Widefield focus with DSLR

[kirkster501]

Hi all,

Trying my hand at this with my daughter.  Just using my terrestrial camera for now.  I have a modded 1100D to play with too.

In below picture 5 seconds focused at infinity on the electronic view finder.  None motorised static tripod.  Fuji XT2 with 16mm Fixed lens at ISO 800 and at F2.2.  Need to stop down a bit for the corners so not too worried about that or the light pollution.  Strictly speaking the XT2 is not a DSLR but is mirror-less camera.

I'd have expected sharper stars than this though at only five seconds and that rotation would not have been such an issue?  Camera was pointing upwards at about 70 degrees.   Is the blobbyness of the stars down to lack of tracking do you think?  Or focus?  And how to focus if none live-view camera?

Thanks for your thoughts.

[kirkster501]

Here's another of Orion.  8 seconds.  The focus at Infinity is not correct....

[Scooot]

Hi, I suspect focus is out slightly. I don’t know your camera but I don’t think setting to infinity is usually accurate enough. If that’s the case, on a non live view camera it’s trial and error. Alter the focus at infinity slightly, take a shot and repeat as necessary. You could try something in the distance during the day to get a feel how much to tweak it maybe?

[Space Hopper]

Does it have the 'focus peak' feature on it ?

I use that on my A7 and it works great, especially for Lunar.

[wxsatuser]

Focus is out.

Same as scooot
I just trial and error the focus, take a shot zoom in and see what stars are like, tweak focus, repeat.

[Owmuchonomy]

Usual method on mine (canon dslr) is to find a bright star, centre it on the screen, press 10x to zoom and then focus.  Using a marked infinity point on a focus ring is never reliable.

[maw lod qan]

I use a Canon SL1 and even when I'm certain I have it focused perfectly,  sometimes on the computer it's a bit out. 

I try a very bright star or even a planet when I'm lucky to have one visible.

Keeping saying I'm going to get my computer out with the camera. but just haven't yet.

Hang in there and enjoy the fun you're having with your daughter.