I'd like to share my experience with Voigtlander's clip-on optical viewfinder and my X-E1 and 18mm lens: View attachment 892 (sorry for a crappy shot made using an iphone) Overall I'm extremely pleased with the experience. Optical viewfinder helps a lot for street photography when you really need to anticipate the right moment. Unlike EVF there is no lag and together with "on-demand" manual focusing this lets you shoot the same instant you've pressed the button. Also during daytime you can set your lens at f/8 and focus and infinity and everything is going to be in focus. Interestingly enough I don't find lack of autofocus/exposure/level information in the viewfinder to be a huge disadvantage. This actually helps to concentrate on shooting and makes camera feel even closer to old-school film cameras. The only pitfall here is that unless you have sound turned on you won't know if the camera managed to focus successfully. After some practice with CDAF it's not an issue for me most of the time. Another downside is that framing isn't precise especially when your subject is close. So I wouldn't recommend using the viewfinder for shots when you want precise framing or strictly straight horizon. With some experience you start compensating for the parallax in your head and it stops being a problem. But it was definitely challenging at first. The viewfinder itself is really great. Solid metal build. Bright glass and easy to see framelines. As it's a brightline viewfinder you see a bit more of the scene than the actual 28mm lens. I really recommend it to anyone who does street photography.