Author Topic: Question about Shutter Speed  (Read 7373 times)

lwaters

  • Newbie
  • *
  • Posts: 39
    • View Profile
Question about Shutter Speed
« on: December 06, 2018, 10:14:19 AM »
Hello!
  I have been trying the achieve a shutter speed of 1us or faster. I've noticed that on a couple of the Chronos presets the minimum shutter speed can go as low as 850ns (800x480 & 3,587 fps). A few other presets's shutter speed minimums are at 1.010, 1.210, 1.040 and the majority at 1.200. The preset with the highest frame rate at 31,191 fps has a minimum SS of 1.040... while another preset for 21,649 fps has minimum SS of 1.210...
What am I missing? I just can't find any rhyme or reason to this and i'm wondering how that limitation is calculated. I need to maintain a frame rate of at least 15k. Is there a combination of resolution and frame rate that will allow for a shutter speed faster than 1us?
Thank you for any input!
Laura

Nikon1

  • Hero Member
  • *****
  • Posts: 983
    • View Profile
Re: Question about Shutter Speed
« Reply #1 on: December 06, 2018, 10:27:00 AM »
As far as i know, there is an Limitation on ANY Highspeed-Camera out there in the whole market, that the fastest shutterspeed must not be shorter than 1us.
There is some kind of limitation, and i was always interrested why that is... If it goes slightly faster than that on some of the Presets, i think its still kind of borderline ok for that.
If you want faster Shutterspeed, you need some kind of special permission and a good reason, why you would even need to have such a camera... (or just hack /Modify the firmware on your own...?)
.
Please dont quote me on that, this is just from what i heard other people say and as good as i could remember, i never did the acutal research myself.
.
I think i´ve seen someone of the Kron-Staff say here in the forum, that the chronos Camera itself ist capeable of way shorter/faster shutterspeeds per frame, but it is not enabled due to this (legal?) Limitation. If i remember correctly, the talk was about reducing the resolution to actually just a single Line of pixels at some kind of crazy framerate to create some kind of line-scan-camera. In such a mode the chronos should be able to push tons of frames (lines) per second...

#Edit: Sorry if Bad english BTW...
« Last Edit: December 06, 2018, 10:30:32 AM by Nikon1 »

NiNeff

  • Full Member
  • ***
  • Posts: 169
    • View Profile
Re: Question about Shutter Speed
« Reply #2 on: December 06, 2018, 11:32:09 AM »
As far as i know, there is an Limitation on ANY Highspeed-Camera out there in the whole market, that the fastest shutterspeed must not be shorter than 1us.
There is some kind of limitation, and i was always interrested why that is... If it goes slightly faster than that on some of the Presets, i think its still kind of borderline ok for that.
If you want faster Shutterspeed, you need some kind of special permission and a good reason, why you would even need to have such a camera... (or just hack /Modify the firmware on your own...?)
.
Please dont quote me on that, this is just from what i heard other people say and as good as i could remember, i never did the acutal research myself.
.
I think i´ve seen someone of the Kron-Staff say here in the forum, that the chronos Camera itself ist capeable of way shorter/faster shutterspeeds per frame, but it is not enabled due to this (legal?) Limitation. If i remember correctly, the talk was about reducing the resolution to actually just a single Line of pixels at some kind of crazy framerate to create some kind of line-scan-camera. In such a mode the chronos should be able to push tons of frames (lines) per second...

#Edit: Sorry if Bad english BTW...
If there is such a legal speed limitation, it would most likely be due to ITAR. For example, thermal (IR) cameras are limited to be below 10 fps and/or 640 x 480 px to be exempt of ITA-regulations. So if you see any IR camera above those limits, the manufacturer got a specific permit from the US government to do so and the sales are very likely restricted to certain regions and so on.
Now you might say what has this to do with equipment coming from countries other than the US (like Canada ;))? Well they just claim world wide jurisdiction...

I did not search for ITA-regulations regarding regular high-speed cameras, and honestly I don't want to dig into that rabbit-hole ;)
« Last Edit: December 06, 2018, 11:35:56 AM by NiNeff »

Nikon1

  • Hero Member
  • *****
  • Posts: 983
    • View Profile
Re: Question about Shutter Speed
« Reply #3 on: December 06, 2018, 11:35:44 AM »
If there is such a legal speed limitation, it would most likely be due to ITAR. For example, thermal (IR) cameras are limited to be below 10 fps and/or 640 x 480 px to be exempt of ITAR regulations. So if you see any IR camera above those limits, the manufacturer got a specific permit from the US government to do so and the sales are very likely restricted to certain regions and so on.
Now you might say what hast this to do with equipment coming from spaces other than the US? Well they just claim world wide jurisdiction...

I did not search for ITAR regulations regarding regular high-speed cameras, and honestly I don't want to dig into that rabbit-hole ;)
Ok, thats good to know.
I always wondered why those IR-Cameras always just had such crappy resolution and framerate....even nowerdays....
That explains a lot.

Nikon1

  • Hero Member
  • *****
  • Posts: 983
    • View Profile
Re: Question about Shutter Speed
« Reply #4 on: January 01, 2020, 05:59:07 PM »
Hello!
  I have been trying the achieve a shutter speed of 1us or faster. I've noticed that on a couple of the Chronos presets the minimum shutter speed can go as low as 850ns (800x480 & 3,587 fps). A few other presets's shutter speed minimums are at 1.010, 1.210, 1.040 and the majority at 1.200. The preset with the highest frame rate at 31,191 fps has a minimum SS of 1.040... while another preset for 21,649 fps has minimum SS of 1.210...
What am I missing? I just can't find any rhyme or reason to this and i'm wondering how that limitation is calculated. I need to maintain a frame rate of at least 15k. Is there a combination of resolution and frame rate that will allow for a shutter speed faster than 1us?
Thank you for any input!
Laura
I just got to thinking, there is an Option for "Gated Shutter" that means the Sensor only exposes An Image as long as it has an Voltage signal on an dedicated input Pin if used in that mode.
So if i not wrong, one should be able to achieve an Shutter Speed of 1µs and well below with an external frequency generator with adjustable Duty Cycle if i am not mistaken here....?
Framerate in this case would be adjusted by the Frequency, the Shutterspeed by the On-Time Of the Duty Cycle. Should allow for an Quite capeable Setup. i Dont Know how far this could be pushed in terms of RAW Framerate, but i would at Least expect that you should be able to push the Minimum Shutter speed to rather low values with this. Not sure where the hardware Limit on the Chronos Cameras is for this kind of stuff, but with a Frequency Generator you would at least be able to bypas those Preset Minumum Values for Shutter Speed. Framerates Are Propably pretty close to the "hard Limit" the Hardware would be able to do with external Generator like this in the Software allready.