|
There are too many missconceptions about ISO and noise out there.
As a basic fact most high ISO settings are only useful if you shoot JPG. For astro Work you use RAW and then it hardly makes sense with ANY DSLR to go beyond ISO1600.
If you take a shot at ISO6400 for a given aperture and exposure and the same shot at ISO1600 and then push the exposure up 2 stops in post the result is exactly the same. Furthermore using the higher ISOs you are losing dynamic range.
We'll have to test if this holds or not for the 5DIII, if there is a visible difference between a ISO3200 shot and a ISO1600 shot pushed 1 stop then it might be worth the upgrade. If the ISO1600 noise is better than the ISO1600 noise in the MKII then it will also be worth the upgrade.
We are seeing a lot of JPG examples where the high ISOs make sense and where the noise reduction applied by the DIGIC processor is heavy, all this stuff is totally irrelevant for astro work.
So I would say you should wait.
Unfortunately for all of us shooting Canon the logical evolution of the 5DII was made by Nikon.
|