I have an iPhone 7+, and cannot the problem. On my device, the minimum focal length is the same in both LRM and native camera apps.
Are you running the latest LRM app version 2.5.2 that's on the app store?
What iOS version specifically are you running?
Is it possible you had toggled on the telephoto optical zoom, or in some other way zoomed digitally by pinch gesture?
If you can still reproduce, could you share a couple sample images, one from from each app?
I see the same problem. I've attached three pictures:
1) An image captured by Lightroom. Note how blurry it is.
2) A screen capture of the Lightroom app while capturing the photo. Note that the upper right-hand corner shows that the telephoto lens is selected.
3) An image captured by the native iPhone app.
Adressing your questions:
Yes, the app version is 2.5.2.
The iOS version is 10.0.2.
I toggled the telephoto and set a focus reticle. I did not pinch or otherwise zoom.
I confirmed with a developer, this is a hardware limitation of the telephoto lens. In the native camera, if you tap the 2x button and try to focus on something that's too close for the Tele lens, iOS actually switches to the wide lens and does a crop. In LR Mobile if you choose the Tele lens, the app stays on that lens even if your subject is too close and out of focus. Our advice is to avoid using the 7+'s Telephoto lens for close-ups.
Hope this explanation helps.
Interesting! Thank you for the explanation.