Noise at iso 200? (another one, i know, canon 200d)

BalanisUK wrote:

Hi all, long time lurker, first time poster.

to not make the story too long, i just wanted to have some insight as into if im being too nit picky or there is somethingfunky going on. i seem to be getting some noise on my shots

The only digital photographs that will have no noise at all are those where every pixel is blown (pure white), and possibly ones in which no light at all has been captured (pure black).

Noise in a photo is variation in pixel values. Most noise in a photo is due to naturally-occurring variation in the arrival rate and colour of photons that are captured by your camera's sensor. Since light is full of variation it follows that photographs have variation too.

The way to produce a photo in which the noise is not apparent is to capture so much light that all the variations seem to average out. It follows that if you find your photos too noisy. the only way to address that at capture time is to capture more light. One does that by increasing the exposure.

(visible zoomed in on lightroom web) even at iso 200?

im shooting with a cannon 200D and the meter on the cam looks to be properly exposed ...

The definition of "properly exposed" that you are using is not of much value for the problem you are having. By "properly exposed", you mean that the lightness of the photos is what you wanted it to be, and what you wanted it to be was similar to the lightness of the scene as you saw it.

Exposure is not the lightness of the image. It is the amount of light that hit the image sensor per unit area during the time the shutter was open. In your four sample images, the image lightness was about the same, but the exposure was different for each of them. In the first image the exposure was eight times what it was in the fourth image. How can exposures of the same scene that differ by three stops both be correct?

Since you are shooting RAW, image lightness is trivially easy to correct in development. Other visual aspects of the image are not so easy to correct in development: noisiness, DoF, motion blur, blown pixels... So what might be more useful to you is a definition of "correctly exposed" that takes those factors into account -

A correct exposure is the largest exposure that does not blow desired highlight detail, has adequate DOF and no more motion blur than is tolerable. When you are shooting static subjects from a tripod, you can probably omit the part about motion blur.

You should probably also throw out the notion that an image that is too light is necessarily overexposed. If you took a shot of that scene with the settings {1/6 f/1.8 ISO 100} the resulting photo would be too light. But its exposure would be exactly the same as the first sample photo. It isn't over-exposed. By the standards of the definition of "correct exposure" I'm suggesting you adopt, it is underexposed.

im attaching some samples at 100,200,400 and 800 ISO , these are just exports (no editing) using lightroom (web) ; like i said, you may need to zoom into the image and blow it up to see it.

How noisy an image looks depends primarily on how much light was captured in it. The more light you captured, the less noisy it will look. This has at least two implications: the obvious one is that a higher exposure will produce a less noisy image., The other is that since any subset of an image has captured less light than the whole image, when you look at a subset of an image it will look noisier than the whole image. When you zoom into a small part of an image. it will look noisier than when you examine the whole image at once.

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