I am a beginner in photoshop, I'm so confused between 'Content-Aware fill', 'Healing brush tool' and 'spot healing brush tool'. All of them do the same thing, then why are there 3 different tools for that?
Spot healing brush, healing brush, and content aware fill all work to a similar end - removing and replacing areas of color and texture. But it's a matter of using the tool that's appropriate for the area that you're working in.
To me, the spot healing tool is used for very small areas in very simple backgrounds. No reference point is needed - all you do is grab the tool/brush and paint over the area. It creates a blend from the surrounding area in order to "heal" the deletion. Actually pretty much the way your skin heals after a wound. But again, only in small, isolated areas.
The regular healing brush uses a reference point - ie click on a part of the skin and then use the brush to heal a separate section of skin. It will blend the color/tone of the area you chose with the area surrounding the blemish you're removing. Gives you a larger range of choice than the spot healing. But I've found it works best in small, simple areas.
Content aware is the heavy lifter. You can choose an area with a selection tool and the use Edit-Fill-Content Aware to fill the area with the information from the area surrounding the change. I'll use it to work in larger spaces than using the healing brush. But the complication is when the algorithm using it this way chooses information from unwanted areas. Then it just gets messy.
The next option is select an area with the lasso tool, then go up to your menu and choose Edit-Content Aware Fill and then a dialog box will come up that lets you choose from what areas you want the tool to pick from when filling in.
Not to confuse you, but there also is the patch tool and the clone tool that can work in similar fashion. As the saying goes, Photoshop often gives you several different ways to do the same thing. But again, learn to pick the right tool for the project.
As a coach once said, to learn the thing you've got to do the thing. So choose some video tutorials and actually work with the tools to understand what they do, how they work, and which one is best to use. Reading about it here or reading about it in books won't get you there. It's going to take some time and practice on your part. And when you use the wrong tool, Photoshop will let you know very quickly. A shotgun just doesn't work for target practice. It might - but it's gonna make a hell of a mess. :)
They don't do the same thing. They do, however, roughly work in the same problem space. So superficially they do the same thing, in the same way as a four door sedan car and a full trailer truck move things from place A to B. Simply they deal with texture replacement.
Content aware fill fills a newer tool it does some pattern recognition of the surrounding area and tries to fill the interior with the simplest possible pattern that it can synthesize you could then blend this in and achieve same result as the healing tools. Essentially it might work for the task so adobe allows you to have that as a option for healing texture source.
Normal healing works by copying the texture form elsewhere and blending it into the work. Essentially it is a cloning tool that copies high frequency content form elsewhere but tries to retain the lower frequency content. Spot healing is meant for blemishes and patch is for larger areas to be transplanted elsewhere.
Personally I don't do the kind of workload where either of any healing tools become handy. When i really need this stuff, i will construct the data source by combination of content aware fill on a separate layer and frequency separation then cloning frequency ranges. But if i were to do a lot of fashion photography then the healing brushes would become handy for the preparation of retouching candidates. But work like this is quickly becoming a job for AI retouchers.