Sensor Analysis for DSLR

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admin
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Re: Sensor Analysis for DSLR

#11

Post by admin »

Hi,

there are some lumps in both the read noise and relative gain. The gain could be down to variations in illumination levels - phones and tablets can actually be bad as illumination sources for sensor analysis, as by default they vary screen brightness as the environmental light level changes.

It looks like the sensor in your camera has a big drop in read noise between ISO 320 and 400 - probably a switchover from LCG to HCG mode. I would suggest using the camera at ISO 400 or above for best results for astro imaging. The camera is certainly doing a lot better than older Canon DSLR, where the read noise can be well above 10 for low ISO...

cheers,

Robin
blavenn
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Re: Sensor Analysis for DSLR

#12

Post by blavenn »

Thanks for this info Robin. I just remembered that I didn't end up using my iPad for this analysis, I have some professional LED lighting panels I use for videography and I just put a diffuser on it. So I shouldn't have been getting variations in illumination levels. Now I'm even more curious where these lumps are coming from. Any ideas?

I would like to retry the analysis again to see the results under a different source of consistent illumination. Although the whole sensor analysis process takes a couple hours to complete due to the nature of how these huge 50mb RAW files are transferred through the usb/driver, it will be quite a challenge to do outside due to the nature of constant changing south Florida weather.

Also I'm wondering if those lumps you saw in the analysis would largely skew the results of the smart histogram feature?
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Re: Sensor Analysis for DSLR

#13

Post by admin »

Hi,

I don't think the lumps will cause a major problem with the smart histogram - the algorithm is likely to home in on ISO 400 as the optimum setting and the figures for that look 'good' rather than 'odd'.

Do make sure you are in 'still mode' before running the analysis - it reduces the number of frames needed, since it eliminates the 'waiting for image to settle' frames.

cheers,

Robin
Miesilmannimea
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Re: Sensor Analysis for DSLR

#14

Post by Miesilmannimea »

Hi

I managed to do an analysis of my 550D (w/o any filter). Below is the result.
Now I need to understand what it means in practice :)
550D.jpg
550D.jpg (141.48 KiB) Viewed 5004 times
Last edited by Miesilmannimea on Wed May 25, 2022 9:36 am, edited 2 times in total.
Miesilmannimea
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Re: Sensor Analysis for DSLR

#15

Post by Miesilmannimea »

How can I transfer the test results to another computer -
so I don't have to do it again?

M.
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Re: Sensor Analysis for DSLR

#16

Post by turfpit »

See viewtopic.php?t=4568

Found by using +sensor +analysis +transfer in the search box at the top right of the forum screen.

Dave
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Re: Sensor Analysis for DSLR

#17

Post by Miesilmannimea »

Thank you :)
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