Tele convertor

I can use my Kenko 1.5x on my Pentax 55/300 lens at the long end with problems only occurring in very low/poor light. My Kenko 2x however is a no go on this lens. Main problem you will have is the image degrades somewhat through the converter...

You got me thinking about this so I got the Tamron out with the Kenko and took this about 1 hour ago link I can't get close to these birds and I took this hand held panning as they are fast little bu***s and it's well cropped.

So does the lens work well at all the focal range with the converter ?.

Yes it works, however as I said there is some image degradation/softness to the image with the convertor on.

Thanks everyone for the input I need to think about this purchase. I have waited two years for the show as the show was canceld last year due to heavy fog off the coast so I want to try and get some nice shots this year all being well.
Ian

Hello everyone

Reading all the replies in regard to the 1.5x, 1.7x, 2x teleconverters; i'm sort of deciding against purchasing one. I take alot of Birding / action pictures, using my Pentax ISTDL and Pentax-DA 55-300 f4-5.8 lense, and find the lense fishes around for focus when zoomed to the MAX 300mm foacl length.

With a 1.5 or 2x teleconverter I can see it being extremely difficult to maintain a quick and accurate focus, especialy when action can be swift and not too forgiving. I cannot afford a expensive f2-f4 lense as this is well beyond my means, so I'm trying to decide how to get more magnification without sacrificing clarity, grain(pixels), or image quality.

Can anyone recommend a specific teleconverter that may not reduce the aperature too much at 50-100% of magnification. If need be I can stay within a 400-500mm magnification.

Thanks

Hello Tony and welcome to the forum.

With all TC you lose light and image quality, there is nothing you can do about it.
The more expensive TC might preform better then some of the cheaper ones and also less magnifications helps a lot.

with tc around the 1.5x you would lose one stop and with 2x 2 stops of light. so f/5.6 would be f/8 with one stop and f/11 with two stops.

With such zooms like you've a TC of 1.5X or 1.4X is the best with 2X you lose too much light and AF would certainly not work although with 1.5X you atleast have a change it might.

Hi Stefan

Thanks for the reply and the welcome. I guess with a 1.5 TC I would sacrifice some aperature/light but, if I stayed around 75% of the 300mm, (say 200-250mm and use the TC I would sacrifice some light but not as significant as if I used all my magnification.

Also, on the DL if I used Aperature priority vs: Shutter Priority and use the -1EV setting, this may help with the overall image quality, ISO speed vs: aperature.

What is your thoughts on this logic?

Thanks

Tony

I'll go along with those who champion the combination of the Kenko 1.5x converter with Tamron 70-300 lens. I'm no expert but I think it gets decent enough results for a relatively inexpensive cost.

Tony if you use an 1.5 tc at 200mm you get 300mm so not sure if that's worth it? and 250 would be 375mm that sounds a lot but really isn't so much more then 300mm you might be better off cropping the photo to be honest.

Sorry tony I can't follow you there, the DA 55-300 is already good wide open so use that and iso400 or what needed to keep your shutterspeed down, if shutterspeeds gets to high and you cant keep the lens still you get blurry photos so better to have more noise then that.

I hope that helps Tony
with kind regards,
Stefan

Thanks Stefan

I guess I was over complicating the idea I had. At any rate, I think I will opt to purchase a Kenko 1.5x TC. I've seen some on Ebay that are within the price range I was looking for.

As for magnification ratios with a TC I would probably max out the lense anyways. 300mm x 1.5 seems a pretty good compromise at f8.0 or so. Still would take nice shots on bright days.

How often can you get within 150 or so yards to a Hawk or Eagle anyways.

I appreciate the information

Thanks

Tony

Hi Tony,

I don't know how much they are on ebay but I can recommend SRS Microsystems (also see them recommended elsewhere on this forum).

SRS - Kenko 1.5x TC Clicky

They have it for £89 and if you mention you are a member here you'll get free postage..

Hello again

What about the Tamron 1.4 X Pz-AF teleconverter for Pentax? This is on Ebay as well.

Thanks

Hi GDN

Looked at your link, "SRS - Kenko 1.5x TC Clicky", the Tamron looks like the same item.

Thanks

Tony

Talk about serendipity! I signed on today with the intent of posting a question about teleconverters. From reading the above thread it appears that most of my questions are answered. The responses kept me from acquiring a 2x. The Kenko prices were within "tolerance" (as I recall about $80 US on Ebay).

I have a K10d with an 18-250 Pentax lens. While, as someone pointed out, 375 isn't a lot more reach, it is a lot more tolerable than the large $$ for a longer lens.

There are some hawks and eagles which perch on some trees about 200-250 yds distant. Plus some of the small critters here in the desert are quite skittish and another 50% should lower the odds of spooking them.

Thanks!