Unit Four : The Exposure Triangle
Noise reduction in Lightroom Classic.Noise Reduction
Okay, so now you have some noise in your image. Is there anything you can do about it? As discussed in our raw vs. JPEG lesson, an in-camera JPEG will always have some processing applied - noise reduction is one of these processes. This is why if you shoot a raw+JPEG, the raw file will look grainer/noisier. The raw has had no noise reduction applied (that’s your job in post processing), whereas the JPEG would have had some applied.
Generally, good raw editors contain their own version of noise reduction, with some people gravitating to specific software just for this process. There have also been advances in neural network-driven (“AI”) noise reduction - with Adobe Lightroom AI Denoise, Topaz DeNoise AI, and Luminar Neo among the main players. We’ll explore noise reduction a little more in our editing lessons, but you can see an example in the video above.
Sean Makin © 2018 | Nikon D610 | 17.0mm | ƒ/4.5 | 1/40s | ISO 800Dynamic Range
When you change the ISO on your camera, it affects the camera's ability to capture a wide range of tones, from dark to bright - also known as dynamic range. A higher dynamic range helps the camera capture details in both bright and dark areas, even in challenging light. Conversely, a lower dynamic range may cause lost details in either bright (overexposed) or dark (underexposed) areas.
Practically, if you increase the ISO beyond the camera's base setting, it reduces the dynamic range. This means you must be more cautious about the contrast between shadows and highlights in your pictures, ensuring it's not too extreme to avoid losing important details.
You can see how the change in ISO changes your dynamic range here.
Chelsea London © 2017 | Fujifilm X100F | 23.0 mm | ƒ/2.0 | 1/250s | ISO 2000ISO Invariance
ISO invariance in digital cameras means that the amount of read noise remains relatively consistent across the ISO range of the camera's sensor. This is helpful because it allows you to take a darker photo and brighten it later without losing much quality. This can be advantageous when you want to preserve highlights, if you prefer to adjust exposure in post-processing, or if you accidentally didn't get the exposure right.
It's important to note that not all cameras are equally ISO invariant. The extent to which you can adjust brightness without losing quality can vary between different camera brands and models. Generally, cameras with modern Sony-made sensors (used in Sony, Nikon, and Fujifilm) show good ISO invariance. On the other hand, even the latest Canon sensors usually don't exhibit as much ISO invariance. Some cameras may become ISO invariant only after a certain ISO setting (like ISO 400-1600), depending on the specific camera and sensor.
You can see how the read noise changes with ISO in your camera here.
Chelsea London © 2015 | Nikon D7000 | 102.0 mm | ƒ/5.0 | 1/60s | ISO 1600Further Reading
Here are some links if you would like to go further down the rabbit hole of what becomes an incredibly technical topic
DPReview also has an excellent studio shot comparison tool where you can compare cameras at different ISO, under the same lighting though with different shutter speeds. This is handy for seeing real-world camera performance.