Cave 5dm3 samyang 14/2.8 iso 4000

[Nick_Andr]

5dm3 samyang 14/2.8 iso 4000

quite a lot of noise, unfortunately

[ThatCameraGuy]

Nick!!! wth? you would get less noise shooting at iso 6400. look into it Hufflepuff

[vastunghia]

Mmh not so sure. I think each sensor has a sweet spot.

For instance, for 70D this is 1600, while 5D3 should fall somewhere between 1600 and 3200.

[Sweet spot = break-even point where amplifying in-camera the signal more starts leading to a lower SNR (Signal-to-Noise Ratio), I think mainly due to sensor read noise being amplified as well.]

Googling should help.

[ThatCameraGuy]

No, when you need extra light, more ISO its better for noise reduction on post, you google it hufflepuff

[vastunghia]

You seem pretty sure. Good for you. I'm just saying that I'm not so sure.

Check these resources for a start: DSLR Astrophotography and Photons to Photos.

[Nick_Andr]

Everything is just like that.
in my opinion, at 5d 3, the maximum iso at night is 1600. Further, the noise grows unbearably.
in this case it was an experiment.