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02-22-2020, 09:31 AM - 1 Like   #1
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Why haven't Pentax made more Plm lens ?

Yeah, just why, plm is fast and silent. It's a game changing for Pentax and can rival other brands. Why???


Last edited by redcat; 02-22-2020 at 11:04 AM.
02-22-2020, 09:42 AM - 1 Like   #2
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QuoteOriginally posted by redcat Quote
Yeah, just why, plm is fast and silent. It's a game changing for Pentax and can rival other brands. Why???
PLM does not have much torque, and therefore is not suitable for larger, heavier lenses, which is what Pentax has been releasing lately.

Basically, the same thing as Canon's STM.
02-22-2020, 09:42 AM   #3
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Probably mainly because they are focused on full frame lenses and lenses with faster apertures.

My understanding is that to make a PLM lens you need to have relatively small elements. You just can't use that drive system on a 70-200 f2.8 or even a DFA 28-105 f3.5-5.6. I do imagine that if they ever replace the 18-135 or even the 20-40 limited, maybe it would work there.
02-22-2020, 09:46 AM - 1 Like   #4
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almost all the Limited prime lens are small and light weight, they can just upgrade them to Plm, what an amazing opportunity to refresh lens line up !

02-22-2020, 09:52 AM - 2 Likes   #5
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QuoteOriginally posted by redcat Quote
almost all the Limited prime lens are small and light weight, they can just upgrade them to Plm, what an amazing opportunity to refresh lens line up !
Pentax already refreshed the DA Limited lineup a few years ago. Adding a PLM motor to already tiny lenses would require a significant amount of re-engineering. Pentax has meager resources and much work to do elsewhere in their catalogue.
02-22-2020, 10:45 AM   #6
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Yeah, I don't think that you could put the PLM motor in anything like the Limited bodies...those are mostly screw-drive, so no motor in the lens. Would require a full redo.

Some thing like the 18-135 or 16-85 with the PLM might be possible, but I'd imagine there's things that are higher on their priority list right now.
02-22-2020, 11:05 AM - 2 Likes   #7
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QuoteOriginally posted by SteveinSLC Quote
Yeah, I don't think that you could put the PLM motor in anything like the Limited bodies...those are mostly screw-drive, so no motor in the lens. Would require a full redo.

Some thing like the 18-135 or 16-85 with the PLM might be possible, but I'd imagine there's things that are higher on their priority list right now.
The 18-135 and 16-85 are among the fastest focusing lenses out there. The DC motors on them are awesome.

It's the DA* SDM lenses that need to be redone. After using the DA 55-300 PLM, it's painful using my DA*60-250.

But they need to be redone with ring motors, not PLM.

02-22-2020, 11:39 AM - 1 Like   #8
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Funny thing about the 16-50 and 50-135. I had to have mine converted to screwdrive right after I bought them (used). When they had working SDM motors you could read Moby Dick between half press and AF Lock. With screwdrive on my KP they are fast - enough. Surely faster than SDM. They’re slower on my K5lls.
02-22-2020, 11:58 AM   #9
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QuoteOriginally posted by SteveinSLC Quote
Yeah, I don't think that you could put the PLM motor in anything like the Limited bodies...those are mostly screw-drive, so no motor in the lens. Would require a full redo.

Some thing like the 18-135 or 16-85 with the PLM might be possible, but I'd imagine there's things that are higher on their priority list right now.
Probably the only current Pentax lens that I could see being updated to PLM would be the DA 17-70 which has its share of SDM autofocus issues. Mine is stuck with a dead SDM motor. I have both the DA 16-85 and the 55-300 PLM and both have the best autofocus performance of all of my lenses which include DA* 200 & 300 and DA limiteds. The 16-85 does not need any autofocus update. The DC motor is fast and reliable. I believe the same applies to the 18-135 as well.

Last edited by jddwoods; 02-22-2020 at 12:03 PM.
02-22-2020, 12:34 PM   #10
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QuoteOriginally posted by luftfluss Quote
Pentax already refreshed the DA Limited lineup a few years ago. Adding a PLM motor to already tiny lenses would require a significant amount of re-engineering. Pentax has meager resources and much work to do elsewhere in their catalogue.
They would also have to convert the lenses to "focus by wire", so the motor control focus even with manual focus.
Not something I would like to have on Limited lenses, as the distace scale and mechanical stops on focus ring would be removed.
02-22-2020, 12:42 PM   #11
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QuoteOriginally posted by Rondec Quote
I do imagine that if they ever replace the 18-135 or even the 20-40 limited, maybe it would work there.
No point to that, they are already pretty fast. My slowest focusing (beside the original DA 55-300 that my son now has) lens is the DA*300, which sees a little less usage since the PLM arrived. The image quality is better, but not when you miss the shot entirely.
02-22-2020, 04:35 PM   #12
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I think you could actually put a small motor, like the stepping motor Fuji uses, into a lens like the 35 2.8 limited. But I don't think Pentax has the resources for a retrofit like this.

In any event the DC motors they use are decent and the more recent SDM lenses have seemed fine as well. The problem is more a lack of budget to replace older screw drive lenses.
02-22-2020, 05:53 PM - 2 Likes   #13
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QuoteOriginally posted by Fogel70 Quote
They would also have to convert the lenses to "focus by wire", so the motor control focus even with manual focus.
Not something I would like to have on Limited lenses, as the distance scale and mechanical stops on focus ring would be removed.
Focus by wire is one of the main reasons why I still don't want to go mirrorless yet. Focusing by wire just doesn't suit me at the state it's in right now. Maybe someday when every camera body allows the customisation of focus direction, rotation distance, and focus distance limits, and once the latency is 100% unnoticeable, I'll reconsider, but until then classic helicoid focusing is the only method that appeals to me. Plus, one of the main reasons I still prefer OVFs is because I can see through them without powering up the camera, but if I use a focus by wire lens on a DSLR I wouldn't be able to focus and that advantage would be lost for me.


Again, once mirrorless tech gets better I can reconsider, but in the meantime I'm more than happy with having both AF motors and image stabilisation systems consolidated into the camera body, rather than inserted into every single lens. It just makes more sense to me to avoid redundancies and over-engineering, because having more electronics in the lenses just means there's more components susceptible to failure.
02-26-2020, 05:30 PM   #14
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After the SDM mess, perhaps Ricoh wants to make sure PLM actually holds up in the field before using it extensively.

Thanks,
barondla
02-26-2020, 07:34 PM - 1 Like   #15
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I believe one main reason the Limiteds, with the exception of the 20-40mm zoom lens, remaining as screw-driven is the technology having less to it therefore develop problems- more long term reliability. The camera supplies the motor, so you get a new motor when replacing the camera. They do have a point there

I agree, the screw-driven system with the KP is noticeably better. So with this system, a new camera body can potentially include a lens upgrade as well.
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