Comparison
Hamilton Khaki Field vs
Seiko Alpinist
Pick the Hamilton for titanium and an 80-hour reserve; pick the Seiko SPB121 for 200 m, a date and a compass ring.
Compare Hamilton Khaki Field Titanium Automatic and Seiko Prospex Alpinist SPB121
Pick Hamilton Khaki Field Titanium Automatic if
you want a Swiss titanium field watch with an 80-hour reserve.
Pick Seiko Prospex Alpinist SPB121 if
you want 200 m, a date, and a compass ring.
Notes
Hamilton Khaki Field vs Seiko Alpinist
Two field watches. Different metals. Different water.
Hamilton Khaki Field Titanium Automatic, H70545550. Swiss. 42 mm titanium. Sapphire. H-10. 80 hours. 100 m. Three hands; Hamilton’s page shows no date window. Two-year international warranty. Thickness, lug-to-lug, and weight stay off this page.
Seiko Prospex Alpinist SPB121. Japan. 39.5 mm steel. 13.2 mm. 46.4 mm lug-to-lug. 87.0 g. Sapphire with a cyclops and inner AR. 6R35. About 70 hours. +25 to −15 seconds a day. 200 m. Date. Compass ring. Screw-down crown. Exhibition back. Three years if you bought it from Seiko or an authorized dealer.
No prices. No Amazon. Official brand pages only.
Hamilton if you want titanium and more reserve. Seiko if the job is wetter and you want the compass. Skip Hamilton for 200 m or a Japanese dial.
Casio W-221H is the quartz field detour if automatic reserve is not the point. Timex Expedition Capstone is the quartz field option in the same hub.
Questions
What is the water resistance of each?
Hamilton 100 m (10 bar). Seiko 200 m (20 bar).
What movements do they use?
Hamilton H-10 automatic, 80-hour reserve. Seiko 6R35 automatic with manual winding, about 70 hours.
What is the warranty length?
Hamilton, 2 years international. Seiko USA, 3 years from purchase from Seiko or an authorized dealer.
What are the case sizes?
Hamilton 42 mm. Seiko 39.5 mm, 13.2 mm thick, 46.4 mm lug-to-lug.
What are the power reserves?
Hamilton 80 hours. Seiko about 70 hours on SPB121.
Sources
No single winner. Hamilton for everyday wear. Seiko for wetter, more tooled use.