Just thought I'd post my experience of focusingscreen.com.
I have a Nikon D800E, not a Nikon Df - but I mostly use manual lenses, so was interested in fitting a microprism screen. Focusing manual lenses using the default ground glass screen is usually easy, but with certain subjects (lacking detail, low contrast, etc.) are problematic. I don't like the green dot, which I generally ignore - it has "slop" resulting in focusing errors, and I prefer to look at the view not an LED to the side!
So, the aftermarket screen...
I ordered an Ec-A - which is a modified Canon screen.
The company communicated well, and the kit arrived after a few weeks with everything extremely well packaged.
It was a doddle to install - 5 minutes, if that, and focus is perfect: I can focus my 55mm Micro-Nikkor to the millimetre! The ground glass background seems as bright as the standard one, and is slightly easier to focus. The microprism spot works as expected - slightly annoying having the D800 central focus rectangle slap in the middle of it, but not that big a deal.
Installation instructions are on the focusingscreen.com website, and you can also Google for other people who've installed a focusing screen. I think the Nikon Df screen is retained like the Nikon D800.
The kit contains nearly everything you need. I'd add a clean microfibre lens cloth and a rocket blower (NOT canned air!).
A quick overview of installation - which is easy for anyone not completely ham fisted:
- Test your camera on a close object to ensure its standard focusing screen focuses accurately! Being a new and expensive camera, it should do - no point changing the screen if your camera misfocuses!
- Get everything ready on a clean, dust-free table (hoover it!). You don't need to decontaminate the room - avoiding dust in the viewfinder is not problem!
- Invert the camera so you can see the focusing screen in the lens throat.
- You'll see a strip of foam in front of the screen - the mirror cushion. Behind this foam you'll see a rectangular wire retaining clip that runs around the edges of the screen.
- Use your thumbnail to hook it upwards from behind the foam. This should be quick and easy - if you need force, or if you can't release it, you're doing it wrong. (The kit comes with a special tool to release the clip - but it's a bit unwieldy, and could scratch your screen. Your thumbnail is a better tool - easier, and less likely to scratch anything.)
- Rotate the camera gently away from you. The screen and the shims below it are loose, and will tip upwards. Use the supplied tweezers to lift out the screen by the little locating tab on its front edge. (You can't put things back in the wrong order, so don't worry about the shims falling out! If they do, just pop them back in. Note: the locating tab should be nearer the left side of the camera (with the camera held upside down) - it can only go back in that orientation, as the tab fits in a cut-out.)
- Use the rocket blower to ensure the camera lens throat is dust free - look through the eyepiece at a white wall or the sky to check for dust. Hold the new viewfinder by its edges and give it a few good puffs with the blower, and inspect for dust. If everything seems dust free, pop the screen into the camera, holding the tab with the tweezers. If you've forgotten how everything goes back together, the screen sits atop the shims (my Nikon D800 has two: a silver one, with a gold one above it - viewed with the camera upside down); the top of the screen has grooves along the left/right sides were the retaining clip locates, while the bottom of the screen has the matt surface. Like the shims, the tab on the screen locates in a cut-out, so it's impossible to fit upside down!
- Once the shims and screen have been popped in, and are seated correctly, use the special tool to push the retaining clip into place (easier than using your thumbnail when replacing the clip!). It clips behind a post behind the mirror cushion foam, and requires no force or fiddling - if it won't clip home, something's not right.
- Check for dust in the viewfinder. If dusty, disassemble and clean. repeat until dust free. My second attempt was dust free.
- Check focus accuracy. Mine was spot on using the standard shims. However, extra shims are provided in case the camera screen front or back focuses. If the focus is off, use various combinations of shims until the focus is perfect.
If you don't like the new screen, simply refit your old one.
The downside (apart from additional screen clutter from the microprism spot) is that matrix metering is reportedly buggered. I say "reportedly" because I've not checked: like any photographer worth their salt, I use centre-weighted average, which remains predictable and accurate. Spot metering using the centre point will also be off. This isn't new: Canon warns about these two metering issues in its official info accompanying its interchangeable screens (for some of their early pro dSLRs).
This shows that you can have a traditional focusing in a modern dSLR - but Nikon don't want you to! Presumably because they either don't want the hassle or are concerned about potential complaints regarding incorrect metering. (I wonder why Canon used to supply alternative screens for their pro dSLRs but no longer do so...)
