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07-08-2016, 05:16 PM   #1
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Long exposure sensor noise testing...interesting read

It doesn't take long to read and it appears Pentax scores better than most. Particularly the K-5

The Sensor Noise DB. Brendan Davey Photography

07-08-2016, 05:45 PM   #2
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I was just reading that and I was surprised at how well the K5 performs compared to the K1 and almost all of the other cameras.
07-08-2016, 05:56 PM   #3
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K-5 brought noticeable advancement.
07-08-2016, 06:14 PM   #4
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I think that bodes well for my K-01 and K-5ii s...

07-08-2016, 06:56 PM   #5
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I suspect the noise in the K3 might be due to increase sensor heat in the extra long exposure. The K1 performed better as it has a larger sensor thus heat is more easily managed.

In all practicality, it doesn't seem that there is much difference between the K-1 and K-5 at 30 seconds. The numbers suggest the K5 is better, but, the 'difference' is probably marginal.

Agree re K-01 and K5iis - might be worth keeping these cameras specifically for astrophotography
07-08-2016, 07:17 PM   #6
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That's what I'm thinking. I converted the K-01 to full spectrum. If I could just get someone to hack the firmware to make the O-GPS1 work on it....
07-08-2016, 08:56 PM   #7
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QuoteOriginally posted by SointulArt Quote
I was just reading that and I was surprised at how well the K5 performs compared to the K1 and almost all of the other cameras.
QuoteOriginally posted by Wild Mark Quote
In all practicality, it doesn't seem that there is much difference between the K-1 and K-5 at 30 seconds. The numbers suggest the K5 is better, but, the 'difference' is probably marginal.
The K-5 does a great job with dark noise. Pentax engineers really got the most out of that sensor. By the numbers, the K-5 scores better than the K-1, but the sensor size isn't being taken into account in the scores. The sample patches look marginally better for the K-1 than the K-5, IMO. Fully expected that; newer sensor, same pixel size and density, twice as many total pixels due to larger sensor.

The K-1 looks better than the Nikon D810. Same sensor believed to be in both cameras.

Note this portion of the article:
QuoteQuote:
...A few points to keep in mind when reviewing the results: ... The size and pixel density of the sensor....
07-08-2016, 11:11 PM   #8
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5-minute exposures get you into the realm of deep-sky astrophotography where Peltier-cooled CCD sensors and elaborate PP including dark and bias frames, and stacking reigns. Shorter exposures with CMOS sensors still benefit greatly from the same PP techniques. Single-shot exposures of 5-minutes are rare, even for the currently popular nightscape type of photography, and almost unheard of for aurorae. Knowing per-pixel noise levels is interesting but the diffrerences in the given numerical values aren't as scary looking as they appear given real-world applications.

07-09-2016, 03:24 AM   #9
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QuoteOriginally posted by DeadJohn Quote
The K-5 does a great job with dark noise. Pentax engineers really got the most out of that sensor. By the numbers, the K-5 scores better than the K-1, but the sensor size isn't being taken into account in the scores. The sample patches look marginally better for the K-1 than the K-5, IMO. Fully expected that; newer sensor, same pixel size and density, twice as many total pixels due to larger sensor.

The K-1 looks better than the Nikon D810. Same sensor believed to be in both cameras.

Note this portion of the article:
It's not easy to understand the figures, I mean some of the samples with a low mean value looks much worse then samples with a higher value.

Anyhow, does this mean that if I where to shoot some deep space object like the Andromeda galaxy with a 200mm lens, (which means cropping to 100%) that I would be better off using the K5 than the K1?

The number suggests this, and if so it's kind of disappointing, I where expecting at least the same performance on a pixel level.
07-09-2016, 06:52 AM   #10
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Wow. Why does the Nikon D7100 look so bad?
07-09-2016, 09:51 AM   #11
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@Gimbal - Not in my experience. The K-1 makes a great astro tool.
07-09-2016, 02:13 PM   #12
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QuoteOriginally posted by Gimbal Quote
It's not easy to understand the figures, I mean some of the samples with a low mean value looks much worse then samples with a higher value.

Anyhow, does this mean that if I where to shoot some deep space object like the Andromeda galaxy with a 200mm lens, (which means cropping to 100%) that I would be better off using the K5 than the K1?

The number suggests this, and if so it's kind of disappointing, I where expecting at least the same performance on a pixel level.
It's worth a test. The K-5 and K-1 have almost identical pixel density and I don't think you'll be able to notice a difference. On the other hand, the K-1 is a bigger sensor and might heat up more during long exposures.

A real world test, done on the same night so the air temperature and sky conditions are the same for both cameras, is a good idea.

Or just use the K-1, and frame the 200mm shot to show the galaxy at one side of the frame and something else at the other side of the frame; use the bigger sensor instead of cropping. Software like Stellarium can be used to plan your composition.
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