Touptek ATR585M + Sharpcap sensor analysis = Massive Confusion.

ToupTek ATR585M
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John Stone avatar
John Stone avatar


Info       00:46:43.289585    #1     Opening SharpCap.Cameras.ToupTek.sdk.SDKWrapper`1[SharpCap.Cameras.ToupTek.sdk.Toupcam] Camera ATR585M(USB2.0) (#\\?\usb#vid_0547&pid_157d#7&33b0be72&0&1) : FLAG_CMOS, FLAG_ROI_HARDWARE, FLAG_MONO, FLAG_TEC, FLAG_USB30_OVER_USB20, FLAG_GETTEMPERATURE, FLAG_RAW16, FLAG_FAN, FLAG_TEC_ONOFF, FLAG_TRIGGER_SOFTWARE, FLAG_TRIGGER_SINGLE, FLAG_BLACKLEVEL, FLAG_BUFFER, FLAG_DDR, FLAG_CG, FLAG_RAW8, FLAG_CGHDR, FLAG_HEAT, FLAG_EVENT_HARDWARE using SDK version 59.29331.20250824                    in new


Can anyone help me make sense of these results?

I thought the ToupTek camera was "locked" at Gain 100, Offset 512 no matter how you tried to change it? 

Shouldn't SharpCap's analyses have the same results for every gain value if this were true?

And what's up with 23.39 e- of read noise at gain 100?  And a Full-well of only 24778e-?  I thought the full-well on the IMX585 was 47ke- (at least according to Player One on their version)
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andrea tasselli avatar
andrea tasselli avatar
SharpCap doesn't lie. Others may…
John Stone avatar
John Stone avatar
An update:

Here's a single 1 second dark frame stretched with screen stretch in pixinsight:



And here's the statistics for it:


If there really were 23.36e- of read noise we'd see huge variations in the ADU counts as at gain 100 it's 0.38e-/ADU which would be expected ADU count variations of 62-63 which is simply not here.  We're seeing 1.7 - ish.

I think SharpCap's sensor analysis of this HDR mode is "borked".

I've opened a ticket on the SharpCap forum about this topic.
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Tobiasz avatar
Tobiasz avatar

John Stone · Nov 17, 2025, 08:10 AM



Info       00:46:43.289585    #1     Opening SharpCap.Cameras.ToupTek.sdk.SDKWrapper`1[SharpCap.Cameras.ToupTek.sdk.Toupcam] Camera ATR585M(USB2.0) (#\\?\usb#vid_0547&pid_157d#7&33b0be72&0&1) : FLAG_CMOS, FLAG_ROI_HARDWARE, FLAG_MONO, FLAG_TEC, FLAG_USB30_OVER_USB20, FLAG_GETTEMPERATURE, FLAG_RAW16, FLAG_FAN, FLAG_TEC_ONOFF, FLAG_TRIGGER_SOFTWARE, FLAG_TRIGGER_SINGLE, FLAG_BLACKLEVEL, FLAG_BUFFER, FLAG_DDR, FLAG_CG, FLAG_RAW8, FLAG_CGHDR, FLAG_HEAT, FLAG_EVENT_HARDWARE using SDK version 59.29331.20250824                    in new



Can anyone help me make sense of these results?

I thought the ToupTek camera was "locked" at Gain 100, Offset 512 no matter how you tried to change it? 

Shouldn't SharpCap's analyses have the same results for every gain value if this were true?

And what's up with 23.39 e- of read noise at gain 100?  And a Full-well of only 24778e-?  I thought the full-well on the IMX585 was 47ke- (at least according to Player One on their version)

No it is not locked at gain 100. It predetermines the offset only, so the hdr algorithm does not mess up the image merge. You can choose whatever gain you want, but only gain 100 makes sense in HDR mode.

The read noise at g100 is weird, which FPGA (firmware) version does your camera have? You definetly need the newest one including the driver that is shipped with it.

The full well of 24k is right (in HDR mode). The value 47ke- is only for LCG and lowest gain. If you compare two vendors cameras, you have to compare them in the same conversion mode (LCG or HCG). HDR mode will never be the same, because every vendor uses a different HDR algorithm (with QHY being the best: 47ke- with 1e read noise).

CS

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