Summary: I read some good reviews of these magnifying eyepieces and just had to try them. I bought two, one for each of my D700 and D800's. I ordered at the same time two DK-19 eyecups. They were very easy to fit, even though there are a lot of reviews that say the opposite. Follow Nikons instructions and there are no problems.I have found this combination a great success, and am only sorry I haven't discovered them earlier.
Summary: I shoot mostly wedding and portraits on a Nikon D4, I bought this eye piece as I noticed that some of my shots were not focused dead on especially when using very shallow depth of field, this eye piece is superb and easy to fitThe magnification is only slight but makes a huge difference.
Summary: A well made and securely fitting design, which has provided a little extra magnification to the viewfinder image of my D800e. It does 'vignette' the displays a tiny bit, but they are still perfectly usable by moving your eye ever so slightly.The only con is that it sticks out a bit, especially with my DK-19 eyecup, so can catch on your bag / case, but just a minor niggle.
Summary: I bought this from WEX for £23.99, and fitted it to my camera. It magnifies the viewfinder a bit and makes the viewfinder information clearer, but, if you wear glasses you can only see about ¾ of the viewfinder and the information along the bottom of the viewfinder is not visible until you shift your eye around. Without glasses the viewfinder is fully visible except for vignetting in the corners so still a little disappointed. I think Nikon could have done better.
Summary: I love the larger view, but I've found I need to get my eye in the right position otherwise the view can be cut off. With the standard eye piece I could put my eye anywhere around the opening and see the whole view including the information area. With the DK-17M I often find I'm missing part of the view which can be distracting and could mess with my composition.
Pros: Improves Product Function, Magnifies View, Simple To Install
Summary: Even though it only magnifies by 0.2x it does make a difference, but after a using a couple of times you dont notice it any more,(took it off to clean once then you notice it)..Some people find it a bit of a nuisance having to move eye position to view the lighting info at the bottom of screen, but it does not bother me at all.
Summary: Don't expect a miracle from this lens. 1.2 times magnification is subtle. Some of us are happy with any help we can get. The view is bigger, so you might ask why didn't Nikon fit this as standard ? well, on the down side, the corners of the viewfinder are now darker or slightly vignetted. Where you place your eye relative to the viewfinder is more critical. The viewfinder now stands out about 6mm. from the back camera body. I like this.