55-300 PLM

The very generous double discount offer from SRS this weekend is tempting me to purchase the PLM version of the 55-300mm lens. I already have the original green ring version and so I'm asking if there is anyone here who has had experience of both and who is willing to share their thoughts to help me decide if it's worth taking advantage the SRS offer. I am aware that its auto focus capabilities are far superior to it's predecessor, however, the screw drive AF is reliable if somewhat slow. Will the pulse motor prove to be more robust than the 'self destruct motor' it has replaced?

Thoughts anyone?

Thanks in advance.

You don't see much interest in this lens from Pentaxians probably because it's FAST AND QUIET so seen as two less things to moan about which would be very sad.

I almost bought it myself this morning, but SRS's site wouldn't work so I left it. Probably a good thing because I only have a K-1 to use it on. I don't think it will work with my K-5.



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I've owned three variants, smc da, hd & plm. Although I do believe there's a marginal optical improvement as they progressed, it's not massive. The focus on the plm is a vast improvement and virtually silent, although occasionally it still does hunt, it's far less annoying. The girth on the plm is thicker which might be a consideration, but then it also retracts, so a bit of give and take. Build quality is great, and nothing to worry about.

If you currently pre focus using quickshift and then snap autofocus using your current 55-300 as a technique then I don't think you'll notice a massive difference in focusing speed. However if you just want to point and shoot is a major improvement. I can't speak of the stability of the new plm motor, other than I haven't had any issues with it.

Having replaced the old DA version with a PLM my impression is that it is fast & quiet and works pretty well on any body that has the right f/w (inc my K-30 now running the hacked K-50 f/w!), and it seems pretty sharp.

The only problems I've seen so far in limited usage of the PLM is that, on the K-3 or K-3 II at an airshow, when it lost focus lock it just went "haywire" and focused "anywhere" - whereas the Sigma 100-300 F4 on "the other body at the same time" fairly quickly re-established focus. Won't be an issue in most situations but, so far, I wouldn't recommend the PLM for situations where the subject is moving very quickly towards or away from the camera!

PS: and it won't work properly on any K-5 because Pentax have never released suitable updated f/w.

I had the screw drive lens back on my K5. I had the 300mm star F4 and tele adapter and now a K3II and the 55 - 300mm PLM.

The first used to hunt noisily, might have been the camera.

The star lens was great BUT focused slowly and too heavy/bulky for my travels.The tele adapter made focus too critical, cropping achieved much the same image.

The PLM lens failed several times due to the retraction button failing to lock at 55mm. My current copy I live with (Amazon replaced twice but only offered the £249 back this time) but would have preferred no retraction mechanism.

The PLM lens does focus quickly and quietly in good light BUT is not great in flat overcast light and does not cope well in the third plane near to far with movement. This i put down to the Pentax AF on my K3II. I gather some attempts have been made to improve this in current models. I'm sceptical.

My gallery on here has pics from all three lenses over time with some success of dogs, whales, dolphins, raptors etc. I doubt I have the keep rate of say a Nikon D500 but that's outside my buying budget!

Thanks for that Algi.
I believe the site may have been down because it was swamped by closet canikon and sony users who tempted by SRS's excellent deals and Pentax's superb equipment could no longer resist coming out!

Out of curiosity, did you try to purchase later?

Grateful thanks for your input on this, that's just the sort of real-world information I was looking for. And it's in the real world that I have to decide if the upgrade (as good as the price may be) is worth the investment. From the photographic viewpoint, would I really notice a difference in a side-by-side comparison of photo's taken with each of the three models - and if I'm honest - probably not. So it comes down to end user experience and whether I can get by without faster auto focus - and the honest answer to that is probably yes!

Thanks again.

Following on from, my earlier comments about the PLM v earlier versions:
Ref Bill's comment about K-3 II f/w, I swapped the the PLM and the 100-300 F4 Sigma between my K3-II and K-3 quite a few times at that airshow, and the PLM "issue" "followed the lens" and showed up on each body, whereas the Sigma did'nt show anywhere near the same problem.

By comparison, the now-departed DA version would also hunt a lot, but because it was a much slower focusing lens then it probably didn't change the focus distance as far as the PLM version does

So I'm inclined to think that it is a specific PLM issue related to the speed at which it reacts to the command signals from the camera body - and Bill's comment/experience may have confirmed that. Nevertheless I do prefer it to the older lens.

BTW: as far as reliability is concerned, I also read on the US forum that the PLM can be more sensitive to impacts than the older versions (which were mechanically pretty "bullet-proof") because some plastic parts in the internal focusing mechanism can break - possibly making the lens unrepairable!

Thanks for that observation about losing focus. I have used my DA 55-300 at airshows on several occasions but it was very slow to focus if at all on the K5 far better on the K3 but like yourself I'm very fortunate to own a splendid Sigma 100-300 f4, though it's not really conducive as a walk around lens.

Thank you too Bill for your valuable observations. Judging by what research I have done I think the quiet and speed of focus with the PLM is truly excellent though by it's nature possibly more delicate. It's clearly a trade-off of superior technology against older, slower but probably more robust and reliable mechanics.

I was on the point of pulling the trigger to buy this weekend, but having mulled over the thoughts and the experiences of people here, for which by-the-way I am most grateful, I think I shall save my money, stay with what I have and reappraise when the much anticipated Pentax 70-210 f4 is finally released.

Thanks again everyone and enjoy the summer.

Ref Defragged's last post, I agree about the weight of the Sigma as a "walkaround" lens - not ideal - which is why I don't use it in that role since my "walkaround" body is the K-30 (which now thinks it's a K-50 so that I can use the PLM!), and so that's where the PLM comes in for "days out" and holidays = "horses for courses"!

OTOH, I took the PLM to an airshow to find out just how well the PLM would actually work in that environment - the conclusion being as I outlined above.

I think the main problem with focusing is that this one (PLM) is really finicky about the accuracy of where you are pointing it. I used to swear considerably at it until I realized this. If you are trying to catch a moving object the problem is multiplied. It didn't help that my copy was back focusing as well and needed +7 to set it right. It is now the lens that lives on the camera.

It's interesting reading the comments above. I bought a 55-300mm PLM very soon after they were launched. In use I like that it 'parks' to a size not hugely greater than a standard kit zoom and I have had no problems with doing that or using the lock button. My initial observation was that the zoom ring was slightly stiff to turn and that was an issue raised by others in various reviews. I do like the reassurance of WR.

I have to admit I have not used it for photographing aerial displays so cannot comment on its performance in that context. For general photography I have found it very satisfactory and, like davidwozhere, I use it as one of the two lenses that I carry with me the most, the other being the Pentax 20-40. Although not of the same optical quality the PLM has rather replaced the Pentax 50-135 in my walkabout bag and I have found myself even using the PLM where I might previously have taken my Pentax 150-450 - simply for convenience. Auto-focusing is fast and quiet and, on my K3, is only very occasionally caught out in particular conditions.

So overall I have been pretty pleased with the 55-300 PLM. Despite a slightly compromised but quite acceptable optical performance its compact size, comfortable weight and zoom range have made it a very worthy addition to the bag. Unfortunately, like my other DA lenses it will become a casualty of the planned move to a K1ii. I will miss it.