Photographica Pages

An online guide to collectable cameras and related stuff

Nikon F, Mirror lock-up Modified (Celestron and Otherwise)

When Nippon Kogaku developed the Nikon F, they were breaking new ground. They didn't have other designs to follow, other people's mistakes to learn from. And they came up with a camera design that lasted for 15 years.

There was a design flaw in the F, though. Although the mirror could be locked up, you wasted a frame of film to do so. If you needed reflex viewing and focusing (the whole point of using a reflex camera), half of your film was wasted. . I'm told the problem is the mirror mechanism itself. The Nikon F is the only camera that I know of where the mirror is locked in the down position. The reason for this probably revolves around the motor drive running the mirror at speeds never dreamed of with manual advance.

In the greater scheme of things, it's pretty trivial. The concept of mirror lock-up was new, nobody else had it. And most people were even aware of the problem. But enough people were that somebody figured out a solution. Nobody seems to know who. But different modifications were offered by different sources. I don't know how they differ mechanically, but I do know how they differ cosmetically.

One version was reportedly offered by East Coast repairman who specialized in modifications. The mirror was released with a plunger that came out of the side of the mirror housing on the wind side. The fit and finish, while acceptable, doesn't quite match that of the camera, and does not appear to be a factory modification.

The other version uses a small button under the depth of field preview button to release the mirror. I've heard rumor of an example with an ugly brass button, that was obviously an aftermarket modification.

But on an example that we owned the release button is the exact same style of button that releases the self timer. It came to us in very clean condition, boxed, with original instructions. And in the instruction book was an insert detailing the operation of the modified mirror lock-up. Our camera was a late camera, a FTN with F2 cosmetics, yet the insert showed an older style self timer lever, and the pub code was 64.4.A or April 1964. Every indication is that this was a factory modification.

I have also heard of a collector being offered three late Nikon Fs as new old stock. They were modified like mine, came fitted with waist level finders, and had the insert in the instruction books. Who did these modifications? Seems like an open and closed case.

But I've also heard rumors about cameras modified by Celestron, Questar modified, even "Q" Nikons. Two different collectors have told me about these cameras being modified by Celestron. One even said his camera had a sticker on it claiming it was modified. I know that Celestron modified Topcon cameras. Did they do the modification? No mention has been found going through old Nikon dealer catalogs. Perhaps they were marketed through the microscope division. At this point nobody seems to know.

There are some mysteries yet to be solved. The biggest for me is why Nikon didn't modify all of their cameras once the solution was found. Or, if it interfered in the operation of the motor (or something else), why didn't they at least offer the modification through the dealer catalogs, marked as such, and rendered unable to accept the motor?

The Nikon FTn we owned with mirror lock-up modification, boxed.

Close up photo of the mirror release button.

The insert that was in the instruction sheet with the camera.