In close-up photography, you often use fast shutter speeds to help battle the wind or freeze the action of your subject (such as a butterfly feeding on a flower).
To get these faster shutter speeds without sacrificing your desired depth of field, your only option is to use higher ISOs (making your camera’s sensor more sensitive).
Unfortunately, at these higher ISOs, sometimes you get some really ugly noise in the background.
Well, there just happens to be a great way to reduce this noise in Photoshop. Here’s how:
1. Duplicate your primary photo layer by selecting the layer in the Layers window, and then going to the “Layer” menu at the top of the screen and select “Duplicate Layer” (you can rename the duplicate layer if you want, but otherwise just hit “OK” after that).
2. Add a layer mask to the duplicate layer by clicking the “Add Layer Mask” button in the Layers window:
3. Draw an outline around your subject with the lasso tool. You want to get close, but not too close, because then you’ll lose sharpness on the edges of your subject. Here’s an example of how close you should get:
4. Fill your selection with black by going to the Edit menu and selecting “Fill…” and then under the “use” drop-down list select “Color…” and choose pure black (red=0, green=0, blue=0). Now, with this part of the layer mask filled in with black, any changes you make to the layer will only show up on the background of your subject.
5. Clear your selection by going to the “Select” menu and clicking “Deselect”
6. Blur the edges of your layer mask by going to the “Filter” menu and selecting “Blur” and finally “Gaussian Blur” — usually a radius of around 40 pixels works well.
7. Select the raster part of your layer in the Layers window:
8. Apply a median filter by going to the “Filter” menu and then under the “Noise” menu, select “Median” — usually a radius between 10 and 20 pixels works well.
That’s it, you’re done!
If you notice a thick layer of noise around your subject, then you can try blurring your layer mask some more, outline your subject with the lasso more closely, or go in with a paintbrush tool and paint white just outside the edges of your subject (make sure you select the layer mask before you start painting!).
Also, note that this method only works well for close-up photos where you have an out-of-focus background. And, it works best when the background is mostly one color.
Do you have another method for removing noise?
If you’ve discovered another method for removing noise in the background of close-up photos, please tell us about it by leaving a comment below. Or better yet, contact me about writing a guest post about your method 🙂 Thanks!
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About the Author: Steve Berardi is a naturalist, photographer, software engineer, and founder of PhotoNaturalist. You can usually find him hiking in the beautiful mountains and deserts of southern California.