9 out of 10 points and recommendedLight, good build, very sharp, very practical view angle for general photographymanual focus by wire: no tactile feedback, no indication of where you are (if past target and reached closest or infinity)
A camera cannot be better than the lens that is on it, no matter how good or expensive the body is. And the Samsung 45mm lens yields images that are sharp and pretty darn close to perfect. It is among the best consumer lenses out there. It is not to be confused with the other 45mm lens produced, the 2d/3d. This is the "normal" lens.reviewed November 1st, 2014 (purchased for $200)
It focuses very well, images are very sharp. Auto-fucus works flawlessly. I use it on an NX20, and auto-focus is dependent on both the lens and the camera's auto-focus system; your results may vary depending on whether you have an older camera model or a more recent one.
Build: The lens seems to be very well built. There are no loose parts, the control ring turns smoothly, buttons work as they should. It mates well with the camera: not snug that you have to push it in, not loose that there is any tilting play. However, once locked into place, there is a little bit of turning play (where you can turn the lens' mount in relation to the camera just a little bit), but this is not something that would affect sharpness or image clarity. Mating the surfaces, and a good snug fit, is important - but the width of the tabs, so the lens doesn't rotate even slightly when you try, would have enhanced the owner's impression of quality.
Don't try this at home, but I've already dropped the ensemble a couple of times, and no damage to the lens (or the camera). In all fairness, I had a lens cap on it, which, being pushed into the threaded opening, absorbed some of the impact, but still, it this lens is not as fragile as one would fear of a lens with a plastic body.
iFn Control: like all Samsung iFn lenses, pushing the iFn button gives you immediate access to the main functions you want to change on the fly while doing your creative photography. Your Samsung camera menu, under iFn Customizing allows you to choose up to 5 out of 6 of the following features you want to appear in your sliding iFn menu: Aperture, Shutter speed, EV, ISO, WB, iZoom - the ones you have access to depend on what your mode-dial is set on (ie: P, A, S, M). This is with 2014 firmware on Samsung NX20 and the 45mm respectively. The lens has the usual switch for selecting AF and MF modes. In AF, it works as it should according to your preference settings in your camera, where you determined how you want the AF to work, ie. whether you want just auto-focus, or auto-focus with the possibility of manual override, etc.
Manual focus: the same control ring is used for the iFn menu and manual focus/MF override. Turning the focus ring gives absolutely no tactile feedback, and nothing tells you if you should turn clockwise or counter-clockwise to focus closer or farther. There is also no indication whether you have reached infinity or the closest focus: you can just keep on turning and turning, not sure where the focus is at in the scheme of things. If I am trying to photograph a small bug on a thin branch, for example, where the camera's focus system only picks up other objects in the background with auto-focus, I don't know if I am turning the ring too fast, too slow, if I have overshot the right point and should continue turning or if I should turn back the opposite way. Although technically it works flawlessly, manual focus can be a bit frustrating in sutuations like my bug on a branch. The manual focus ring is much more convenient when you are using a wide-open aperture, with a very shallow depth of field, and you just need to make fine quick adjustments - for example to bring a subject's eyes into focus, where the camera may have locked focus not exactly at the depth you wanted.
Bokeh: Bokeh is simply a side-effect of larger openings, where it becomes impossible to have everything in focus at all distances. Surprisingly, although at f1.8 the DoF is as shallow as one would expect, background defocus is not as marked as one would think. There are no huge spheres being produced in the background as with some vintage lenses or as we see from a Leica $10,000 lens - rather, focus drops off predictably as the distance increases from the focused pane. Yet the subject still "pops" out from the background. For example, shooting my dog or daughter, they are in very sharp focus, and look to separate and stand out from the background, but a background where you can still make out some fuzzy shapes. The background blur is not as significant as one might hope - although this lays testament to just how phenominally good the optics design and execution are, it might not be what eveyone would hope for (ie: less-good design for more blur).
Despite the turn-forever manual focus ring, this is an outstanding lens, which is right up there with some of the best lenses available for much more money. This lens allows my Samsung NX20 to perform at it's utmost, and I'm certain it will do the same for more recent NX cameras. It has been permanently on the camera now, as I prefer it to any of my other NX lenses. the only lens I could see replacing this one, is Samsung's new, but (understandably) much more costly $1200, 16-50mm S-series f2-2.8 zoom lens. I also own a vintage Minolta Rokkor 50mm f1.4 lens, with a modified-for-NX lens mount, that I no longer use now that I have this 45mm. At f1.8 the depth of field for portrait and street is so shallow already, that I no longer see the point to use the vintage lens (unless I would be out to do night-photography with manual focus).