The insulating tape is just to keep it tidy and to avoid dust traps. The clever bit, apart from strong glue, is a) use an old SD card in between to fill the void and b) when you bring the two together, have lenses in place so you can line them up.
another review, from lenstip. what i like about their review is that they used an older generation body, the x-e1. if the lens is a good performer on that body, then i would assume it would be as good, if not better, on a newer body. i certainly hope that this kind of performance will also be on the upcoming 50mm f2..
and their conclusion:
handy but solid and weather-resistant casing,
excellent image quality in the frame centre,
sensible image quality on the edge of the frame,
negligible longitudinal chromatic aberration,
low lateral chromatic aberration,
lack of distinct problems connected to spherical aberration,
practically zero distortion,
silent, reasonably quick and accurate autofocus.
very high vignetting for RAW files.
Small, shapely, weather-resistant, optically good, with interesting optical parameters – can you ask for more? Of course grumblers might carp about high vignetting or coma levels but fighting those aberrations would also mean bigger physical dimensions of the tested lens so removing one of its more important assets. I guess such a price is worth paying in order to enjoy the Fujinon XF 23 mm f/2 R WR as it is. After all the instrument is a joy to use and completely recommendable.
Surprised about the coma comment. I'm not seeing that at all. On the raw, they don't as far as I can see actually say what converter they are using. I use the in-camera one and wouldn't say I'm seeing anything untoward on that front. It's all very well saying "independent converter" but we all know very well that they vary substantially in their ability to get the best out of Fuji raw files.
Those are diffraction effects. they result from a strong light source in this case the Sun, being diffracted through a grid, in this case the tree branches. they're far from lens specific (and can be quite attractive!)