Author Topic: Chronos 2.1 newbie questions and impressions  (Read 670 times)

clkdiv

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Chronos 2.1 newbie questions and impressions
« on: February 12, 2020, 02:10:32 PM »
Hello girls and guys,

I received my Chronos 2.1 two days ago and I am a little bit overwhelmed understanding how to deal with it. So I have several questions and I would be very happy to get some help here.

  • Lens: Since I accidentally did not order a Canon EF adapter but wanted to start with some tests, I bought a Fujinon HF12.5HA-1S 12mm F1.4 C-Mount lens, thinking I could start over with it. I was really astonished how small this thing is, and even more that it does not cover the sensor when recording higher resolutions. I need to record 1920x1080 with 28 mm wide angle with respect to the 35 mm format. This is because I am driving a Bullet-Time-Rig made from DSLRs with APS-C sensors and 18mm lenses, thus I have 28mm there. Now I want to integrate the Chronos into this rig. Any idea how to achieve this the best way? Should I try to get a 14mm CS-lens, should I better go with a Canon EF-adapter and a 14mm EF lens, and what about these speedboosters I saw?

  • Special: I need to trigger a studio flash each frame the Chronos 2.1 exposes. Now it seems I could achieve this two different ways. I either could use the Frame-Sync-Output, capture it with an Arduino and then trigger a flash with it, right? Or I could provide a trigger signal both for the camera and the flash, making the camera expose and the flash trigger. I was thinking to use Input 3 for that by sending 5 Volt ramps into it. What do you suggest is the best way to try?

  • IO: Also I have a general question triggering the camera via IO. If each frame of the camera is triggered by an external source, would it be possible then to make the camera do a speed ramp? Or make it film at 30fps? Or even use it like a normal camera, that exposes and then waits until the next signal arrives for the next single frame to capture?

Thanks a lot for your thoughts! Martin
« Last Edit: February 13, 2020, 01:10:33 AM by clkdiv »

skronstein

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Re: 2.1 newbie questions
« Reply #1 on: February 12, 2020, 07:07:24 PM »
I either could use the Frame-Sync-Output, capture it with an Arduino and then trigger a flash with it, right? Or I could provide a trigger signal both for the camera and the flash, making the camera expose and the flash trigger.
Either one should work, but if you use the same signal to both expose the camera and trigger the flash, you don't need the arduino, and you can also use the Exposure Trigger or Shutter Gating trigger modes.

If each frame of the camera is triggered by an external source, would it be possible then to make the camera do a speed ramp?
Yes, you can do speed ramps with an external source.  With the Exposure Trigger or Shutter Gating set on the Trigger/IO settings screen, the camera will record a new frame with every pulse.  The difference between the two is that with Exposure Trigger, the sensor will expose for whatever the exposure time is set to on the camera, and with Shutter Gating, the exposure will last for as long as the signal is high.

clkdiv

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Re: Chronos 2.1 newbie questions
« Reply #2 on: February 13, 2020, 01:09:58 AM »
Thanks a lot for your reply. Please, I don't get this:

Either one should work, but if you use the same signal to both expose the camera and trigger the flash, you don't need the arduino, and you can also use the Exposure Trigger or Shutter Gating trigger modes.

What gear should provide a signal to both expose the camera and trigger the flash, then? I was thinking to use an Arduino for that. What do you have in mind as a trigger provider, then?

Also, I have another question: The battery drains incredible fast. I already read somewhere here, one can sit and wait the percentage decreasing, and that is really true. At least here this is not due to temperature. I think after 20 minutes the power is gone. Do you think, there will be any solution for that?

 Thanks! Martin.
« Last Edit: February 13, 2020, 02:22:19 AM by clkdiv »

tesla500

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Re: Chronos 2.1 newbie questions and impressions
« Reply #3 on: February 13, 2020, 01:20:15 PM »
If you want to do a speed ramp, an Arduino would work, as would pretty much any programmable signal generator. You need to generate a TTL pulse for each frame capture.

You mentioned wanting to trigger a studio flash on every frame, which one did you have in mind? Most studio flashes I know of can only fire at a rate of a few Hz or maybe tens of Hz at most, with a low flash power setting, not the kilohertz rate needed for this application.

The battery gauge isn't the most accurate, and will decrease quite quickly at the start of discharge then slow down later. The battery should last 1 hour before the camera shuts down. I just tested mine and it ran for 1 hour and 5 minutes. How long were you seeing until the LED on top starts flashing red? It's possible your battery is defective.

David

clkdiv

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Re: Chronos 2.1 newbie questions and impressions
« Reply #4 on: February 13, 2020, 01:59:15 PM »
Hello David,

thank you so much for your reply, I really appreciate that. I will do my best to generate a TTL pulse, never did that, but it seems to be possible with an Arduino. The flash system I use is a special one being able to fire at speeds up to 4k and more, I hope. I'll start testing this weekend, I suppose.

If you don't mind to help me with my first question I had here in the thread? I am a little bit concerned at the moment. The more I dig into the lens topic, the more I get the feeling that I won't be able to mount a focal length that delivers a FOV equivalent of a 28mm fullframe lens? Might that be true? I need to have these 28mm.

Thanks a lot again!
« Last Edit: February 13, 2020, 02:05:25 PM by clkdiv »

Nikon1

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Re: Chronos 2.1 newbie questions and impressions
« Reply #5 on: February 13, 2020, 02:07:53 PM »
Hello David,

thank you so much for your reply, I really appreciate that. I will do my best to generate a TTL pulse, never did that, but it seem to be possible with an Arduino. The flash I use is a special one being able to fire at speeds up to 4k, I hope. I'll start testing this weekend, I suppose.

If you don't mind to help me with my first question I had here in the thread? I am a little bit concerned at the moment. The more I dig into the lens topic, the more I get the feeling that I won't be able to mount a focal length equivalent to a 28mm fullframe lens onto the Chronos? Might that be true? I need to have these 28mm.

Thanks a lot.
Chronos 2.1 Sensor is around 2x Crop in relation to 35mm Film Full-Frame.So what you need is an 14mm Lens.If you want to make sure, that your Field of view ist *EXACTLY* The same, just compare the actual sizes in mm of the Sensors with each other and calculate the resulting Focal Length. You will propably need an Zoom Lens then.If an aproximate same Field of view will be enough, i would reccomend an 14mm 2.8 Prime Lens. Rokinon offers one, but there are several other ones as well.Also keep in mind that your depth of field will be different between different sensor sizes.Assuming you use an Zoom Lens with 18mm at apperture f/3.5 on an Nikon DSLR, you would need to use an 13,5mm Lens with Aperture setting f/2,63 to get the exact same image on both cameras. 14mm f/2.8 is about as close as you will be able to get with an prime Lens.