Messages

46

Chronos User Discussion / Chronos 2.1 color study

« on: July 07, 2021, 10:42:38 AM »

I wanted to do a quick color analysis to see what was happening at the various primary resolutions of the Chronos 2.1.
All the tests shown here are all taken with the same lens, exact same lighting conditions and exact same frame rate and shutter.

I have included an image from my Canon 1DX2 DLSR @ ISO 500 and 1/2000 as a comparable "reference" shot.

Each DNG image was given a simple white balance in Photoshop with the white target, but no other adjustments were made.

It's interesting to note that not only is there some serious color changes at the lower resolutions, but we're losing overall sensor sensitivity as well.  Is this a bug in the firmware or just an unfortunate characteristic of the sensor?  I'm not sure, but it's most likely the latter.

I'm just presenting this info for folks to be aware of.  If you want the absolute best quality, stick to 1920 and 1472 horizontal resolutions.  Only drop to the lower resolutions if you absolutely need the speed and know what the trade-offs are with respect to color quality and sensitivity.

I hope this type of data is useful to others.  I am coming to the conclusion from all my testing that the 1472 horizontal resolution is the absolute sweet spot for this camera as you gain ~43% speed for only a ~26% drop in resolution and the color, noise, and sensitivity is very close to shooting at full resolution.
 

47

Chronos User Discussion / Re: Post Chronos 2.1 clips here!

« on: July 06, 2021, 10:26:36 AM »

Here is a follow-up video of my water rocket static testing where I actually make the test-rig static

There is some 10186 fps footage from before as well as 12684 fps footage.

Same Canon 135mm f2 @ f2 lens as before.

https://youtu.be/ZKzczldrZnE

48

Chronos User Discussion / Re: Chronos 2.1 noise study

« on: July 04, 2021, 08:57:32 AM »

It's the amplification of the signal which causes the noise.  I'm just suggesting/speculating that if it were possible to read just the green channel off the sensor, you might be able to not amplify the blue/red channels and get a cleaner overall signal.  I have no idea if the hardware can do that. 

Of course it'd be better to also have a monochrome version.  It would also be nice to have a Phantom TMX 7510. 

49

Chronos User Discussion / Re: Chronos 2.1 noise study

« on: July 04, 2021, 06:50:23 AM »

Yeah, I'm not talking about getting the best BW image from the camera as it is, that's not too difficult in post.  What I was wondering if there were some hardware level adjustments that can be done in the firmware to allow for better noise characteristics if you are only concerned with BW.  It's definitely not the same as using the BW sensor with no Bayer filter, but I was just speculating that maybe some of the amplifier gains could be tweaked (or turned off) if it could be run in single color mode or something like that.  This would require firmware changes, but it'd be neat option if it helped.   If you check the Chronos manual, they show the spectral response of both the color and monochrome sensors.  The monochrome is much better (almost double - thus the base ISO at 1000 instead of ISO 500), but if you look at the color graph, the green response is better than either the red or blue.  It might be possible to just read the green channel from the color sensor and tweak the gains to make it a pseudo BW sensor with slightly better noise.

I hear you on remembering the resolutions.  There are only 4 you need to remember with the Chronos 2.1:  1920, 1472, 1152, and 832

It would be nice if there was a way to program the default drop-down resolutions and base them on those 4 values, but I understand from a marketing standpoint why they want the standard HD and SD numbers.

50

Chronos User Discussion / Re: Chronos 2.1 noise study

« on: July 04, 2021, 05:09:16 AM »

Thanks for the reply!  Yeah, this was just an attempt at a scientific noise study, so the black frame is the best way to do that.  To scientifically measure dynamic range across the entire range of sensor options would be a huge task.  Also, I kinda already have an idea about the dynamic range... it goes from fair to really bad  

Personally, I don't think the Chronos is the right tool for the job at shooting anything below 300 fps.  Something like the Blackmagic URSA Mini can shoot 4K at 120 fps and 300 fps at 1080p.  Cheaper options like a GoPro Hero9 or a modern phone will give better results at 240 fps and below.  300 fps to 1000 fps is a bit of a no-man's land with current cameras.  The Chronos is really the only reasonably priced option that is a pretty awesome 1000-4000 fps camera but the base ISO of 500 is somewhat limiting.   To get good results with the Chronos in the 10k+ fps range is really challenging, but it's fun to play around with.

I have a feeling the way the camera is windowing down the resolution and adjusting framerate/shutter is very complex at the hardware level.  It probably involves changing a whole bunch of amplifier gains that effect the noise and noise patterns quite a bit.

I was wondering if it'd be possible to have an option to shoot the color Chronos in BW to try and reduce the noise or perhaps increase the base ISO.  I know the BW version of the Chronos uses a completely different sensor, but it'd be interesting if the color sensor could be tweaked in software in a way to get some of the benefit of the BW hardware.

P.S.  Look into shooting 1472x720 instead of 1280x720.  I think you'll find there is no difference in speed and you'll have an extra 192 pixels to play with framing your shot in post.

51

Chronos User Discussion / Chronos 2.1 noise study

« on: July 03, 2021, 07:21:01 PM »

I spent a fair amount of time trying and understand the noise characteristics of my Chronos 2.1.  From previous work, I determined that there are really only 4 native horizontal resolutions that should be used from a speed perspective: 1920, 1472, 1152, and 832.  Anything else is the same as cropping in post.

I wanted to better understand the noise of each of those base resolutions as well as if vertical resolution had any effect.

Unfortunately, it does look like vertical resolution effects noise level and patterns, especially at the higher gain levels.

My process for all of these runs were as follows (all done via the web interface):

  1. All tests were done with the lens cap covered at all times and the camera had warmed up for 30+ min.
  2. Select the resolution, gain level, and max frame rate
  3. Do two black level calibrations in a row
  4. Save the 100th image as a DNG file
  5. Load the raw images into Photoshop
  6. Overlay the images, flatten the layers, and then boost the global image gain equally across all tests


I also ran a test to see if speed itself made a difference.  It looks like it does somewhat.

I'm not sure what my conclusions from all this testing are.  1920 and 1472 are definitely the best resolutions to use and keeping gain to 0 or 6 dB is ideal.  I was a bit disappointed at what a mess the 832 resolution was even at 0 dB.   The noise seems very inconsistent and all over the place.  I would use 1152, but only sparingly.

Let me know what you think!  This type of testing should be reproduceable fairly easily.  It might be interesting to see if different sensors behave differently. 

My camera is using version 0.6.0 of the software and reports FPGA Revision 3.24 and PMIC Firmware Version 11.

I can zip up all the DNG files I used if anyone is interested in looking at them directly.

52

Chronos User Discussion / Re: Post Chronos 2.1 clips here!

« on: June 27, 2021, 11:15:18 AM »

This was my first attempt at using a static test rig to capture the interesting fluid dynamics of a water rocket @ 100 psi.   Unfortunately, the test rig wasn't quite as static as I'd hoped and the whole thing kinda blew off the table mount, but it was a cool video so I'd thought I'd share.

I think it's really interesting to see the air blow through the water and "sneak" around the edges when it's almost empty. 

I plan on building a more sturdy test-rig in the future to get more footage like this in a more controlled fashion.

It was shot at 10186 fps on a Chronos 2.1 at 1472x144 resolution.  The lens was a Canon 135mm f2 @ f2.

https://youtu.be/NURaIiya_uQ

53

Chronos User Discussion / Re: UNSOLVED (again): Neither Frame Sync Output nor Triggering working, why?

« on: June 20, 2021, 05:20:04 AM »

Thanks. What do you mean exactly? You triggered it via web interface and afterwards it worked again without ethernet but with the BNC?

Just asking, because triggering via web has not been an issue here, but it also is no option for what I want to do. Thanks!

Yeah, once I triggered it via the web, it worked again via the BNC without being connected via Ethernet.   Give it a try the next time it happens.  I'd be curious if it (temporarily) fixes the problem for you too.  It's not an ideal work-around, but certainly better than reloading the OS!

54

Chronos User Discussion / Re: UNSOLVED: Neither Frame Sync Output nor Triggering working, why?

« on: June 20, 2021, 04:09:06 AM »

Jesus! After testing more with the camera, same thing happened again! Starting possible, ending not.

After reinstallation of the OS everything fine again! @nikon1: Did you ever really work with the trigger-IOs?

Thanks! Martin

I think I have run into this before and my solution was to connect the camera to a computer via Ethernet and trigger it via the web interface and then it worked again.  This definitely sounds like a software bug of some kind.

55

Chronos User Discussion / Re: Post Chronos 2.1 clips here!

« on: June 16, 2021, 04:11:36 PM »

I used the Chronos 2.1 to figure out the 0-60 time of a water rocket!  Spoiler, it's VERY fast

Lots of 1920x570, 1884 fps, 162 deg shutter, Cinema DNG footage in this video:

https://youtu.be/ZstN5pW3nGM

Lens was a Canon 24-70mm f2.8 II shot at 2.8.

Be sure to watch the ending for some very cool drag race footage.

56

Chronos User Discussion / Re: Post Chronos 2.1 clips here!

« on: May 22, 2021, 06:57:32 PM »

"Cards"
 Shot at 1000fps

Nice!  Looks a bit overexposed though.  Maybe experiment about -1 to -2 stops from this to not blow the highlights.  I know it's tough with the Chronos as the dynamic range isn't great, but if you expose the highlights correctly, you can boost the mids a bit and it'll be OK.

I guess thats a bit up to personal Preference, i personally dont mind if some of the most extreme Highlight spots are blown out a bit, as long as the Camera handles it well. So i usually like to expose a bit brighter, than having the Image too dark and needing to boost exposure.
 At least with the Chronos, as from all the Stuff i shot, i got better results with brighter footage, Boosting the Lows or Mids usually results in a bunch of Weird Lines showing (note that this is a Fairly old shot, recorded on the 5.1 Unstable Firmware still, where the Vertical Lines where still a big problem when underexposing. Should be way less of a Problem with the 6.0 Firmware, as it gets rid of all the Lines almost completely).
 On most other Cameras i would as well stay far away from Overexposing, as they usually handle Boosting the Lows way better (unless you use crazy ISO setting and stuff...) than overexposing.
 .
 But have to say, you are right. Didnt really notice bevore, but i think i could drop exposure like 2/3 Stops or 1 Stop on some of the Shots.
 This Clip was also a bit of a test and the First thing i edited with Resolve. Bevore i only used Adobe After Effects, and i have to say, Resolve is a Beast when it comes to Rendering DNG Footage, Worlds Faster.
 As at the Time of editing this, i didnt really know how to actually use Resolve yet however, and was mostly just playing around, all the Footage is just Droped in there, some Time-Ramping added, Music, and Rendered. So color is untouched on those, as out of Camera. After looking through the DNGs once again, some of them only look too bright and can be dropped in Exposure in Post just fine, plenty of room to spare bevore clipping; but a few of them are actually clipping on the Bright parts.

I am a HUGE fan of DaVinci Resolve Studio.  I switched from Premiere a couple years ago and haven't looked back.  I've found that the built-in noise reduction tools can help a lot with the banding of the Chronos, but like with any noise reduction, you need to be careful not to ask it to do too much or it'll destroy the detail.   You will find you'll want a very high end graphics card if you start to do a lot of effects work with it, especially if you are on a 4K timeline.  They are hard to get right now, but the RTX 3090 with 24 GB of video ram is very useful for that kind of work.

The color correction tools within Resolve are really great too.  That was what Resolve was known for before it became a complete NLE system.  If you have something like a ColorChecker video chart you can really dial in the proper colors.  Again, with the Chronos, it's not ideal because its sensor is nothing like a modern video camera in terms of color quality, but you can get pretty good results with it.

57

Chronos User Discussion / Re: Post Chronos 2.1 clips here!

« on: May 22, 2021, 11:53:28 AM »

"Cards"
 Shot at 1000fps

Nice!  Looks a bit overexposed though.  Maybe experiment about -1 to -2 stops from this to not blow the highlights.  I know it's tough with the Chronos as the dynamic range isn't great, but if you expose the highlights correctly, you can boost the mids a bit and it'll be OK.

58

Chronos User Discussion / Re: Post Chronos 2.1 clips here!

« on: April 02, 2021, 12:22:06 PM »

Here is my first attempt at filming birds with the Chronos 2.1.

https://youtu.be/LMwjMFW57EE

1920x1080 at 1000 fps, 180 deg shutter
Canon 70-200 f2.8 IS II w/Canon 1.4x Teleconverter  (280mm @ F4)

59

Chronos User Discussion / Re: Newbie Questions

« on: February 24, 2021, 12:32:04 PM »

From your image, it definitely still looks like you're running in to overexposure issues.  It looks like maybe they didn't update the software to notify overexposure when they went to the latest software version.  The latest software trades some dynamic range for less pattern (striped) noise.

Try underexposing another full stop and see if you can fix the image in post.

As for saving, yeah, it's slow.  I use the eSATA to SSD for Cinema DNG.  It's much faster than the SD card, but the real limit is with camera hardware, not the save medium.  You'll never see the 500+ MB/sec an SSD card can actually do.

Recently I've been playing with Samba share connecting the camera directly to my wired network.  It's really handy for controlling the camera via the web interface and downloading the video is reasonably fast 10 to 20 MB/sec depending on resolution.  Very long Ethernet cable is extremely cheap, so depending on how you have things set up, maybe that's an option for some things.  Certainly not good for hand-holding birding though!

60

Chronos User Discussion / Re: Newbie Questions

« on: February 24, 2021, 10:28:08 AM »

I think the red/pink in the snow hightlights are due to overexposure, not white balance issues.  That might be more of an issue with the latest software revision.  As with general photography, as I'm sure you're aware, it's WAY better to underexpose and bring up in post a bit than to blow out the highlights.

The sensor in the Chronos doesn't have anywhere near the dynamic range as modern DLSRs or high end video camera.  You need to be very careful not to blow out the highlights and get the exposure right.  Which is why a histogram would be so nice to have!!