Skyline help please

[mkoop]

I've been working on my techniques to capture a good skyline.

What I fail to understand is why the sky looks so noisy.

d750 105mm
ISO 100
f11
SS 2.5,5,10

I was trying to expose for skyline and dome while keeping it from blowing out. I just don't know why it looks like there is so much noise. I merged in Lightroom CC.

Any guidance is appreciated.

AAA_3031-HDR by Meriwether Kenfield, on Flickr


Some noise reduction work to attempt to improve quality...

AAA_3031-HDR-6 by Meriwether Kenfield, on Flickr

 

[snowbear]

I'm guessing the merge is combining what noise is in all three images.


edit:reworded

 

[BillM]

Were they a little under exposed and brought back up in post ?

 

[agp]

Turn off your in-camera noise reduction, image stabilization, etc etc. Obviously this is only if you're using a tripod, which if you're shooting a skyline at night you should be.
Shoot in RAW.
Shoot bracketed at -2, -1, 0. There is no need to shoot an overexposed image as it won't add any light information the normal exposure does not contain.

Also zoom in a little bit? There's too much nothingness in your photos. A skyline should mainly contain the skyline, like below, not the empty sky or water.

 

[mkoop]

Great advice, I will give it another whirl taking these comments into consideration.