Assuming this comes from a Leica lens and according to this post, font should be 'LG 1045/1050', proprietary and exclusive to Leica.
Alternatives: Vox Round (and mixing it with Sol could work), Basic, Zolan (Mono)

Can't find an exact match either. Take into account that this is probably a custom OEM font of the lens manufacturer designed for the lens production machine and not a commercially available digital font.
You may like one of the following replacement candidates, here is a square looking one:
http://Thud (Medium) by Suomi Type Foundry [2010]
...and some more round ones:
http://Zetta Sans by Jonas Hecksher [PlayType]
http://Coda by Vernon Adams [Google Web Fonts, 2010]
http://Eurostile Medium

PS: I now see that Ryuk confirmed it's a custom font...

I had a feeling that might be the case.
Thud, Basic and Eurostile were the closest I could find.
Many thanks for your efforts.