Author Topic: Cooled D850 Modification Available for Sale  (Read 2441 times)

Macro_Cosmos

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Cooled D850 Modification Available for Sale
« on: June 05, 2018, 11:16:39 »
http://www.centralds.net/cam/?p=10796
Passive and active cooling with impressive long exposure performance.

Example here:
http://www.centralds.net/cam/wp-content/uploads/2018/02/org_compare.jpg

 ??? Not exactly that expensive either, considering how much the D810a cost... which is not a cooled camera.
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Macro_Cosmos

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Re: Cooled D850 Modification Available for Sale
« Reply #1 on: June 05, 2018, 11:37:09 »
This thingy also begs the question. If one has that much money laying around, might as well just buy a cooled monochrome CCD camera, a really good one costs less! A really good cooled CCD camera is around the $3500-4000 mark. A reputable Chinese one by QHCCD is about $2500-$3500. What's the point of this thing?

Also I am highly sceptical about the fan cooling system. It's just a fan behind the sensor, which is pulled out of the body losing all protection it's intended to give. For astro, it shouldn't be much of an issue; for macro though... yeah. Imagine that shake magnified by more than 10 times.

Then we have the issue of flange distance. I cannot buy the hypothesis that a camera modder is able to keep the calibration as precise as Nikon's factories. They'd have to prove me wrong.

In essence, this in my opinion an utter waste of both time and resources. For specifically deep space astro, a real cooled monochrome CCD camera would be better[1]. For conventional photography, the D850 as it is would be better. For my type of thing, a good stable setup with my D810 which I paid barely $1000 for suffices. It's a pretty cool modification though... oh and that pun was not intentional.

[1]: Referring to cameras that actually cool the sensor down to -20C or even lower, I've seen -40 and more. Not a fan installed behind the sensor.
I also think a cooled heatsink would be better, but it is maybe not feasible?  :o
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Ilkka Nissilä

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Re: Cooled D850 Modification Available for Sale
« Reply #2 on: June 05, 2018, 14:26:27 »
This thingy also begs the question. If one has that much money laying around, might as well just buy a cooled monochrome CCD camera, a really good one costs less! A really good cooled CCD camera is around the $3500-4000 mark. A reputable Chinese one by QHCCD is about $2500-$3500. What's the point of this thing?

Well, if I understand correctly, this camera is self-contained and can be used to capture images without a laptop. Dedicated astro cameras normally require some accessories to use and if you travel to get to the location (outside of city light pollution) having fewer items to carry is convenient.

Also, the 45MP FX sensor likely gives high image quality with less setup time (than stitching with an astro CCD camera).


Jack Dahlgren

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Re: Cooled D850 Modification Available for Sale
« Reply #3 on: June 05, 2018, 15:00:34 »
Note that this is not just a fan. The block which holds the lens is using a peltier element to cool the chip. The fan is to remove heat from the hot side of that unit. Also responding to the note about the sensor being unprotected, it is in a sealed block with a clear cover glass to prevent moisture and condensation. The cover glass is attached to the hot side of the peltier unit so it will resist condensation. Finally, achieving flange distance accuracy is not hard using modern tools. It is mostly a question of quality control.

Macro_Cosmos

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Re: Cooled D850 Modification Available for Sale
« Reply #4 on: June 07, 2018, 10:00:40 »
Well, if I understand correctly, this camera is self-contained and can be used to capture images without a laptop. Dedicated astro cameras normally require some accessories to use and if you travel to get to the location (outside of city light pollution) having fewer items to carry is convenient.

Also, the 45MP FX sensor likely gives high image quality with less setup time (than stitching with an astro CCD camera).

Yeah, it's easier to setup, until one carries a celestron out in those Pelican Cases, the counterweight for my amateur starwatcher is about 2.5 kilos, imagine a professional one. This modded Nikon is just not a serious astro camera. A modded D5100 with NikonHacker firmware and DIY heatsinking would do a far better job actually. Say the entire modding process takes $1000 inclusive of the camera ($250 used), one has $3500 lying around. A good equatorial mount could be anywhere from $450-2000+ depending on the application one wants. The Samyang 135/2 and/or the Nikon 180/2.8 ED ais are both great lenses for amateur deep space. Comparatively speaking, this camera is just not worth it.

The 45MP will deliver superior detail per square millimeter but lower quantum efficiency compared to higher end cooled CCD cameras. Moderately priced ones go up to 70-80% easily, the top of the line consumer dslr/mirrorless cameras are 60-65% at best. Also coloured cameras always have lower quantum efficiency than monochrome cameras if we control every other aspect (the tech, actual sensor unit... etc) In addition, dark current and readout noise are an annoyance, very problematic when the sensor packs more pixels in it. QHCCD offers a 36mp cooled sCmos camera, I believe it's about $3800.

What I'm getting at is, by pulling the sensor out of the camera and modding it in such a way basically tarnishes the advantage  of modding consumer cameras for astro use -- that being the modded camera is also capable for normal photography (a bit red shifted... makes skin tones look great  ;D). In such a case, what's the point?

Note that this is not just a fan. The block which holds the lens is using a peltier element to cool the chip. The fan is to remove heat from the hot side of that unit. Also responding to the note about the sensor being unprotected, it is in a sealed block with a clear cover glass to prevent moisture and condensation. The cover glass is attached to the hot side of the peltier unit so it will resist condensation. Finally, achieving flange distance accuracy is not hard using modern tools. It is mostly a question of quality control.
Yeah, you're absolutely right here. The fan as I've said won't matter for astro, and it's intended for astro -- moot point on my end.
On the sensor stuff, I didn't say it's unprotected, it's rather not protected in the camera body, where it's supposed to be. My wording wasn't concise, point taken. As for calibration, I'd have to be convinced on that one. I'm sure they did a great banging job though.

So summing up, the advantage of this camera over a cooled CCD/CMOS is its self-containment. No dongles and linking required to take photos.
One must still supply their own lens, their own equatorial mount, their own registered software, and so on. It's still a pretty brave and cool modification though.
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Jack Dahlgren

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Re: Cooled D850 Modification Available for Sale
« Reply #5 on: June 11, 2018, 04:11:38 »
What makes CCD better than CMOS for Astro? Less noise? Please educate me as I’m ignorant about this subject.