Vivitar 1.4x TC Adapter for Pentax AF

**Pepe Guitarra** · 02-11-2014, 09:25 PM

Has anyone used this adapter? Any opinion? Does it work with the FA lenses? Is it better than the Pentax AFA 1.7x TC (which is too much really!).

1.4X-P :: 1.4x Auto Focus Tele Converter for Pentax :: Vivitar

Adam · 02-11-2014, 09:35 PM

Originally posted by Pepe Guitarra

Has anyone used this adapter? Any opinion? Does it work with the FA lenses? Is it better than the Pentax AFA 1.7x TC (which is too much really!).

1.4X-P :: 1.4x Auto Focus Tele Converter for Pentax :: Vivitar

It adds a noticeable amount of fringing, but yes it does AF with FA lenses. The effective aperture and focal length are not transmitted to the camera, but auto metering still works.

**Pepe Guitarra** · 02-11-2014, 09:39 PM

Originally posted by Adam

It adds a noticeable amount of fringing, but yes it does AF with FA lenses. The effective aperture and focal length are not transmitted to the camera, but auto metering still works.

Adam, what would the best 1.4X TC AF be to use with the Pentax F* 300mm f4.5 ED?

Adam · 02-11-2014, 09:41 PM

Originally posted by Pepe Guitarra

Adam, what would the best 1.4X TC AF be to use with the Pentax F* 300mm f4.5 ED?

Probably the new one that's just coming out. But time will tell!

Adam
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dansamy · 02-11-2014, 09:45 PM

Originally posted by Adam

Probably the new one that's just coming out. But time will tell!

I thought the new one will only work with aperture up to f/4.0?

Adam · 02-11-2014, 09:51 PM

Originally posted by dansamy

I thought the new one will only work with aperture up to f/4.0?

It's not going to be any better with any other TC at far as AF goes though. Pentax is just using F4 as a rule of thumb. You might run into trouble with the DA 55-300mm F4-5.8 at 300mm, but a F4.5 on the F* lens should still be fine.

**Lowell Goudge** · 02-12-2014, 04:50 AM

Originally posted by dansamy

I thought the new one will only work with aperture up to f/4.0?

It is not so much that the TC will only work to F4 but that AF in general does not work with native apertures smaller than F6.? I put a question mark there because no AF lens is slower than F6.3 but from experience it is clear that AF can be reliably achiveed at about a limit of F6.9

Originally posted by Adam

It's not going to be any better with any other TC at far as AF goes though. Pentax is just using F4 as a rule of thumb. You might run into trouble with the DA 55-300mm F4-5.8 at 300mm, but a F4.5 on the F* lens should still be fine.

Agreed. The AF1.7x converter works very reliably on F4 lenses, so a 1.4x should work on F4.5 lenses. Note when sold, the AF1.7x was marketed to work on F2.8 and faster. At the time I contacted pentax service and (since they were local at the time) got to test the AF converter on my other lenses. It worked fine on my Series 1 70-210/3.5(version 1) and on my M100/4 macro, but not on my 400/5.6.

I bought it because except for the 400 it worked for every other lens I owned at the time

For me the real question is will it (pentaxes new 1.4x) work with the latest sigma 500/4.5?

**boriscleto** · 02-12-2014, 05:56 AM

I use the Vivitar with the DA L 55-300. Autofocus is noticeably slower at 300mm but still useable. Fringing in high contrast situations can be increased, but the 55-300 tends towards green rather than purple. And since it costs 1/6th of what the new one does I wouldn't worry too much about trying it out.

**Pepe Guitarra** · 02-12-2014, 06:22 AM

Nice shots. I saw some purple fringing in the first shot.

Oldbayrunner · 02-12-2014, 07:13 AM

Does any one know how well the Series 1 2x 7 element TC or the Series 1 4 element 2x TC work? i would be using it on a DA 55-300mm WR primarily.

**boriscleto** · 02-12-2014, 07:51 AM

Originally posted by Pepe Guitarra

Nice shots. I saw some purple fringing in the first shot.

I included that one to show fringing. Very difficult conditions to shoot in. The sun was low in the sky (just after sunrise) and directly behind the trees. The 55-300 handled it much better than my Promaster 100-400...

---------- Post added 02-12-14 at 09:53 AM ----------

Originally posted by Oldbayrunner

Does any one know how well the Series 1 2x 7 element TC or the Series 1 4 element 2x TC work? i would be using it on a DA 55-300mm WR primarily.

The 55-300 will only AF out to about 135mm on a 2x converter.

Adam · 02-12-2014, 11:02 AM

Originally posted by Lowell Goudge

It is not so much that the TC will only work to F4 but that AF in general does not work with native apertures smaller than F6.? I put a question mark there because no AF lens is slower than F6.3 but from experience it is clear that AF can be reliably achiveed at about a limit of F6.9

Agreed. The AF1.7x converter works very reliably on F4 lenses, so a 1.4x should work on F4.5 lenses. Note when sold, the AF1.7x was marketed to work on F2.8 and faster. At the time I contacted pentax service and (since they were local at the time) got to test the AF converter on my other lenses. It worked fine on my Series 1 70-210/3.5(version 1) and on my M100/4 macro, but not on my 400/5.6.

I bought it because except for the 400 it worked for every other lens I owned at the time

For me the real question is will it (pentaxes new 1.4x) work with the latest sigma 500/4.5?

Modern AF systems by other manufacturers work up to F8. I'm sure Pentax's latest ones do too!

Oldbayrunner · 02-12-2014, 05:59 PM

Originally posted by boriscleto

The 55-300 will only AF out to about 135mm on a 2x converter.

Thanks... I just got my WR 55-300mm today so was wondering what TC would work.

02-11-2014, 09:25 PM	#1
Pepe Guitarra Site Supporter Join Date: Nov 2010 Location: California Photos: Gallery \| Albums Posts: 2,223	Vivitar 1.4x TC Adapter for Pentax AF Has anyone used this adapter? Any opinion? Does it work with the FA lenses? Is it better than the Pentax AFA 1.7x TC (which is too much really!). 1.4X-P :: 1.4x Auto Focus Tele Converter for Pentax :: Vivitar

02-11-2014, 09:35 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Originally posted by Pepe Guitarra Has anyone used this adapter? Any opinion? Does it work with the FA lenses? Is it better than the Pentax AFA 1.7x TC (which is too much really!). 1.4X-P :: 1.4x Auto Focus Tele Converter for Pentax :: Vivitar It adds a noticeable amount of fringing, but yes it does AF with FA lenses. The effective aperture and focal length are not transmitted to the camera, but auto metering still works. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

02-11-2014, 09:51 PM	#6
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Originally posted by dansamy I thought the new one will only work with aperture up to f/4.0? It's not going to be any better with any other TC at far as AF goes though. Pentax is just using F4 as a rule of thumb. You might run into trouble with the DA 55-300mm F4-5.8 at 300mm, but a F4.5 on the F* lens should still be fine. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

02-12-2014, 11:02 AM	#12
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Originally posted by Lowell Goudge It is not so much that the TC will only work to F4 but that AF in general does not work with native apertures smaller than F6.? I put a question mark there because no AF lens is slower than F6.3 but from experience it is clear that AF can be reliably achiveed at about a limit of F6.9 Agreed. The AF1.7x converter works very reliably on F4 lenses, so a 1.4x should work on F4.5 lenses. Note when sold, the AF1.7x was marketed to work on F2.8 and faster. At the time I contacted pentax service and (since they were local at the time) got to test the AF converter on my other lenses. It worked fine on my Series 1 70-210/3.5(version 1) and on my M100/4 macro, but not on my 400/5.6. I bought it because except for the 400 it worked for every other lens I owned at the time For me the real question is will it (pentaxes new 1.4x) work with the latest sigma 500/4.5? Modern AF systems by other manufacturers work up to F8. I'm sure Pentax's latest ones do too! Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

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02-11-2014, 09:39 PM	#3
Pepe Guitarra Site Supporter Join Date: Nov 2010 Location: California Photos: Gallery \| Albums Posts: 2,223 Original Poster	Originally posted by Adam It adds a noticeable amount of fringing, but yes it does AF with FA lenses. The effective aperture and focal length are not transmitted to the camera, but auto metering still works. Adam, what would the best 1.4X TC AF be to use with the Pentax F* 300mm f4.5 ED?

02-11-2014, 09:41 PM	#4
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Originally posted by Pepe Guitarra Adam, what would the best 1.4X TC AF be to use with the Pentax F* 300mm f4.5 ED? Probably the new one that's just coming out. But time will tell! Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

02-11-2014, 09:45 PM	#5
dansamy Site Supporter Join Date: Nov 2013 Location: Alabama Posts: 2,450	Originally posted by Adam Probably the new one that's just coming out. But time will tell! I thought the new one will only work with aperture up to f/4.0?

02-12-2014, 04:50 AM	#7
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,887	Originally posted by dansamy I thought the new one will only work with aperture up to f/4.0? It is not so much that the TC will only work to F4 but that AF in general does not work with native apertures smaller than F6.? I put a question mark there because no AF lens is slower than F6.3 but from experience it is clear that AF can be reliably achiveed at about a limit of F6.9 Originally posted by Adam It's not going to be any better with any other TC at far as AF goes though. Pentax is just using F4 as a rule of thumb. You might run into trouble with the DA 55-300mm F4-5.8 at 300mm, but a F4.5 on the F* lens should still be fine. Agreed. The AF1.7x converter works very reliably on F4 lenses, so a 1.4x should work on F4.5 lenses. Note when sold, the AF1.7x was marketed to work on F2.8 and faster. At the time I contacted pentax service and (since they were local at the time) got to test the AF converter on my other lenses. It worked fine on my Series 1 70-210/3.5(version 1) and on my M100/4 macro, but not on my 400/5.6. I bought it because except for the 400 it worked for every other lens I owned at the time For me the real question is will it (pentaxes new 1.4x) work with the latest sigma 500/4.5?

02-12-2014, 05:56 AM	#8
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,475	I use the Vivitar with the DA L 55-300. Autofocus is noticeably slower at 300mm but still useable. Fringing in high contrast situations can be increased, but the 55-300 tends towards green rather than purple. And since it costs 1/6th of what the new one does I wouldn't worry too much about trying it out.

02-12-2014, 06:22 AM	#9
Pepe Guitarra Site Supporter Join Date: Nov 2010 Location: California Photos: Gallery \| Albums Posts: 2,223 Original Poster	Nice shots. I saw some purple fringing in the first shot.

02-12-2014, 07:13 AM	#10
Oldbayrunner Pentaxian Join Date: Mar 2013 Posts: 1,665	Does any one know how well the Series 1 2x 7 element TC or the Series 1 4 element 2x TC work? i would be using it on a DA 55-300mm WR primarily.

02-12-2014, 07:51 AM	#11
boriscleto Loyal Site Supporter Join Date: Dec 2009 Location: North Syracuse, NY Photos: Gallery Posts: 16,475	Originally posted by Pepe Guitarra Nice shots. I saw some purple fringing in the first shot. I included that one to show fringing. Very difficult conditions to shoot in. The sun was low in the sky (just after sunrise) and directly behind the trees. The 55-300 handled it much better than my Promaster 100-400... ---------- Post added 02-12-14 at 09:53 AM ---------- Originally posted by Oldbayrunner Does any one know how well the Series 1 2x 7 element TC or the Series 1 4 element 2x TC work? i would be using it on a DA 55-300mm WR primarily. The 55-300 will only AF out to about 135mm on a 2x converter.

02-12-2014, 05:59 PM	#13
Oldbayrunner Pentaxian Join Date: Mar 2013 Posts: 1,665	Originally posted by boriscleto The 55-300 will only AF out to about 135mm on a 2x converter. Thanks... I just got my WR 55-300mm today so was wondering what TC would work.