Tag Archives: Sigma

Geminid Photobombing Orion 14 December 2020

Canon 60D, ISO 1600, f/2, 15 seconds, Sigma 30mm F1.4 EX DC (HSM).* The lens is 48mm equivalent field of view with the 60D’s 1.6X crop factor. For meteors, a wider lens is better but this is what I have in sharp, fast glass. I got a couple of meteor images at 30 seconds but the stars are little glow worms.

Geminid meteor photobombing Orion

No post processing other than resizing.

Geminid meteor photobombing Orion

I’ll list post processing below.

Some of the stars in the original, particularly Orion’s belt, have red halos so looking at them zoomed out they look pink.

First, I desaturated the red channel on selected stars.

Next I used the Focus Magic filter to undo some motion blur (about 7 pixels). I’m using a demo version and still learning my way around it. It tends to oversharpen but I think that’s more a function of my ignorance than anything wrong with the algorithm. The demo is nice. It doesn’t cripple the software or add a watermark, you just have a limit of 10 images.

Pixel-peeping to see how well the blur removal worked, I found more red halos and did another round of selective red desaturation.

In GIMP, I adjusted the exposure to -0.750. An un-adjusted image comes up with exposure ‘0’. I’m not sure what the units are but I tweaked to taste. The trees lost a little glow but the sky looks more like what my eyes saw. I’ll probably play some more. If anything worth seeing comes out of it, I’ll update this post.

* This lens is discontinued. I got mine as a Sigma factory refurbished lens when the model was still current. Some “new old stock” is available depending on mount and mint used ones can be picked up inexpensively. The newer version is part of Sigma’s “Art” series. It costs a bit more (MSRP $499) and is tweakable with their USB dock.