Teleconverters

I have seen quite a few different teleconveters from different manufacturers. I see MC4 and MC7 mentioned with the Kenko's, the MC7 is more expensive and so I expect that it is better but what is the difference optically? Are the Sigma's worth the greater cost? Should I just buy a bigger lens? Are there cheap converters that are worthwhile.

I would like to use it on a *ist DS.

Thanks.

Pete D

I personally would not buy the cheap ones. The best ones will be the ones made by the manufacturer of your lens and dedicated to be used with your lens.
The cheap ones will give you inferior results.
You don't mention the lens brand so I'll assume it's Sigma since you mention that brand. There extenders are probably pretty good. I would spend the extra $$$ for the lens brand name extender.
Look for multiple elements and corrective coatings, etc.

WHAT LENS do you own first of all ;)

The Sigma TC's only work with a few(pro quality) lenses due to the front element PROTRUDING from the lens mount on them(I think this is why atleast)
.http://www.bhphotovideo.com/bnh/cont...=145100&is=USA

The KENKO MC7(7 elements) is Much nicer than it's MC4 brother in image quality(though I can't find a link to prove it)

Do ote that a 2X TC will degrade image quality NO MATTER which one you choose, so get THE best one you can match to your gear to minimize the loss . Also note that you will loose AF (I THINK) if you put a 2X TC(2 stop loss ) on a lens slower than F2.8( a Sigma 100-300 f4 lens w/ 2x would become a 200- 600 f8 combo and not auto focus most likely)

I was wondering the same thing. I want to get a teleconverter but I can't spend 150+ on one

Thanks for the info guys, I want to use it on a Sigma 55-200mm, it's an F4-F5.6 so should autofocus in good light at least. I tried a Kenko MC7 with a 18-50mm Sigma DC and of course it was okay but a waste of time. I think that I will just save the extra and look at the Sigma 170-500mm or a fixed 400 or 500 or something like that as I will end up with much better results. If I was doing this to make money I would had a different setup completely but I do this for fun and do not have a very large budget so want to make every dollar count.

Cheers.

Pete D.

get a fixed 400 F5.6(if you can find one cheap?), the sigma 50-500 , or the tokina 80-400. While I own the 170-500 and got AMAZING detail for the cost, most people Don't . The 50-500 is a much nicer, better built lens.

Unfortunately, PENTAX MOUNT 3rd party lenses are few and far between compared to nikon and canon mount. It could be a licencing issue or just that the pentax mount is in less of a demand?

A friend has the 17-500mm on order, the cost is probably more than I want to spend at the moment. I looked at the 50-500mm and it looks amazing, perhaps the tokina 80-400mm will be more reasonable. Any recomendations on the fixed 400mm?

Thanks.

Pete

Quote:

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Originally Posted by paulnj

The KENKO MC7(7 elements) is Much nicer than it's MC4 brother in image quality(though I can't find a link to prove it)

Do ote that a 2X TC will degrade image quality NO MATTER which one you choose, so get THE best one you can match to your gear to minimize the loss . Also note that you will loose AF (I THINK) if you put a 2X TC(2 stop loss ) on a lens slower than F2.8( a Sigma 100-300 f4 lens w/ 2x would become a 200- 600 f8 combo and not auto focus most likely)

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When I tried the MC7 it was with a 18-50mm F3.5 Sigma lens and from what I understand as long the original lens has a max apperture of at least F4 then it will auto focus so it should work on my 55-200mm Sigma and auto focus.

When I have the cash in my pocket I will take my camera into the shop and try it out with the MC7 TC.

Thanks.

Pete

I checked the price on the 50-500mm here in Australia and they want around Aust$2,000.

YIKES!!!!!!!!!!!!!!!!! B&H will send you it OVER SEAS and from there you may need to pay an IMPORT TAX I think. But even with the shipping and taxes, the exchange rate should still make the import a WISE choice. But, Sigma may not warranty the lens depending on their warranty type.

As for a fixed 400mm.... Tokina 400mm 5.6 ! USED is the only way to buy it, but mine was worth EVERY penny(and they run $200 or so(US dollars) compared to $500 for the 80-400 which replaced it. The 80-400(as with most zooms) has image quality fall off at the long end. Not real bad, but the fixed is far better at 400mm.

Don't get me wrong, the Sigma 170-500 is a good lens, but you need a steady , solid support to optimize the lens's ability. The faster the shutter speed, the more sharp images.

Now all of the above lenses will NOT focus lightning fast, yet they are not annoyingly slow either ;)

Because any teleconverter degrades the image you should:

1. Start with a very good lens

2. Don't save on the tele converter

I have some good results using the Canon 1.4x with our 70-200mm f/2.8 IS lens. but there is a price to pay:

a) chromatic aberrations on high contrast edges
b) distortions (can be fixed with PTLens)
http://www.outbackphoto.com/workflow/wf_43/essay.html

Uwe