Teleconverters
 

Got a sigma 70 - 300 F4-5.6 APO DG Macro lens and want to buy a 2X teleconverter for it. The Sigma one is not compatible so must go third party. Does anyone have any experience of the Kenkos and Jessops ones?

Hi there.... a 2x converter will reduce the amount of light available to the camera by two stops, which, given the relatively slow nature of your lens (f4.5 -5.6), may mean that you will be restricted to bright sunny conditions when using the converter.

Yeah i realise that but I would like to know about the quality of the kenkos and jessops converters, is one better than the other one?

Hi affirmation;11904

Don't bother with the Jessops converter, go for the Kenko or Tamron!

nirofo.

I used a second hand cheapie Jessops 2x on a nikkor 80-200mmf2.8 last winter and it was surprisingly good. But at the same time I had a sigma 70-300 and tried it on that just to see what 300mm x2 actually gave me. Did manage AF in bright conditions but the quality of the results was very bad and I'd only recommend for record shots.

I've got the Kenko Pro 1.4 which is excellent and in tests I've seen is not much behind the Canon which is one of the best. I would not touch any 2x converter as they all degrade the image too much. You would do better to crop the image and ''blow it up'' rather than use a 2x according to Pro wildlife photographers I have talked to. Hope this helps.

When I first saw this posted I was going to say don't waste your money. I knew Sue (Greypoint) has a Jessops x2 so I thought I would wait until she reponded and she has pretty much confirmed that the results will be quite bad. One would question the logic of putting a x2 on a budget zoom.

It might be OK if you always use the full frame. If you discount the loss of 2 stops of light and AF problems introducing a converter will magnify the lens errors, increase the flare plus add the TC's own set of errors.

If you trawl the web these are the perls of wisdom you will find.

More people are happy with a x1.4 converter than a x2.
More people are happy with a converter on a Prime lens than a Zoom.
More people are happy with a converter on the Best Glass than Budget Glass.

There are a number of demostrations that show that upsizing gives better results than a x2 converter on good glass.

One reason why Canon's TC will only fit a limited range of L lens.

I use a Canon x1.4 on a 300mm f4 prime. You can see a slight degradation but the results are better than cheap the Sigma 135 - 400 zoom.

If you do go ahead and buy a x2 for the hell of it please post your results because I believe this forum should be more fact based than hearsay.

Here's a photo of a Short-eared Owl taken with a Tamron 60-300 SP zoom lens at 300mm plus a Teleplus 2x converter, aperture set at f5.6 on lens (effective f11). Olympus OM1n + Sunpak GT32 flash, Kodachrome 64. Quality can be obtained if the converter isn't used outside it's capabilities.

nirofo.

Don't really understand what you mean by ''Quality can be obtained if the converter isn't used outside it's capabilities.''

I agree with nirofo, see image below. Quality results can be obtained using TC's but use them carefully.

As I remember taken f9.5 (effective) 70-200 f2.8 TC17E (1.7X TC)

Hi miketoll;11934

A teleconverter is usually only at it's best when used with a long prime lens, such as a Nikon 500mm f4 and a TC14E or a TC20E, Canon have similar spec converters. However, very good results can be obtained using other combinations of Lens + Teleconverter. 'providing', certain conditions are applied when using them! Zooms can be very good if used at or near their long end, if the light is good, the camera/lens support is good and the subject is photogenic. By photogenic I mean plenty of edge detail available giving good contrast between itself and an adjacent item, enabling point of focus to be accurately obtained either manually or by autofocus. Note, some lens / 2x converter combinations will not autofocus with lenses that have maximum apertures > f5.6. All Sigma converters lock up at apertures > f5.6. Kenko, Tamron and Teleplus all do a good range of 1.4 and 2x converters, they also do pro versions at higher prices. I've used the Tamron and Teleplus converters with some great successes, many of my bird pictures taken with these combinations have been published in various books and magazines.

Here's a couple more photo's taken with Tair 300mm f4.5 + Teleplus 2x converter, (Buzzard) and Tokina 150-500mm f5.6 zoom + 1.4 Tamron converter, (Stone Curlew). Both were taken using a substantial tripod and head from a hide.

nirofo.

Thanks for the explanation. Those two shots are certainly nice and sharp.

From time to time I ponder buying a 2X converter to use with my 500mm f/4 Canon lens and 20D. Two things hold me back: loss of autofocus, and concerns about image quality.

I really need the autofocus - these useless damn modern viewfinders are too dim and small to focus manually without a proper split image focus aid, which the 20D doesn't have. I suppose I'd get the Canon one even so, as I'm certainly very happy with the results that my Canon 1.4 converter delivers with the 500. It isn't as incredibly sharp as the bare 500 alone, but it often comes remarkably close, particularly if the light is good. As a general rule, I leave the 1.4 on the 500 all the time, only removing it when the light is problematic or when I expect to be close enough not to need it.