Originally posted by 8540tomg The K, M, A etc. debate has gone on for some time in this forum. It is often emotionally charged and always fun. I have a bag full of old M series glass and I like them a lot. They are fine lenses and very well built but they are smaller and “feel” less substantial than the K series. I used to think the Ms were the best in terms of build until I got a few K series lenses. I suspect this build quality is what Lowell is referring to in his post. This will be immediately evident to you if you hold a K lens in one hand and an M in the other. By extension the K series lenses are less substantial than the old Takumars I have seen. Those puppies seem to have been milled out of solid blocks of aluminium.
It's not an emotional issue for me, but an interesting one. What I'm seeing here is a fundamental difference in how one judges build quality. Some see greater weight as a sign of greater quality right there. Others see it precisely the other way around. I'm more in the latter category.
The first type of product I ever really got into at this level was the mountain bike. And there was no question there: heavy meant bad (more weight to have to pedal uphill!). Sure, you didn't want to achieve lighter weight through too much plastic, either, as that would impact durability. But the higher quality bikes were lighter through the use of more expensive materials and more precision engineering, not through the use of plastic. In practice, while it would be *possible* to make a cheap and lightweight bike by making more and more of it out of plastic, people knew there were limits, as you needed it to be strong enough to support rider at least. So they used cheaper heavier grades of steel for parts you really *need* to be strong - where failure means injury to the rider and a lawsuit on your hands - and cheap plastic on the parts where failure meant only "planned obsolescence" and hence wasn't even bad thing in itself from the manufacturer's perspective. Which is to say, cheap bikes were heavy and still more fragile than more expensive bikes. A lighter bike was always a more expensive and better made bike, and of course weight translates directly into performance in mountain bicycling.
I suppose that basic experience has shaped how I think of lenses. Takumars strike me as the equivalent of a department store mountain bike - heavy chunks of cheap grade steel whose greater weight is an indicator of *lesser* quality. Now, of course I realize this isn't a fair comparison, because weight for lenses is not as directly performance-related as it is for bikes. Heavy isn't necessarily bad, although I do prefer lighter lenses, as I don't like carrying more weight than necessary. But obviously, a simple "hold one in each hand" test isn't judging quality in any real sense - it's simply forming a gut impression. And as far as that goes, I'll favor the the lighter lens every time. Of course, I will then check to see that this low weight doesn't seem to have been achieved through use of too much plastic, and if it's both light *and* cheap, I'll also consider whether the low price was achieved through shoddy workmanship, poor design, etc. But my impression with M lenses is that nothing of the sort is the case. The low weight gives me an immediate sense of higher quality than the K's or Takumars, which I know is just a gut impression, but further inspection of the lenses does nothing to dissuade me.
Anyhow, I think it's basically issues like this that explain why people can have such different impressions of lens quality. The very things that cause one to form an impression of higher quality can have the reverse effect on someone else.