There isn’t just one industry-standard focus stacking app, but several commonly used options exist.

Popular choices mentioned include:

• Helicon Focus: a well-known dedicated focus-stacking program.
• Adobe Photoshop CS5 or later: you can stack manually by loading images as layers, then using Auto-Align Layers followed by Auto-Blend Layers. This works well because focus changes at macro distances can slightly shift perspective even on a tripod.
• Hugin tools: specifically align_image_stack plus enfuse. These are free, open source, and available on Mac, Windows, and Linux. EnfuseGUI can make them easier to use.
• CombineZP: another open-source stacking program.

So yes, focus stacking has dedicated tools, but Photoshop is also a practical mainstream option if you already use it. If you want a purpose-built workflow, Helicon Focus is a common choice; if you want free options, Hugin’s tools and CombineZP are worth looking at.