During the first half of the 1990s, around 30 ALPA Reflex cameras put together from old spare parts appeared on the market. The experts are not enthusiastic, for example, about the optics of these pseudo-ALPAs which are said to differ considerably from the genuine article.

Lately, ALPA 10d, 11si and 11si gold allegedly in mint condition have appeared in surprising numbers. It is not always easy to distinguish duplicates from the genuine article.

How many parts need to have been produced at Ballaigues to make the difference between a genuine ALPA 24x36mm SLR and a duplicate?

Does it matter who assembled it, when and where?

The room for interpretation is rather wide: there are Bugattis around with only one or two screws originating at Molsheim.

The value of imitations to collectors and museums may be close to NIL.

Unfortunately, the authoritative production list of Lothar Thewes, is of no help here - it is not difficult, after all, to use a genuine production number a second time. Therefore: be suspicious especially of cameras that show little or no sign of use.

A couple of things you can check.

• The serial number under the eyepiece should match the serial number stamped inside the back cover, just to the right of the pressure plate.
• There also is a factory plate containing the patent number inside the back to the left of the pressure plate.
• The body of a 10d is machined out of a chunk of metal. It is not cast. I have one of the bodies as it came out of the mill. This is difficult to fake.