Sorry! Did not have access to the web other than my iphone, so I could not easily reply.
OK. First thing, YES, I confirm that the lens only focuses, no zoom. There is only one rotating ring on the objective, and that is for focusing from about two inches (actually slightly less than 5cm) to infinity. No infinity stop either, so it actually focuses a bit beyond infinity... at least on my sample, which is one of the very first batches made for evaluation.
No gradient issue, whatsoever, but as Aurora justily pointed out, I'm using 1.7.4 so... but, there's this interesting info.
The About page on the app reports the following,
camera hardware for both units is 0.0.0.5
and also everything else is perfectly the same, only the SN is different.
What I have seen is extremely poor performance in very cold weather (after the Blizzard that hit New England), to the point of almost not producing a usable image.
The performance is bearable in moderate climate or indoors.
After a little while the image muddles up a lot, sometimes it works better, sometimes worse and I cant figure out what really triggers it. The sw is buggy with the XR as well, always popping up the question on what to do when the camera is attached to the phone.
I'm still happy, because the first Seek made me discover this world, and I'm so hooked that I even managed to get a great deal on a uuused BAE Systems SC500 MicroIR core that I am experimenting with (BTW, since I'm a complete NOOB on electronics stuff, and I don't want to hijack this thread, could a gentle soul point me to which forum dept could I start a thread to get help with this core?).
On the aperture issue, I'm not too sure. Aperture is function of the focal length, and since the XR has a FOV of 20°, instead of 36°, so it could be that the actual F-number, whatever that may be, is the same.