anyone ever take picture of night sky ?

Started 10 months ago | Discussions thread
Messier Object
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Re: anyone ever take picture of night sky ?
In reply to arief poerniawan, 10 months ago

arief poerniawan wrote:

hi my name is arief, recently i had been ask by one of my friend to shot night sky, in which the object is milky way. i try but i fail.. as my gear is oly E 5 and ZD 7-14mm and i used cable shutter release so i can use bulb mode, the AF is set to infinity, and using tripod... what happend to my picture is too noise because i i took 90 second.

i would appreciated if anyone can show me the picture..

thanks

arief

Hi arief

Here are some points to consider:

1.  exposure duration
on a fixed tripod for a given focal length there will be a maximum exposure duration you can use before stars will start to show obvious trails due to Earth rotation.
The easiest way to work this out is by trial an error. Examine the image using magnified view on your E-5 screen.

At 300mm I can get away with 2 seconds. 
300mm/14mm x 2 sec = about 40 seconds.   So at 14mm a 40 second exposure should keep your star images still looking like points.

2.  noise
the E-5 sensor is not a good choice for astro photography. High ISO settings will amplify the noise and you will get colour banding.  ISO 400 might be your limit.

Be sure to enable Noise Reduction in the E-5.  In this mode the E-5 will take a second frame with the shutter closed and subtract noise from your image

Even with these precautions a 40 second night sky exposure on an E-5 will be pretty noisy
I fully understand why you would be disappointed with a 90 second shot

3. the lens
14mm should give you a nice wide sky panorama. 
Light gathering is more important than sharpness so open the lens right up

4.  Light pollution
Make sure you use the lens hood to keep out stray light. Avoid side lighting from houses and street light. The smallest amount of unwanted light will spoil a long exposure.
If you live in a big city then try to get away to a darker sky.  Sky glow from city lights will spoil most sky shots and longer exposures will cause the image to be washed right out

5.  Camera shake
Set your E-5 for mirror lock-up and delayed release. Even with a cable release the mirror shake will cause every star in your image to have a little tail

6. post processing
You should shoot RAW. Out of camera jpg will usually not give a nice result
PP has a big part to play in astro shooting. Play around with the Exposure and Contrast settings.

If you look around you might find some free software that can overlay (stack) multiple shorter exposures. This has the effect of improving Signal to Noise, but can't remove  sky glow caused by city lights

7.  Check out the Astrophotography Talk Forum here on DP Review

Peter

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