The probable best is a Minolta X-500/570 at 480g - better for manual metering and lighter that the X-700, auto exposure is available. Usually harder and more expensive to find than the X-700 though. The X-700 offers Program operation metering at 505g. Both Minolta X bodies have superb viewfinders, I find them better than the Olympus OM series.
An OM-1👎 Olympus is always good at 490g for the body. Although in my experience the OM-2 (530g) actually takes sharper pictures as it's shutter seems to exhibit less vibration. Plus if you are having balance issues auto exposure may be a real help.
For M42 lenses a Fujica ST-605n is cheap and light at 565g and has a good SBC meter. Completely manual operation.
The Praktica Nova 1B is again fairly light at 560g, has a selenium meter that is normally very accurate if working and the shutter is very simple to use/fix.
Another favorite is the Pentax S3 at 548g, although no meter...
The following tables may help. You might need to copy it into a text editor and reformat it. I find the internet tends to mangle my formatting...
1 oz = 28.3495231g
Camera L H D Mass
Contaflex II 126 85 60 720g
(body 45 thick)
Bessamatic 140 105 83 946g
Minolta X-500 137 89 51.5 480g
Olympus OM-1 136 83 50 490g
Minolta X-700 137 89 51.5 505g
Praktica BC-1 138 87.5 49 530g
Nikon FM2n 142 90 60 540g
Pentax S3 143 92 47 548g
Contax S 140 85 50 (32) 550g ••
Praktica Nova 1B 152 100 48 (35) 560g
Fujica ST-605n 133 86 50 565g
Pentacon F 140 85 50 (32) 570g
Praktica MTL5B 140 96 48 (32) 575g
Praktica LTL 140 96 48 (32) 580g
Minolta SR-1s 145 94.5 47.5 600g
Praktica LLC 140 96 48 (32) 605g
Praktica Super TL 152 100 48 605g •
Fujica ST-701 133 91 88 610g (585=manual)
Zenit- S, 3 135 92 50 620g
Zenit 3M 135 89 50 630g (1967)
Fujica ST-801 133 91 88 635g
Praktina 146 89 59.0 660g
PrakticaMat 152 100 48 690g
Yashica TL-Super 151 100 96 691g
Zenit TTL 135 91 50 (32) 700g (1980)
Minolta SR-T 101 145 94.5 47.5 705g••
Zenit E-FS 135 91 50 (32) 715g (1978)
Nikkormat FTn 146 95 54 745g
Praktica IVB 152 100 48 750g
Exakta VXIIA 150 90 45 755g
Leitz Leicaflex SL 148 97 57 757g ••
Nikon F+FTN 146 102 95.3 830g
Leitz Leicaflex 148 97 57 860g (w/batt+film) ••
M42 Lens Weights
Lens Mass Filter Close
4.0/20 Flektogon Zebra 320g 77.0x0.75 0.15m
2.8/20 MC Flektogon 350g 67.0x0.75 0.19m
3.5/30 Lydith 195g 49.0x0.75 0.33m
2.8/37 MIR-1 200g 49.0x0.75 0.7m
2.8/35 Flektogon Alloy 200g 49.0x0.75 0.35m
2.8/35 Flektogon Zebra 230g 49.0x0.75 0.18m
2.4/35 MC Flektogon 250g 49.0x0.75 0.20m
3.5/50 Industar-50 45g 33.0x0.5 0.65m
3.5/50 Primotar-E 180g 49.0x0.75
2.8/50 Tessar Leather 155g 49.0x0.75 0.50m
2.8/50 Tessar Exakta 170g 49.0x0.75 0.50m
2.8/50 Tessar Zebra 175g 49.0x0.75 0.35m
1.8/55 Fujinon 190g 49.0x0.75 0.45m
2/58 Biogon 200g 49.0x0.75 0.50m
1.8/50 MC Pentacon 220g 49.0x0.75 0.33m
2/58 Helios 44-2 220g 49.0x0.75 0.50m
1.7/55 Minolta Rokkor 220g 49.0x0.75 0.55m
1.8/50 Pancolar Zebra 225g 49.0x0.75 0.35m
1.8/50 MC Pancolar 225g 49.0x0.75 0.35m
1.8/50 Oreston 235g 49.0x0.75 0.33m
1.4/50 Nikkor 325g 52.0x0.75 0.60m
2/50 Summicron-R(I) 355g s.VI 0.50m
2/50 Summicron-R(II) 290g 55.0x0.75 0.50m
1.8/80 Pancolar 310g 58.0x0.75 0.83m
2/85 Jupiter-9 (Zenit) 360g 49.0x0.75 0.80m
2.5/90 Tamron SP 420g 49.0x0.75 0.39m
4.0/135 Sonnar Alloy 370g 49.0x0.75 1.2m
3.5/135 Sonnar Zebra 425g 49.0x0.75 1.0m
3.5/135 MC Sonnar 430g 49.0x0.75 1.0m
2.8/135 Pentacon Black 530g 55.0x0.75 1.5m
5.5/180 Telemegor 315g 49.0x0.75 2.0m
3.5/180 Primotar 1070g 67.0x0.75 2.2m
4.0/200 MC Pentacon 600g 58.0x0.75 2.7m
2.8/200 Sonnar 1200g 77.0x0.75 2.2m
4.5/300 Tair-3 PHs 1600g 72.0x0.75 2.2m
4.0/300 Sonnar 2070g 77.0x0.50 3.5m
SLR + Lens Combinations
Zenit 3M + 50 Industar 630+45 675g
Contaflex II 720g
Contax S + 58 Biotar 550+200 750g
Pentacon F + 50 Primotar-E 570+180 750g
Fujica ST-605n + 1.8-55mm 560+190 750g
Pentax S3 + 1.8-55mm S. Tak 548+215 763g
Praktica Super TL + 50 Tessar 605+175 780g
Praktica MTL5B + 50 MC Pentacon 575+220 795g
Fujica ST-701 + 55 Fujinon 610+190 800g
Praktica LTL + 50 Pancolar 580+225 805g
Praktica LLC + 50 Pancolar 605+225 830g
Praktica Super TL + 50 Pancolar 605+225 830g
Contaflex Super-B 840g
Zenit 3M + 58/2 Helios 44 630+220 850g
Praktina+ 58 Biotar 660+200 860g
Praktica IVB + 50f/2.8 Tessar 750+155 905g
PrakticaMat + 50f/1.8 Oreston 690+235 925g
Minolta SR-T 101 + Rokkor 55f1.7 705+220 925g
Bessamatic + 50f/2.8 Color Skopar 946g
Leicaflex SL+50 Summicron-R(II) 757+290 1047g
Leicaflex SL+50 Summicron-R(I) 757+355 1112g
Leicaflex + 50 Summicron-R 860+355 1215g