Install KatzEye Focusing Screen in Nikon D300

Focussing manually has it's advantages. First, the number of potential lenses for your body sky-rockets. There are numerous old and new extraordinary good MANUAL FOCUS lenses available for the modern DSLR. Examples are lenses by Voigtlander, Carl Zeiss, and the old Nikon (Ai-S) lenses. The problem is that most of the modern cameras lack a decent (visual) indicator for when your object is in focus. My Nikon D300 has a small indicator (a dot) in the viewfinder which notifies you when you've got focus. But when you shoot with large apertures (e.g. f/2, f/1.8, f/1.4 or f/1.2) on MF lenses you have to keep track of your composition (through the viewfinder), and watch the 'in-focus' indicator. Something I find very hard to do. I allways seem to miss at least one of them. Missing composition is easy to fix in post-processing, but fixing focus can't be done.

Thankfully, there's a solution to this problem; Katz Eye Optics. These guys offer old-skool focusing screens for the modern digital SLR's. All you have to do is replace the focusing screen with theirs. You can do this yourself, or your camera brand service-center should be able to do it for you (at additional cost). I did it myself though, and ran into a problem (of course). But more on that later...

An important thing to realize is that replacing the focusing screen won't replace or remove your regular AF points. You only add more information in the viewfinder.

The actual replacement process is explained through a manual on the KatzEye website. All you need to bring yourself are optional gloves (which I didn't use), a small rocket/bulb blower, tweezers, confidence and 'balls' (you will be using sharp objects in your camera body!!!).

Removing the old screen is a piece-of-cake. Installing the Katz Eye screen took a bit more effort. After installing the new focusing screen I tried it, and the focus was way off. At an aperture of f/1.8 I had about 1.5cm back-focus (the actual focus was 1.5cm BEHIND the intended part). Even when I used a tripod. Now that's not good......
Using the small visual indicator of the camera for determining the focus turned out to be accurate, so the indicator prism on the new focusing screen was the problem.

During the installation of the focusing screen I also removed and re-installed two thin metal frames (shims). These shims are places on both sides of the focusing screen. The shim which is placed on top of the focusing screen (when putting the camera in an upright position) also increases the space between the ocular and the focusing screen. And this could give a wrong visual indication of focus.

I removed the metal shim from between the screen and the ocular. This resulted in even more back-focus. Almost twice as much. So logic dictates that adding more space between the ocular and the screen should decrease the back-focus. And indeed, it did. After placing both frames between the screen and the ocular removed the back-focus all together.

For those interested in what you eventually end up with; The first pair shows an out-of-focus view through the viewfinder (left), and the resulting photo (right). The photos with the viewfinder view are taken with an iPhone... Hence the crappy quality.

And these two show an in-focus image through the viewfinder (left) with the photo result on the right. The small dot on the left (left photo) is the camera focus indicator.

I will add additional photos explaining some of the things I ran into (on the inside of the camera), when I got a hold on my P&S camera.

Posted on April 22, 2011 and filed under Hardware, Photography, Review.