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Has anyone tried making flats field with the Optolong L-PRO FF filter?

Optolong L-Pro Equipment Calibration Vignetting
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Giulio Ercolani avatar
Giulio Ercolani avatar
Hello, has anyone tried to make flats field with the Optolong LPRO filter and a full frame reflex? With my Canon 5DMKII with LPRO filter and a Canon f 2.8 100mm lens with hood, flat fields made in AV mode are completely overexposed. In Live View the exposure seems correct, but the flats field created still fail to remove the vignetting from the images. I made the flat at 200 ISO, without exposure correction and with a correction of + 2 stops. I also tried with different exposition time in manual mode. I checked the saturation level of the sensor which is around 16,000 ADU and I checked with Pixinsight statistics that the flats were about half the saturation value (half well depth 8000 ADU). However the flats I made are not able to eliminate vignetting at the edges of the images.
I would like to know if anyone has encountered the same problems.
dkamen avatar
dkamen avatar
When you stretch a flat, can you see the vignetting? If not then (and this is just an idea) maybe in-camera lens aberration correction is at play. Which would probably lead to wrong results by the presence of the filter.
Giulio Ercolani avatar
Giulio Ercolani avatar
Hi dkamen, your is a good idea, but I think flat area fine , you may give a look here https://astrob.in/414068/0/
Giulio Ercolani avatar
Giulio Ercolani avatar
And here a light frame calibrated with Pixinsight, with strong vignetting at the corners  https://astrob.in/414068/D/
Here a light frame with no calibration at all https://astrob.in/414068/E/