at this price point??

As a practical matter, I think most users (and viewers) are still happy with "HD", it will likely be a viable capture and delivery format for some time, 4K just represents the next stage in imaging, I'd rather spend a smaller amount to experiment with it than a larger amount - either way, these first models to market will probably be "obsolete" pretty fast anyway!

[Ron Evans]

You may find this presentation on XAVC useful.

XAVC: Advanced Video Coding Technology on Vimeo

Ron Evans

[Kate Spiegel]

I am not barking. I find 4k = 3D. We all saw where that ended up.

[Ozzy Alvarez]

Only time will tell if 4K gets accepted or if it ends up like the 3D cams and TVs. Each innovation in video runs thru this test. The transition from analog to digital to HD has been amazing and now we are at the precipice of another video evolution. Of course, it usually takes a revolution for that evolution to take place. People literally needed to revolt from analog for digital to become the standard bearer. And once again, for HD to be accepted by the masses.

There were those who questioned whether camcorders would go tapeless or not. But, now I can't think of any major manufacturer who has an active camcorder brand new camera that shoots on Mini DV tapes, although I still have plenty of camcorders which still shoot onto Mini DV/HDV like my trusty HVR-A1.

My point is that technology is moving so fast that today's technological breakthrough or innovation becomes obsolete tomorrow. The speed which things are moving is so rampant nowadays that I question whether the public is as ready as the manufacturers want them to be. It's not that 4K may be a flash in the pan like 3D, it's that it may be too much too soon for some or for many. I know certain friends and families that finally may the jump to HDTVs from their old SDTVs. I doubt they'll be ready all of the sudden to jump to 4K TVs.

Like I said, only time will tell. I'm not ready to believe that 4K or XAVC will becomes a standard bearer or not. I suspect the pros and aspiring filmmakers will love it, but, I suspect the average consumer will still be happy with their little HD Handycams.

[Jack Zhang]

The video that Ron just posted contradicts the whole expected HD 10bit 4:2:2 50/60p spec in XAVC-S. Seek to around 24:46.

So we are getting 4:2:0 50mbps after all. No different from the GH3's 50mbps.

The only camera likely to get 10bit 4:2:2 1080 50/60p at 50mbps is the PMW-300 since it's real XAVC. It will have to be Long-GOP, and there's no certainty it's not the S variant.

[Dave Blackhurst]

3D is a "gimmick", one that has come and gone more than a couple times... It's known to give some people headaches and eyestrain. No amount of marketing hype will beat that and the funky glasses with limited viewing angles...

4K is an extension of a legitimate demand for sharper images (Retina displays anyone?), and better capture and display devices. It's not "needed" per se (nothing wrong with old "I Love Lucy" reruns in B&W, right?!), but when pretty much anyone can see the improved image quality if the screen is large enough, there WILL be a demand, I don't see it as a "gimmick".

Tablets and phones are already touting 4K, and it's not like there is any big blockage to higher resolutions - people expect high resolution STILLS, and it's logical to expect that if that level of sharpness can be made available at reasonable prices on display screens, and in capture devices, it won't be terribly long before there will be plenty of options at "consumer-y" prices.

A $2K camera is at least in the "consumer" ballpark, and if it represents "better" quality (than phones or tablets), even if not "best" (studio/pro cameras), it will likely be a breakout product. Much will depend on the workflow and overall support for content creators, but Sony seems to have laid out a pretty good roadmap (even if the AX100 wasn't apparently on it - I still say this sensor/processor seems to have come out of nowhere!).

You can look at it and say "why doesn't it do this or that like the $5K camera does", or if it turns out to produce a fairly high quality image for a lot less, be happy with what it CAN do. I suspect the higher bitrate 1080 60p may be worth the price of admission for many, just in case 4K for some reason turns out to be a dud or a speed bump on the way to 8K or holographic 3D or whatever...