Adobe Camera RAW is part of Photoshop.
RAW is a proprietary format with which the camera records the information that comes in to the sensor when you take a photo. Unless you have a reader for that format, you can’t see the image.
Contrast that with, for example, JPEGs and TIFFs, which every camera and every computer can read.
Every camera manufacturer has its own RAW format. Nikon cameras record in a format named .NEF. Fuji cameras record in a format named .RAF, Olympus cameras record in a format named .ORF, and so on.
Photoshop can read all these different formats, but unless you have the latest version of Photoshop it may not be able to read the format for a recent model of a particular camera even if it can read the format for that brand of camera – that’s how specific the readability of RAW formats is.
If you open a RAW file in Photoshop it will open in Adobe Camera RAW. It will read the information and give you the option of tweaking it and then opening it in Photoshop ‘proper’ and tweaking it some more.
You then have the option of saving it in a number of different formats. There is PSD, which is Photoshop’s own format, and there are JPEGs and TIFFs and PNGs and… etc.
And now to the point of this article which is about lens correction and how versatile Photoshop is.
You may not know how much lens correction is possible in Adobe Camera RAW.
This is one of the screens you see in Adobe Camera RAW and on the right you can see ‘Lens Corrections’ and a set of sliders. (Click the image to see it larger)
I took the photo you can see at the top of this article, and I moved it around in Adobe Camera RAW using these sliders.
Then I opened it as a PSD in Photoshop ‘proper’ and used the Transform/Skew and Transform/Scale tools to tweak the image a bit more. And then I cropped it to end with the part of the image I wanted.
Here is the uncorrected ‘out of the camera’ version again, and then the corrected and cropped version. As you can see, with Adobe Camera RAW you can ‘swing’ the perspective around and see a completely different aspect of the photo.