IN-CAMERA Noise Reduction!

Hey all!

Today we are hitting a cool topic that photographers often talk and think about all the time. The question? NOISE! The talk? How do we get rid of it?! So, today we are going to talk about two techniques that you can do to actually reduce noise in the camera! You know we are all about that!!

Back in the film days, noise, or “grain” as they called it way back then (what was that like 5 years ago?) was actually part of the beauty of the final shot. Digital grain, at low levels, can look cool, but usually once it gets going it starts to look like someone left your photo out in a sand storm and is not all that appealing. So we do need to be able to control noise when needed and not have it blast the faces off of our clients! We have images printed in albums that were shot at ISO 6400 that are 10 inches high and 20 inches tall and they have zero noise reduction done on them. So the real question is, how do we do that without the latest and greatest noise reduction software? Let’s break it down!

There is two things that we need to keep noise to a minimum. Exposure and a correct understanding of ISO.

Exposure:

Whenever you are shooting at low ISO, like 100 or 200, we always preach that if you are at all concerned about not having the correct exposure, that you should be sure to shoot it a little bit dark. That is because you have more room for error in the shadows when using digital, then you do with the highlights. You typically have (when shooting in RAW on most modern cameras) between 2 and 3 stops of correction that you can make on the dark side (shooting too dark then brightening the image later) vs about 1 stop of correction that can be made on the bright side. Anyone who has blown highlights on a photo will tell you that there is not too much room for error. The cameras are getting better and tolerating more variance, but when shooting in really bright situations, it is better to slightly underexpose and brighten the image in Lightroom if need be, rather than have hot spots in your photo where you cannot pull back any of the detail.

The same idea translates when shooting in darker situations, but reversed. When shooting at high ISOs (like 1600, 3200 or 6400 depending on your camera) you should purposely overexpose your images by about 1/3 of a stop. Why? Because the noise in digital images is mostly in the shadows! If you have ever shot an image that was under-exposed at a high ISO, then took into Lightroom and cranked up the exposure, it all of a sudden dies right in front of your eyes! Then, you go and start running those awesome actions to reduce noise (which mostly make your image lose all the clarity that those fancy lenses provide). So, if you purposely shoot it slightly brighter than you normally would want your image, later in Lightroom you can pull the exposure down to where you want it, but without the noise increasing!

So, lets take a look at a few images that we just shot sitting here in the office of our lovely model, Star (our cat).

Star is perfect for this test because she is jet black, and any noise in the image will be pretty obvious on her little mug! All of these shots were taken at the exact same settings except the shutter speed was changed to adjust the exposure.

Camera Settings on the Canon 5D Mark II (all shots below were taken at these settings, minus the shutter speed):
f/2.8
ISO 3200
Color temperature: 5600k
Lens: 24-70-L 2.8
For these camera settings, the correct shutter speed for a perfect exposure is 1/30th of a second.

Image #1:

Above shot stats: 1/125th of a second (2 stops under exposed, then brightened in Lightroom 3 by 2 stops)

As you can see in this first image, the noise is everywhere on this shot especially in the shadow areas of the cats fur. Yuck! There are even these little red dots where there is no usable data on the image.

Image #2:

Above shot stats: 1/60 th of a second (1 stop under exposed then brightened in Lightroom 3 by 1 stop)

You can see that this image looks MUCH better and even though it still has some lines in it sweeping back and forth in the shadows, it is much more presentable than the last one. The color is even more accurate on this shot!

Image #3:

Above shot stats: Shutter Speed 1/25th of a second (1/3 over exposed, then exposure reduced by 1/3 in Lightroom)

You can see that the image above has almost zero noise on it after using the over exposure technique! Even at ISO 3200, it looks clean and sharp and no chunks of noise anywhere. So, if the noise is in the shadows and we purposely overexpose the shot, then reduce the exposure later in Lightroom, the noise that is there gets hidden even more as we take the exposure down in post. Magic!

Now, on to technique number 2:

REAL ISO

Now this could get really technical, but we will spare you the details as not to bore you all. The short version is this. Each camera company produces a censor that has a NATIVE ISO setting. In other words, an ISO that the camera is designed to take the best quality (with the least noise) image. On Canon cameras, this is typically ISO 100 and on Nikon, this is many times 200. So, for you Canon users, ISO 100 is the best quality lowest noise ISO setting you can possibly use to get the clearest prettiest shot possible. Any other ISO that you use is a reduction in quality. But wait, there is more!

The camera is designed to work on whole ISO settings that are a doubling, or halving of the NATIVE ISO. What? What that means is, the camera yields the best quality results when you double the ISO from 100 to 200, 200 to 400, 400 to 800, 800 to 1600 and so on. Those are the REAL ISO settings. ALL the other ISO settings (with the exception of ISO 500 on Canon) are there for YOUR convenience, not for quality.

Here is what the camera does: When you adjust your ISO to one of those in-between settings, like ISO 640, your camera looks for its nearest NATIVE ISO (in this case, ISO 800 is closest to ISO 640) then drags the quality down to give you that “pretend” ISO. What that means is that ISO 640 is actually WORSE quality than ISO 800! Does that not blow your mind?!

So, ISO 1000 for example IS better quality then 1600 (because the camera goes to it’s nearest NATIVE ISO setting which is ISO 800, and drags down the quality to 1000), but ISO 1250 is worse quality than 1600 because the camera goes to the nearest NATIVE ISO, 1600, and drags down the quality to achieve that ISO.

So what do we do to remember what ISO to go to? We simply set our cameras in the custom function to change ISO in whole stops instead of 1/3 stops. This give you an overall ISO choice that is better quality and if you over-expose by 1/3 on the high ISO images at the reception, then you should have no problems with noise at all!

For those super nerds out there, check out this blog post to get really techy about ISO, analog to digital conversion and the like! Better quality here we come!!

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