teleconverters

John A. · 01-31-2012, 12:43 PM

Fairly new to this forum and Pentax. Having run the gammet with Panasonic FZ series. I do mostly outdoor (nature shots). Currently own
the kit lens 18-55 and the DA 55-300 ( the plastic mount DAL 55-300 broke ) Cameras are KR & K5. Like the 55-300 but always want a bit more reach. Thinking of the Sigma 1.4 teleconverter. Does Pentax even make one in that designation ?? Am I going to loose an appreciable amount of IQ & light. Or am I just better off to crop ?

Thanks for the insight. Also looking for a good macro, to get that elusive bee inside the flower.......

claimed4all · 01-31-2012, 12:57 PM

Off Subject here

How did your 55-300 DA-L Break? Did the mount break or something else?

Adam · 01-31-2012, 01:21 PM

Pentax doesn't currently make any, no.

This is a good one if you can get it used as it makes your MF lenses AF compatible:
SMC Pentax-F 1.7x AF Adapter Reviews - Pentax K-mount Teleconverters and Adapters - Pentax Lens Reviews & Lens Database

**baro-nite** · 01-31-2012, 01:48 PM

Originally posted by Adam

This is a good one if you can get it used as it makes your MF lenses AF compatible:

OP doesn't indicate any MF lenses.

I don't know much about the Sigma TCs, but it's often stated that these are best used with Sigma lenses. You could get the Vivitar or Pro-Optic 1.4 TC (they're identical, I'm pretty sure) as a new item for around US$100; they're not bad. You'll get mixed opinions as to whether or not this is an improvement over simply cropping the 55-300. No question you will lose a stop of light, with any 1.4 TC.

For macro, options abound. See https://www.pentaxforums.com/forums/lens-clubs/143202-macro-any-means-necessary-club.html and https://www.pentaxforums.com/forums/pentax-lens-articles/152336-cheap-macro-b...lose-work.html for some interesting ones. Otherwise there are plenty of good choices in dedicated macro lenses; just be sure to get a true macro lens (that goes to at least 1:2 and preferably to 1:1 magnification) and not a "macro zoom" that only goes to 1:3 or so.

John A. · 01-31-2012, 02:28 PM

Reply to Claim4all

The plastic mount of the 50-300 DAL broke while on the KR body. Pentax wanted $180.00 to fix it. I bought a new 50-300 DL, with metal mount.
Do not know how this transpired BUT, I do travel rough terrain, and the camera is in a carrier on the back of a mountain bike.
All my other cameras have sustained quite well, but I can see the constant jarring could have contributed to the break. Pentax folks said that I had dropped it....I did NOT !!!.

Stone G. · 01-31-2012, 04:25 PM

You will hear different opinions about the use of teleconverters in general - but I find they have their uses because sensor resolution (sampling) can be a limiting factor, where you cannot just crop and get fine detail. A 1.4 / 1.5X TC will of course require either require a doubling of exposure time or a higher ISO. With your K-5, higher ISO would actually work fine. I am quite happy with the TAv feature of the K-5!

Teleconverters for Pentax that will give you both AF and AE can be quite hard to find (at least in my part of the world) but I have and can recommend the Kenko SHQ 1.5 converter, that has also gotten decent reviews in this forum: Kenko Pz-AF 1.5x Teleplus SHQ Teleconverter Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database

One word of warning though: Zooms are "optimized compromises" in design with their many groups moving relative to each other. Adding another group (the TC) not optimized for specific zomm lenses may cause additional IQ degredation. I mainly use mine on primes.

Marc Sabatella · 01-31-2012, 07:32 PM

Generallly speaking, you will only see the theoretical advantage of a TC over simply cropping with certain combinations of (mostly expensive) tc's pn certain (mostly expensive) lenses. Most combinations do demonstratably worse than cropping - an easy enough test to perform if you've got the glass to test with. And in particular, your basic relatively inexpensive TC with a constumer zoom - even a relatively good one like the 55-300 - is virtually always going to do no better than cropping. There are plenty of test images posted here and elsewhere oer the years to demonstrate this.

John A. · 01-31-2012, 07:44 PM

Marc & others

Thanks for the info. Will be staying with what I have.

John A.

01-31-2012, 12:43 PM	#1
John A. Junior Member Join Date: Jan 2012 Location: Westmeath Ontario Posts: 47	teleconverters Fairly new to this forum and Pentax. Having run the gammet with Panasonic FZ series. I do mostly outdoor (nature shots). Currently own the kit lens 18-55 and the DA 55-300 ( the plastic mount DAL 55-300 broke ) Cameras are KR & K5. Like the 55-300 but always want a bit more reach. Thinking of the Sigma 1.4 teleconverter. Does Pentax even make one in that designation ?? Am I going to loose an appreciable amount of IQ & light. Or am I just better off to crop ? Thanks for the insight. Also looking for a good macro, to get that elusive bee inside the flower.......

01-31-2012, 01:21 PM	#3
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Pentax doesn't currently make any, no. This is a good one if you can get it used as it makes your MF lenses AF compatible: SMC Pentax-F 1.7x AF Adapter Reviews - Pentax K-mount Teleconverters and Adapters - Pentax Lens Reviews & Lens Database 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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01-31-2012, 12:57 PM	#2
claimed4all Forum Member Join Date: Sep 2011 Location: Grand Rapids Michigan Posts: 96	Off Subject here How did your 55-300 DA-L Break? Did the mount break or something else?

01-31-2012, 01:48 PM	#4
baro-nite Loyal Site Supporter Join Date: Aug 2011 Location: North Carolina, USA Photos: Gallery \| Albums Posts: 5,295	Originally posted by Adam This is a good one if you can get it used as it makes your MF lenses AF compatible: OP doesn't indicate any MF lenses. I don't know much about the Sigma TCs, but it's often stated that these are best used with Sigma lenses. You could get the Vivitar or Pro-Optic 1.4 TC (they're identical, I'm pretty sure) as a new item for around US$100; they're not bad. You'll get mixed opinions as to whether or not this is an improvement over simply cropping the 55-300. No question you will lose a stop of light, with any 1.4 TC. For macro, options abound. See https://www.pentaxforums.com/forums/lens-clubs/143202-macro-any-means-necessary-club.html and https://www.pentaxforums.com/forums/pentax-lens-articles/152336-cheap-macro-b...lose-work.html for some interesting ones. Otherwise there are plenty of good choices in dedicated macro lenses; just be sure to get a true macro lens (that goes to at least 1:2 and preferably to 1:1 magnification) and not a "macro zoom" that only goes to 1:3 or so.

01-31-2012, 02:28 PM	#5
John A. Junior Member Join Date: Jan 2012 Location: Westmeath Ontario Posts: 47 Original Poster	Reply to Claim4all The plastic mount of the 50-300 DAL broke while on the KR body. Pentax wanted $180.00 to fix it. I bought a new 50-300 DL, with metal mount. Do not know how this transpired BUT, I do travel rough terrain, and the camera is in a carrier on the back of a mountain bike. All my other cameras have sustained quite well, but I can see the constant jarring could have contributed to the break. Pentax folks said that I had dropped it....I did NOT !!!.

01-31-2012, 04:25 PM	#6
Stone G. Pentaxian Join Date: Jun 2010 Location: North Zealand, Denmark Photos: Gallery \| Albums Posts: 1,516	You will hear different opinions about the use of teleconverters in general - but I find they have their uses because sensor resolution (sampling) can be a limiting factor, where you cannot just crop and get fine detail. A 1.4 / 1.5X TC will of course require either require a doubling of exposure time or a higher ISO. With your K-5, higher ISO would actually work fine. I am quite happy with the TAv feature of the K-5! Teleconverters for Pentax that will give you both AF and AE can be quite hard to find (at least in my part of the world) but I have and can recommend the Kenko SHQ 1.5 converter, that has also gotten decent reviews in this forum: Kenko Pz-AF 1.5x Teleplus SHQ Teleconverter Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database One word of warning though: Zooms are "optimized compromises" in design with their many groups moving relative to each other. Adding another group (the TC) not optimized for specific zomm lenses may cause additional IQ degredation. I mainly use mine on primes.

01-31-2012, 07:32 PM	#7
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	Generallly speaking, you will only see the theoretical advantage of a TC over simply cropping with certain combinations of (mostly expensive) tc's pn certain (mostly expensive) lenses. Most combinations do demonstratably worse than cropping - an easy enough test to perform if you've got the glass to test with. And in particular, your basic relatively inexpensive TC with a constumer zoom - even a relatively good one like the 55-300 - is virtually always going to do no better than cropping. There are plenty of test images posted here and elsewhere oer the years to demonstrate this.

01-31-2012, 07:44 PM	#8
John A. Junior Member Join Date: Jan 2012 Location: Westmeath Ontario Posts: 47 Original Poster	Marc & others Thanks for the info. Will be staying with what I have. John A.