Early Box Tengor Focus

I somehow managed (GAS) to acquire an early (1926-28) Box Tengor camera in great condition. But in trying to understand it I find that it is significantly more primitive than later versions, ie, that it has no focus adjustment. The later cameras have three focus settings but this one has none. So I guess that means that every thing from a certain distance from the camera is more or less in focus. Any idea what that distance might be? The camera does have three F-stops, F11, 16 and 22, so I guess that the smaller stops would give sharper focus. Any other advice for using this camera would be much appreciated.

There should be a "tab" you pull up to place the close up lenses in front of the lens. Maybe the earliest ones didn't have them.

Most cameras with fixed focus for 120/620 film had focus from around 5-6 feet to infinity at f/11, and of course would gain a small amount at f/16 or f/22. Assuming it has a Bulb shutter setting, you could open the back (as if to load film), put a piece of frosted plastic or ground glass at the film plane, and check where focus is sharpest and then use depth of field calculation to verify.

JPD said:

There should be a "tab" you pull up to place the close up lenses in front of the lens. Maybe the earliest ones didn't have them.

Click to expand...

There are two pull-up tabs, one for the aperture settings and the other for Bulb. But nothing for focus.