Is there an all manual digital camera, essentially a digital version of the rangefinders or early SLR’s of yore? The short answer is no.
Automatic exposure modes, followed by autofocus, allowed a larger market to take pictures more easily – and increasing the size of a market is rarely a bad business decision. Needless to say, camera manufacturers began automating things and haven’t looked back.
But, if you’re looking for something all manual with a flair for retro – you can get close with some modern and modern + classic offerings.
To start, the Nikon Df is a modern digital camera but it’s control layout is inspired by the Nikon’s of the 80’s. The shutter speed dial is prominent along with ISO and exposure compensation. This is definitely the most retro DSLR to date.
Leica’s M series of rangefinders also utilizes a minimalist approach that has evolved through the ages – but still gives one the ability to set shutter speed and aperture (if using the appropriate lens) the same way you would as with an old film rangefinder.
Finally, you could use a classic manual film camera like the Hasselblad 500c with a digital back. This would get you absolutely the closest to the request of an all manual digital SLR. [The linked article is old - there are newer digital backs]