Originally posted by GUB Well that opened an interesting can of worms. I have 8 x M50 1.7. Thought I would weigh them and see how consistent the weight was. 4 @ 183 - 1 @ 186 - 3 @189/90. Serials for the 4 were all 6million the one was 4 million and the 3 was 3million. Guessing it was a trend from metal to plastic.
I only have one, purchased fall of 1982...
180gm ser.# 6596445
I prefer to think the lower weight was due to different and better grades of helicoid and aperture mechanism lubricants. Just kidding of course, though I have carried that lens over many miles of rugged trail and off-trail routes in conditions ranging from well below freezing to desert heat. Despite having never been coddled, focus action is still smooth and well-damped and the aperture action is still snappy and without slop.
Six grams is not very much, the mass of 0.2 fluid ounces of water.
Steve