colinelves (Colin Elves)
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Dec 9 2014, 1:09 PM (223 w, 2 d)
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Recent Activity

Apr 2 2017

colinelves added a comment to T244: image pipeline: highlight recovery.

Some form of highlight recovery would still be useful in this instance though - albeit not one based on white balance.

Apr 2 2017, 10:46 PM · AXIOM Beta Software
colinelves added a comment to T244: image pipeline: highlight recovery.

Just to follow up from Sebastian - yeah, it wouldn't be necessary to do it to Raw data - as it is better handled in post.

Apr 2 2017, 10:12 PM · AXIOM Beta Software
colinelves added a comment to T244: image pipeline: highlight recovery.

As I understand it, the approach generally relies upon approximations from adjacent, unclipped pixels.

Apr 2 2017, 10:08 PM · AXIOM Beta Software
colinelves added a comment to T244: image pipeline: highlight recovery.

You're not quite getting it. It would probably easier for you to understand by looking at an example of it in action. If you had a raw data sample in DNG format of a clipped source (such as a domestic light near a white wall) you could load it into Resolve and try turning hightlight recovery on and off - then you'll see the detail appear and disappear in pixels near to the point of clipping (it's often more dramatic with off white lights)

Apr 2 2017, 2:02 PM · AXIOM Beta Software

Feb 28 2015

colinelves added a comment to T276: Accessories / Compatibility.

The Arri mount system seems to just be a plate held in place by four locking screws (like the Red mount) with the mount in the middle so I don't see why the Axiom system couldn't position the locking screws in the same place.

Feb 28 2015, 9:18 AM

Feb 11 2015

colinelves updated subscribers of T279: Slow Motion.

It's worth noting that the 1000fps camera has just been given an upgrade to use the Cmosis CMV12000 sensor being used in the Beta: http://www.eoshd.com/2014/12/kickstarter-fps1000-high-speed-camera-upgraded-220fps-4k-super-35mm-2750/

Feb 11 2015, 4:53 PM · Restricted Project

Feb 8 2015

colinelves added a comment to T276: Accessories / Compatibility.

Ah, okay. I've had a quick look at the Wooden Camera website - it's not entirely clear what is going on there.

Feb 8 2015, 10:23 PM
colinelves updated subscribers of T276: Accessories / Compatibility.

Red mount is a good idea - but you should asses any potential licensing issues.

Feb 8 2015, 6:59 PM
colinelves added a comment to T277: Overscan (see area around the recorded one).

Or just having good solid frame lines.

Feb 8 2015, 6:47 PM · AXIOM Beta Software
colinelves updated subscribers of T277: Overscan (see area around the recorded one).

Personally I think I'd find odd colours around the image distracting. Having the area outside black and white and/or partially shaded would be better for me.

Feb 8 2015, 6:46 PM · AXIOM Beta Software

Feb 5 2015

colinelves added a comment to T136: 4K RAW PC recording.

The MOX is open source open format and I know Brendan Knows about the Axiom and I think Sebastian et al have been in contact with him about maybe using it. As I understand it, however, MOX is essentially a flexible wrapper - it could be used as a production format, you just need to include an (open source) compression codec in the wrapper.

Feb 5 2015, 9:13 PM · 4k Raw recorder, Brainstorming

Feb 1 2015

colinelves added a comment to T268: Exposure Compensation.

That sounds like a good idea - although I'm not sure how this set up would be much different - except as a more basic form of the same thing?! Could you perhaps explain the exposure compensation idea in more detail?

Feb 1 2015, 1:40 PM · AXIOM Beta Software

Jan 31 2015

colinelves added a comment to T268: Exposure Compensation.

Actually I reread the title of this task. Exposure compensation is a pretty good way of describing what I'm talking about (duh! I'm pretty stupid sometimes) - so + or - a stop would be one way of expressing it, although some might prefer to see it as a change in the 'ISO' (not that digital sensors really have an ISO). But ultimately I think we're talking about the same thing, no?

Jan 31 2015, 11:05 PM · AXIOM Beta Software
colinelves added a comment to T268: Exposure Compensation.

So on an Alexa if you close the iris by one stop and increase the ISO by one stop you will end up with a completely different looking image as before?

Jan 31 2015, 9:04 AM · AXIOM Beta Software

Jan 29 2015

colinelves added a comment to T268: Exposure Compensation.

Of course, being able to adjust the ISO using analogue gain settings would also be useful, bearing in mind this would reduce the dynamic range of the chip, especially for low light situations and also for Raw recording. The question then becomes how to communicate to the user what's happening - is it a tone remapping or the application of analogue gain or both?

Jan 29 2015, 12:26 PM · AXIOM Beta Software
colinelves added a comment to T268: Exposure Compensation.

Hi sebastian - take a look at the link I showed you. In the Arri The variable ISO settings are not to do with digital or analogue gain - these both remain the same (to make sure DR is maximised at all times) rather they are to do with tone mapping.

Jan 29 2015, 12:24 PM · AXIOM Beta Software

Jan 28 2015

colinelves updated subscribers of T268: Exposure Compensation.

It's probably more 'standard' to express this as a variable ISO and have it realised through adjusting the gamma curve of the preview LUT. In this scenario the ISO represents the (shifted) mid grey point. It might also help to have a little +/- figure indicating how many stops above and below this mid grey point you have.

Jan 28 2015, 8:15 PM · AXIOM Beta Software

Jan 26 2015

colinelves added a comment to T265: Variable ISO via frame averaging..

I imagine it would depend a lot on how the averaging was done. Anyway - can you post some examples of the sort of artefacts you're talking about? Only I had a look and all I could find were examples of stills built from multiple video frames - and these had quote nice motion blur.

Jan 26 2015, 8:40 PM · AXIOM Beta Software

Jan 25 2015

colinelves added a comment to T265: Variable ISO via frame averaging..

Also there is a marked difference between 10bit and 12bit - which is worth bearing in mind.

Jan 25 2015, 11:38 AM · AXIOM Beta Software
colinelves added a comment to T265: Variable ISO via frame averaging..

I believe Alex was talking about the mk1 sensor. The latest version is faster I believe.

Jan 25 2015, 11:37 AM · AXIOM Beta Software
colinelves updated subscribers of T267: Preview 3D LUT - FPGA feature.

I doubt you'd be able to do any processing on 4K (above 30fps) or high speed data would you? It'd be straight raw out.

Jan 25 2015, 10:01 AM · AXIOM Beta Software

Jan 24 2015

colinelves added a comment to T265: Variable ISO via frame averaging..

I did find this, however: http://www.cambridgeincolour.com/tutorials/image-averaging-noise.htm

Jan 24 2015, 10:42 PM · AXIOM Beta Software
colinelves added a comment to T265: Variable ISO via frame averaging..

Can you expand upon that as I'm not too sure what you're talking about and Google doesn't help.

Jan 24 2015, 10:42 PM · AXIOM Beta Software
colinelves added a comment to T265: Variable ISO via frame averaging..

I believe frame averaging doesn't have any motion artefact problems - it's effectively the same as taking one frame of 1/50th second exposure - but temporal noise is effectively lost in the averaging. Fixed pattern noise remains (although a black balance can deal with a lot of that. The main drawback is a significantly reduced ISO.

Jan 24 2015, 3:00 PM · AXIOM Beta Software

Jan 23 2015

colinelves added a comment to T248: Enable windowed and pixel binning modes - potential for high speed filming and increased DR.

I think it's probably not worth it, no? Maybe just work on better processing ;-)

Jan 23 2015, 9:11 AM · AXIOM Beta Software
colinelves added a comment to T248: Enable windowed and pixel binning modes - potential for high speed filming and increased DR.

Response from Cmosis:

Jan 23 2015, 9:10 AM · AXIOM Beta Software

Jan 22 2015

colinelves updated subscribers of T250: Research Packaging Foam Molding Solutions.

I like the idea of the Beta shipping in some sort of foam that can be reused in a case. You could, perhaps, offer backers the option of paying a bit extra to get a solid case rather than a cardboard box.

Jan 22 2015, 10:58 PM · Brainstorming, AXIOM Beta Hardware

Jan 20 2015

colinelves added a comment to T98: "Cupboard" concept design of AXIOM Beta Cage .

Not exactly true regarding the XLRSs - even running dual system sound you may want to use the onboard recording for a scratch track via either an on board mic or a radio mic to help with syncing in post. It's also a useful idea if the camera cannot accept Timecode in as you can use an Audi track to record LTO Timecode.

Jan 20 2015, 9:15 PM · AXIOM Beta Hardware

Jan 19 2015

colinelves added a comment to T248: Enable windowed and pixel binning modes - potential for high speed filming and increased DR.

I'm willing to give it a go. Who do I contact?

Jan 19 2015, 7:20 PM · AXIOM Beta Software

Jan 18 2015

colinelves added a comment to T246: Full HD/16mm crop mode .

Ah, yes. I suppose you would!

Jan 18 2015, 4:09 PM · AXIOM Beta Software
colinelves created T265: Variable ISO via frame averaging..
Jan 18 2015, 4:07 PM · AXIOM Beta Software
colinelves added a comment to T246: Full HD/16mm crop mode .

Okay, so a 16mm crop area would be simple enough to implement then. It might be worth using the line skip as well since this would increase the max frame rate at the same time.

Jan 18 2015, 4:03 PM · AXIOM Beta Software

Jan 17 2015

colinelves added a comment to T201: Research push button options.

Okay, cool - although bear in mind I'm a cameraman not a sound recordist - they may have different opinions. Having said that one of great advantages of the Axiom is that it's open source - if people hate the noisy buttons they can go and make some silent ones...

Jan 17 2015, 9:32 PM · AXIOM Remote
colinelves updated subscribers of T201: Research push button options.

I'm impressed you're thinking about the noise of the buttons- I doubt a angle camera manifacturer has ever thought about that!

Jan 17 2015, 8:54 PM · AXIOM Remote

Jan 11 2015

colinelves added a comment to T231: Current status: What the Beta can do, could do, what the current priorities are etc....

Also: a detailed update on the Gamma (at some point) would be appreciated. I heard Sebastian on Ogy's podcast say that the timeline for delivery is quite strict due to the European funding - so it would be good to find out what the development roadmap for it is. I'd also be really interested to find out who your development partners are and what aspects of the development they are assisting you with.

Jan 11 2015, 10:42 AM · Novice

Jan 10 2015

colinelves added a comment to T248: Enable windowed and pixel binning modes - potential for high speed filming and increased DR.

Although Alex at Magic Lantenr seemed to indicate that the black reference collums are too small to do much to reduce the noise: http://www.magiclantern.fm/forum/index.php?topic=11787.0

Jan 10 2015, 9:52 AM · AXIOM Beta Software
colinelves added a comment to T248: Enable windowed and pixel binning modes - potential for high speed filming and increased DR.

Here's the bit I was thinking about:

Jan 10 2015, 9:02 AM · AXIOM Beta Software

Jan 8 2015

colinelves added a comment to T248: Enable windowed and pixel binning modes - potential for high speed filming and increased DR.

Yes, I'm not sure how it works. There are some pixels on the Cmosis chip set aside as black reference I believe but I'd need to look through the data sheet to find them.

Jan 8 2015, 11:34 PM · AXIOM Beta Software

Jan 7 2015

colinelves added a comment to T248: Enable windowed and pixel binning modes - potential for high speed filming and increased DR.

I think both Cmosis and Alex from Magic lantern should be able to help with this.

Jan 7 2015, 9:09 AM · AXIOM Beta Software
colinelves added a comment to T248: Enable windowed and pixel binning modes - potential for high speed filming and increased DR.

Some info on black shading in Magic lantern http://www.magiclantern.fm/forum/index.php?topic=9861.0

Jan 7 2015, 9:02 AM · AXIOM Beta Software

Jan 6 2015

colinelves created T248: Enable windowed and pixel binning modes - potential for high speed filming and increased DR.
Jan 6 2015, 8:58 PM · AXIOM Beta Software
colinelves updated subscribers of T246: Full HD/16mm crop mode .

The chip has a programable window mode is that means he chip will only read the centre 1080 lines - but I think they are spread across the full width of 4096 pixels - I'm not sure if you can specify a window that has a shorter line length, but perhaps Cmosis could let you know. If you can get the chip to only read out that window it would make processing a lot easier. Or perhaps it's simple enough to disregard the first and last 1,088 pixels per line. One added advantage would be a high max frame rate a la Red.

Jan 6 2015, 8:54 PM · AXIOM Beta Software

Jan 5 2015

colinelves updated subscribers of T98: "Cupboard" concept design of AXIOM Beta Cage .

90 degree connectors would help, as would rotating the IO shield so the ports are at the top rather than the side.

Jan 5 2015, 10:10 PM · AXIOM Beta Hardware
colinelves added a comment to T244: image pipeline: highlight recovery.

Highlight recovery is only of use when recording debayered (non-raw) images since highlight recovery can be carried out in post on raw data. However the process itself needs to be carried out on the Raw data stream itself.

Jan 5 2015, 6:16 PM · AXIOM Beta Software

Jan 4 2015

colinelves updated subscribers of T244: image pipeline: highlight recovery.

I'd put this into the serious consideration category - the dynamic range of the chip is already somewhat restricted - so any in camera processing that can increase dynamic range at the top end or reduce noise in the shadow areas would definitely be welcome.

Jan 4 2015, 7:33 PM · AXIOM Beta Software
colinelves added a comment to T241: Define Image pipeline for triple HDMI shield.

I don't see why not - you could simply disable one of the HDMI 1.0 ports when running the HDMI 1.4 port 'hot' (as it were) - i.e. If it is used for Raw, 4K or high speed output. If it's just used for HD only the bandwidth would be the same as if it were HDMI 1.0 - but you'd have the extra bandwidth when needed and the extra output when you don't - surely it's the most flexible option?

Jan 4 2015, 7:02 PM · AXIOM Beta Software

Jan 3 2015

colinelves added a comment to T241: Define Image pipeline for triple HDMI shield.

It might be easier to produce just one shield that has one 1.4b HDMI (for high speed or 4K) and two 1.0 ports for monitoring.

Jan 3 2015, 5:41 PM · AXIOM Beta Software
colinelves added a comment to T231: Current status: What the Beta can do, could do, what the current priorities are etc....

One more thing: am I right in thinking the Beta will have no LCD, status lights or buttons on it? If so how is it switched on and off? Is simply a question of pulling the power cable or removing the battery (is this likely to damage the unit at all?).

Jan 3 2015, 9:27 AM · Novice

Jan 2 2015

colinelves added a comment to T241: Define Image pipeline for triple HDMI shield.

Alternatively it might be better to save the high speed and Raw modes for SDI shields as these seem to allow much higher data rates even with just 3G SDI (let alone 6G or 12G).

Jan 2 2015, 11:48 AM · AXIOM Beta Software
colinelves updated subscribers of T241: Define Image pipeline for triple HDMI shield.

Those sound plausible to me. However, I do want to throw one thing out there: the Atomos Shogun has an HDMI 1.4b board in it. According to the specs this allows it to accept 4K HDMI signals and HD signals at up to 120fps.

Jan 2 2015, 11:47 AM · AXIOM Beta Software
colinelves added a comment to T233: Zebra Overlay .

By all means, if it can be managed why not do it - there's a lot to be said for doing something that people are used to. I was simy pointing out that blocks of colour might be easier to implement.

Jan 2 2015, 10:42 AM · AXIOM Beta Software
colinelves added a comment to T233: Zebra Overlay .

One thing I realised last night was that there is no particular need these days to have the 'zebras' displayed as an actual zebra pattern (the stripes). The only reason they were originally displayed as stripes was because the first video cameras only had black and white viewfinders hence there was no other way to display this relevant information.

Jan 2 2015, 10:14 AM · AXIOM Beta Software
colinelves added a comment to T233: Zebra Overlay .

Not sure why my previous comment was removed. I was simply pointing out the ideal set of features. As a general rule I don't think anyone is likely to have a problem having one feed permanently clean for recording purposes.

Jan 2 2015, 9:41 AM · AXIOM Beta Software
colinelves added a comment to T233: Zebra Overlay .
Jan 2 2015, 12:05 AM · AXIOM Beta Software
colinelves added a comment to T233: Zebra Overlay .

I think the first thing to consider is that there are multiple image pathways possible on the camera. So one output may be a log or even raw image stream, while another may show a monitoring LUT (e.g. Log to Rec709) so the user needs to be able to select which stream they want the Zebra to be applied to but also to select which stream they want the zebra to be calculated from.

Jan 2 2015, 12:04 AM · AXIOM Beta Software

Jan 1 2015

colinelves added a comment to T231: Current status: What the Beta can do, could do, what the current priorities are etc....

One other thought: It would be good to get an update on the expected cost of the Beta to backers - some of us need to start saving now to afford it!

Jan 1 2015, 11:30 PM · Novice

Dec 30 2014

colinelves updated subscribers of T232: Peaking - FPGA feature.

I find the 'sharpening' approach less helpful than the coloured edges. The former method often leads me feeling a little concerned, whereas the coloured edges leave you in no doubt.

Dec 30 2014, 11:28 AM · AXIOM Beta Software
colinelves updated subscribers of T233: Zebra Overlay .

Yes and no. One traditional use of Zebra patterns was to set correct skin tone exposure levels - roughly 67 IRE in Rec 709 Colour space - if this capability was lost (as the zebras became channel specific only) I think many people would be more than a little annoyed as they rely on it for correct exposure.

Dec 30 2014, 11:25 AM · AXIOM Beta Software
colinelves added a comment to T231: Current status: What the Beta can do, could do, what the current priorities are etc....

Thanks Herbert,

Dec 30 2014, 10:57 AM · Novice

Dec 28 2014

colinelves added a comment to T213: An entry level low price version of the Axiom.

No, they're not - at least not at the moment (I wouldn't put it past Black Magic to release the firmware of the black magic cameras). But they are both incredibly cheap - and I doubt there is much that can be done to the Beta to make it cheaper, except what is already on offer (ie a cheaper sensor).

Dec 28 2014, 5:46 PM · AXIOM Beta Hardware
colinelves added a comment to T231: Current status: What the Beta can do, could do, what the current priorities are etc....

I'd like to see, in the future:

Dec 28 2014, 11:40 AM · Novice
colinelves added a comment to T231: Current status: What the Beta can do, could do, what the current priorities are etc....

Personally speaking:

Dec 28 2014, 11:27 AM · Novice
colinelves created T231: Current status: What the Beta can do, could do, what the current priorities are etc....
Dec 28 2014, 11:25 AM · Novice
colinelves added a comment to T136: 4K RAW PC recording.

Obviously no compression is the easiest to manage in camera in terms of processing required (i.e. none) but further down the image pipeline no compression becomes a problem.

Dec 28 2014, 11:12 AM · 4k Raw recorder, Brainstorming
colinelves updated subscribers of T213: An entry level low price version of the Axiom.

The main problem with this suggestion is that there is already two very good 'low cost' cameras in the market:

Dec 28 2014, 9:27 AM · AXIOM Beta Hardware

Dec 25 2014

colinelves updated subscribers of T223: Image magnification preview in video output - FPGA feature.

Could be useful - but equally tricky to programme I would have thought since the camera has to work out where that is. I suppose, once you have peaking working okay (ie highlighting of high contrast pixels) you tell it to jump to work out a general centre for those areas.

Dec 25 2014, 10:36 AM · AXIOM Beta Software

Dec 17 2014

colinelves updated subscribers of T222: Low Resolution Real-time Preview Video Stream - FPGA feature.

A 512x288 image is insufficient for ensuring correct focus, especially at 4K - in my opinion. I'd also say that line skipping or scaling seems like a lot of extra processor work to me. I was thinking that having a simple black and white image would be the easiest solution: simple conversion of the raw pixel values straight to luma data.

Dec 17 2014, 9:03 AM · AXIOM Beta Software

Dec 16 2014

colinelves added a comment to T136: 4K RAW PC recording.

Fair enough. I was just raising the question as to whether or not own form of lossless compression could be implemented - even if it requires significant post processing to unpack the data afterwards.

Dec 16 2014, 10:55 PM · 4k Raw recorder, Brainstorming

Dec 12 2014

colinelves added a comment to T136: 4K RAW PC recording.

Hi Surami,

Dec 12 2014, 12:15 AM · 4k Raw recorder, Brainstorming

Dec 10 2014

colinelves added a comment to T136: 4K RAW PC recording.

From a practical sense it's rather irrelevant that the compression is lossy. Obviously the ideal would be lossless compression but what is needed is some for of compression that is achievable in real time (no mean feat when dealing with 4K footage, especially at rates above 30fps) and makes file sizes manageable. 4K Raw or Uncompressed (which is actually worse than Raw) is a horrendous amount of data to deal with.

Dec 10 2014, 4:49 PM · 4k Raw recorder, Brainstorming
colinelves updated subscribers of T136: 4K RAW PC recording.

My preference would definitely be for SDI - HDMI connectors are so unreliable and you need a solid connection if you're going to be dealing with that much data.

Dec 10 2014, 10:41 AM · 4k Raw recorder, Brainstorming