[6BQ5]

A plastic or metal barreled lens will probably work equally well but they will feel extremely different from each other. Using a manual lens requires grabbing something, turning it, setting it, etc. I think about how different my SMC 28mm Tak feels to my 18-55 kit lens. The Tak feels "sturdy", "heavy", and "smooth" whereas the kit lens feels "light", "fast", and "easy". This difference in feedback gives the impression that one is "better" than the other but I wouldn't agree with that. One lens can get whacked out of alignment and damaged just as easily as the other. Plastic may absorb more shock and bounce whereas metal will impart more shock but one lens is longer and one lens is shorter. Also, the kit lens is lighter.

I would suspect that Pentax and other lens manufacturers have done some accelerated life testing on their products. That means shaking, baking, dropping, freezing, etc. I doubt that a major company or brand name like Pentax would release a plastic lens that falls apart in 5-10 years. The damage to their reputation would far exceed anything that the lens would suffer. After 10 years I don't think anyone would care about what happens to a "cheap" kit lens.

So, I don't think one is better than the other. Just different. I think the biggest factor that makes things "better" is the optical design. What's the glass inside the barrel like? Coatings? Etc. That's the angle I was looking at for this thread.

Now, here's a can of worms to open up!!

How about the idea of lenses with plastic optical elements? Yikes! How would you feel about a 50mm f/1.4 made of pure and clean plastic?

[nomadkng]

I say avoid any DA or FA Limited lens.

Once you see the images they can produce when you get it right, you'll never be able to go back to consumer lenses. LBA will overcome you and you'll spend hours stalking lenses on PF forums

Also avoid macro lenses, because suddenly flowers and bugs are fun.

And avoid really good long glass capable of f4 or better because you'll start waking up at 330a to take pictures of wolves and bears.

In fact, sell your camera now, you'll get much more sleep and have fewer domestic quarrels. Be thee forewarned!

[c.a.m]

I say avoid any DA or FA Limited lens.

And definitely avoid picking up an M 50/1.7. If the Limiteds don't put you the path to LBA, then this one will do the job nicely. I know - that was the first time I succumbed.

Craig

[6BQ5]

I say avoid any DA or FA Limited lens.

Once you see the images they can produce when you get it right, you'll never be able to go back to consumer lenses. LBA will overcome you and you'll spend hours stalking lenses on PF forums

Also avoid macro lenses, because suddenly flowers and bugs are fun.

And avoid really good long glass capable of f4 or better because you'll start waking up at 330a to take pictures of wolves and bears.

In fact, sell your camera now, you'll get much more sleep and have fewer domestic quarrels. Be thee forewarned!

I will consider myself duly warned!

[johnha]

I'm concerned that now we have 'lens profiles' it is much easier for lens designers to re-write the profile than control aberrations by the lens design as much as they previously did. Before the 'kit' lens arrived, lenses were much more consistent in performance and varied mostly in choice of aperture and price (some of the 'slower' lenses performed better than the faster ones). Even early zooms were better than some later kit lenses because they were sold as regular lenses in the line-up and not built down to the lowest possible price simply to sell a body.

John.

[stevebrot]

Again, care to elaborate?

My pleasure. Many of the A-series lenses, the 50/1.7 in particular, suffer from a weakness in a plastic part in the aperture ring mechanism. This small part breaks resulting in a partial or total freeze of the aperture ring. This is not a huge issue if you always use it on a camera with dial-controlled aperture for Av mode and never take the lens off the "A" setting. It can be a problem if you use it on, say, a Pentax Super Program in Av mode where you have to use the aperture ring and can't get it back to the "A" setting for use on the dSLR. Probably at least half the A 50/1.7 lenses out there have this problem. I read a comment some years back on this site that even if your A 50/1.7 is good, it is only a matter of time before this part gives out. Fortunately I have the optically equivalent and much better built Pentax-M 50/1.7 to use instead on my film cameras.


Steve

[stevebrot]

I have a Rollie, Nikon F, SP 500, Nikon FG 20, Minolta 16mm, Pentax DL, Pentax K20, and finally my "active" camera a K5.
All, so far as I know, in working order.

BTW back in c1991 I bought a Zeiss 7x42 $960, Leica 8x32 $920 and a Sears 7x50 $40 binos.
All of them have seen heavy field use and all of them have not given me a lick of trouble.

Question:

From a purely objective rational design viewpoint why design something to last a hundred years, with all it's added cost to the initial consumer, when you know it will be obsolete within 20?

Looking at your list, I only see three items that might be deemed obsolete. I will let you guess which three, though I will add that two were planned obsolescence. My question would be why anyone would make an expensive and wonderful tool that is only designed to last five years and which is not cost-effective to repair?

My Canon P is over 50 years old and works as well now as when it was new. It is obsolete in the same way that a Leica M3 (made at the same time) is outdated. It is a pleasure to hold and a pleasure to use, is not clumsy in any way, and satisfies the photographic task quite nicely. What is it that makes it obsolete? Only the fact that it takes somewhat higher level of skill and expertise to get top-grade results than a camera with digital sensor and modern automation.

Steve

(...unrepentant Luddite...still uses Windows XP Pro...has an old Riviera for pleasure driving...shoots film...)

[stevebrot]

Care to elaborate on "robust"?

Precision assembly is leagues ahead now than it was even 10 years ago.

An item's construction is is only as precise as its design specification.


Steve

[Sagitta]

Man, as a connoisseur of cheapass lenses, I can't really think of any to avoid. Maybe i it rabid and is trying to bite you?

Even a junked and broken lens is useful for parts or for playing around with.

Worst case you can always sell it on eBay as LIKE NEW MINTY*

* bit of fungus between the elements and a crack in the glass. No returns. As is. Did we say MINTY??!!

[tclausen]

Man, a connoisseur of cheapass lenses, I can't really think of any to avoid. Maybe i it rabid and is trying to bite you?

Even a junked and broken lens is useful for parts or for playing around with.

Worst case you can always sell it on eBay as LIKE NEW MINTY*

* bit of fungus between the elements and a crack in the glass. No returns. As is. Did we say MINTY??!!

Wait, that was YOUR ADD.....!#%£$%#¥%!!!!!

[645]

I don't have LBA (I usually have my lenses from friends since they don't use their pentax lenses anymore), but the worst lenses I've ever use are Takumar F-Zoom.

[wildman]

My question would be why anyone would make an expensive and wonderful tool that is only designed to last five years and which is not cost-effective to repair?

That is a statement not a question. Putting a question mark on the end does not make it a question. It is a loaded question if not an outright tautology - when did you stop beating your wife? Come on try again.

My Canon P is over 50 years old and works as well now as when it was new.

The question is not of longevity but of function. Would a perfectly functioning model T meet my transportation needs as well as a modern car or not?
Do you regularly use the Canon now in preference to your other cameras or not? The fact that it still works is irrelevant.

It is obsolete in the same way that a Leica M3 (made at the same time) is outdated. It is a pleasure to hold and a pleasure to use, is not clumsy in any way, and satisfies the photographic task quite nicely.

"satisfies the [my] photographic task [needs] quite nicely". If so than you have answered your own question. Clearly if it satisfies your needs it is, by definition, not obsolete at least for you. It does not necessarily follow, however, that others would come to the same conclusion.

Different strokes for different folks.

[bdery]

Many of the A-series lenses, the 50/1.7 in particular, suffer from a weakness in a plastic part in the aperture ring mechanism.

That's interesting, but it relates to a lens line that's quite old. Newer lines don't appear to have this problem, I believe. In addition, if the problem is limited to the 50 f1,7, it's much more likely to be a design flaw than anything else. Deciding that all lens lines newer than the M are rubbish that won't last based on the impression that 50 f1,7 lenses are less reliable is quite a stretch.

[mrNewt]

I don't understand the negative feedback for manual lenses... I work with nothing but manual lenses and don't have any complains.
Manual lenses are very fast to use if you know what you are doing.
Also, remember, just because you can't work with a manual lens, it doesn't mean is bad and it should be avoided...

I doubt there is a lens that you should avoid... each can have a purpose and don't forget... best lens is the one you have with you.
In the end is a matter of how willing you are to learn a specific lens and to know when to use it.
Even the worst quality glass can still be useful in more creative images or for a beginner that just wants to learn and image quality is not an issue yet.

[bdery]

I don't understand the negative feedback for manual lenses... I work with nothing but manual lenses and don't have any complains.

I didn't get the vibe that manual lenses ought to be avoided by reading the thread. In any case, I agree they are fine, just like most lenses...