Pano Owl

Pano Owl is a simple iPhone application that allows you to quickly stitch your DSLR photos together quickly and easily into a beautiful Panorama.
It automatically scales down selected images based on a maximum output size. 
Simply grant access to your photos, select your photos and it will stitch the panorama together for you. 
After selecting the different images to merge you can now instruct Pano Owl to apply a HDR merge or a Panorama Merge.
- Panorama will stitch your selected images together based on a minimum of 33% overlap.
- HDR will align, tone map and even offer to normalize your various exposure images.
With this you can now also HDR merge your DSLR photos too!
It will also auto crop your raw panorama image to a rectangle that has no black edges. 
If you are unhappy with the auto crop you can toggle it off by un-cropping it and saving the raw panorama. This allows you to have more control in editing it in other apps you may have on your device.
The app automatically scales the output image to a size that can be safely handled by your current device. If your device is newer the resolution will likely be higher than running the app on an older device. For example a 14MP panorama can be exported on an iPhone 13 Pro Max. This scaling is necessary to ensure the app can operate within your device's hardware. The more images you select the longer the stitching process takes. Also make sure you use images that are exactly the same size and orientation.
It allows you to preview and save the rendered photo to your photos library. 
It can also be used completely offline as no network traffic is needed for this app.