Mounting the Focusing Screen from Old SLR Camera on Nikon D3100

If you use manual focus lenses on modern DSLR cameras, you know how difficult accurate focusing manually is because modern cameras have an autofocus lens.

In old cameras, manual focus was to do more convenient thanks to the focusing screen. I decided to fix a weak spot of modern cameras, putting themselves on the Nikon D3100 focusing screen from the old SLR camera “Kiev 19”.

Here is an article about the principle of focusing screen

In “Kiev 19” the focusing screen has a split image rangefinder and microprism. Constructively it is a circle in the center of the focusing screen.

The focusing screen on Zenith ET

The Procedure for Setting the Focusing Screen from Old SLR Camera on Nikon D3100

1. Take out the Focusing Screen from Old Camera

It is under the prism. To do this, remove the photo lens and see the focusing screen and a magnifying lens. But we take only the focusing screen. It from plastic and can saw through the dimensions of the Nikon APS-C camera, but the lens glass and file away I did not, and besides, she can not get into the D3100 in thickness.

The other camera pulling process may be slightly different, but the method is similar.

Mounting the Focusing Screen from Old SLR Camera on Nikon D3100

In this photo, the focusing screen has already pulled out

2. Take out the Focusing Screen from Nikon D3100
Here, compared to the old camera, removing has a lot easier. To do this, remove the photo lens, are turning the camera upside down, and you can see it. He fixed the metal bracket.

Remove the bracket and take out the screen. It looks like a rectangular lens. Also made of plastic. Behind it, there is still a black stripe on the edge of the screen, and I also took it out.

3. Making the Old Focusing Screen the same Size as the Screen of Nikon D3100.

The size of our focusing screen is 38,8х24mm, while the Nikon D3100 screen is 28,6×19,5mm. We need to cut the extra, so he entered instead of the standard screen.

It is important to know that on the axis Y, it is necessary to shift a little bit because if it is placed in the center when you insert it in-camera, the circle in the viewfinder is not in the center (at me and came out), so I recommend below cut down to 1mm more than on top.

But even if you do not get to make the circle perfect in the center of the viewfinder, do not worry; the focus is not affected. Also does not affect which side you took to cut more, above or below, because it can be turned as we need and placed into the camera.

4.  When the Focusing Screen is Ready, Insert it into Place on the Nikon Genuine Focusing Screen

It needs to insert a microprism. Now put back the metal bracket. And clamped screen. In theory, the closer it is to the prism, the more it will show focus.

Focusing screen adapted for Nikon D3100.

Therefore, putting the screen, try it as close as possible to the prism. First, I put the black gasket, and then when adjusting, pulled it out because, without gasket, focusing becomes more accurate.

5. Go to the Focusing Screen Calibration

6. Mounting the lens back on the camera
Put a ruler on the table and put something small, something to be focused on. I used to do this screw. Put it next to the line in front of some numbers.

Next, open the aperture as much as possible to ensure a minimum depth of field. Put the camera at an angle to the line, about 45 degrees to the image display area. Are focused on the screw (by split-image rangefinder or micro prism, you can check in two ways, they should give the same result). And the picture is taken.

Винтик был поставлен напротив метки 11 см. Как видим резкость там где нужно

Screw was placed in front of the mark 11 cm. As you can see sharpen is where you need.

Then look at it on display. If the figure is near the maximum screw sharp, it means that the focusing screen mounting was successful, and now we can enjoy the manual lens focusing.

Test shot on the middle string

If sharpness is abnormal (front or back focus), you need to pull the screen, and as you move closer to the prism, we can not; now, you need to enclose the gasket. You can put a black native; also, I read that was excised from the plain paper on the forums. But in my case, it turned out, on the contrary, I had to pull the pad and press the screen closer to the prism.

The focusing screen allowed me to use some manual focus lenses even in reportage shooting, where you need to catch the focus of the desired object quickly.