K-1 1.4x teleconverter

**UncleVanya** · 05-03-2023, 06:12 AM - **1 Like**

Originally posted by gatorguy

To partially dispel two generally held beliefs:

1. The Pentax DA70 is not full-frame compatible. It is, and works well on my K1
2. The HD 1.4TC isn't full-frame either. It is with at least some lenses, and surprisingly enough, combining both the DA70 "not FF" and Pentax 1.4TC "not FF" on a K1 works fine too.

I can confirm that on my Sony the DA 70 offers very good ff coverage.

I haven’t used this lens with the 1.4x on my Sony.

tryphon4 · 05-03-2023, 09:56 AM - **1 Like**

I own one Tamron 1.4X Pz-AF MC4 and one Pentax-F 1.7x AF adapter.
I just tested both with 2 different lenses: a Pentax A 20mm F2.8 and a Tokina 28-70mm F2.8 (at 35mm only). Both lenses are film-era ones.

In both cases, the lens without TC produces some visible vignetting, then with a TC it produces less vignetting.

**acoufap** · 05-03-2023, 10:31 AM

No vignetting on FF if you combine M1.7/50 with DA TC1.4x. This combo builds a M2.4/70.

**Scorpio71GR** · 05-04-2023, 04:20 PM

I own the Tamron 1.4 TC. I often combine it with my Tamron 70-200 F2.8. I do get some minimal vignetting wide open at F2.8. The amount I see really is not worth mentioning. The Tamron TC does path all the lens information through, but it doesn't compensate for the aperture and focal length. I also combine the Tamron TC with my Tamron 90 macro and DA 100 macro. The TC also works with Pentax SDM and Sigma HSM lenses.

05-03-2023, 09:56 AM - 1 Like	#17
tryphon4 Pentaxian Join Date: Apr 2011 Location: Drome, France Posts: 305	I own one Tamron 1.4X Pz-AF MC4 and one Pentax-F 1.7x AF adapter. I just tested both with 2 different lenses: a Pentax A 20mm F2.8 and a Tokina 28-70mm F2.8 (at 35mm only). Both lenses are film-era ones. In both cases, the lens without TC produces some visible vignetting, then with a TC it produces less vignetting. Last edited by tryphon4; 05-03-2023 at 10:02 AM.

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05-03-2023, 06:12 AM - 1 Like	#16
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,445	Originally posted by gatorguy To partially dispel two generally held beliefs: 1. The Pentax DA70 is not full-frame compatible. It is, and works well on my K1 2. The HD 1.4TC isn't full-frame either. It is with at least some lenses, and surprisingly enough, combining both the DA70 "not FF" and Pentax 1.4TC "not FF" on a K1 works fine too. I can confirm that on my Sony the DA 70 offers very good ff coverage. I haven’t used this lens with the 1.4x on my Sony.

05-03-2023, 10:31 AM	#18
acoufap Site Supporter Join Date: Jan 2011 Location: Munich, Germany Photos: Gallery \| Albums Posts: 4,190	No vignetting on FF if you combine M1.7/50 with DA TC1.4x. This combo builds a M2.4/70.

05-04-2023, 04:20 PM	#19
Scorpio71GR Loyal Site Supporter Join Date: Nov 2014 Location: Michigan Photos: Gallery \| Albums Posts: 6,014	I own the Tamron 1.4 TC. I often combine it with my Tamron 70-200 F2.8. I do get some minimal vignetting wide open at F2.8. The amount I see really is not worth mentioning. The Tamron TC does path all the lens information through, but it doesn't compensate for the aperture and focal length. I also combine the Tamron TC with my Tamron 90 macro and DA 100 macro. The TC also works with Pentax SDM and Sigma HSM lenses.