[Theov39]

Thanks to the great advice I received on this forum I recently bought a Pentax DA*300 lens. I love this lens but for my intended use (wildlife photography) I need even a bit more reach.

Has anyone used the Kenko Pz-AF 1.5X Teleplus SHQ teleconverter with this specific lens?

1. If so, is it a good combination?

2. Does it work with SDM? I heard that the one with "Pz" does but not sure.

I did do a forum and general search but most posts relate to using it with other lenses besides the DA*300.

Of course the best would be the Pentax HD DA 1.4x teleconverter but that is out of my price range, even at second hand prices.

Thanks in advance!

Attached Images

   

[surfar]

Tamron-F 1.4X Pz-AF MC4 Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database

---------- Post added 12-05-16 at 06:04 PM ----------

Kenko (?Promaster et al..) AF/Pz-AF 1.4x/1.5x Teleplus.... Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database


Its believed these are similar/same ???


I own one labelled Vivitar....very good....I don't have a 300mm prime but use it mainly on 55-300mm DA and Sigma 135-400mm..These are good TCs...IQ is reasonably good, shooting in good light suits them.

It works just fine with SDM. This is about 3KM away. Full image (cropped for composition) and a detail cropped from it. My normal post processing.

[Theov39]

It works just fine with SDM. This is about 3KM away. Full image (cropped for composition) and a detail cropped from it. My normal post processing.

Thanks Brooke. Great shot.

[pathdoc]

Nice.

I wonder how easy these are to reversibly deglass. I could do with an extension tube that isn't quite so long as the P-KA/R 2X I have, and which will pass MTF and focal length data. A 2X converter means you have to get up the left nostril of anything you want to take a macro shot of with a 28mm lens, and that can be a pain.

[Des]

Theo, yes you need a TC with the pz contacts to drive the SDM autofocus.

There is more than one version of the Kenko 1.5x pz. Not that the AF will be different, but the magnification is. The one pictured in your post looks the same as mine. Its real magnification is about 1.4x. (It is believed to be identical to the Tamron 1.4x pz.) It works well with my FA*300 f4.5 (effectively 420mm f6.3) in reasonable light; should be even better with the DA*300 because it's one-third of a stop faster (ie effectively 420mm f5.6). The other version (which is said to be identical to a Promaster Spectrum 1.7x) has a slightly smaller rear element (27mm v 25mm) which sticks out a little further; that version actually magnifies by a little more than 1.5x. Read more here: https://www.dpreview.com/forums/thread/3537477

I find the TC hardly affects IQ at all. A comparison between a Tamron 1.4 pz teleconverter and the DA teleconverter in the PF review showed no practical difference in IQ: https://www.pentaxforums.com/reviews/pentax-da-14x-aw-af-rear-converter/telec...omparison.html (Corner performance was a little better with the DA, but that doesn't usually matter for wildlife shots.) The main limitations of third party models compared to the DA TC is that they are not WR and they don't pass focal length information to the camera (so the EXIF shows the wrong FL and SR is affected).

The $64 question with teleconverters is: at what point do you get better results with the TC than you would get by using the lens without TC and cropping?

That will depend on the sensor of course. With a 24mp sensor and a sharp lens, there is a lot of scope for cropping - especially if your images are mainly for viewing on screen rather than for large-size printing.

My Kenko was about $200 second hand. If you haven't already upgraded the body from K-50 to K-70 or K-3, personally I'd say there was more value in putting the $200 or so towards that first. If you get a K-3 you will also get a big improvement in AF performance with every lens.

Edit: I note that PF member Klaus, who contributed to the DP Review linked above, reports that the version of the Kenko 1.5x with the 25mm diameter rear element (that is, apparently the same as the Promaster Spectrum 1.7x) does not work properly with SDM lenses. As for the other version, see Audiobomber's post below.

[Theov39]

Theo, yes you need a TC with the pz contacts to drive the SDM autofocus.

There is more than one version of the Kenko 1.5x pz. Not that the AF will be different, but the magnification is. The one pictured in your post looks the same as mine. Its real magnification is about 1.4x. (It is believed to be identical to the Tamron 1.4x pz.) It works beautifully with my FA*300 f4.5 (effectively 420mm f6.3); should be even better with the DA*300 because it's one-third of a stop faster (ie effectively 420mm f5.6). The other version (which is said to be identical to a Promaster Spectrum 1.7x) has a slightly smaller rear element (27mm v 25mm) which sticks out a little further; that version actually magnifies by a little more than 1.5x. Read more here: Teleconverter magnification comparison. (5 imgs): Pentax SLR Talk Forum: Digital Photography Review

I find the TC hardly affects IQ at all. The main limitations of third party models compared to the DA TC is that they are not WR and they don't pass focal length information to the camera (so the EXIF shows the wrong FL and SR is affected).

Thanks Des! That is a very helpful and encouraging answer. I went ahead and ordered a second hand one I found online from Japan. There was a local listing for the second hand Pentax DA 1.4 TC but it ending up selling for $405!

Although third-party TCs don't provide correct EXIF info (and i guess also in the viewfinder) will the exposure still be correct? (ie the camera makes the correct exposure eventhough it SHOWS the wrong FL and aperture info).

[Des]

There was a local listing for the second hand Pentax DA 1.4 TC but it ending up selling for $405!

Ouch.

Although third-party TCs don't provide correct EXIF info (and i guess also in the viewfinder) will the exposure still be correct? (ie the camera makes the correct exposure eventhough it SHOWS the wrong FL and aperture info).

Yes, there will be no effect on exposure.

One curious thing about aperture is that you can still set an aperture in the camera up to the widest aperture for the lens. For example, with my Kenko TC and FA*300 f4.5, in the camera I can set an aperture of f4.5, even though theoretically the widest aperture with the TC should be f6.3. I just tested it and got a correctly exposed image with no vignetting, showing as f4.5 in the EXIF. I don't know how that works (presumably the aperture was really f6.3 but the EXIF is wrong?). Maybe someone can enlighten us.

[Theov39]

Ouch.

Yes, there will be no effect on exposure.

One curious thing about aperture is that you can still set an aperture in the camera up to the widest aperture for the lens. For example, with my Kenko TC and FA*300 f4.5, in the camera I can set an aperture of f4.5, even though theoretically the widest aperture with the TC should be f6.3. I just tested it and got a correctly exposed image with no vignetting, showing as f4.5 in the EXIF. I don't know how that works (presumably the aperture was really f6.3 but the EXIF is wrong?). Maybe someone can enlighten us.

Thanks Des. That is very helpful. Sounds like I did the right thing ordered the Kenko TC. Also, it was only AU$90 including postage.

[audiobomber]

I own the Kenko Pz-AF 1.5X Teleplus SHQ, the good one, with 1.4X magnification. I agree with others above that the IQ is really good, very nearly as good as the Pentax HD 1.4X RC (which I also own).

AF however, is massively different. The Kenko works perfectly with compatible screw drive lenses, but is virtually useless with SDM or DC lenses. Focus is painfully slow and aggravatingly approximate with the DA*300, DA 18-135 (both of which I own) and DA*50-135mm (which I tried out in a store). You will never be able to use the DA*300 with Kenko PZ for action, other than in MF mode. The K-3/DA*300 auto-focus takes a step backward with the HD 1.4X, but is still useable, even for BIF.

[Theov39]

I own the Kenko Pz-AF 1.5X Teleplus SHQ, the good one, with 1.4X magnification. I agree with others above that the IQ is really good, very nearly as good as the Pentax HD 1.4X RC (which I also own).

AF however, is massively different. The Kenko works perfectly with compatible screw drive lenses, but is virtually useless with SDM or DC lenses. Focus is painfully slow and aggravatingly approximate with the DA*300, DA 18-135 (both of which I own) and DA*50-135mm (which I tried out in a store). You will never be able to use the DA*300 with Kenko PZ for action, other than in MF mode. The K-3/DA*300 auto-focus takes a step backward with the HD 1.4X, but is still useable, even for BIF.

Thanks Dan. Good to know. I will just be using it for slow moving wildlife photography so fir my purposes it should be OK but i guess I can forget about photographing dolphins which is a shame.