Sharpening is one of the first things I do after importing images for post processing.
There is rarely a time when sharpening is not needed if you're working with RAW files (which you should be!). It's one of the first steps I perform after importing my images into Photoshop from Adobe Camera RAW.
I'll first cover the main sharpening tools I use in my workflow, as they appear in order in the sharpen toolbox. Then I'll show you my brief step-by-step procedures I use every time when editing new images.
The shake reduction tool is the first in the sharpening tool set. You access the sharpening tools by going to the Filter tab and then scroll down to Sharpen.
This tool has literally saved me from deleting images. It has transformed out-of-focus images or blurry shots alike into either acceptable images or made them perfect in the sharpening department. On that note, this tool is to be used sparingly. It's a strong effect and should be considered a Hail Mary tool when you first look at an image to discover that it's possibly too blurry to save. That's when you try shake reduction.
The plain old sharpen is the sharpening method I most commonly use. It's not too strong on skin, skies, and water, where you're most apt to see a botched sharpening job.
What I do after importing an image into Photoshop is to copy the background layer. I used to name this layer sharpening, but I tend to leave it unlabelled these days because it's been a habit of mine for so long. Then I'll apply the sharpen tool. This is usually enough sharpening for my images. When you zoom in to 100% or more, you'll be able to see what a difference this tool makes.
As the name of this tool suggests, it will sharpen your edges. I rarely use this tool unless my images have a lot of patterns or interesting lines which are important features I'd like to highlight. Typically, I'll use this tool only after I've applied the regular sharpen tool first.
Having all my sharpening retouches on one layer makes it easy to adjust. I rarely work with smart objects, so I may end up with two or three sharpening layers which I'll eventually merge into one layer - if I have an image that demands more than general sharpening.
This is another tool I seldom use and should only be used rarely. It's a heavy-handed sharpening tool and once again, as the name suggests, it will sharpen more indeed. When using this method of sharpening, you should be checking your image from regular view down to 100% or more to see what this effect is doing to different regions of your image. Also, whenever I have used this tool, I've used it after the regular sharpen has been applied.
Smart sharpen is one of the last two sharpening tools in the suite which happen to be more complex, customizable, and powerful. It has three main sliders (Amount, Radius, Reduce Noise) and a drop-down menu with options to remove Gaussian Blur, Lens Blur, and Motion Blur.
This is another tool I rarely use. But it's very useful if you're working with images where you'd like to sharpen select regions of an image which are blurry.
The best way to learn this too, which I do recommend, is to import an image with a blurred out background or where there's a shallow depth of field. Then set the sliders to Amount 100%, Radius 1.0, and Reduce Noise 0.0%. Then zoom into 100% and look at the various regions of your image (and don't forget to also zoom back out to regular view) while playing with the three remove blur options. The preview window within the tool box is extremely useful in seeing what your sharpening settings is doing to a particular region.
I used to use this tool quite a bit as one of my first actions in Photoshop but I've since replaced this with the regular sharpen tool. That being said, this is a very handy tool to check out when you're first diving into the world of sharpening because there are just three primary sliders which can greatly impact the overall image.
Like the smart sharpen tool, best to import an image and play with the sliders to learn the tool and to see how and when it can be put to good use. The best times to use this tool is when I've had images with signs or other textures I wanted to highlight with more control than what the sharpen tool would give me, which I'd call a "dumb" tool, only because it's not adjustable except by adjusting the opacity if you have it on a separate layer.
Smart Sharpening vs. Dumb Sharpening
I made reference to dumb sharpening above, but I want to go into this concept a little more to help you understand when to use each of these tools.
The dumb sharpening tools include Sharpen, Sharpen Edges, and Sharpen More. They basically apply the sharpen effect blindly and globally. The only way to adjust them is by reducing the opacity level when you apply each effect on a separate layer or by converting the layer to a smart object to make it adjustable at any time during post processing.
The smart sharpening tools, which are adjustable (globally and sometimes locally), make
up the rest of the suite: Shake Reduction, Smart Sharpen, and Unsharp Mask. I'd recommend using a separate layer too when using these tools so they can be adjusted afterwards - or convert your layer to a smart object.
A word of caution. Sharpening is but one stop in the post processing world. It can be a rabbit hole, with no end in sight, if you let it be. You can spend literally tens of minutes in sharpening but seldom would you ever need to do so apart from certain commercial-client jobs. Learn to balance your time in sharpening and develop a workflow that works for you.
You may have asked yourself why I use "dumb" sharpening as my default, when there are all these wonderful tools at my disposal. The reason is simple: I use layer masking to apply sharpening to areas which need it, especially if I'm working with images with close-ups of people. Layer masking is worthy of talking about separately elsewhere, but I'll break it down briefly here.
There will usually be regions of an image which require more sharpening than others. For example, in the above image, I created another layer and applied a layer mask to add more sharpening to the sign only. I didn't want to affect the sky, which would likely highlight the noise or introduce unsightly artefacts to the image.
There are two ways in which I use layer masks with sharpening. The first would be to apply dumb sharpening on a separate layer, then create the layer mask. Then I'd invert the layer and paint in the areas where I'd need sharpening.
The second method, which I'm using more frequently these days, is to create another layer and open up the Camera Raw filter once again. From there, I will go to Adjustment Brush tab, go to the sharpen slider, and paint in the effect directly onto the image where needed. Then I'll bring the image back into Photoshop onto my current sharpen layer. I'll then merge this layer down to my first sharpen layer.
My Sharpening Workflow (including steps leading up to it)
1. Import image into Camera Adobe Raw. Make adjustments. Rarely do I sharpen here.
2. Import image into Photoshop.
3. Crop, adjust horizon line, resize image to original size - if necessary.
4. Create copy of background layer. Name it "sharpening" (I rarely name it these days).
5. Apply appropriate sharpening.