[dms]

The online photographer has fairly extensive discussion about the K-1, including reference to an article that looked at TC w/ APS-C lens on FF, and that resolution can be better this way than w/o TC on APS-C. It is following (BTW I have not read it yet---other than what was said in the online photographer).
Mixing and matching sensor format with lens coverage: Adapted Lens Talk Forum: Digital Photography Review

The article was by ProfHankD--I believe he is a PentaxForums member.

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Last edited by dms; 02-20-2016 at 10:26 PM.

[Barry Pearson]

The online photographer has fairly extensive discussion about the K-1, including reference to an article that looked at TC w/ APS-C lens on FF, and that resolution can be better this way than w/o TC on APS-C. It is following (BTW I have not read it yet---other than what was said in the online photographer).
Mixing and matching sensor format with lens coverage: Adapted Lens Talk Forum: Digital Photography Review

The article was by ProfHankD--I believe he is a PentaxForums member.

I have just downloaded and read the interesting and informative PDF paper by ProfHankD. (Link below). It didn't mention the Pentax TC, so doesn't help much with this particular debate.

The corresponding DPReview article (at the link above) did say: "You need a good FF teleconverter. For example, the teleconverter Pentax sells is APS-C only", but that may just have come from Ricoh/Pentax, not from any test. (I've responded on that DPReview thread, asking him where he got that information).

Mixing And Matching Sensor Format With Lens Coverage

[npc]

The x1,4 TC itself certainly is FF compatible, there is no shadow of doubt on this.

The question is if some people have the specs to understand how photography works.

They could have easily put something like "Only when used with FA/D-FA lenses" instead of "Crop Mode Only" if the only problem were some "tight" APS-C lenses.
Or maybe Ricoh engineers just do not understand how photography works.

[D1N0]

according to asahiman it works with the DFA 150-450 on FF:
Re: Pentax 1.4x TC Crop Mode Only???: Pentax SLR Talk Forum: Digital Photography Review

[biz-engineer]

We can't have it all.... it's already a huge task for Ricoh to release a FF camera with skinny resources compared to Canikon. In short, if you want less limitations (I write "less limitations" because there are always limits to what camera and lenses can do), go to Canikon.

[D1N0]

I think Pentax is just being conservative in what they deem full frame compatible because they do not want to get slammed in reviews. They'd rather have less FF compatible lenses than a lot of mediocre stuff. We'll have to stop down for sharp corners on al lot of lenses. In the film days you didn't enlarge each image to a 4 foot size and scrutinize corner performance.

according to asahiman it works with the DFA 150-450 on FF:
Re: Pentax 1.4x TC Crop Mode Only???: Pentax SLR Talk Forum: Digital Photography Review

Also my conclusion.

[D1N0]

According to to Ricoh representative in the interview it will vignette. I guess it is dependent on the lens used. Hopefully they will make a new one that provides a slightly larger image circle.

Youtu.be

Youtu.be

[Mikesul]

According to to Ricoh representative in the interview it will vignette. I guess it is dependent on the lens used. Hopefully they will make a new one that provides a slightly larger image circle.

No way to be sure until the camera arrives but I expect the vignetting to be minimal at most settings. That is what I found using it on the A7RII.

[Sandy Hancock]

There is a better (and potentially cheaper) alternative to using the HD DA 1.4x AF AW Rear Converter on the K-1.

...an APS-C body.
It's guaranteed to work on all K-mount lenses, and you don't lose a stop of light. Use the TC on that if you want even more reach.

[D1N0]

There is a better (and potentially cheaper) alternative to using the HD DA 1.4x AF AW Rear Converter on the K-1.

...an APS-C body.
It's guaranteed to work on all K-mount lenses, and you don't lose a stop of light. Use the TC on that if you want even more reach.

But that doesn't do FF

[Sandy Hancock]

But that doesn't do FF

What I'm suggesting is that if you have a full frame system, it might be more useful to pack a second (crop) body rather than a teleconverter.

So I did some testing with the TC and my DA-lenses, DA 10-17 and DA*16-50 on my old Pentax MZ-30. When putting the TC on the lenses the vingetting dissapeared on the 10-17 and on the 16-50 it was a little vingetting between 16-20 mm. It will be really interesting to se the results on the K-1.

[D1N0]

What I'm suggesting is that if you have a full frame system, it might be more useful to pack a second (crop) body rather than a teleconverter.

nah just get both, and everybody already has aps-c anyway.

[noelpolar]

nah just get both.

Sandy does not need any encouragement on such matters.