2x Teleconverter For Canon

Thanks, Ian. I look forward to seeing your photos. Don't go out of your way--as I said, it's only on my Wish List right now. I wonder if I could also use it on my Sigma 70-300 APO DG Macro as well. Wouldn't THAT be great if I could! Then I could finally get a chance for some great close-up bird shots.

Well, it works great on my Sigma 100-300 f/4, but that is an EX series lens and that is what the TC was designed for. Do you have a local Sigma dealer that has one you can try?

I am a firm believer in e-bay for this sort of thing, BTW. I even bought that 100-300mm f/4 that way for under half the list price.

I just grabbed this off e-bay ... don't know anything about this vendor ...
Sigma 1.4x APO Teleconverter for Canon EOS AF DG NIB - eBay (item 230387917614 end time Oct-20-09 07:45:58 PDT)
 
As an eBay Associate we earn from qualifying purchases.
The sigma TC won't fit on the 70-300mm lens - I have its older non-APO edition version and the TC simply won't attach at all. There is a small protruding lens element on the TC which hits the back element on the 70-300mm lens.
Further even if you could add the 1.4TC, the max aperture of the lens would go smaller than f5.6 - which unless your on a pro end camera body is the cut off point for AF working - after that point it simply will not AF. Though with the sigma's there is a chance they won't report correctly to the camera so the AF function might remain, but the cut off is there because accuracy and speed drop way off after f5.6.
In addition whilst the 70-300mm APO has improved glass over the nonAPO edition I do think that with a TC added its overall image quality would be far less than desirable.
Just keep saving for that birding lens (I know I am -- well at least trying to)
 
The sigma TC won't fit on the 70-300mm lens - I have its older non-APO edition version and the TC simply won't attach at all. There is a small protruding lens element on the TC which hits the back element on the 70-300mm lens.
Further even if you could add the 1.4TC, the max aperture of the lens would go smaller than f5.6 - which unless your on a pro end camera body is the cut off point for AF working - after that point it simply will not AF. Though with the sigma's there is a chance they won't report correctly to the camera so the AF function might remain, but the cut off is there because accuracy and speed drop way off after f5.6.
In addition whilst the 70-300mm APO has improved glass over the nonAPO edition I do think that with a TC added its overall image quality would be far less than desirable.
Just keep saving for that birding lens (I know I am -- well at least trying to)
Which 70-300mm lens won't it fit on? I have the Canon 70-300 f/4-5.6 IS USM, will it work with that?
 
When I first became interested in Canon DSLRs over a year ago I spent a lot of time in the dpreview forum for Canon lens. Every month or two someone in that forum would ask about using a teleconverter. The usual and intuitive response would be that adding another piece of glass would invariably degrade the image.

The proof offered for this observation was that the Canon teleconverters would visibly display a degraded image with a Canon lens. Then some pixel peeper, whose name I don't recall now, decided to try some other teleconverters. He discovered and proved that the Kenko 1.4X Teleplus Pro 300 DG does not degrade the image in any measurable manner.

If I recall correctly he also demonstrated that 2 Kenko 1.4X teleconverters would just barely degrade the images. Again if I recall correctly, he determined the Kenko 2X for some reason would noticeably degrade the image. So, if memory serves, you would be better off using 2 Kenko 1.4X Teleplus Pro 300 DGs rather than one 2X teleconverter.
 
I find it hard to belive that the kenko showed no image degradation when the canon did when tested under the same conditions on the same lens.
This test might interest you: Juza Nature Photography

If you look at shots taken with the 200mm and the 200mm +1.4TC aside from a slight drop in contrast the TC shots show very little image degradation at all. In the field such image degradation is going to be very minor when compared to softnes caused by camera shake and subject movement - as well as haze if shooting over a longer distance.

As for the 2*1.4 VS a 2*TC I recall seeing tests, but can't find them, which I think showed the opposite of what your saying - that the 2*TC was beaten by the 1.4s.

Decado - I was refering to the sigma 70-300mm before the canon I have no idea of if the sigma TC will or will not fit the lens
 
Another great link Overread, the two reviews you posted make me think I'll get both the 1.4 and 2X, Canon of course. Just bid on them over on ebay, if I cant save $100 on them, then I'll get them from a local dealer.
 
Another great link Overread, the two reviews you posted make me think I'll get both the 1.4 and 2X, Canon of course. Just bid on them over on ebay, if I cant save $100 on them, then I'll get them from a local dealer.

Remember the lenses (and camera) the guy in the reveiws is using are top range things - which will affect what you get out of the setup. A 1.4TC is a great thing so certainly go for it - the 2*TC is fun but don't expect to use it as often (unless you have a toprange prime lens ;) )
 
Another great link Overread, the two reviews you posted make me think I'll get both the 1.4 and 2X, Canon of course. Just bid on them over on ebay, if I cant save $100 on them, then I'll get them from a local dealer.

Remember the lenses (and camera) the guy in the reveiws is using are top range things - which will affect what you get out of the setup. A 1.4TC is a great thing so certainly go for it - the 2*TC is fun but don't expect to use it as often (unless you have a toprange prime lens ;) )


I will use them with an EF 70-200 f/2.8L USM, other postings I've read claim to have good results with that lens. Once I actually get 1 and try it, I'll post my findings, if I don't like the results, I can eBay it with little or no loss.
 
I find it hard to belive that the kenko showed no image degradation when the canon did when tested under the same conditions on the same lens.
This test might interest you: Juza Nature Photography

If you look at shots taken with the 200mm and the 200mm +1.4TC aside from a slight drop in contrast the TC shots show very little image degradation at all. In the field such image degradation is going to be very minor when compared to softnes caused by camera shake and subject movement - as well as haze if shooting over a longer distance.

As for the 2*1.4 VS a 2*TC I recall seeing tests, but can't find them, which I think showed the opposite of what your saying - that the 2*TC was beaten by the 1.4s.

Decado - I was refering to the sigma 70-300mm before the canon I have no idea of if the sigma TC will or will not fit the lens

It turns out I did misremember a few things. It was a bit over 2 years ago when I first started posting in the Canon Lens Forum at dpreview.com. The older I get the faster time flies. :( I lurked there for months before I ever posted.

I too couldn't find what I was seeking but I did see a name that frequently popped up in postings regarding teleconverters and stacking them. So I emailed the guy, Lee Jay, and he does indeed use 2 1.4X teleconverters instead of a 2X teleconverter. However it's because a 2X teleconverter causes the lens be very slow when autofocusing. It's designed that way. With 2 1.4X teleconverters this doesn't happen because the camera only recognizes the first 1.4X teleconverter and focuses much faster. Thus 2 1.4 teleconverters are more desirable than a 2X converter.

Lee Jay advises me that the most important thing is using excellent glass such as an L lens. I believe someone else mentioned this here. Lee also said:

"The Canon 1.4x and 2x TC-IIs are very close to perfect optically. The Kenko
Pro is in the center, but not as good at the edges."

So regarding the original question from decado:

"What's a good brand for a 2x teleconverter? I was reading reviews of canon's EF 2x teleconverter and they say that it degrades the image. Are there 2x teleconverter's that don't degrade the image or would I be better off sticking to a 1.4x?"

I believe a Canon 2X may cause some slight degradation and focus slower but give greater magnification. The Canon 1.4X probably won't cause any noticeable degradation and will focus rapidly but provide less magnification. Using 2 1.4Xs may be your best choice. Kenko 1.4X Teleplus Pro 300 DG teleconverters can be used if the images will be cropped since they are not as sharp at the edges.
 
ErectedGryphon - Ahh in that case - I am no Juza (yet ;) ) but:

70-200mm f2.8 IS L +1.4TC : IMG_1025 on Flickr - Photo Sharing!
any mostly anything else that's not a bug and taken with the 70-200mm has the 1.4TC attached as well

70-200mm f2.8 IS L +2*TC : little birds photos test - a set on Flickr
There are 100% crops with that last set as well

edit - ahh that sounds a little better! Though I always thought that the drop in AF speed was not the TC acting, but the light loss at the result of using the TC. Two 1.4s is still around only 1.8*magnification so maybe that little 0.2 loss is something that makes all the difference in the longrun since the light lost is a physical factor. Unless the lack of reporting the other stop of light lost from the two 1.4s adjust some setting in the camera?
 
ErectedGryphon - Ahh in that case - I am no Juza (yet ;) ) but:

70-200mm f2.8 IS L +1.4TC : IMG_1025 on Flickr - Photo Sharing!
any mostly anything else that's not a bug and taken with the 70-200mm has the 1.4TC attached as well

70-200mm f2.8 IS L +2*TC : little birds photos test - a set on Flickr
There are 100% crops with that last set as well

edit - ahh that sounds a little better! Though I always thought that the drop in AF speed was not the TC acting, but the light loss at the result of using the TC. Two 1.4s is still around only 1.8*magnification so maybe that little 0.2 loss is something that makes all the difference in the longrun since the light lost is a physical factor. Unless the lack of reporting the other stop of light lost from the two 1.4s adjust some setting in the camera?

Your photos look terrific to me. Did you notice any slowness in the focusing of the 2X teleconverter when shooting the birds?
 
For those bird shots the light was already rather poor (hence why I used flash to boost the lighting) so focusing was slower. Overall the speed does drop, but I have never been in a massivly fast situation with the setup so the AF was mostly good enough to get a lockon when needed and I've never really compared by how much the speed does drop.
 
I use the Kenko pro 300 2X on my Canon 300mmF2.8L and it rocks
Kenko 2X
577227593_SCUXw-L.jpg


with canon1.4x handheld
568967888_BD5gh-L.jpg


Kenko 2x + 1.4x on 300mmF2.8L
568921041_KMoMx-L.jpg
 
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gsgary, I zoomed your bottom image (#88) to 300% and it appears flawless to my old eyes. Now that you are boldly going where no one has gone before :sillysmi: , when can we expect to see some shots with Kenko's 3X teleconverter?
 

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