K5 teleconverter problem

rossph · 05-26-2014, 06:08 PM

Hello,
I purchased a sigma APO TELE converter 1.4x EX DG the problem is I have a K5 with a 18-55 pentax DA lense and a 55-300 Pentax DAL lense. the teleconverter fits on the camera body but it is to large to fit the lense itself.
Any Idea's I did lots of research and it seemed like it should work?
I am a newbie to this and thank you for your help.
Thanks

Adam · 05-26-2014, 06:22 PM

Teleconverters with protruding elements don't work with all lenses. Try the Tamron 1.4x or the newer Pentax 1.4x if you want something that's a bit more universal.

**jatrax** · 05-26-2014, 06:44 PM

This might give some insight as to which lenses that TC will work with. Teleconverter Compatibility | Sigma Corporation of America

These are the ones Sigma says will work, others might work as well but you would need to test.

**Lowell Goudge** · 05-26-2014, 10:22 PM

While this is the current list from sigma, the product sheets shipped with the older tele converters also included some long pentax tele lenses and zooms. There is a similar pentax rear converter that protrudes well into the rear of the lens, and actually is even longer than the sigma one.

The bottom line is your lens needs a rear opening 35mm in diameter, 12mm deep, to accept a sigma TC.

Also not, if you ever get to stacking TCs , I know you really should not, but I have done so with the 1.4x and 2x, the 1.4x can only be stacked behind a 2x, not the other way around, for the same problem.

The sigma TCs are optimized to work only with their long AND FAST glass, not their consumer lenses

awaldram · 05-26-2014, 10:44 PM

Originally posted by rossph

Hello,
I purchased a sigma APO TELE converter 1.4x EX DG the problem is I have a K5 with a 18-55 pentax DA lense and a 55-300 Pentax DAL lense. the teleconverter fits on the camera body but it is to large to fit the lense itself.
Any Idea's I did lots of research and it seemed like it should work?
I am a newbie to this and thank you for your help.
Thanks

You've recieved correct advice that the Sigma is a 'matched' converter for only a select number of lens.

A word of warning you may be able to shoe horn a different lens on but if the rear element move during focusing or zooming you may well smash the lens rear element in to the converters forward element destroying both.

One othe point putting a conveter on a cheap lens is a complete waste of time and money , Though your Sigma is a good converter and will produce decent results with high quality matched glass (SIgma 70-200 f2.8 etc) it will just magnify the aberations of a cheap lens resulting in a worse image than cropping alone would achieve.

05-26-2014, 06:08 PM	#1
rossph New Member Join Date: Mar 2013 Posts: 9	K5 teleconverter problem Hello, I purchased a sigma APO TELE converter 1.4x EX DG the problem is I have a K5 with a 18-55 pentax DA lense and a 55-300 Pentax DAL lense. the teleconverter fits on the camera body but it is to large to fit the lense itself. Any Idea's I did lots of research and it seemed like it should work? I am a newbie to this and thank you for your help. Thanks

05-26-2014, 06:22 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Teleconverters with protruding elements don't work with all lenses. Try the Tamron 1.4x or the newer Pentax 1.4x if you want something that's a bit more universal. 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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05-26-2014, 06:44 PM	#3
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	This might give some insight as to which lenses that TC will work with. Teleconverter Compatibility \| Sigma Corporation of America These are the ones Sigma says will work, others might work as well but you would need to test.

05-26-2014, 10:22 PM	#4
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,892	While this is the current list from sigma, the product sheets shipped with the older tele converters also included some long pentax tele lenses and zooms. There is a similar pentax rear converter that protrudes well into the rear of the lens, and actually is even longer than the sigma one. The bottom line is your lens needs a rear opening 35mm in diameter, 12mm deep, to accept a sigma TC. Also not, if you ever get to stacking TCs , I know you really should not, but I have done so with the 1.4x and 2x, the 1.4x can only be stacked behind a 2x, not the other way around, for the same problem. The sigma TCs are optimized to work only with their long AND FAST glass, not their consumer lenses

05-26-2014, 10:44 PM	#5
awaldram Veteran Member Join Date: May 2008 Location: Hampshire Photos: Gallery Posts: 732	Originally posted by rossph Hello, I purchased a sigma APO TELE converter 1.4x EX DG the problem is I have a K5 with a 18-55 pentax DA lense and a 55-300 Pentax DAL lense. the teleconverter fits on the camera body but it is to large to fit the lense itself. Any Idea's I did lots of research and it seemed like it should work? I am a newbie to this and thank you for your help. Thanks You've recieved correct advice that the Sigma is a 'matched' converter for only a select number of lens. A word of warning you may be able to shoe horn a different lens on but if the rear element move during focusing or zooming you may well smash the lens rear element in to the converters forward element destroying both. One othe point putting a conveter on a cheap lens is a complete waste of time and money , Though your Sigma is a good converter and will produce decent results with high quality matched glass (SIgma 70-200 f2.8 etc) it will just magnify the aberations of a cheap lens resulting in a worse image than cropping alone would achieve.