Tuesday, January 28, 2014

Lunar Photography on the Cheap

Well, this is not the usual thing I would do. However, since those things are possible, I will show 'em to you... and also explain how I did it.

First of all, when doing astro-photography, I would usually use a decent telescope, e.g. an APO refractor w/ a fluorite-glass lens... or a decent reflector with some decent optics.

However, today, I show you how you can achieve an acceptable shot of the moon, using an inexpensive Canon P&S (point 'n shoot). I my case, it is my trusty IXUS 140 (ELPH 130). Of course, we need to use CHDK in order to shoot in RAW.

The shot was taken in the blue hour (aka. magic hour or golden hour). According to the exif data, the shot was taken at f/6.9, 1/125s, 40.0mm, ISO400 (date: 10.01.2014 @ 16:40).

Here is what the camera though I was aiming for (jpeg done by the camera, in the hope that blogger does not tweak the image too much):
JPEG as recorded by the camera, scaled and saved as PNG

The same shot, recorded in RAW (DNG) by CHDK, was taken into Photomatix and the GIMP with the following steps performed on the image.

Photomatix:
  • playing with single frame pseudo HDR parameters (tone mapping)
  • tweaking highlights and shadows
  • dropping exposure by some stops
  • increasing contrast
  • etc. 
Actually, for the fun of it, this is the image before I used the GIMP:
as exported from Photomatix, no noise-reduction yet
The GIMP:
  • duplicating the image, creating a second layer
  • creating a layer mask for the first layer (100% opacity)
  • masking out the moon (the first layer now contains clouds only!)
  • reducing the noise in the clouds using wavelet denoise
  • on the lower layer (luna!), increasing sharpness using wavelet sharpen
  • flatten the image
  • export to PNG
the result of the process laid out above

Yep, this is the same shot... compare the cloud pattern...
After some tweaks, the daylight shot looks like a night-time photo. Also, some detail (noise!) was added to the moon, while noise (detail) was removed from the clouds selectively.

Here you have it, it does not take pro-gear to create a cool(ish) shot of the moon. I happen to have access to Photomatix, however, I feel that you might be able to use some free software to obtain the same effect... maybe even the GIMP!

In comparison, on screen, you might like the image before GIMP better... however, I believe on a print, the GIMPed shot might have an edge.

Tweak your photos and enjoy!

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