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Chronos User Discussion / Re: Pre Record Trigger Delay <1 frame?
« Last post by Rainer on Today at 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.
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Software Dev / Re: Faster save by RAM "dump" instead of creating image/movie files?
« Last post by NiNeff on October 13, 2021, 03:17:40 AM »
The processing overhead for creating DNG files or H.264 encoded MP4 files is relatively low compared to the other factors like drive&bus speed.
You won't see a significant speed improvement if you compare raw to DNG saving, but it is there. Mostly because only one large file needs to be created. (Which might lead to FAT32 problems if it gets too big)

The fastest saving is H.264 encoded MP4, but it goes along with quality reduction.

To get the highest speed you should use the eSATAp Port instead of USB and safe to a SSD.
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Software Dev / Re: Faster save by RAM "dump" instead of creating image/movie files?
« Last post by Rainer on October 12, 2021, 11:41:12 PM »
Thanks for this real-world experience and feedback, Nikon1
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Software Dev / Re: Faster save by RAM "dump" instead of creating image/movie files?
« Last post by Nikon1 on October 12, 2021, 01:08:06 PM »
For RAW its supposed to be Faster than all other Formats. Compressed H.264 Is however still fastest overall from what i know, just because of the way smaller Filesize to write to memory.
 .
 See Page 90 of the User Manual for a Comparison:
 https://www.krontech.ca/wp-content/uploads/2021/09/RE-PDEV-10009-Chronos-User-Manual-Full-Software-Version-0.7.0.pdf
 .
 Saving in RAW Format seems to not be too popular amongst the average user, just because H.264 is overall just a lot faster and Smaller file size, and CinemaDNG is a lot easier to work with and wont need to be converted later, and can be directly imported to most advanced Video Editing Software. Only heard a few people use it where they still want some kind of uncompressed Footage, and Save Speed is absolutely critical.
 I tried Saving in RAW, but stayed with CinemaDNG because it just saves me all the work of converting, which makes it overall still fastest uncompressed Format for me, if i factor in processing time after Shooting, even if it takes a little bit longer to save technically. If i need to move really fast, and i just try to get footage at all and not tickle out the Last bit of Quality, i would use H.264 Anyways, its like a order of magnitude faster.
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Chronos User Discussion / Re: Filming Rocket Testing - settings advice welcome.
« Last post by Nikon1 on October 11, 2021, 08:37:15 AM »

My hope was that I could send this camera to the facility with someone who is not familiar with photography but that is out of the question.

 Well, yes. Iīd call that very optimistic. Shooting Highspeed-Stuff like that can already be challenging for People who actually know what they are doing, so just having a random Person operate the Camera would be a pretty risky bet unless you are very sure about your Exposure Settings being spot on. You still could try, but chances to get good resulting footage with Fire and Rockets involved and also just a single chance at actually getting the shot would be very low by just guessing exposure i assume.  .
 Also the 50 Feet cable seems pretty short. just did the math, and thats like 15 Meters. I casually carry a 5 Meter BNC Cable in my Camera Case at all times in case i ever need it, which is just so it wouldnt be to bulky to carry around. 15 Meters still is not what i would consider a "long" cable, so i was a bit surprised that you have not found a longer one yet, but maybe thats just a thing in Germany or something, but 50 to 100 Meters are still somewhat standard, even longer ones are actually rare, but do exist, as i wrote above.
 .
 And regards the Tests / Test Shots: I was very aware that your Rockets would probably be single use with only one chance to capture the Action, thats why i recommended to do two tests or more to really get your Exposure correct for that one Shot you want to be sure to capture at best possible settings. If you figure out the Settings for it, you should be able to get very reproducible results, no matter the Environmental Light or Camera Operator, given of course these Rockets are at least somewhat comparable in Brightness and all that.
 .
 Also depends on just how important it is to get the Shot here. If you shoot an explosion like the First Nukes ( Cost actually expressed in % of GDP and that exact experiment can not be redone ever again) i mentioned earlier or something that is as crazy unique as that, you want to be sure you dont mess up here and get the Shot, thats what i would call highly Critical. If you can redo it with at least somewhat reasonable effort, i wouldnt worry too much about running 100 Test Shots before, and maybe just Try it (testing still never hurts) and adjust exposure as i go on with testing.
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Chronos User Discussion / Re: Filming Rocket Testing - settings advice welcome.
« Last post by Endothermic on October 11, 2021, 07:18:15 AM »
Nikon1, I got the longest (50 feet) wire I could find. I will search further and see if I can get a much longer one. That should essentially get us to where we need to be. The only piece I don't have insight into is the material of the two buildlings that the signal will need to go through.

I've successfully used the 50 foot extension and the remote trigger through a few concrete walls at my office.

The 'remote trigger mod' I referred to is detailed here on the site:

https://forum.krontech.ca/index.php?topic=4.0

<<To actually figure out the Correct settings, i would advise you to do at least two tests before shooting anything critical. >>

So, next up is to test these various settings in some sort of controlled way. I'm going to create a spreadsheet with different settings and test shoot the model rocket nozzles and see what I come up with.

There is no way to test shoot the actual items during a test as the are 'fire once' types of objects.

My hope was that I could send this camera to the facility with someone who is not familiar with photography but that is out of the question. I'm afraid I may have to travel to shoot these tests myself.

Thanks for the help. I'll post my test shots as soon as I get them.

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Software Dev / Re: Faster save by RAM "dump" instead of creating image/movie files?
« Last post by Rainer on October 11, 2021, 01:17:57 AM »
Oh, I did not know that. Is it improving the saving speed?
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Software Dev / Re: Faster save by RAM "dump" instead of creating image/movie files?
« Last post by Nikon1 on October 10, 2021, 03:04:21 PM »
There is an option like this on the Chronos, you can save in RAW, which will essentially dump the Entire RAM Data into one massive File, which needs to be processed by the PC later.
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Software Dev / Faster save by RAM "dump" instead of creating image/movie files?
« Last post by Rainer on October 10, 2021, 03:01:56 PM »
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
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Chronos User Discussion / Pre Record Trigger Delay <1 frame?
« Last post by lwaters on October 07, 2021, 06:50:12 AM »
Hi! I'm back with more weird questions. I'm circling back around again, trying to synchronize two Chronos 1.4 cameras to essentially double our frame rate -IF we can capture interlacing frames-BY having a delay that is exactly HALF a frame long... We are shooting at 25k fps (because we need to maintain what little resolution we have at that rate). So 2 frames at 25k comes up as being .0001 seconds long (at least as shown on the pre-record trigger delay). I cannot get the delay to go any shorter than that...any suggestions/ideas to try? I'm all ears.
Thank you all- so thankful for this "Chronos Support Group" (at least that's what it's become to me).

Laura
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