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Messages - tesla500

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Chronos User Discussion / Re: Insanely high speed slit scan method?
« on: October 21, 2017, 11:15:47 AM »
This could be done, yes. The limitation right now is that the video encoder doesn't support resolutions below 96 pixels height. To get around that, we can add black bars to the video to remain within the encoder limitation. Once Raw/uncompressed saving is done, this won't be a problem at all.

There's also a frame rate limit above which the camera becomes export controlled, I believe the number is 200,000fps but I have to check. But the image sensor itself is capable of well above that when running at 1 pixel height.


Chronos User Discussion / Re: Chronos 1.4 Footage Thread
« on: October 20, 2017, 11:29:25 PM »
Got some new footage:

It was on a German "outdoor" shooting range, so basically indoors... low light conditions. Still don't have constant light sources to illuminate the scene.

There are colored lines visible some times. I know this can happen when the memory is cold, but it was about 16 C, which I wouldn't consider cold. Is there any way to prevent this? I plan to do some more filming in early January, and don't want all of the footage to show these lines.

Also I got trouble with focusing. It seems like the adaptor ring doesn't have a good hard stop, and the backfocus needs to be set depending on the torque that was applied when mounting the lens. I still store the camera in its shipping box, because this is very well stuffed, but that means I need to take off the lens for storing.

Any ideas on how to get this fixed?

The cold temperature RAM issue will be completely fixed in the next update. We're just testing this update right now before releasing it, expect it in a week or so assuming no problems are found. We've tested the camera down to -20C and there is no issue at all with the new software.

To avoid taking off the lens, cut out a portion of the box foam so you can store the camera without taking off the lens. Also, check that you tighten the backfocus lock setscrew enough, if it's not tight the ring will spin and change backfocus when you screw the lens in hard.


Chronos User Discussion / Re: external trigger
« on: October 18, 2017, 12:06:21 AM »
That mode to do exactly what you want isn't yet supported. The closest thing you can do is have the camera recording, and provide it a TTL signal to end record. You can set any desired trigger delay in frames if required. You'll need to manually select the appropriate range and then save the desired 400ms range.

Let me know if you have more questions on how to set this up.

Software Dev / Re: Software v0.3?
« on: October 18, 2017, 12:01:46 AM »

How complicated would it be to allow the user to select what resolutions we want in the drop-down menu?

Maybe we could have a few "user preset" slots in the drop-down menu? Or would this entail too many |UI changes, adding buttons etc for this revision?

That is quite easy, you could do it now manually in fact. If you put the OS SD card into a Linux system, add your resolutions, one per line, in /opt/camera/resolutions

resolutions is just a text file, the default content is:

Code: [Select]

Software Dev / Re: Software v0.3?
« on: October 17, 2017, 06:21:27 PM »
The next version is being worked on right now. Features in this coming version are:
  • Remembering settings across reboots (most common request!)
  • Fix for a potential cold-temperature RAM issue (seen as horizontal bands of colored pixels)
  • Autonomous operation with automatic save-after-trigger and automatic recording start after save
  • Maybe HDMI

If HDMI doesn't get into this release, it will be in the next.

Ethernet will be coming in a subsequent update, it's a big project, the entire low-level camera control needs to be broken out of the user application and made to work over network.

Also, the open source release is imminent, finally have a working build environment that doesn't have any of the NDA code in it! Hopefully within the week.

General high-speed discussion / Re: Triggers?
« on: October 14, 2017, 11:13:34 AM »
Yes, the delay is adjustable in camera.

General high-speed discussion / Re: Triggers?
« on: October 12, 2017, 05:33:52 PM »
What type of trigger are you looking for? Manual button, or something automatic? Triggering on lightning automatically would need a light/flash trigger most likely, anyone have suggestions for this? The camera will eventually be able to do this by itself by triggering on an image change, but that's some time off.

Software Dev / Re: Improving the Jog Wheel, ideas.
« on: October 12, 2017, 05:04:33 PM »
Great ideas there! The original idea behind the design was to use the scroll bar to get close to the point you want, use the pressed-in jogwheel for slightly finer control, then use the frame by frame control to review the video.

I really like the idea of adding more control, how about this:

Pushing and holding the jogwheel opens up a window on screen, allowing you to select from a number of frames-per-detent selections. Rotate the jogwheel to select one you want, then release the jogwheel and that speed is applied. Turning (not pressed) now goes at the speed you selected. This speed selection menu would also be duplicated in the Util menu somewhere. I like having shortcuts to frequently used things like this, because you're often changing the jogwheel rate several times when reviewing or saving a shot.

Question is, what rates are appropriate, without having too many? I was thinking of something like 1, 2, 4, 16, 64 frames per dentet, and maybe some that are a fraction of the buffer length like NoDak suggested, as the small numbers may not be appropriate when you're saving hundreds of thousands of frames at low resolution. Perhaps from 1/1024 of the buffer down to 1/32 of the buffer per detent.

Chronos User Discussion / Re: Triggered Exposure Mode
« on: October 08, 2017, 11:56:58 PM »
Hi Doug,

I just re-read your first message, you were referring to "automatic exposure". The camera does not support any sort of automatic exposure yet, it is entirely manual. The exposure will not adjust by itself, only the slider or setting on the Record Settings page will control it. Is this the problem you were describing?

Auto exposure is coming in a future update.


Chronos User Discussion / Re: Triggered Exposure Mode
« on: October 08, 2017, 04:48:17 PM »
Hi Doug,

In triggered exposure mode, the frame rate display does not show the actual frame rate, only the maximum you can run it at. You can't run triggered exposure faster than the camera is set to, it will drop frames.

The exposure control will control the shutter speed, provided you are triggering the camera at or below the frame rate it's set to. If you for example set the camera to 30fps and provide a 1000Hz trigger signal, undefined operation may occur. Let me know if you still have the problem with the shutter control when operating within limits.

Sound is not supported yet.


General high-speed discussion / Re: Multiple Cameras synced together
« on: October 07, 2017, 10:54:46 AM »
Set the master to frame sync output in trigger settings, and the slave cameras to shutter gating mode. Then connect all the cameras BNC ports together The master will then control the frame rate and shutter speed of the slaves, and they will be synchronized.

Edit: The slave cameras must be set to the same or smaller resolution, and the same or greater frame rate than the master camera.


Chronos User Discussion / Re: F-stop when using lenses from 35 mm camera
« on: October 07, 2017, 12:27:51 AM »
Hi - crop factor affects both focal length and f-stop - so f/4 on a 35 mm sensor will look like f/16 on the Chronos' sensor.

Unfortunately that's not correct. F-stop does not change with crop factor. f/4 on a 35mm sensor is the same as f/4 on the Chronos sensor. The only way the f stop will change is if you are using a speed booster.

Effective focal length will change, for example Chronos is about a 4:1 crop factor from 35mm, so a 28mm lens on Chronos would be like a 112mm lens on 35mm.

Chronos User Discussion / Re: C moutn adapotor
« on: October 06, 2017, 12:04:11 PM »
Hi Scott,

Check if your adapter has a facility to rotate the C mount relative to the B4 mount, sometimes you need to loosen a few screws to do this. If it doesn't support that, you can install the adapter on the camera, then loosen the set screw on the bottom of the camera using the included allen key. This lets you rotate the entire mount ring and lens/adapter assembly relative to the camera body. You can then re-tighten the set screw with the lens oriented correctly. Not that this will effect backfocus, you'll need to check your backfocus after doing this, and potentially rotate the lens by full turns to get the backfocus set properly.

As far as I know there is no standard orientation for a C mount, the lens will end up at an arbitrary rotational position when installed. Some lenses such as the Computar 12.5-75mm can be rotated relative to the mount to correct this, by loosening a black ring near the lens mount.


Chronos User Discussion / Re: Focusing Troubles
« on: October 03, 2017, 06:23:31 PM »
What settings are you typically using for aperture when you're having focusing problems?

Sometimes I find it helps to leave the aperture wide while focusing then close it down after, the increased reduced depth of field makes it easier to find focus.

Chronos User Discussion / Re: Streaming capacity
« on: October 03, 2017, 12:17:49 AM »
Hi Roger,

The h264 encoder is currently limited to 60fps due to driver issues. It's in the pipeline to try to speed it up, it should be capable of about 120fps at 720p based on pixel rate.


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