[Progbusters]

I took the Pentax 12-24mm f4 rental from borrowlenses for a spin to do hot night astro in death valley and mojave last week. Went manual at 12mm and F4. Got it to about ISO 1600 and 3200 for any image at 30 seconds. The photos on my K50 are okay and could pull out more from photoshop raw. But not spectacular and sharp. Maybe I should try to use a lens that can get me to lower the ISO. I got a few other images to the left and right of this one on flickr.

The lens is okay and useful to have that infinity mark on the lens. The focus and zoom play is loose so one could mess it up in the dark. I did like that it didn't have too much distortion. I would use this lens for landscape in the daytime and street and indoors.

[Shuttershew]

Nice. The editing for astrophotos are tricky as hell.

[torashi]

You have to constantly watch out for perfect focus. With wide angle lenses it's really tricky, even with live view and digital zoom. If you can make your own Bahtinov mask, it's of great help. Better than eye guesswork. I don't trust mine, since I'm as near sighted as a mole.

[wtlwdwgn]

Nicely done. Lots better than me so far.

[bwgv001]

congratulations; nice work

[ibike2work]

Nice work. Wish I lived near someplace where you can see this.

[MossyRocks]

Better than anything I have been able to capture this summer which is a whole lot of nothing. Try stacking to work around the noise and go for shorter exposure as there is some noticable trailing. Maybe go for a pile of 20 second exposures at ISO 1600 when at 12mm.

[DeadJohn]

Your focus is reasonably good, and not much star trailing at 12mm 30 seconds. There's also a small amount of coma distortion visible if I look at the brightest stars in your 2028 pixel version on Flickr. None of that is harming the image; it's all trivial and only other astrophotographers will notice it.

Here's one way to try accentuating the Milky Way. It works best with raw but you can try it on jpg too. I'm using Lightroom terminology but other software has similar features. Apply color noise reduction. There's quite a bit of noise to deal with because it was a hot night. Then raise the white point to bring out more of the Milky Way. Maybe boost shadows. If those prior steps made the sky too gray and lacking contrast, back off a little on the whit or shadows, or reduce the black point. Finish with a small touch of the clarity slider.

If you can make your own Bahtinov mask, it's of great help.

I've only used a Bahtinov with an 8" Schmidt-Cassegrain telescope. Have you had success with ultrawide camera lenses? My expectation is that the spikes would be too faint to see in the viewfinder or liveview.

[TedH42]

I've only used a Bahtinov with an 8" Schmidt-Cassegrain telescope. Have you had success with ultrawide camera lenses? My expectation is that the spikes would be too faint to see in the viewfinder or liveview.

My experience is that the longer the focal length, the more useful the Bahtinov mask. With short focal lengths, the spikes are smaller, and it is not as precise. I would try live view, using the OK button to get the 10X magnification, to adjust the focus so that the stars are the smallest possible dots (no Bahtinov mask). Then tape down (painter's tape works well) the focus ring so that it won't move if touched. Check that the taping operation didn't mess up the focus, correct if necessary.

[Progbusters]

cool tips thanks