Author Topic: Moonlit stills, Chronos suitable?  (Read 630 times)

Nikon1

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Re: Moonlit stills, Chronos suitable?
« Reply #15 on: October 16, 2018, 11:41:50 AM »
Thanks NiNeff for trying and Posting that.
I guess DDR is Right, too much noise.
If the Camera would be stupid cheap like around 100$, it would be worth try modify it and Cool the Sensor down really cold. that COULD help somewhat with the noise. But at that price point i wouldnt risk that.
I guess you CAN get something remotely "useable" form it in such low-Light-Long-Exposure Situations but nothing really super high Quality.
But since it is not intedended for anything like this, i am Not surprised at all with exposures that long.
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Keep in mind that your usual DSLR or astro-CCD-Camera on the other hand canīt even remotely touch the 1000+++ fps of the Chronos but will perform Better in Low Light /Crazy Long exposure :)
There is an tool for every job!

BiduleOhm

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Re: Moonlit stills, Chronos suitable?
« Reply #16 on: October 16, 2018, 02:39:21 PM »
Well... with a lot of averaging (like hundred of frames) it's maybe possible.

I guess the thing is as the sensor is very sensitive you don't need the multiple seconds exposure (as your test at 10 fps proves it) so you can do a lot of shoots in a relatively short amount of time and average them to have a better SNR. I'd say to also test at a higher framerate (something like 20 or 30 fps for example) to see if it improves things, or not... (I don't know if the SNR is the same at 10 fps and 30 fps so I guess only a test will answer that).

tesla500

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Re: Moonlit stills, Chronos suitable?
« Reply #17 on: October 16, 2018, 04:44:34 PM »
The noise you're seeing here is actually just dark noise. Black cal won't work below about 60fps, so what you're seeing is an uncalibrated image. Try doing a black cal at 60fps then changing to 10fps.

Nikon1

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Re: Moonlit stills, Chronos suitable?
« Reply #18 on: October 17, 2018, 03:01:28 AM »
@tesla500
Ok, that is good to know.
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@BiduleOhm
Well, the moon is actually quite a bright object in the Sky. If you want to do some deep Sky-Object Photography you will have to deal with far less bright objects in the Sky.
Also i guess that image of the moon was shot on the Kit Lens @75mm...? Based on the Size... Dont know what apperture tho, could be anything from 1.2 (Rather unlikely that NiNeff used 1.2 on that) to like 11...?
As far as Sensitivity of the Sensor goes, i found in side-By-Side testing with my Nikon1 that the Base-Gain (Gain 0) is about as sensitive as ISO 160 or 200 and the highest available Gain-Setting should be compareable with ISO 3200 as far as Sensitivity goes, but i havent tested that side-By-Side for the higher Gain-Values for verification.
While it is possible to use 1.2 on something like the Kit lens, if you want something longer (Like Telescopes), you will get appertures of 5,6 or below. Also most Lenses Wont perform best when wide-Open, so you will need to Stop most of them down a bit to get good image Quality. And if you simply expose your image Longer then, i guess Noise will get even Worse.

Sael

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Re: Moonlit stills, Chronos suitable?
« Reply #19 on: October 17, 2018, 03:15:15 AM »
While not suitable for it, decent results can be gotten from the Chronos. Because the noise gets worse as you below 60FPS that's the lowest I went. The lens is a Tamron 150-600mm F/5-6.3. Video recorded at 600mm F/6.3, Moon at 60FPS, and mars at 500FPS.

BiduleOhm

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Re: Moonlit stills, Chronos suitable?
« Reply #20 on: October 17, 2018, 03:57:18 AM »
Wow, mars is pretty decent for a camera who wasn't designed to do this, especially at 500 fps.

Nikon1

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Re: Moonlit stills, Chronos suitable?
« Reply #21 on: October 17, 2018, 04:24:39 AM »
I downloaded the Video from the moon now 3 times but cant open any one of them... Dont know what that is all about. Maybe just my bad internet connection here.
But the Mars one is actually pretty impressive.
If the Noise gets so much worse below 60fps, then maybe just use 60fps or faster i guess...

BiduleOhm

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Re: Moonlit stills, Chronos suitable?
« Reply #22 on: October 17, 2018, 04:35:51 AM »
I was able to open and play it with VLC without any problems.

Nikon1

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Re: Moonlit stills, Chronos suitable?
« Reply #23 on: October 17, 2018, 04:44:19 AM »
I was able to open and play it with VLC without any problems.
I tried again, and now i can open it. The other 3 Downloaded Files from the Same Video wont open in VLC or in AE CS6
While the noise is still quite strong for my taste on this shot with the moon, all things considered its still rather impressive for an camera which wasnt meant to do anything like this, especialy with the mars one at 500fps.
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@Sael:
What Gain settings did you use on those? Propably Base-Gain (0) for the moon, but it propably has to be an higher Gain-Setting for the Mars one at that framerate?

NiNeff

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Re: Moonlit stills, Chronos suitable?
« Reply #24 on: October 17, 2018, 09:31:00 AM »
The noise you're seeing here is actually just dark noise. Black cal won't work below about 60fps, so what you're seeing is an uncalibrated image. Try doing a black cal at 60fps then changing to 10fps.
That's actually what it did. I first did a blackcal an then changed the FPS. as it was very bad, I did a second black cal at 10fps with no improvement, obviously.

@nikon 1: I don't remember the f-stop settings, but it was very closed. the exposure time was also way down to about 1% The moon is indeed very bright.

@Sael: that mars video is actually really good, I guess you're using a magnification of about 250x to 300? Now I'll definitively need to hook up my telescope to the Chronos just for the fun of it
« Last Edit: October 17, 2018, 09:33:09 AM by NiNeff »

Nikon1

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Re: Moonlit stills, Chronos suitable?
« Reply #25 on: October 17, 2018, 11:20:29 AM »
@Sael: that mars video is actually really good, I guess you're using a magnification of about 250x to 300? Now I'll definitively need to hook up my telescope to the Chronos just for the fun of it
You could try just using Some Old Paper-Core from Toilet Paper or alike and A bunch of Tape for an Adapter if you want to go really ghetto and cheap with the adapter. Just cut it down to about the right Length and make sure you secure the Camera, so it wont drop down...
If you are patient enough and want to spend the Money there Should be Canon to C-Mount Adapters somewhere...i think?

Sael

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Re: Moonlit stills, Chronos suitable?
« Reply #26 on: October 17, 2018, 06:36:57 PM »
@Nikon1 6 or 12dB, I don't remember... I did abuse levels correction to hide noise however, because it's a black background with a bright object you can crush the shadows and hide a lot of the lower intensity noise. Attached is an example without the crushed blacks. Nikon to c adapters and Canon to c adapters are available on ebay for ~$40-$60CAD.

@NiNeff 600mm on a ~4x crop makes for ~2400mm 35mm equivalent. "magnification" doesn't really make much sense in the photography world unless you have a reference point. Some camera lines use a times zoom, but that's relative to the widest view of the camera. The field of view of a lens is mainly dependent on the focal length and the sensor size. A 50mm lens on a 35mm "Full Frame" sensor (arguably the most common lens and format in the film days) has about a 40 degree FOV, 600mm on a full frame is about 3.4 degrees, and with the size of the sensor on the Chronos it would be about 0.85 degrees. I guess that would be 47x then? Or 4x compared to the widest the lens goes... (150mm)

NiNeff

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Re: Moonlit stills, Chronos suitable?
« Reply #27 on: October 18, 2018, 09:49:41 AM »
I was using Magnification in the sense most Binoculars are displaying it. But actually I don't quite know how that is specified then. Googling reveals "an object viewed through 10x magnification glasses appears 10x times closer" which is not the same as 10x larger one might think. Also I have a feeling there's quite a bit of marketing involved so not really a good measure.