I understand selective focus I've been a photographer for sixty three years, and have owned a Mamiya C330 F for more than thirty of them, what I'm trying to tell you is that the depth of field on a Mamiya TLR at close distances with the bellows extended is only millimetres deep, look at the depth of field scales.
http://grahampatterson.home.comcast.net/~grahampatterson/grahamp/mfaq/m_faq.pdf
I agree DOF is narrow with MF but a little bit can make a big difference and the smaller the aperture the more in focus you get regardless.
6x6 film
65mm lens
subject distance 2.50 ft
f-stop=4
Depth of field
Near limit 2.43 ft
Far limit 2.58 ft
Total 0.15 ft
In front of subject 0.07 ft (49%)
Behind subject 0.08 ft (51%)
f-stop=5.6
Depth of field
Near limit 2.4 ft
Far limit 2.61 ft
Total 0.21 ft
In front of subject 0.1 ft (48%)
Behind subject 0.11 ft (52%)
f-stop=8
Depth of field
Near limit 2.36 ft
Far limit 2.66 ft
Total 0.3 ft
In front of subject 0.14 ft (47%)
Behind subject 0.16 ft (53%)
f-stop=11
Depth of field
Near limit 2.31 ft
Far limit 2.73 ft
Total 0.42 ft
In front of subject 0.19 ft (46%)
Behind subject 0.23 ft (54%)
f-stop=16
Depth of field
Near limit 2.23 ft
Far limit 2.84 ft
Total 0.6 ft
In front of subject 0.27 ft (44%)
Behind subject 0.34 ft (56%)
f-stop=22
Depth of field
Near limit 2.14 ft
Far limit 3 ft
Total 0.86 ft
In front of subject 0.36 ft (42%)
Behind subject 0.5 ft (58%)
f-stop=32
Depth of field
Near limit 2.02 ft
Far limit 3.28 ft
Total 1.26 ft
In front of subject 0.48 ft (38%)
Behind subject 0.78 ft (62%)