There is a series of free video tutorials online for taking and editing photos. The camera used in the tutorial is a DSLR. Don’t let that distract you because there is an app for the iPhone that essentially turns the iPhone/iPad into a DSLR. That app is called 645 Pro. And there are apps for taking HDR photos. These are HDR+ Camera, HDR Photo Camera, Pro HDR, Pro HDR Free, and Pro HDR X. There are others, but these are the ones I was attracted to try out. Keep in mind that the Camera app in iOS 9 also does HDR. The free photography tutorial starts here with an introduction. At the end of each video, you are taken to the next one of the 15 tutorials in the series. The professional photographer walking you through his techniques for taking and editing photos is Trey Ratcliff, and he’s also the author of one of my favorite Mac apps for editing photos: Aurora HDR Pro. Aurora HDR Pro is sold by Macphun software. Macphun also has a set of Mac apps called Creative Kit that contains just about all the tools you need for editing photos - if the editing features of Photos doesn’t satisfy you.
On the free side, there is Nik Collection being offered now by Google. The HDR and Dfine tools in that collection are quite amazing, and the really good part is that those tools are not just standalone apps, but they work as plugins to the Adobe apps as well.
The latest Adobe Elements 14 claims to have everything you would need for editing photos - although not quite as much as is available in Adobe Photoshop CS. I have to admit that when I first opened Elements 14 and tried to do some of the magic it claims to do, I was stumped. I had to rely on the free tutorials that Adobe provides online to do much of what it claims to do.
If the price of Photoshop CS and Photoshop Elements is too much for you, there is a Mac version of Photoshop CS called Pixelmator. You get this in the App Store. Pixelmator has all the same features as Photoshop CS, albeit not arranged nor named as they are in CS. Pixelmator, like CS or Elements, does require a rather lengthy learning curve. Let’s face it, nothing is as easy to use as the editing features in Photos. Pixelmator also has an iOS app, but it performs filters - like changing the overall hue-saturation. Still, it can be fun to play with.
To get a lot of editing features on the iPhone/iPad, you really must try Camera+. It is not only a stand-alone app in iOS, but it also acts as a plug-in for the Photos app on the iPhone/iPad.
In the past, I have mentioned PhotoForge2 as a fantastic app for the iPad for editing photos. Unfortunately, that app doesn’t seem to be available anymore.
Not to be outdone, Adobe provides several iOS apps in the App Store, and they are all free (Adobe wants to tease you with the hope that you’ll purchase their full apps for the Mac). You might want to try Adobe Photoshop Lightroom for iPhone. Be aware that the organizational feature in Lightroom only applies to those photos that you import into Lightroom. Also, even though Lightroom can access the images in the Photos library, you have to import them into Lightroom to edit them, and then export them back into Photos. Basically, Lightroom and Photos are two separate and distinct ways of organizing and editing photos.