[SteveD]

The "DA" leads me to believe that this will require croppedmode only. Any information on using this?

[tduell]

I use the 1.4xTC with the 150-450mm on a K-1 in FF mode, and it does vignette, but not much.
Generally I can crop out the vignetting and still leave an image larger than I would have using crop mode.
Whilst I can live with this, what I would really like is a 1.7xTC designed for FF, and essentially the same as the 1.4x i.e.AW, work with all the latest lenses etc.

Cheers,
Terry

[Barry Pearson]

The "DA" leads me to believe that this will require croppedmode only. Any information on using this?

It appears to be lens-dependent. Some lenses are worse than others. I haven't done detailed tests, but in most cases I get far more image in FF mode than Crop mode.

[rawr]

For info, the Pentax lens accessories catalogue [PDF, 15 MB, in Japanese] shows the 1.4TC as an 'APS-C' accessory.

Which is not to say that it won't work fine on K-1 in FF mode. Performance of each lens + TC on FF will be an individual judgement call.

[LilithBaerchen]

Are there any photos available with the DA 60-250 and the TC in FF-Mode with the amount of vignetting visible? For me the vignetting of the 60-250 is perfectly acceptable, does the TC make it much more worse?

[phat_bog]

On K-1 :
tested with FA* 300mm 2.8 & 400mm, optically perfect but AF is tremendously slow, and hunts a lot.
also tested with sigma 500mm APO, it's worse than the 2 others.

but, works great with DFA WR 100mm.

Nevertheless, personally not suffcient to consider the investment for using on the K-1.
Didn't buy it after test.

[Barry Pearson]

Are there any photos available with the DA 60-250 and the TC in FF-Mode with the amount of vignetting visible? For me the vignetting of the 60-250 is perfectly acceptable, does the TC make it much more worse?

Worse!

My own quick test; the whole thread may be useful

[nomadkng]

On K-1 ... tested with sigma 500mm APO.....

I did my own testing, and was originally excited about options with my lenses.

The 1.4x TC was awesome with my Sigma 500 and K3. Then my K1 arrived and I stuck it (TC) on my Sigma 70mm macro. No vignetting. Was even more excited. I then put it on my 500 and it is just useless. You can see massive distortion and CA as the image bends into black corners. YIKES!

I have since handed over the TC to my GF who is still shooting with a K3. But not without a tear because it's a great TC. <sigh>

I am now in the course of testing the Tamron and Sigma TCs with the 500 to see if either provides acceptable results. On to plan B.

[LilithBaerchen]

Worse!

My own quick test; the whole thread may be useful

Thanks for the test. No TC for me then ^^

[rvannatta]

I use the 1.4xTC with the 150-450mm on a K-1 in FF mode, and it does vignette, but not much.
Generally I can crop out the vignetting and still leave an image larger than I would have using crop mode.
Whilst I can live with this, what I would really like is a 1.7xTC designed for FF, and essentially the same as the 1.4x i.e.AW, work with all the latest lenses etc.

Cheers,
Terry

I've certainly felt that the HD TC 1.4x was unacceptable with K-1 from my perspective. (it's great on the K-3)

I recently returned from Alaska on a photo trip among other things. My wife carried a K-3 with the F*300 4.5 + HD 1.4x TC.

I used the K-1 with a Pentax-A 400mm f/2.8 and as needed the Pentax 1.4x-L TC or the 2x-L converter. Mostly I used the 1.4x-L converter as I could manage that with
a monopod. Those old 'dash-L' converters protrude into the rear of the lenses so are only compatible with with the fairly exotic long lenses, but since my 600 f/4 was a bit large
for the airline carryon bag anyway, I lost nothing by using the manual focus TC's, but I certainly hope that a FF compatible TC on somewhere on the Pentax "to do" list.