15th Feb 2024: Astro Pixel Processor 2.0.0-beta29 released - macOS native File Chooser, macOS CMD-Q fixed, read-only Fits on network fixed and other bug fixes
7th December 2023: added payment option Alipay to purchase Astro Pixel Processor from China, Hong Kong, Macau, Taiwan, Korea, Japan and other countries where Alipay is used.
Hi!
What process would you recommend for processing images taken with second generation Sony A7 cameras?
Their problem is that there is an internal light leak, due to an infrared LED in the shutter, moreover, the sensor moves slightly due to the internal stabilization mechanism making the dark less effective.
Using "Adaptive data pedestal" the result should improve significantly but as you can see from the attached image, the stacking output is pretty awful ...
Sony A7RII, 680x30", ISO 3200 (300 flipped 180°)
240 darks, 20 flats
Settings used:
2)
Everything else set to "automatic"
4)
5)
6)
I think I can't do better to fight gradients but I'm probably wrong...
Here is a single dark, unstretched:
You can clearly see the patterns in the final image.
Is the adaptive data pedestal performing bad with this kind of data?
I thought that flipping the sensor 180° would help APP to determine a better normalisation map, but in fact I just destroyed both sides of the picture doing this...
I finally arrived to a "good" image with this data but you'll imagine how much work it represented:
Thanks in advance!
Hi,
and sorry for reviving such an old thread. I also have an astro modified A7rII and it has a replacement filter from baader which takes care of some of the ir light leak ( http://www.astrosurf.com/buil/baader/eval_us.htm). One thing I noticed was, that the amount of the light leak depends on the physical orientation of the camera. So when the camera is pointing down the leak is less severe than when it is pointing up. This can also interfere with taking proper darks. During acquisition it is advisable to keep the general orientation of the camera the same or else some darks fit the ir leak and some darks are just wrong. Since I acquire my data from city skies, I have to stretch my images very hard in order to get decent images and some remainders of the ir leak are always present and I need to do cosmetic corrections and gradient removal in post.
The A7rII has some internal raw baking and bit depths vows on top however. Depending on your shooting mode it differs from 14 to 12 bit and differing amounts of raw baking in regards to the star eater issue. This is another way to ruin your darks, bias and flats. 14 bit is only availabe in single shot up to 30 second exposures. single shot bulb exposures are only saved with 12 bit precision. You can force the camera to use 12 bit precision by using continuous low shooting mode for shorter exposures.
My goto settings for DSO, broadband and duo narroband are : single shot, bulb, 180s/300s at ISO 640 (as iso 640 is fine with 12 bits) for lights, same for darks at same temperature and physical camera orientation and continuous low at iso640 for flats and bias frames.
Best regards,
Ben
