First we have a comparison of the field of view of the iPhone lens and that with the Moment Telephoto lens.
Now for the lens test to answer some of the questions I had.
Q1) Does it have any distortion?
Ans: No. The edges look fairly straight.
Compare this with the XCSource telephoto lens, which shows the pincushion distortion which you get with less well constructed (cheaper) optics.
Q2) Does it capture more detail than compared to 2x digital zoom on the iPhone?
Ans: Yes. See images to compare (both shot at same distance to subject but iPhone shot was digitally zoomed in to give the same field of view as that shot with Moment telephoto lens).
Q3) Does it allow the iPhone camera fto take better portrait shots (I used my daughter’s Minion for this test)?
Ans: Yes. The first shot with Moment telephoto lens gives a better reflection of what the Minion looks like, whereas the second shot was with the camera much closer to the subject and as a result there is some exaggeration of the subject which is closest to the camera.
Q4) Is there any chromatic aberration in high contrast shots?
Ans: Yes and no. See images below.
Q5) Does the Moment telephoto lens slow down the autofocus of the iPhone camera?
Ans: Yes. So don’t expect to have the same speed of autofocus as without the lens. But it is still usable.
Here are some more images taken with the Moment telephoto lens:
The Moment telephoto lens does tick the box in terms of its image quality, although there may be chromatic aberration in high contrast areas. But the one big negative point against it is that though it costs US$99.99, it does not come with a lens cap – I would have thought this was essential for such a lens; if the XCSource budget lens kit can come with all the lens caps for each lens, how can such a costly lens not have one. Recommended (if it came with a lens cap). I’ve made my own lens cap to protect it using blue Sugru.