[ZombieArmy]

Pentax only, no off brands. And I don't mean JUST sharpness by the way as that wouldn't be fair to something like the soft lenses. I mean a lens you put on your camera and just went "eugh",

My vote would be for the Pentax M200 on digital. When I got mine I was SO convinced it was defective that I got another... and it was identical

CA is bad, sharpness is worse, the bokeh is bad, rendering is uninspiring and the focus is INSANELY hard to nail for some reason even with its long throw and mere 200mm focal length (probably because it's f/4, and not sharp to boot).
This lens is in fact so unsharp I at one point had compared it to my Tak Bayonet 135 f2.5 and found that at f4 the Tak bayonet was sharper... when cropped to the same fov. Yikes!

Pros of this lens are obviously the size and build quality. It makes a wonderful paperweight or doorstop.

What is your worst?

[FozzFoster]

I was never impressed with the Pentax M 50mm f/2 or the Pentax A 50mm f/2.
Maybe it's cause I've seen so many of 'em but to me they are just 'eugh'.

Any of the FA J lenses were off too.

[AfterPentax Mark II]

Pentax only, no off brands. And I don't mean JUST sharpness by the way as that wouldn't be fair to something like the soft lenses. I mean a lens you put on your camera and just went "eugh",

My vote would be for the Pentax M200 on digital. When I got mine I was SO convinced it was defective that I got another... and it was identical

CA is bad, sharpness is worse, the bokeh is bad, rendering is uninspiring and the focus is INSANELY hard to nail for some reason even with its long throw and mere 200mm focal length (probably because it's f/4, and not sharp to boot).
This lens is in fact so unsharp I at one point had compared it to my Tak Bayonet 135 f2.5 and found that at f4 the Tak bayonet was sharper... when cropped to the same fov. Yikes!

Pros of this lens are obviously the size and build quality. It makes a wonderful paperweight or doorstop.

What is your worst?

Well, you tried it on a digital, but to be sure that it is the worst lens, you should have tried it on a film era Pentax, because it was designed for using it with a film era body. And on a film era camera it is a terrific lens. So is the Takumar you mentioned. The worst lens in my opinion is the 40mm Ltd. I still regret buying (and still having) it.

[shyrsio]

From my collection it has to be the SMC Pentax-F 28-80mm F3.5-4.5. I shouldn't complain since I got it for free but man that thing is awful! the built seem ok, the weight is there, the design look intriguing, but none of this is justified when you put it on the camera. the results are just uninspiring. The loud noise, and that damn front spinning element???

[MossyRocks]

And here I've always like the 200/4 lenses. They are great astro lenses (run at f/5.6) and I still haven't given up on my S-M-C 200/4 Takumar even with digital. I've don't use it much as I either want wider and often use the D FA 100/2.8 WR Macro, or one of my 135mm lenses or I want more reach and go for my 300/4.

Of all the Pentax lenses I've had the one I've liked the least is the SMC Pentax-FA 28-80mm F3.5-5.6 and the only reason I bought it was I needed an autofocus zoom lens right now (well within 2 days) so I had to go local and that was the only one available. The kid dropped my camera and the DA 18-55 kit lens broke the fall and in 2 days was the cubscout scout campout so I needed an AF zoom lens.

I now have a better beater but I haven't used it in ages personally but let scouts use it for photography merit badge.

[Kwong]

Pentax only, no off brands. And I don't mean JUST sharpness by the way as that wouldn't be fair to something like the soft lenses. I mean a lens you put on your camera and just went "eugh",

My vote would be for the Pentax M200 on digital. When I got mine I was SO convinced it was defective that I got another... and it was identical

CA is bad, sharpness is worse, the bokeh is bad, rendering is uninspiring and the focus is INSANELY hard to nail for some reason even with its long throw and mere 200mm focal length (probably because it's f/4, and not sharp to boot).
This lens is in fact so unsharp I at one point had compared it to my Tak Bayonet 135 f2.5 and found that at f4 the Tak bayonet was sharper... when cropped to the same fov. Yikes!

Pros of this lens are obviously the size and build quality. It makes a wonderful paperweight or doorstop.

What is your worst?

For me it is the da 35 2.4. For some reason never got comfortable with it and pictures were flat and color rendition was not to my liking. Maybe got a bad copy as i know it is very well liked by other users.

[kiwi_jono]

Interesting, I don't have a Pentax lens that is completely horrible (unlike some off brand lenses I have had). But then I don't have a 50 f2 or a FA 28-80.
I do have a FAJ 18-35 which is pretty craptastic (build wise and IQ isn't that wonderful either) but then I still use it occasionally (as its very light weight and relatively small) - perhaps until the new DFA 21 limited comes out anyway.

I don't how the M200 (which I don't have) compares to the Takumar 200 f4 (which I have) but I like my Takumar (sure there are sharper modern lenses etc but I like its rendering and its nice to use).

[Bosse]

M 200/4 on digital the worst Pentax lens? My experience with them (I have two) is rather the opposite. Sharp, good colours and contrast. I tested it on my K 1 against the 150-450 on 200, and they came out quite even from 5,6 and up. Good and bad samples, I guess.
I have no specific candidate to "Worst Pentax lens", but I agree with FozzFoster, the FA J series could end up there.

[FozzFoster]

The worst lens in my opinion is the 40mm Ltd. I still regret buying (and still having) it.

oof that one hits me in the feelers haha I just bought the 40 Ltd and really enjoy it! Do you have the smc or the HD version?
My HD version is sharp and characterful...

[photoptimist]

The silver FA 100-300 f/4.7-5.8. Cheap-o plastic mount, loosey-goosey barrel, sloppy focus, wobbly zoom, & everything. Images softer than meringue. Oh, but at least it provides pretty purple fringe coloration if you like that sort of thing.

Maybe I got a defective unit. It did come from a garage sale. Or maybe the cheap build makes it defective by design. LOL!

[Kerrowdown]

What is the worst Pentax lens ever made?

The one you hanker over but can't find or afford.

[FozzFoster]

but I agree with FozzFoster, the FA J series could end up there.

we'd joke that the 'J' stands for 'junk'...

[RICHARD L.]

My worst lens in K mount was the infamous FA J 75-300 mm. It had good contrast but it died above 135 mm, no sharpness at all (bottom of a Coke bottle, you know). Once I had a DA 18-55 mm II that was terribly decentered. The left side of the images was quite sharp but the right side was totally fuzzy. Not being patient, I replaced it after 2 weeks of agonizing frustration with a DA 16-45 mm f/4. P645 lenses were all quite good except the A 200 mm f/4, a dismal failure of a lens, no sharpness and no contrast. All P67 lenses were terrific performers except the 90 mm f/2.8 that never exposed correctly on my 67 film cameras (constant overexposure on slide films and no contrast anyway). I replaced it with a wonderful P67 105 mm f/2.4, a darling of a lens.

Regards

[KiloHotelphoto]

The FA 80-320 F4.5-5.6 I didn't have high expectations for this lens because it was only $100 but it wasn't good at anything on the K1.

[boriscleto]

I was never impressed with the Pentax M 50mm f/2 or the Pentax A 50mm f/2.
Maybe it's cause I've seen so many of 'em but to me they are just 'eugh'.

Any of the FA J lenses were off too.

The A 50/2 on my K1000 was the combo I used right through my high school photo classes. It took the photo I won a gold key for in the Scholastic Art Awards...almost 30 years ago, really feeling old