What is the oldest functional camera you have?

That would probably be my Retina 1, the one with an uncoated f3.5 Ektar in a Compur shutter. It works perfectly. Unfortunately I somehow put it away with a fingerprint on the front element, which has etched the glass. Mea culpa!

I restored a 1910-1915 Seneca 4x5 View camera. With the removable lens mounts, I use a 125mm Wollensak, a 165 mm Raptar and a Pinhole lens for taking pictures.

Lately I have been experimenting with pinhole photography. Nothing quite a versatile as film box with bellows.