First Shots with my 100mm macro

[E_ri_k]

Thought Id set up the HEQ5 and try some widefield shots with my Canon 100mm Macro lens. I was surprised how good they came out. I had previously been using my 24-105 L series, which produced terrible coma. I have high hopes for it in the future!

Antares was 1 Hr at f 2.8. Carina was 1 Hr at f4.
I think at f4 the stars are a bit tighter, but it has introduced a bit more coma around the edges?

Erik

[jjjnettie]

:) You're using Photoshop to process?
Use their lens distortion filter to fix up your coma.
Filter - Distort - Lens Correction Adjust the top slider to the left to about 17.

[E_ri_k]

Thanks, I'll give it a go. I could never get the lens correction filter to work properly. When you say: Filter-Distort-Lens Correction, I don't have Lens Correction in the Distort menu? Are there 2 different filters? Done some screenshots of the menus. When I adjust the sliders in the lens correction, everything goes MAD! Or do we have different versions of PS?
Erik

[E_ri_k]

Actually you know what, it worked. It looked like it kinda enlarged the whole picture a bit though, which to me looked wrong at first. But you were actually spot on with the -17! Well done! It just messed with my eyes a bit.....

[jjjnettie]

Hmmmm, I wonder why you don't have it in yours??

[jjjnettie]

:) Cool. Yes, it does enlarge the image. It almost seems like it's turning it into a "fisheye" look eh. LOL But it's all good.

[E_ri_k]

Thats exactly what it did, messed with my head! Haha. However, it corrected for the coma in the bottom right of the image, but now it has messed with the other corners? Is there a way of fixing that?

[jjjnettie]

You can delve deeper into the filter and fix areas selectively, but I've no experience with that. You can't crop it out?

[E_ri_k]

Just a quicky, but here are the 4 corners before and after.
the first one is before the filter.

[jjjnettie]

It works a treat doesn't it. :)

[E_ri_k]

Yeah I can crop it out I guess, just thought the distortion would be the same across the whole field? All good though, no big deal. You cant really see it unless you zoom in at 300%!

[E_ri_k]

It does! I think i might play with it, and use it in moderation, to remove the worst areas, if I cant crop it out. Thanks for the help!

[jjjnettie]

Exactly right. :)

[jjjnettie]

You can also use the Star Rounder plug in. Select a region of the image and apply the filter to it. But it does leave artefacts in the image if used to harshly.

[E_ri_k]

Yeah, I have seen that, need to download it again, since I lost everything......Didn't get a chance to use it before the crash!

[jjjnettie]

http://www.grekalova.com/photo_Astroplugins.html