Quote:
Originally Posted by Dennis
What was the issue with stars inside/outside of focus? Did you use manual or auto focus?
|
It was just a case of getting the focus spot on. I found I needed to focus on a bright star in the centre, then do more focus on a fainter star nearer the perimeter of the FOV. Doing a combination of that I ended up with a sharper focus.
This lens is very hard to focus for astronomy. It is a push-pull style zoom with a lock which locks both the zoom and the focus. So to stop the zoom sliding down you need to lock the lens a little, but that makes the manual focus more grippy and harder to make minor adjustments with. It also means if you want to change the zoom you need to tweak the focus because it's near on impossible to slide the zoom without rotating the focuser slightly at the same time.
But it does give me 400mm without the hassles of a 6 point ring system on the guide scope. So there's pluses and minuses.