Re: Jupiter/Saturn Conjunction with the M6 II
stephen83 wrote:
What is the ISO sweet spot for astrophotography on the M6 II? I've heard every camera has one and is a bit different.
There's some truth to the 'sweet spot' but as with many kinds of low light photography the answer is 'it depends' on a lot of things:
- the final target image size
- whether you shoot in JPG or RAW and how you post-process
- the 'quality' of your light soutce... full spectrum lighting or a dim 'noisy' night sky, for example
- the contrast of the subject.... are you trying to pull every last ounce of detail out of the shadows?
For Milky way shooting on a star tracker, I actually find low ISOs like 100 - 400 work very well allowing me to get decent image out of a single frame without having to 'stack'.
For Moon and Sun images through the telescope where I need to use de-noise and push contrast to high levels, again low ISOs work best.... 200-800.
For deep sky imaging where I can stack images, or really need to push to get enough signal, ISO 1600 - 3200 seems optimal. For stacking dozens to hundreds of frames, ISO 3200 works very well with an optimal signal to noise ratio (as prescribed by looking at the read noise curves for the current gen of 'M' sensors on photonstophotos.net). higher than ISO 3200 does not reduce the noise and starts to really reduce the dynamic range.
I don't even shoot normal night photography at an ISO any higher than 3200 or 6400 --- I will underexpose 1 - 3 EV at ISO 3200 and then push the result in DxO PL5 (as I've explained in my DxO thread). For a while I was shooting at ISO 6400 a lot (like in the post below) but more recently I've capped my Auto ISO to 3200 for the extra dynamic range. Changing the ISO in camera is just turning up the electronic gain --- it appears that turning up the gain in post actually is better, producing no more noise but adding more dynamic range to the image to work with.
https://www.dpreview.com/forums/post/65548513