When you’re buying a camera, what do you do first? Well, most of us go online and look for reviews. We look for the reviews about the parts of the camera that relate to what we're going to use the camera for. The majority of the time, we’re looking for things like low-light performance, color depth and resolution, but there’s a decent group among us that are looking for something entirely different.
The Long Exposure Sensor Noise.
Why is this important? Well, the low-light performance of a camera like the Sony A7S doesn’t always translate to great performance with long exposures.
Knowing that no one was going to do it for him, Brendan Davey of BrendanDaveyPhotography.com took it upon himself to find out what cameras truly performed the best and the worst under these conditions. And the results are pretty enlightening.
The names I expected to see at the top of the list weren’t there. How is the Sony A7S’s groundbreaking low-light sensor not at the top of the list?! An APS-C Fuji sensor tops the list? Davey has tested a huge range of cameras when completing his tests so more than likely, your camera is on the list. Check out his page and see where your body stacks up.
Comparing the Sensor Noise of Top Cameras
As a photographer who shoots a lot of nightscapes and auroras, Davey values cameras that have minimal noise when shooting long exposures at high ISOs. To find the baseline performance of cameras, Davey shoots long exposures with a body cap attached instead of a lens.
For each camera he tests, Davey shoots 3 different exposures at 1 second, 30 seconds, and 300 seconds (i.e. 5 minutes). Other factors are held constant: no light is entering the viewfinder, the environment is room temperature, ISO is set at 3200, NR is off, and RAW capture at max bits per channel.
Davey tells PetaPixel that his tests have yielded some interesting observations. One is that cameras often perform well at 1 second and 30 second exposures, but very badly in 5 minute exposures (such as the two cameras above).
Read full article at PetaPixel “Comparing the Sensor Noise of Top Cameras”
The Sensor Noise DB
The results speak for themselves, however it is interesting to note that some cameras hold up very well having hardly any more noise at 30 seconds than compared to 1 second. Since most of the work I do is normally in the 15-30 second range this gives me a good idea how quickly the sensor deteriorates and it’s usefulness, and of course the 5 min exposure is the real leveller.
So what does this test show?
Well assuming that the camera is totally light sealed it should, in theory be showing nothing more than sensor noise and what you have at a staring point before NR is applied in camera or in post.
Cameras that have a long exposure NR feature actually create this image to deduct from the previous exposure, which in theory leaves you with a clearer exposure. However the noise pattern is never the same, so the subtraction method is never perfect, and it also requires you to wait just as long as the first exposure to calculate the noise. For more about this see my long exposure NR page.
A few points to keep in mind when reviewing the results:
- The age of the camera.
- If the camera supports fully disabling NR (some do not, and in some models it can affect the RAW file).
- Additional processing applied to the image regardless of the NR settings.
- The size and pixel density of the sensor.
- The accuracy of the ISO, in some cases this can be almost a full stop out either side of 3200. (1600-6400 ISO).
- Manufacturing variation (tolerances).
Read full article at Brendan Davey Photography “The Sensor Noise DB”
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(cover photo credit: snap from PetaPixel)