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Messages - Rainer

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1
Chronos User Discussion / Re: Post Chronos 2.1 clips here!
« on: September 01, 2022, 11:51:00 AM »
I admire not only the slow mo shots but also the consistent color grading and the shot where the shoe stays in the image center of the bicycle pedal :-)
Very well done!

2
Chronos User Discussion / Re: Resolution other than in manual
« on: May 01, 2022, 06:56:36 AM »
Thanks a lot. I searched for "resolution" in the forums and missed the 1 Mio fps thread.
So 96px is a good information, thanks a lot. We might buy or test a Chronos soon and this is an info we could not find in the manual.
Firmware changes are also above my skill level. If we get the cam, I'll post our results with small resolutions at 20k fps.

3
Chronos User Discussion / Resolution other than in manual
« on: May 01, 2022, 05:51:44 AM »
Hello,
I have a question regarding resolutions: In the manual (1.4 and 2.1) the example resolutions have a lower vertical limit of 640 pixel. Can anyone confirm, that also a resolution less than 640 pixel is possible.

Example: the smallest resolution/framerate combination in the 2.1 manual is 640x96 at 24.046 fps.
Is it possible to record at e.g. 288x212 also at 24.000 fps.
Or is the minimum horizontal resolution 640 pixel?
I hope my question is clear enough.

4
The Paul Scherrer Institute in Switzerland built a sophisticated setup that allows them to stream 7 GB/s to servers using a highly modified PCO camera:
https://journals.iucr.org/s/issues/2017/06/00/pp5108/pp5108.pdf
It is surely difficult and expensive to replicate but I wanted to share this paper here.
dr_innovation, if you can share any infos about your application this would be very interesting to read. I'm just curious :-)

5
Chronos User Discussion / Re: Post Chronos 2.1 clips here!
« on: January 02, 2022, 12:31:35 PM »
Although I did not make these shots with a Chronos (but a PCO camera) I post this video here because I also shot some sprinklers some years ago.
Later in the video there are some macro shots of matches being lit, these turned out quite well.
https://www.youtube.com/watch?v=T9thf8uVWuM

6
Chronos User Discussion / Re: Low light capture
« on: November 05, 2021, 12:40:35 PM »
I really like the viewing angle. The whole Life Saver lights up where it's being hit. Really nice shot.

7
Chronos User Discussion / Re: Low light capture
« on: November 05, 2021, 07:14:30 AM »
There doesn't seem to be a gain setting in this camera. At least I did not find one in the manual or software. I always records in RAW and with a histogram-like window I can convert these RAW images into JPG or other formats. For the low light shots I tried to squeeze the brigt light out of these RAW images as much as possible.
I am very interested if anybody else is recreating the Life Saver shots!

8
Chronos User Discussion / Re: Low light capture
« on: November 03, 2021, 06:56:21 AM »
my lens/settings were the following:
PCO.dimax HD with Zeiss 1.4/50mm lens (Nikon DSLR Mount)
5000 fps
720x684 pixel
0.179100 ms exposure time

9
Chronos User Discussion / Re: Low light capture
« on: November 03, 2021, 02:39:58 AM »
I also recreated the Life Saver video with my high speed camera - not a Chronos but a PCO dimax HD.
It's important to use the Wint-O-Green version since the included oil shifts the light into the visible wavelength. I totally missed this at first and hammered lots of normal ones.
I recorded with 5000 fps in RAW and then tried to squeeze everything out of the images when converting them to a video.
I come nowhere close to the quality of the Phantom shots, but I see the sparking quite well which made me happy.

YouTube is doing terrible compression thing to noisy videos, so if you want the original files, PM me.
https://www.youtube.com/watch?v=vzPAz24czHM
https://www.youtube.com/watch?v=iWxgRPquz3w


10
Chronos User Discussion / Re: Pre Record Trigger Delay <1 frame?
« on: October 15, 2021, 02:05:01 AM »
Hi,
I had the same challenge with two other high speed cameras and solved it via an external trigger.
Both camera where in triggered mode, taking a picture whenever an external trigger is received. I triggered them first with an arbitrary function generator. This worked well - I could trigger the camera "interleaved". When it became too complicated to program the function generator with different frame rates, I used an Arduino setting two pins alternating high and low. This also worked very well.
Meybe external triggering is also an option for you.

11
Thanks for this real-world experience and feedback, Nikon1

12
Oh, I did not know that. Is it improving the saving speed?

13
Hello all,
I don't have a Chronos (yet) but another HighSpeed Cam from PCO. The limiting factor when shooting multiple scenes is the time it takes to save the buffer via USB to disk.
On the forum I read a lot about Chronos saving speeds with different file formats and storage media and I feel that this would affect me heavily when I get a Chronos.

Would the following suggestion increase the saving speed (mainly a questions for the Krontech devs):
Instead of converting the RAW image data from the RAM into h264, DNG, ... do the following: dump the data from the RAM exactly as it is in the RAM (no conversion to any file format).
One would end up with a huge binary dump on the storage medium.
Later - on the computer - one could convert this binary dump into h264, DNG, ...
I have the feeling that the conversion from RAW to an image format is a time consuming step for the FPGA in the Chronos. If this step is "outsourced" to a computer, would it make continuous shooting faster?
It's just an idea, but I would use it right away with every high speed cam I ever used.
Thanks for reading my suggestion, I am really interested if this would be feasible.
Rainer

14
For my tests with cameras and external triggers I tried a function generator and an Arduino.
tl;dr: it was easier with the Arduino

I have a two channel function generator (Rigol DG1032Z to be precise). I configured it in a way, that on channel 1 I get a 5V trigger with my desired framerate, e.g. 1000 Hz.
Then I configured channel 2 in the same way. Then I set channel 2 in a way, that the triggers from channel 2 are exactly inbetween the triggers from channel one.
(Google "phase difference" for more info) Some function generators specify this in degrees, so a 180 degree phase difference means that channel 1 is shifted half the frequency.
This did work. Out of my two channels came alternating triggers.
And now the "BUT":
When I wanted to change the frame rate, I had to configure the second channel again and completely new. I tried all settings (locking the channels to each other,...) and read the manual, but changing the frequency (which means framerate) always made the settings from the 2nd channel messed up. I configured the generator with the buttons on the device. You can also do this via an USB connection, but then I used an Arduino.

And there - within 5 minutes I had 2 pins alternating the triggers with ease. It is basically just some delays and pulling the pins up and down.
I did this "manually" by changing the delay times in the source code and it worked good enough for my basic tests. I wanted to test the beam splitter after all.
One could modify the Arduino sketch maybe even with a display to create a changeable frequency with a rotary enoder as an input. But this was too much effort since I had a running solution for my tests.

I hope I explained everything in an understandable way.
Tell us when you ever try it, lwaters, I'm interested in your solution.

15
Hi,
I once tried this with two other cameras which have an external trigger. I got a cheap beam splitter from Aliexpress which is a small piece of glas which reflects 50% of the light and lets 50% of the light pass through it. When you arrange the two cameras 90 to each other, one looking "through" the beam splitter and one looking on the reflective side, they both see the thing you want to image. (It's best to google some images for this, it's hard to describe with words)
Then I triggered the cameras alternatly and combined the two "picture stream" in an interleaved way afterwards to a movie.
In principle this worked, but it became evident, that you need more light and that the alignment of the cameras and the beam splitter is crucial. If they are slightly off, the image jumps frame by frame. If the offset is only small, one can try and correct this in the final images and "shift" one image stream in a way that the overlap better.
So it is possible (with Chronos or other triggered cameras) but it takes quite a lot of preparation.
Best regards
Rainer

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