A PHOTOGRAPHY QUESTION...(on an astronomy forum!!! )

cheers paul.

its all makin sense now.. :lol:

thanks for time... very helpful.. now all i need is time and cloudless skies!!!

all the best.
kevin..

Hi Kevin,

When it comes to shooting big things like the milkyway what you really want is a fast lens. You want as much light on that sensor in as little time as possible. As Paul has said, zoom lenses have much more glass in the way so they are much slower.

If I were to be looking for a lens for this kind of work I'd be looking for an 18mm f1.4 lens.

Hope that helps,

Bart.

That's right Bart, although the trouble with that sort of aperture is that there tends to be coma which causes stars towards the corners to look more like comets - cured by stopping a bit which of course is what you don't want to do, so then you turn the sensitivity of the sensor up which makes it noisy, so you take lots of shots and stack them which takes a long time!

It's not easy is it

That's right Bart, although the trouble with that sort of aperture is that there tends to be coma which causes stars towards the corners to look more like comets - cured by stopping a bit which of course is what you don't want to do, so then you turn the sensitivity of the sensor up which makes it noisy, so you take lots of shots and stack them which takes a long time!

It's not easy is it

Lol ... no ... there's always a gotcha. I just picked up a good high quality 30mm f1.4 lens that I'm hoping to turn skyward soon. Obviously a smaller field than an 18mm but should still be nice.

Bart.