Teleconverters...

**ismaelg** · 05-07-2009, 04:08 AM

I was not aware there were so many choices in TCs. I was surprised to see so many cheap ones on eBay. So, going back to a more basic question: What is a good TC for a manual SMC Pentax A-70-210 f/4? I have one of those lenses on its way and I have learned on this thread that not all TCs work well with all lenses. I usually go fully manual.
I would use it with the K100D and maybe also with the K1000 and MV-1 just for fun.
I would like a 2X but I see there are 1.7X , 1.4X etc.
Any suggestions?

Thanks,

**Lowell Goudge** · 05-07-2009, 04:28 AM

the best choise for the SMC Pentax A-70-210 f/4 is the SMC-F 1.7x AF TC

it is a high quality TC allows all auto functions of the lens to work corectly on a DSLR AND gives limited auto focus function to the lens

what else could you want.

also this will allow the autofocus to work, where as a 2x (but manual focus) will be too dark for AF indication

**ismaelg** · 05-07-2009, 04:38 AM

Thanks! I'll be on the lookout for it.
This darn LBA...

F16 · 05-07-2009, 08:23 PM

I agree that the 1.7 Pentax is a great TC, it's both good optically and does something that no other can in adding AF abilities to a manual focus lens. It's not for everyone though, being as expensive as it normally is - if you can find it cheaply or are not put off by its cost, certainly worth having. Beyond that TC, for a zoom I would generally suggest trying a 1.4x/1.5x before a 2x, optically they're less damaging to image quality, sometimes to the point where it's hard to notice at all. If going for a 2x TC, most recent 2x TCs seem to use either 4 elements or 7, & in nearly all circumstances you should see better results using a 7 element TC.

**Canada_Rockies** · 05-07-2009, 09:13 PM

I also find the A 1.4X-S works well with the A 70-210/4. This gives you a 100-300/5.6. Not too shabby image quality, either.

aCIDfire · 07-19-2009, 08:03 AM

Can you recommend me some 2.0x teleconvertor for my Voigtlander 180? I know that 2.0x TCs aren´t best for IQ, but my Voigt180 is brutally sharp so it shouldn´t
interfere. Maybe Pentax 1.7 AF TC would be a best choice talking about the IQ (I don´t need AF function). What do you think about 2.0 TC. Which one?

Ben_Edict · 07-19-2009, 01:15 PM

Originally posted by aCIDfire

Can you recommend me some 2.0x teleconvertor for my Voigtlander 180? I know that 2.0x TCs aren´t best for IQ, but my Voigt180 is brutally sharp so it shouldn´t
interfere. Maybe Pentax 1.7 AF TC would be a best choice talking about the IQ (I don´t need AF function). What do you think about 2.0 TC. Which one?

Try to get a Pentax 2x-S A-converter. It is the next best thing to the 2x-L converter, which does not fit onto the Voigtländer, because of its protruding lens elements. Another option (but with more IQ loss) is the Kenko MC7 2x-tc A-version. It is visibly better than the old Pentax K6T, but not quite as good as the Pentax 2x-S. I have all of the tcs mentioned and also the 180 Apo-Lanthar.

Ben

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05-07-2009, 04:08 AM	#46
ismaelg Loyal Site Supporter Join Date: Apr 2009 Location: Puerto Rico Photos: Gallery Posts: 2,681	I was not aware there were so many choices in TCs. I was surprised to see so many cheap ones on eBay. So, going back to a more basic question: What is a good TC for a manual SMC Pentax A-70-210 f/4? I have one of those lenses on its way and I have learned on this thread that not all TCs work well with all lenses. I usually go fully manual. I would use it with the K100D and maybe also with the K1000 and MV-1 just for fun. I would like a 2X but I see there are 1.7X , 1.4X etc. Any suggestions? Thanks,

05-07-2009, 04:28 AM	#47
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,886	the best choise for the SMC Pentax A-70-210 f/4 is the SMC-F 1.7x AF TC it is a high quality TC allows all auto functions of the lens to work corectly on a DSLR AND gives limited auto focus function to the lens what else could you want. also this will allow the autofocus to work, where as a 2x (but manual focus) will be too dark for AF indication

05-07-2009, 04:38 AM	#48
ismaelg Loyal Site Supporter Join Date: Apr 2009 Location: Puerto Rico Photos: Gallery Posts: 2,681	Thanks! I'll be on the lookout for it. This darn LBA...

05-07-2009, 08:23 PM	#49
F16 Senior Member Join Date: Feb 2009 Location: U.S. Posts: 104	I agree that the 1.7 Pentax is a great TC, it's both good optically and does something that no other can in adding AF abilities to a manual focus lens. It's not for everyone though, being as expensive as it normally is - if you can find it cheaply or are not put off by its cost, certainly worth having. Beyond that TC, for a zoom I would generally suggest trying a 1.4x/1.5x before a 2x, optically they're less damaging to image quality, sometimes to the point where it's hard to notice at all. If going for a 2x TC, most recent 2x TCs seem to use either 4 elements or 7, & in nearly all circumstances you should see better results using a 7 element TC.

05-07-2009, 09:13 PM	#50
Canada_Rockies Loyal Site Supporter Join Date: Nov 2007 Location: Sparwood, BC, Canada Photos: Gallery \| Albums Posts: 12,385	I also find the A 1.4X-S works well with the A 70-210/4. This gives you a 100-300/5.6. Not too shabby image quality, either.

07-19-2009, 08:03 AM	#51
aCIDfire Senior Member Join Date: Dec 2008 Location: Czech Republic Posts: 110	Can you recommend me some 2.0x teleconvertor for my Voigtlander 180? I know that 2.0x TCs aren´t best for IQ, but my Voigt180 is brutally sharp so it shouldn´t interfere. Maybe Pentax 1.7 AF TC would be a best choice talking about the IQ (I don´t need AF function). What do you think about 2.0 TC. Which one?

07-19-2009, 01:15 PM	#52
Ben_Edict Veteran Member Join Date: Jul 2007 Location: SouthWest "Regio" Photos: Albums Posts: 3,309	Originally posted by aCIDfire Can you recommend me some 2.0x teleconvertor for my Voigtlander 180? I know that 2.0x TCs aren´t best for IQ, but my Voigt180 is brutally sharp so it shouldn´t interfere. Maybe Pentax 1.7 AF TC would be a best choice talking about the IQ (I don´t need AF function). What do you think about 2.0 TC. Which one? Try to get a Pentax 2x-S A-converter. It is the next best thing to the 2x-L converter, which does not fit onto the Voigtländer, because of its protruding lens elements. Another option (but with more IQ loss) is the Kenko MC7 2x-tc A-version. It is visibly better than the old Pentax K6T, but not quite as good as the Pentax 2x-S. I have all of the tcs mentioned and also the 180 Apo-Lanthar. Ben