Sony a7 V long exposure worsens noise?

Rialto
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p.1 #1 · Sony a7 V long exposure worsens noise?

I do a bit of astrophotography, from which I learned that a camera's noise characteristics can be quite different for long exposure than for shorter ones, so I've been looking for reviews about the Mark V's astro performance specifically.

What I've found - admittedly, from a few obscure sources - has been discouraging.

This astrophotographer compares a1 II to a7 V for astro, and for 30 s exposures, a7 V's hot pixels and color noise are much worse than a1 II, even though the former is known to have better DR for regular-length exposures.

The only reviewer I can find who has specifically tested the DR for 30 s exposures is a Chinese rental company called Irentals Space ("兰拓空间").

To establish some trust in their result, I first compared their DR test result for short (1/60 s) exposure to Photons to Photos.

a7 V vs a7 IV, 1/60 s, mechanical shutter

https://community.irentals.cn/compare/cameraCompare/110,113

This is in good enough agreement with Photons to Photos.

Now, for 30 s:

a7 V vs a7 IV, 30 s, mechanical shutter

If we trust this source, then a7 V seems to have a problem with noise in long exposure compared to its predecessor.

May 17, 2026 at 04:03 AM

snapsy
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p.1 #2 · Sony a7 V long exposure worsens noise?

The sensor characteristics that determine its long-exposure noise performance don't necessarily correlate to the characteristics that determine its short-exposure noise. Jim has a great article on this:

https://blog.kasson.com/the-last-word/how-sensor-noise-scales-with-exposure-time/

May 17, 2026 at 09:32 AM

Rialto
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p.1 #3 · Sony a7 V long exposure worsens noise?

snapsy wrote:
The sensor characteristics that determine its long-exposure noise performance don't necessarily correlate to the characteristics that determine its short-exposure noise. Jim has a great article on this:

https://blog.kasson.com/the-last-word/how-sensor-noise-scales-with-exposure-time/

Thanks! Learned a lot about how different noise sources evolve with time.

May 17, 2026 at 10:13 AM


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