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Thinking of getting a Sony A7Riii and have some questions


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Up til how I've been a hard core Pentaxian, using a full frame K-1 & medium format 645z. The Sony A7Riii has perked my interest. 42mp full frame mirrorless, faster buffer & write speeds than the Pentax, much better focusing than the Pentax.  Many features of the Sony A7Riii appeal to me I'm wondering how they do at night. I do a lot of night photography, long exposures, some astro (moon, milky way, auroras, not deep space stuff.) Also wondering about battery life as that seems to be a problem with many mirrorless systems. I've heard of the 'star eater' issues and wonder iwhat exactly that is and if there is a fix like turning off a noise reduction? Again, thinking and researching and hoping for answers. Please feel free to jump in.

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Inherent to mirrorless technology, battery life in general is worse than for DSLRs. That being said, the A7Riii has the Z100-battery. Cameras with this battery have the longest battery life of pretty much any mirrorless camera.

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1 hour ago, thebeardedgroundsman said:

I turn off in-camera noise reduction

This does not help against the star eater algorithm, which is impossible to bypass and is baked into the RAW-file. What's more, it is generally a bad idea to turn off long-exposure noise reduction, as this corrects for the sensor becoming hotter in some areas than others during a long exposure. Fixing this in post is tedious and makes no sense as the camera can perfectly do this for you.

I'm not an astrophotographer but the star eater algorithm is usually a minor concern, but an annoying one nonetheless for astro purists. Especially because there's no way to turn it off.

Have a read here:

http://www.markshelley.co.uk/Astronomy/SonyA7S/sonystareater.html

Edited by Pieter
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I'm sorry Pieter. The "Star Eater" may effect Craig's milky way photos (but probably not by much unless he is using a tracking tripod) but I don't see it causing a problem with Moon, Aurora or other night time shots.

And, as I understand it, for long exposure noise reduction the camera effectively takes a blank exposure of the same length and works the two together. Using ON1 No-Noise I do not find this part of editing tedious. So that is why I turn off Long Exposure de-noise (on the advice of a number of Astro photographers).

 

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In part you are correct @thebeardedgroundsman, except that the camera subtracts the dark image from the original exposure rather than adds them together. Unlike normal noise reduction (which is only applied to JPEG-output) this procedure is baked into the RAW-file, resulting in a single file. No additional post-processing is needed. Long-exposure noise reduction is not meant to correct for 'regular' noise (often related to ISO-setting) but corrects for 'amp noise', which is a result of the sensor becoming hot during a long exposure. This heating is not uniform, and results in halos in the hotter areas of the frame. By subtracting a dark frame with the same exposure time, the final image is corrected for these hot areas. This is impossible to do in post with regular noise reduction and requires local corrections and knowledge of where your sensor tends to get hotter.

Edited by Pieter
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