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07-27-2017, 04:39 PM   #16
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QuoteOriginally posted by MacLoz Quote
Even more, it seems that Pentax TC1,4 is not admitted by the K-70... KAF4 looks like a rather tricky subject.
I do not understand this comment, or perhaps you have miss-read all of the other comments. The K-70 has no problem at all with the 1.4x TC. However, using it with slow consumer zooms like the 70-300 or the 55-300 is going to be a problem. For example I have used the Pentax HD 1.4x TC on my DA*60-250 with very good success. Note that this lens is constant f/4 so the TC makes it f/5.6 and auto-focus works fine.

Mostly the 1.4x TC lives on my DA 100mm f/2.8 macro giving me a 140mm f/4 macro lens.

07-27-2017, 09:15 PM   #17
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QuoteOriginally posted by jatrax Quote
I do not understand this comment, or perhaps you have miss-read all of the other comments. The K-70 has no problem at all with the 1.4x TC. However, using it with slow consumer zooms like the 70-300 or the 55-300 is going to be a problem. For example I have used the Pentax HD 1.4x TC on my DA*60-250 with very good success. Note that this lens is constant f/4 so the TC makes it f/5.6 and auto-focus works fine.

Mostly the 1.4x TC lives on my DA 100mm f/2.8 macro giving me a 140mm f/4 macro lens.
Thanks, jatrax , for your comment. I should have mentioned the following link:

HD PENTAX-DA AF REAR CONVERTER 1.4X AW / Converter / AF Lens Adapter / K-mount Lenses / Lenses / Products | RICOH IMAGING

That link is the one available from Ricoh for 1,4X TC. The document is unclear or not updated, because it does not make any reference to K-70/KP. Please, see footnote about "AF support confirmed models". At the bottom it can be read 2017.
I understand that 55-300 PLM f6.3 works with limited number of bodies, assuming their firmwares were updated. Not only that: the f/6.3 makes a difficult focusing in low light conditions, so, it is worsened with 1,4X TC and not recommended to use with it
The above document refers on compatibility with lenses up to April 2015, so it does not mention 55-300 PLM, but after reading the limited performance of DA 55-300mmF4-5.8ED W in Phase-matching, we can assume that performance of 55-300 F6.3 PLM is going to be even worse.
07-28-2017, 08:53 AM   #18
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QuoteOriginally posted by MacLoz Quote
That link is the one available from Ricoh for 1,4X TC. The document is unclear or not updated,
Not updated. Note that the last camera mentioned is the K-3. There is no compatibility issue with the 1.4x TC with any newer camera. The problem is as you noted: using the TC with a slow lens is unlikely to work well, though it might work in good light.
07-28-2017, 01:47 PM - 1 Like   #19
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QuoteOriginally posted by MacLoz Quote
I am considering to purchase the new HD Pentax-DA 55-300mm F4.5-6.3 ED PLM WR RE as a fast focusing lens for bees and flies macro photography, using the K-70 body.
I wonder if the HD Pentax-DA 1.4X AW AF Rear Converter is compatible -and effective- with that combination of K-70 and 55-300 PLM lens, or which could be the main limitations for that combination of body and lens.
Anticipated thanks !
I have both the HD DA 55-300 PLM and the DA 1.4 Teleconverter. I like and use both but not together. I found that the TC causes you to lose an extra F stop and by increasing the focal length of the lens you limit your ability to do what is needed, and that is to use a higher shutter speed to offset the increase in camera shake that will occur. The TC did not affect the PLM autofocus. It was just as fast with the TC as it is without but I just did not like the results as I needed to bump up the ISO and shutter speed more than I would like. I found the 55-300 PLM was best on its own and is sharp enough for cropping. Also I zoom up to slightly less than 300 mm where it stays at f5.6 ,rather than 300 mm f6.3.
I have found the TC works best with f2.8 primes like DFA 100 Macro WR, DA 70 Limited (f2.4), and DA*200. The TC is a really a good pairing with the DFA 100 macro

07-29-2017, 03:01 AM   #20
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QuoteOriginally posted by jddwoods Quote
I have both the HD DA 55-300 PLM and the DA 1.4 Teleconverter. I like and use both but not together. I found that the TC causes you to lose an extra F stop and by increasing the focal length of the lens you limit your ability to do what is needed, and that is to use a higher shutter speed to offset the increase in camera shake that will occur. The TC did not affect the PLM autofocus. It was just as fast with the TC as it is without but I just did not like the results as I needed to bump up the ISO and shutter speed more than I would like. I found the 55-300 PLM was best on its own and is sharp enough for cropping. Also I zoom up to slightly less than 300 mm where it stays at f5.6 ,rather than 300 mm f6.3.
I have found the TC works best with f2.8 primes like DFA 100 Macro WR, DA 70 Limited (f2.4), and DA*200. The TC is a really a good pairing with the DFA 100 macro
Thanks, jddwoods
Your entry/reply is the precise one I expected: both good, but not together… other details of your experiences are also very valuable to understand the limitations or capabilities of 55-300 PLM.
I do, too, have the TC as a permanent companion of 100/f2.8 WR in my K-5.
I will wait for a good occasion to purchase the pair K-70 + 55-300PLM and, perhaps, in the meantime, new lenses could appear to take profit of the advantages of the Hybrid AF
07-31-2017, 07:15 PM   #21
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I guess there is a market for everything, and what "works" as opposed to what gets you good macro results is a pretty vast expanse.

Serious, consistent macro on the Pentax system requires manual focusing. An older Pentax MF macro will be an economical, quality option that will far outperform any of the consumer lenses and TC mentioned in this thread. Heck, even B+W photo diopters on a Pentax prime lens will outperform any of the consumer zoom + TC combos mentioned. And anyone who even tries to mount a TC on a 4.5-6.3 zoom (PLM) for macro work really must believe that monkeys type the works of Shakespeare - as that is just how likely the subject will achieve sharp focus - AF or MF.

Even on the most capable AF systems, committed macro users opt for MF. I guess someone needs to post a 20-minute video explaining how to manual focus a lens on Pentax.
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