Chas Dickinson photographer was working in Port Elizabeth about 1882 -1887.
OK. My best estimate is mid-late 1870's but could be into the early 80's depending on how up to date he dressed.He looks 65-70 to me.
Whether this is 1870's or 80's & he's aged badly he stillisn't someone born in the 1830's.Beware of confirmation bias says he.
I would suggest a birth of around 1810-20.
The old man looks well dressed, but must be 80 or well into his 70's.If the photo was taken in South Africa, he may have died there. Were there lots of family ancestors in Port Elizabeth?