Nikon's compact manual 135mm — f/3.5 Ai, the lightest and most affordable 135mm Nikkor.
The Nikon Nikkor 135mm f/3.5 Ai is the most compact and affordable 135mm in Nikon's manual-focus lineup. The f/3.5 is slower than the f/2.8 and f/2 alternatives but the compact size compensates.
Optically good — sharp from f/5.6 with the 135mm providing useful telephoto compression. The f/3.5 limits subject separation vs faster alternatives but the lightweight design is practical for travel.
Nikon F mount with 52mm filter thread. Approximately 430g — significantly lighter than the f/2 or f/2.8. Ai coupling. Full-frame coverage. The lightest manual 135mm Nikon.
Available used very cheaply. The f/2.8 Ai-S and f/2 are optically superior. The f/3.5 is the most compact and affordable. For budget manual 135mm or adapted mirrorless use where weight matters.