Like many of you I've not been thrilled with the stock screen of my Df and D800. The D800 isn't such an issue since I use AF lenses most of the time but with my Df I'm primarily using manual focus lenses.
I happened to check Nikon Rumors and saw that focusing screen.com is making several screens for the D800 and Df. These are cut down Canon screens and having owned a Canon I was pleased with the screen I had in my 1D series cameras. They aren't particularly expensive so I thought I'd give one a try for the Df. I like a micro prism center so I ordered the A screen. I selected my screen on their website and made payment through paypal. I was notified by focusing screen.com that payment had been received and it would take about a week to make it. When the screen was completed in about seven days I received another email giving an EMS tracking number. The screen arrived in about four days at my home in the US and was packaged very well. It was wrapped in a plastic package and sealed. Inside there was a box inside a padded bubble envelope. Inside the box was an instruction sheet, heat sealed plastic bag with tweezers, screen in the Canon box, finger cots and tool to open the screen frame in the Df.
Instructions were actually on their website and not as clear as they could have been. Removal of the old screen wasn't difficult after figuring things out how it worked but I did accidentally scratch the old screen in the process. Installation was easy but my screen combination required shimming the screen for proper focus. Nikon had used two thin metal shims for the original screen but the two were too thick for the new screen causing a serious back focus. There were two very thin plastic shims provided with the new screen and after a lengthy process of trying different combinations I finally arrived at using the two provided with the new screen.
Actually I tested and replaced shims in different combinations for a couple of hours. At this point I think I'm very close to perfect but not 100% certain it it couldn't be improved on with a slightly thinner shim. I'm thinking about using one of the thicker Nikon shims with a single layer of magic mending tape on it. A few more days of use and I can evaluate how accurate calibrations / shimming is.
Now to how I feel about using the screen in daily use. I shoot documentary and commercial work and work under a variety of low light conditions. Focusing in dim room light and under low modeling lights has proven a bit more difficult than expected. The screen isn't as bright as the original screen but things do snap in and out of focus faster. I use several fast lenses including a 50mm f1.2 and 85mm 1.4. These focus like a dream but even at that I find I double check my focus accuracy with the focus confirmation green dot in the camera. Out doors focus is relative easy but inside it take concentration. Slow lenses like my 20mm f3.5 are tough even outside. My 28 f2.8 and 35 f2 are fairly easy as are longer lenses like my 105 2.5 but again there is some light loss with this screen and it requires good eyes and concentration on the screen.
Shooting and testing with my 85 at 1.4 and my 50 at 1.2 I find I can still miss focus. When focusing you I can rotate the focusing ring ever so slightly before the screen / micro prism fractures the image. This leaves some room for focus error and this I why I use the green dot focus confirmation when things are critical. Outside this isn't so much of a problem as it is inside.
I don't know if focusing is any less accurate than it was with my old Nikon F. I think why we perceive that it is or that it's more critical is because we look at our images at 100%. In the sold days we looked through a 4x or 6x loupe and that was the test. Now we see them at 100 inches on screen and see all the flaws. I'm finding that images that aren't tack sharp at 100% are fine for most applications. the focus error isn't nearly as great as we perceive it on screen.
I will say that I'm generally happy with the screen. Anyone have any experience with a split image screen?