Testing a 1936 ZEISS IKON Folder I was given-- I cleaned lens surfaces but there is still a bit of 'Haze' inside. Here I took the Ruins of the Becket Chapel in Brentwood High Street, an old ROMAN Road from London to Colchester. i cut off top as viewfinder is so poor ! Light was terrible too.
Should be the 510/2 with the optical indirect vision viewfinder on the lens (image is very reduced in size) ... ?
Using the second viewfinder frame on body one have to go quite close to get the image correct.
IIRC there was an additional magnifier attachment (5x) for the optical viewfinder.
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I like your image - the old 3-element Nettar is not that bad as often reported. It renders beautifully.