[HanSch]

The focal length of the lens, needed for correct SR, is for most lenses automatically set. If I use an older (e.g. MF) Pentax lens, the camera requests to manually set the focal length. So far everything is fine.
I often use my Sigma EX DG 4/100-300mm with a 1.4 or 2x TC. The TC is not recognized by the camera, if I believe the Exif: the Exif file always shows the focal length as automatically set, without the TC. This means that the SR is not applied correctly.

Is there any way to overrule the automatically set focal length? I can't find anything in the menu or in the camera manual. Same problem with the K5, by the way.

[UncleVanya]

The focal length of the lens, needed for correct SR, is for most lenses automatically set. If I use an older (e.g. MF) Pentax lens, the camera requests to manually set the focal length. So far everything is fine.
I often use my Sigma EX DG 4/100-300mm with a 1.4 or 2x TC. The TC is not recognized by the camera, if I believe the Exif: the Exif file always shows the focal length as automatically set, without the TC. This means that the SR is not applied correctly.

Is there any way to overrule the automatically set focal length? I can't find anything in the menu or in the camera manual. Same problem with the K5, by the way.

The Pentax HD DA converter should correctly change the focal length communicated to the camera. Most third party converters will not.

[pschlute]

Is there any way to overrule the automatically set focal length?

So your FL with the TC is only being recorded as between 100-300 ?

If you go into the SR FL menu can you change it ?

[MossyRocks]

I don't know if it is possible to overrule the automatically read focal length. I don't think it is but I could be wrong. The lenses that I can use my handful of converters with are all A or older so I have to enter the focal length manually anyway.

[snappyhoffy]

So your FL with the TC is only being recorded as between 100-300 ?

If you go into the SR FL menu can you change it ?

Doesnt seem possible in the Menu you can either have - Auto, Panning or Off

[kypfer]

Is there any way to overrule the automatically set focal length? I can't find anything in the menu or in the camera manual. Same problem with the K5, by the way.

There's nothing that can be done about it … the camera either gets the information from the lens and uses that or it does everything manually.
If your converter doesn't "intercept and translate" the signal from the lens, or at least notify the camera of it's presence, as the Pentax item does, then the camera is simply unaware of it's existence.
So, although the final Shake Reduction may be less than optimum, it should still give at least a stop or so of correction, so just take that little bit more care when using the converter.

FWIW, in my experience with my lenses, the 26M-pixel image from the K-3iii will often give a cropped image of similar quality to that obtained through a converter with less cropping. This, of course, may simply reflect the possible lower quality of my Kenko converters or the lower resolution of my non-OEM lenses
The K-5 and cameras of similar or less resolution can seem to benefit from the use of a converter to a greater degree … again, in my experience.

[Kozlok]

If you shorted out the pins on the mount with a piece of foil, the camera will think it's an M-Lens and let you set the FL. I'm sure it's one specific pin, but don't know which one. You could experiment.

[vonBaloney]

Yes, save for tricks trying to block off pins (not worth it) there is nothing you can do about it (you could possibly edit the EXIF data later for record-keeping, but that won't help you at shooting time) -- advantage of the Pentax HD converter (or using manual focus lenses). However, this doesn't mean that SR won't work at all -- it will just be less effective but still no reason to turn it off.

[erikro]

Have you updated the firmware in the camera?

[MossyRocks]

FWIW, in my experience with my lenses, the 26M-pixel image from the K-3iii will often give a cropped image of similar quality to that obtained through a converter with less cropping. This, of course, may simply reflect the possible lower quality of my Kenko converters or the lower resolution of my non-OEM lenses

I've only done one shot with my K-3iii and a TC in the mix but there the TC did provide a benefit. However there I was using the SMC A * 400/2.8 and A 2X-L converter so an exceptional lens with a great 2x converter so probably not a good example for how a run of the mill lens and converter would perform on a modern camera.

[hcc]

+1 for the Pentax HD-TC1.4x. This is a great converter, which is recognised by the camera. I have used it with several prime lenses, and the IQ is excellent. It is well worth the investment IMHO.
Nowadays, I always take my Pentax HD-DA TC1.4x with me when I shoot with a prime because it give me another focal length option.
My 5 cents hoping that it may help.

[kkoether]

+1 for the Pentax HD-TC1.4x. This is a great converter, which is recognised by the camera. I have used it with several prime lenses, and the IQ is excellent. It is well worth the investment IMHO.
Nowadays, I always take my Pentax HD-DA TC1.4x with me when I shoot with a prime because it give me another focal length option.
My 5 cents hoping that it may help.

+2 for the Pentax HD-TC1.4x. It lives on my K-3 during racing season along with my DA* 60-250mm. It's a GREAT combo.

[HanSch]

Thanks everyone for the replies.

It seems, that the only solution with the 2 converters that I own is to fool the camera by blocking the contact. Maybe I'll give that a try.

[MossyRocks]

+1 for the Pentax HD-TC1.4x. This is a great converter, which is recognised by the camera. I have used it with several prime lenses, and the IQ is excellent. It is well worth the investment IMHO.

+2 for the Pentax HD-TC1.4x. It lives on my K-3 during racing season along with my DA* 60-250mm. It's a GREAT combo.

Now I'm kind of curious how it stacks up against the 1.4X-L I have. I kind of want to see about getting on as a loaner for a bit and seeing how they compare with moon shots. It has been my understanding that the 1.4x converters are better IQ wise than the 2x ones.

[kypfer]

Now I'm kind of curious … It has been my understanding that the 1.4x converters are better IQ wise than the 2x ones.

Or it could be that the 2x amplifies the lens' failings that much more … assuming both items are of similar quality