As manufacturers cram more and more megapixels onto the same size sensors, vibrations, heat, and other natural forces have a larger effect on the image. The result? Some high resolution image sensors actually take noisier pictures than their lower resolution counterparts.
To solve this problem, some camera owners are intentionally lowering their camera’s resolution to reduce the noise in their images. The underlying thought is that the same image sensor, set to a lower resolution, will be less affected by heat and small vibrations. But does this really do anything, or is it another camera gear myth? Let’s dig a little deeper and find out.
How most digital cameras take lower resolution images
Just like you use 100% of your brain, most digital cameras use 100% of the sensor for every photo, whether you set them to a lower resolution or not. What cameras do is take a picture at full resolution and then resize it to a lower resolution through onboard conversion software. This, it would seem, is easier on the manufacturers because they don’t have to program the camera to use the sensor in a bunch of different ways.
In other words, it’s much easier to take an image and convert it than it is to use the same sensor to take a smaller image. And when it comes to industrial design, simplicity often wins.
A resized image will always appear less grainy than its higher resolution cousin
It doesn’t matter what image sensor you’ve used to take a picture. Whenever you resize an image, it will appear less grainy. Why is that? Because you’re effectively zooming out. The noise is still there. You just can’t see it as well as you used to.
It wouldn’t matter if you took the image in high resolution mode and resized it in Photoshop or just used the lower resolution option on your camera. The result is likely to be the same. That’s because both processes (probably) use similar techniques for resizing the image. You don’t see less grain because there is less grain. You see less grain because there is less detail in the photo overall.
Always run a few tests
There’s a reason I keep using words like “probably” and “likely”. No two cameras are alike. Some cameras might use more sophisticated techniques to take a lower resolution image, and in that case, you might end up with less noise. If you want to find out, you don’t have to send a long-winded email to your camera’s manufacturer. You can perform a simple test.
Take one picture at each of your camera’s different resolution settings. Use a tripod and keep the ISO, aperture, shutter speed, and other variables exactly the same. Then, blow up the pictures on your computer so you can see the details. If there is a big difference in terms of graininess between one photo and the next, then your camera’s resolution settings have an effect on noise. If not, stick with your camera’s highest resolution all the time. It’s really that simple.
As I said earlier, it’s my hunch that most cameras use the full sensor and then do some kind of resize, if only because it’s the easiest way to get the job done. Either way, you’re just a few photos away from finding out.
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