# A99 focus for astrophotography



## cchoate (Sep 14, 2014)

I was out the other night trying to shoot the northern lights. Here was my set-up: Sony A99 with Konica Minolta 17-35 Af lens and a 5" external video monitor attached to the hs. The trouble I have is the inability to see stars with the external monitor or evf. Of course without seeing a subject you can't manually focus. Does anyone have advice on focusing with a wide angle lens on the night sky?


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## astroNikon (Sep 14, 2014)

I don't know about your  lens but I just set the lens to infinity.  Nikon lenses have a window on it where you can manually set the distance such as infinity.


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## cchoate (Sep 14, 2014)

Infinity is just a hair to far. I take the lens to infinity then move it back a touch and shoot. I continue that procedure until focus looks sharp but there must be a way to actually see what you're trying to focus on. With a long lens I don't have a problem.


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## astroNikon (Sep 15, 2014)

cchoate said:


> Infinity is just a hair to far. I take the lens to infinity then move it back a touch and shoot. I continue that procedure until focus looks sharp but there must be a way to actually see what you're trying to focus on. With a long lens I don't have a problem.



That's actually the way I do it.
Take a shot, zoom in and check focus, make a slight adjustment and try again.

There's really no alternative as the camera many times is focusing on what ?. .. a "dot" in the sky?

to prevent the movement issue, a elongated blob, you have to be at 0.6 sec speed in my tests.

In order for me to get focus on any planet or star - the Sun, Moon,, Mars, Saturn, Jupiter, Uranus, Neptune, UWA on the sky I have to take a photo, zoom in to see the focus (or movement) and make adjustments as necessary. This is on a lens or a telescope.

Everytime I set up for a shoot .. the first xx photos are junk because of OOF or movement.  One you get it set though you'r golden.

one reason I abandoned astrophotography back in the film days as you can't really check focus like you can today in digital.


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## TreeofLifeStairs (Sep 26, 2014)

I've had the same issue. The EVF is useless in extreme low light. I've done exactly what the others have mentioned. One other tip for focus was I bump up the ISO all the way and open up all the way. so I don't have to wait for a long shutter. Changing the ISO back to what you want after finding the focus has no impact on focus what so ever. Changing the aperture does have a minor role in focus but unless you're trying to do star trails you probably want it open anyway.


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## theraven871 (Nov 4, 2014)

I remember my father teaching me the art of astrophotography.  More of a deep space photography than just shooting the night sky.
I remember mounting a film camera to telescopes that were HUGE.
Then we would have an eye piece to look through that resembled a "targeting reticle".
Then you would have to wrap your arms around the telescope, and slowly rotate it to keep your object in the "crosshairs" while you had a trigger to hold the shutter (on the camera) open.  
Then, you had to develop your rolls of film to verify if you captured anything usable.
All the while you're standing in complete darkness, freezing your butt off. 
Eventually we got motors that would help rotate the telecope in relation to the night sky.  But they never seemed to work as accurately as rotating the telescope with your arms.
It was a ridiculous, tedious and extremely challenging task. 
But some of the best photos I've seen in my life were taken this way.  They are memories that I will never forget.


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## JustJazzie (Nov 4, 2014)

TreeofLifeStairs said:


> I've had the same issue. The EVF is useless in extreme low light. I've done exactly what the others have mentioned. One other tip for focus was I bump up the ISO all the way and open up all the way. so I don't have to wait for a long shutter. Changing the ISO back to what you want after finding the focus has no impact on focus what so ever. Changing the aperture does have a minor role in focus but unless you're trying to do star trails you probably want it open anyway.



Have you tried turning off the live view setting? It will bump up the screen without changing your iso.

That said, I gave up trying to shoot fire works with my nex7 evf. As far as I know the lens, I have do NOT have an infinity focus, and even with the screen looking correctly exposed the picture was so noisy it was absolutely impossible for me to focus.


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