With a smaller screen, he will be smaller. The camera I used was a 1930's Leica IIIA with a 1950's Jupiter F2 50mm lens. It was overhauled by me using the methods in my books. Most really good cameras from the 1950's or later should do as well. If not, they have probably been damaged by careless CLA or a bump or a fall.
Age has little to do with the performance of a camera.
We publish a text on evaluating and testing lenses with a fine test chart that will help you. It was cleaned, lubricated, adjusted, and collimated using the methods in my Revised Basic Training book. The car is a local 1948 Pontiac, still in use too. The picture is not quite as sharp as the one of the river above, made with a Leica. However it is quite adequate for many applications.