Teleconverters - Pentax v Kenko v Tamron

**marcusBMG** · 09-14-2021, 01:10 PM

I've done several sets of pics comparing 1.4/1.5/1.7x tc's, using primarily my adaptall 300mm f2.8's and my DFA 150-450mm. My pentax 1.4x tc was definitely not the worst, however it wasn't really conclusively the best either - tending to best but within the errors and inconsistencies of the testing. Just emphasises that it is the base lens quality that counts really.

**UncleVanya** · 09-14-2021, 01:23 PM

I see a bit more detail in the non-Pentax shots and less purple fringing. It is quite close. It would also be useful to see a cropped image (no tc) and see how the underlying lens performed. This is also a sample size of 1. So drawing conclusions seems difficult.

---------- Post added 09-14-21 at 04:24 PM ----------

Are these made on a crop body?

**alfa75ts** · 09-14-2021, 01:40 PM - **1 Like**

Originally posted by Spock

but now with pixel-dense cameras like the K3 and later cameras you get better results cropping the images taken with just the lens than with the lens+converter.

I sort of agree with you but it's close. I also think the bigger focus target helps as in the Goshawk above.

Originally posted by UncleVanya

What was the underlying lens used?

Originally posted by UncleVanya

Are these made on a crop body?

K3III + DA*300 (see EXIF)

Originally posted by dlhawes

I'd pick 'em in this order: tamron, kenko, pentax

Originally posted by luftfluss

The Pentax TC is pretty obviously the worst performer here.

In tests the other day I'd put the Pentax first, which is why I started my post with the conclusion I did. I suspect that multiple tests under controlled conditions would be needed to pick a winner optically and even then it may not be a clear winner.

**UncleVanya** · 09-14-2021, 01:45 PM

Originally posted by alfa75ts

K3III + DA*300 (see EXIF)

On my mobile the Exif doesn’t show (iOS safari).

Originally posted by alfa75ts

In tests the other day I'd put the Pentax first, which is why I started my post with the conclusion I did. I suspect that multiple tests under controlled conditions would be needed to pick a winner optically and even then it may not be a clear winner.

And in my opinion multiple copies of both lens and tc. Additionally more lenses to cross check interactions. This is a tough area. Ideally Pentax would allow a setting to enable third party teleconverters that tool Exif and changes it by a user entered factor. But that’s probably a pipe dream.

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09-14-2021, 01:10 PM	#16
marcusBMG Site Supporter Join Date: Nov 2012 Location: North Wales Photos: Gallery \| Albums Posts: 2,868	I've done several sets of pics comparing 1.4/1.5/1.7x tc's, using primarily my adaptall 300mm f2.8's and my DFA 150-450mm. My pentax 1.4x tc was definitely not the worst, however it wasn't really conclusively the best either - tending to best but within the errors and inconsistencies of the testing. Just emphasises that it is the base lens quality that counts really.

09-14-2021, 01:23 PM	#17
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,400	I see a bit more detail in the non-Pentax shots and less purple fringing. It is quite close. It would also be useful to see a cropped image (no tc) and see how the underlying lens performed. This is also a sample size of 1. So drawing conclusions seems difficult. ---------- Post added 09-14-21 at 04:24 PM ---------- Are these made on a crop body?

09-14-2021, 01:40 PM - 1 Like	#18
alfa75ts Loyal Site Supporter Join Date: Jun 2009 Location: Melbourne Australia Photos: Albums Posts: 1,356 Original Poster	Originally posted by Spock but now with pixel-dense cameras like the K3 and later cameras you get better results cropping the images taken with just the lens than with the lens+converter. I sort of agree with you but it's close. I also think the bigger focus target helps as in the Goshawk above. Originally posted by UncleVanya What was the underlying lens used? Originally posted by UncleVanya Are these made on a crop body? K3III + DA*300 (see EXIF) Originally posted by dlhawes I'd pick 'em in this order: tamron, kenko, pentax Originally posted by luftfluss The Pentax TC is pretty obviously the worst performer here. In tests the other day I'd put the Pentax first, which is why I started my post with the conclusion I did. I suspect that multiple tests under controlled conditions would be needed to pick a winner optically and even then it may not be a clear winner.

09-14-2021, 01:45 PM	#19
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,400	Originally posted by alfa75ts K3III + DA*300 (see EXIF) On my mobile the Exif doesn’t show (iOS safari). Originally posted by alfa75ts In tests the other day I'd put the Pentax first, which is why I started my post with the conclusion I did. I suspect that multiple tests under controlled conditions would be needed to pick a winner optically and even then it may not be a clear winner. And in my opinion multiple copies of both lens and tc. Additionally more lenses to cross check interactions. This is a tough area. Ideally Pentax would allow a setting to enable third party teleconverters that tool Exif and changes it by a user entered factor. But that’s probably a pipe dream.