Focus to Infinity

[Blasted]

In another thread it was suggested that in order to take some star trail shots I should point camera to sky and focus to infinity.

I'm using a canon 17-55, do I simply turn the focus ring all the way to one side so that it lines up with the infinity sign.

I'm assuming that on a focus to infinity setting it will look bad through the viewfinder but the final image with have an infinate depth of field and wont require me to focus on a singular point.

 

[futureal33]

For star trails I tend to focus to infinity then turn it back slightly - the amount will of course vary from lens to lens. However on infinity all my shots were OOF

 

[hollis_f]

Do you have a camera with LiveView?

If Yes: Point camera at something a long, long way away. Stars are preferable if you've got some bright ones. Put the lens in MF mode and turn the focus to the infinity mark. Engage LiveView, zoom in to 10x and change the focus manually until the stars are in sharp focus.

If No: Do the same, but take a photo of the stars and zoom in to check focus. Tweak the focus ring and take another image and check it. Repeat until stars are acceptable sharp. Remind self to buy a camera with LiveView, preferably with an articulated LCD.

 

[Blasted]

I have a 450d which I understand has live view, I've still to suss out how it works, but thanks anyway.

 

[Scarecrow]

Turning your focus ring to the stop will, in all likelihood, not be focussed on infinity and will not give you infinite depth of field.

With the ring on the stop, your lens will probably be focussed beyond infinity, which means that everything will be out of focus. Greatest depth of field is achieved by focussing on the hyperfocal distance, which generally is a third of the way in to the scene you are photographing.

For star trail shots, if it's possible try and focus on a light some way off in the distance to achieve focus before pointing the camera at the sky. If no lights are in view try using your live view, zoomed in, to focus either on the moon if it is in the sky or one of the brighter stars you can see.

 

[craig.walton2]

Not that I'm an expert but I find it handy to focus on the moon the change to manual and use that.

Sent from my iPhone using TP Forums

 

[Blasted]

For star trail shots, if it's possible try and focus on a light some way off in the distance to achieve focus before pointing the camera at the sky.

So, If i'm on a hill side could I point the camera at a light a couple of miles away for example, focus on that, switch to manual leaving the focus as is then point to sky?