Quote:
Originally Posted by SteveInNZ
Greg,
I haven't really kept up with the pros & cons of the various Sony cameras, so I'm not sure how my A7s compares to the one you have.
I have astro cameras too but in your opinion, would the standard R be a step up, down or sideways from the A7s for nightscape use ?
Steve.
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That's a harder one as the spatial filtering that Sony uses on RAW images that creates the "star eater" effect has varied over the various models.
Later models have that star eater filter cut in after 3.2 seconds or later 4 seconds. The earlier models may have it cut in only in bulb mode of longer than 30 second images. I'd have to check on that but I think that is how it went.
EOS R would be noisier than A7S as A7S is the low light camera Sony created. lonelyspeck.com uses an A7S and they get good results.
I think its less about the camera really and more about using a tracker and taking several images and stacking them. Noise then is eradicated from any manufacturers' images by doing that.
The star eater issue is not too bad for nightscapes and if you stick to 30 second exposures (I do anyway) then you should have no issues.
The star eater effect on my A7riii is mild and consists of some dimmer stars being turned green. If I run HALVG free plugin for Photoshop it removes the excess green but it also leaves the stars white. I do get nicer star colours from the EOS R.
As far as EVF and focusing etc I think A7S should be excellent for that. EOS R is fine as well with its 10X zoom.
So in that case the cost of an EOS R does not make a lot of sense.
Sonys best nightscape camera currently would seem to be the A73. Very low noise, largish pixels good Ha response.
A7riv seems a bit of a dud for nightscapes. Much higher noise and I read a lot of people having issues with the AF system giving slightly off focus.
The EOS R is really just a modded EOS which you can get modified by several companies like Lifepixel etc for around US$250.
So you could get one 2nd hand and have it modded. The 30X zoom may be nice but not really necessary as I have no trouble with either my Sony or EOS R focusing on a bright star at 10X. Also the AF will work sometimes on bright stars on the EOS R. The AF system works well in low light, I think better than any Canon DSLR.
Even my Sony A7Riii will focus on a bright star at F1.8. Better to use manual focus
though.
As far as Factory calibrated white balance you simply use custom white balance and take a midday shot of an 18% photographic grey card and use that image for custom white balance and it should correct for the excess red in normal day images.
But you would have to be clear on why you would want your expensive mirrorless modded. If its just for nightscapes then you'd have to be fairly keen. Unmodded the EOS R is reasonably good at picking up Ha.
Greg.