Camera crop mode to cut out vignette

[Jezphil]

Newbie question here. If I use my TeleVue barlow 2.5x with my Skywatcher Evostar 120ED Pro and Canon EOS Ra,  I get a round black vignette around the image which seems to be the round mount adapter or tube that it is looking through. I don't get this with the field flattened/reducer so that's fine. If I go into crop mode in the camera , wich crops x1.6, the vignette disappears. I presume this is in effect a digital zoom using less of the sensor. Presumably this loses quality, but at least gives a non-vignette frame. So is it worth me doing this in-camera crop mode for stills, or am I better cropping in post? In which instance do I lose less quality? I know there is a recommendation to go into crop mode whilst taking video of planets for stacking, but should I use it in this instance? Thank you in advance.  

Edited July 28, 2020 by Jezphil

[michael8554]

If the x1.6 crop is by Interpolation then No, crop in Post.

Taking Flats may reduce the vignetting.

Michael

[Jezphil]

Thank you. The vignette is a solid circle which is an image of the equipment rather than a lens feature so this is about getting a clean, rectangular image all over, unobstructed by a hole shape. The camera is full-frame mirrorless so I think I will try the cropping and see how that goes, as there is a bit of room for manoeuvre, despite ending up with fewer megapixels. 

[michael8554]

With 30Mpix you can afford to crop.

Flats are still worth taking to remove dust bunnies etc.

Michael

Edited July 29, 2020 by michael8554

[Jezphil]

Yes, I am doing flats, bias, darks.  Thanks for your reply - much appreciated and useful. The TeleVue barlow isn't geared up with a full fame camera so I will crop in camera.