Sony FDR-AX100

[Dave Blackhurst]

Originally Posted by Ken Ross

Not sure that's the way it works in the AX100, Dave. This is the first Sony I've had where CIZ doesn't work like others. As soon as you engage Active Stabilization, CIZ is automatically engaged. Doing so, even at full wide, shows a very slightly cropped area. As someone had measured with a resolution chart, there is a 5% cropping at full wide. So I don't think this is taking place in a purely optical environment, but who knows?

The 5% plus or minus "penalty" is what I described earlier for active (digital) stabilization - the camera effectively reserves those pixels at the edges of the image for use in moving the "center" of the image around (stabilizing it). I'm pretty sure that penalty has been reported on other models? Seems like I've noticed that as soon as you go "active", you lose a bit of the frame all around... not anything new.

It means there's still an optical component, as long as you're in the lens range, but the camera doesn't use ALL of the image the lens puts to the sensor when using digital stabilization - edges are "reserved" to allow digital stabilization. It does however indicate (presuming the 5% figure is accurate) that there's not a LOT of room for digitally stabilizing an image.

Not sure why CIZ and AS are linked together, but steadyshot (no active setting) and both zooms are independent settings on the RX100M2, and they appear to be entirely independent on the RX10 (active DOES reduce the image noticeably over standard). Seems odd that they are interlinked with the AX, with similar tech... only thing I can think of is that "active" is needed once you get to the long end of the range, and they didn't want you to have to dig down and engage it every time, or couldn't do it seamlessly on the fly.

One of the fun things about understanding how these things work is that there are many aspects, and interactions, it's not just "grab a sensor, stick a lens on it and go!". I laugh sometimes when a noob/novice tries to say how "something is wrong" or "the company is crippling things deliberately" or "this camera is crap because..." and they know exactly ZIP about the technology, and what they THINK they know is so far off from reality that you just want to fold up a nice little tinfoil hat and hand it to them...

Here at least, we've got a few experts, and a fair number of generally educated enthusiasts who can take a stab at understanding/reverse engineering these complex toys and how to best use them... even if sometimes we do have to "guess" a bit at what causes the things we "see".

I'm still waiting for the first wave of "this is crap" returns so I can catch a deal... some dealers are asking above retail on new, so I guess the camera is popular! Meanwhilst, I'm starting to collect parts for a new computer to handle this 4K stuff...

[Dave Blackhurst]

@Ken -
The video sure looks good overall, I do see where I'm glad I have all my old "stabilizing" shoulder mounts, brackets, etc., hanging around... you can pick up a bit of "roll" in places, something I seem to recall was ironed out somewhere around the transition between the SSR11 and the CX550, if memory serves. Not a "deal breaker", but I guess we have all been spoilt a bit by small sensor stabilization tech!

[Mark Rosenzweig]

4K baseball video:

Sony FDR AX100 Video: Baseball in 4K on Vimeo

[Ken Ross]

Thanks Dave. Yeah, the OIS is a small price to pay for the overall PQ. Still, coming from the RX10, this OIS is still better.

[Steve Mullen]

Originally Posted by Ken Ross

Aliasing? Where??? There isn't a trace of it in any of the videos I've shot.... But edited videos from those that know what they're doing, show no evidence of aliasing.

Look at the brick building in your first couple of shots. The moving funny looking pattern is Moiré which, as I posted earlier, is one of the forms of ALIASING. Because we don't have brick buildings in Vegas I haven't been able to test for it. Thank you for doing the test for me.

Let's do a simple test, play the video below in 4K or 2K -- you need to be able to see it at normal speed. Do you see twinkling lights in he second scene? I do. Others do. But, when my camera is totally still, the lights don't twinkle -- because they don't in reality. This is "interline twitter" -- another form of ALIASING.

Rolling shutter -- a form of temporal ALIASING -- is not evident because I follow pan with the motion. When correctly shot, RS is minimal. The stuttering seen with moving cars -- as seen in the video -- is temporal ALIASING.

AX100 UHD project edited in FCP X - YouTube

FROM BARRY GREEN:
* Aliasing, by way of a definition, is when a sampling system fails to accurately reproduce what it's attempting to sample. Instead of an accurate representation of what you're trying to capture, you get an inaccurate “alias” of it. Aliasing happens when inaccurate or “false data” gets through and is captured by the system as if it was actually accurate information.

* One superb example of aliasing and the dangers it can cause, is a “rolling shutter” for example a warped airplane propeller.

* Some cameras that look like they're rendering incredibly sharp, highly detailed images, but they're not. So – is it a good thing, or a bad thing? In the end, it's all about what you find pleasing to the eye. And, truth be told, many people actually LIKE the aliasing artifacts, they think it makes the images look sharper. But like all aliasing, it can cause problems in the image. The most well-known are moire and jaggy lines (stair stepping). Moire happens when a repeating pattern of detail is too fine for the image sensor to handle it, so it creates a fake pattern.

IN FAIRNESS -- I don't claim the AX100's sharpness is due to aliasing. I suspect Sony is filtering the video to get the maximum possible amount of real detail, with little STATIC SPATIAL aliasing. That's what the German review found. No static aliasing -- which was misunderstood as meaning no aliasing.

[Ken Ross]

Originally Posted by Steve Mullen

Look at the brick building in your first couple of shots. The moving funny looking pattern is Moiré which, as I posted earlier, is one of the forms of ALIASING. Because we don't have brick buildings in Vegas I haven't been able to test for it. Thank you for doing the test for me.

Steve, in the original native version, there isn't a trace of moiré on those bricks. There simply isn't. I know moiré very well from my VG20, VG30, NEX7 and NEX6 when shooting video. The AX100 simply doesn't show it.

In fact, I remember when I first played that scene from AC and thought "Wow, not a trace of moiré in those bricks, how nice".

You are making the mistake that many do, judging a video from a non-native file. That's not the proper way to judge the video from any camera. I don't care if it's streaming from Vimeo or YouTube, any streaming service will introduce artifacts. Additionally, many editing programs will introduce artifacts that are unjustly pegged to the camera. Until you see a native file you have no clue what the camera is producing.

[Marc Salvatore]

I read in a review on Amazon that when recording in 4k you will not get a live HDMI signal. Is this true? I like to monitor my interviews on a large 1080p monitor and this would probably kill it for me.

Thanks, Marc

[Ken Ross]

Marc, the AX100 will only output 4K if you're not recording internally. If you record internally, there is no output.

However, the camera can output a wifi signal that can be useful for monitoring. You can capture the wifi signal with a smartphone or tablet. That may not suit your purposes, but it can be done and for some it might fit their needs.

[Marc Salvatore]

Thanks Ken. Would I get a HDMI feed while the camera is in pause mode?

[Darren Levine]

Originally Posted by Ken Ross

Steve, in the original native version, there isn't a trace of moiré on those bricks. There simply isn't. I know moiré very well from my VG20, VG30, NEX7 and NEX6 when shooting video. The AX100 simply doesn't show it.

In fact, I remember when I first played that scene from AC and thought "Wow, not a trace of moiré in those bricks, how nice".

You are making the mistake that many do, judging a video from a non-native file. That's not the proper way to judge the video from any camera. I don't care if it's streaming from Vimeo or YouTube, any streaming service will introduce artifacts. Additionally, many editing programs will introduce artifacts that are unjustly pegged to the camera. Until you see a native file you have no clue what the camera is producing.

well, i'll get around to doing a moire stress test this week, and see what a somewhat controlled environment can produce

[Darren Levine]

Ken, i'll admit i was skeptical of your claims as to it's moire/aliasing performance, but while there is some present, it is indeed damn good.

Of course, download the full clip to judge, though the online playable clip already shows very very little artifacting as is. (if played at 1080 unscaled)

Sony AX100 Moire/Aliasing Test - 4k Unedited camera clip for download on Vimeo

And here for reference are the bmc4k, c100, rx10, and 5d2

BMC 4k, 5D2, C100, RX10 Moire/Aliasing stress test on Vimeo

[Ken Ross]

Yes Darren, very very tough to pick up. I don't think most would even notice it and certainly nobody would be bothered by it as minor as it is in these 'worst case scenarios'.

That's why it's like knocking your head against the wall when someone makes a claim that there's significant this or that when you know damn well it's just not the case. We've got guys who do edits and re-edits and then claim there's this or that artifact. I just sit here and shake my head.

If you're familiar with video as almost everyone here is or should be, you know the only way to tell if a camera has artifacts and to what extent, is to view native files. Not online videos, not edited videos or re-edited videos. It's just common sense.

[Joachim Hoge]

Just got ours here today. Lucky break as the first ones arrived today and we are leaving for Kamchatka, Russia in 2 days. We were looking into re buying a NX-30 after ours was stolen on our last trip there a year ago, when 2 ex of this camera arrived in Norway today.
Only been playing around with it with out cards, so no shooting. A little bigger than I thought it would be, but certainly a nice feel to it. The IQ seem to be quite good. I did notice quite a bit of rolling shutter when panning at full tele, it got a bit better when I set the stabilizer to active.

This was the last camera in our 4K puzzle, as we now start a new production with all 4K (or better) cameras.
I think it will be a great little B-cam, a camera that we can hand out to our participants in places where we sometimes can´t be with them (top of mountains etc).
I think most people would be able to operate this quite easily, but it can still be quite advanced when needed.

Any thing we should watch out for?
We don´t have much time to test this camera before we go

[Dave Blackhurst]

@Steve -

I'm not seeing objectionable "artifacts" for the most part, maybe tiny, minor ones here or there in a "worst case" scenario, but certainly not something to condemn a $2K camera... the bricks look FINE, minor "twinkling" in some of those lights, but not in all scenes, and a little temporal stutter in moving vehicles (expected w/ lower frame rate)

There are so many places in the chain (INCLUDING my computer/graphics card/monitor!) where "things" can be introduced, I don't think we doubt that YOU are seeing things, but as a practical matter, others ARE NOT, at least not to the degree that you seem to be. The video looks eye popping-ly GOOD overall, even YOURS is not bad!

[Cliff Totten]

AS100 "4K" HDMI out?

I was talking to Atomos at NAB last week. They mentioned that the new "Shogun" WILL record 4k from the AS100's HDMI IF you don't press the cameras record button.

Wait....I know the AX100 will output 4K on playback...but will it output clean 4K when shooting? (while holding in pause mode)

I was under the impression that the AX100 only does HDMI 4K on playback and 1080 output in every other way.

Can somebody confirm this with a 4K monitor? If Atomos is correct, then how long will the camera output 4K while waiting to record? Will it force shut down after a while or will it hold in pause indefinitely?

If true, this is good news!

CT