[RonHendriks1966]

The TC does not reduce image quality on the subject, only over the whole frame. It may infact increase the lw/ph devoted tot eh subject of the photo by 37%. Pentax says the overall loss of quality is about 3% on the hD DA 1.4. The odds of you ever taking a picture where that loss of quality is noticeable is pretty small.

By itself, the statement a TC reduces image quality only refers to over the whole unreduced frame. It doesn't refer to the subject of the photo in my bird images. IN those the TC vastly increases IQ.

Not using a TC just spreads limited lw/ph over a much wider area. If you get 3000 lw/ph in a sensor without the TC, you get 2910 with the TC crammed into 1/3 less field of view. You can lose more resolution stopping down from ƒ5.6 to ƒ8 on some lenses and most of us do that without thinking.

If you have 2000 line pairs on your subject without the TC you could have as much as 2740 on your subject with it. That's a heck of bump.

The Blue Jay knows I'm right.

You are very right on this one. Maybe you can actually calculate the difference. The lens on a K-3ii is 9,5 % longer (690 versus 630 mm) so even getting closer to the subject (Assuming there is still room in the image). The K-1ii still has much more megapixels and thus more line pairs. So the K-1ii will win (Assuming they are of the same quality indivual pixels) but are closing in on each other.

[angerdan]

The only AF-enabled FF converter is the 1.7x Adapter - which is doing the focusing itself. Does it work with KAF4 lenses?

It works with KAF4 lenses, but the electronic lens aperture won't work. The 1.7x AF don't has SDM-contacts.
SMC Pentax-F 1.7x AF Adapter Reviews - Pentax K-mount Teleconverters and Adapters - Pentax Lens Reviews & Lens Database

[hitrate]

there are a few 3rd party makers Teleconverters that offer SDM contacts. all of them are made for FF since they were designed and produced in the "film era"... just sayin.
if they are designated with PZ(that stood for powerzoom - a function that also drew current from the same contacts that the SDM nowadays sucks from) - they should actually also work for KAF4 lenses.
but i wont bet my last cents on that(because at the moment of writing this, i cant become aware of the other pins, and if some(which may be important) may miss on such converters...

how do the young folks say nowadays? google's'yofriend.

[Kunzite]

It works with KAF4 lenses, but the electronic lens aperture won't work. The 1.7x AF don't has SDM-contacts.

Which means it doesn't work.
Losing aperture control, losing autofocus... it might be acceptable for some, but those are critical functions.

[angerdan]

Which means it doesn't work.
Losing aperture control, losing autofocus... it might be acceptable for some, but those are critical functions.

It means it does work with only the limitation of aperture control. If you're usally shoot wide open, it doesn't even matter.
Also no difference rearding autofocus to other lenses, since always the 1.7x TC does the AF.

[Kunzite]

Losing autofocus is referring to the other, A-series teleconverters.
No matter what you say, Ricoh Imaging is lacking modern, FF-compatible teleconverters.

[asahi man]

Manual and new automatic aperture, but no screwdrive,currently.

[jatrax]

but no screwdrive,currently

That would be disappointing but understandable.

It does make one wonder what lenses it would be used with however. Except for screwdrive legacy lenses there are not many long, fast lenses available.

[Chris Mak]

That would be disappointing but understandable.

It does make one wonder what lenses it would be used with however. Except for screwdrive legacy lenses there are not many long, fast lenses available.

Ideal lenses to use on a 1.4TC would be lenses like a 300/f2.8(4), 400/f4, 500/f4.


Chris

[asahi man]

Sorry, little mistake.
No more screwdrive in new Pro* lenses and new lenses mostly with the new electronically aperture.
Converters looks like fully compatible.
But we have to wait for more specifics.
But, it looks really good.
Lots of new developments

[Kunzite]

Lots of new developments, but when?

[angerdan]

That would be disappointing but understandable.
It does make one wonder what lenses it would be used with however. Except for screwdrive legacy lenses there are not many long, fast lenses available.

Not understandable. All legacy third party AF teleconverter did support screwdrive, some screwdrive & PZ/SDM.
35 legacy pentax AF screwdrive lenses with at least 100mm focal length against 6 current internal motor ones (17% means 83% of the lenses wouldn't be usable with AF).

[aurele]

Lots of new developments, but when?

Like many things in the Pentax world, things will come when they will come. Simple, right ?

Jokes aside, you can"t have everything design, build, sold, overnight.

[jatrax]

Sorry, little mistake. No more screwdrive in new Pro* lenses and new lenses mostly with the new electronically aperture. Converters looks like fully compatible. But we have to wait for more specifics.

Better news, it would be sad to not have AF on the lenses that would most likely be used with this TC: 300mm, 400mm and 600mm. Most of which are screw drive and unlikely to be introduced as new any time soon.
But news is news so thank you for posting this.

I wonder if Ricoh would take my DA 1.4x TC in exchange for a DFA one?

---------- Post added 05-17-18 at 03:03 PM ----------

Not understandable.

Understandable as clearly Ricoh is moving away from screwdrive and mechanical coupling. But not a good thing for existing users unless they also replace the legacy long glass. But that has been revised so let's not worry about it.

I can see no more new lenses with screwdrive, but the TC seems to me to require that for compatibility.

[Mistral75]

Like many things in the Pentax world, things will come when they will come. (...)

...or later.