What Kenko or Sigma converters for Sigma 120-300 OS

I am buying a Sigma 120-300mm f2.8 OS soon. I am planning to buy an 1.4 and 2.0 teleconverter along with it. The Canon teleconverters are too expensive for me.

Which converters are best to use with that lens on a Canon body? The Sigma 1.4 and 2.0 or the Kenko Pro 300 DG(X) 1.4 and 2.0 teleconverters? Or maybe a combination of both? They are around the same price in Belgium.

I've heard some say the sigma converters are best when used on sigma glass. Makes sense, but haven't seen any real proof of that.

facedodge wrote in post #14280452
I've heard some say the sigma converters are best when used on sigma glass. Makes sense, but haven't seen any real proof of that.

Me neither, that's why I doubt that. It is something like, Canon glass is always better than 3rd party glass on a Canon body. That is not always the case, a Tamron 70-300 VC for example will perform better than a Canon 55-250IS. With converters it is the same thing, I think.

^^ Stick with the Sigma TCs for that specific lens. My 120-300 was amazing with the Sigma TCs, but it didn't play nicely with the Canon or Kenko Pros that I have.

My Sigma 70-200s take Kenko and Canon TCs just fine, btw- so it's only an issue with the 120-300.

adamo99 wrote in post #14280755
^^ Stick with the Sigma TCs for that specific lens. My 120-300 was amazing with the Sigma TCs, but it didn't play nicely with the Canon or Kenko Pros that I have.

My Sigma 70-200s take Kenko and Canon TCs just fine, btw- so it's only an issue with the 120-300.

Did you have the old version of the 120-300, without OS or the new 120-300 f2.8 OS?

I had both version of the non-OS lens, the EX HSM, and the EX DG HSM.

Have both the Sigma 1.4 and 2X which work fine on mine, I also have the Canon 2X III which is a tad sharper than the Sigma, though not by very much and certainly not £££ sharper.

I've had 4 2x TCs and 1 1.4x. Out of the 2x ones, the Canon 2x III and the Sigma 2x APO DG EX were close, center sharpness equal, corners better on the Canon, the Canon also handled fringing much better. Still I kept the Sigma considering the cost difference. I also had a new, cheap kenko MC4 DGX that wasn't as good as I thought, clearly inferior to the Sigma and Canon. Also had an old MC7 kenko that was only about 1.85x, and fairly sharp but not as sharp as the Canon and Sigma.

As for the 1.4x I only have the Kenko 300 DG which is pretty good for the price ($150 from Hong Kong )

I have a Sigma 120-300 OS, and have the Canon v2 TC's, they work great on the Sigma. When I had my old 120-300 non-OS I used Sigma TC's, but sold them when I sold the lens, and picked up the Canon ones to use with my 70-200 VII.

If you stick to Sigma and/or Canon, I really don't think you can go wrong. The V3 Canon 2x is supposed to be better than the V2, however from what I've read you don't realize a lot of that difference unless you're using a full-frame camera.

Just my 2 cents. I'm happy with the Canons and they work great.

I am sure I would be very happy with the Canon version, but these are clearly out of my budget range.

So for the 2x converter, I think I'll choose the Sigma APO 2.0x EX DG. But for the 1.4x converter I still have no idea what would be best, the Sigma APO 1.4x EX DG or the Kenko Pro 300 1.4x DGX... They are approximately the same price in Belgium so it's a tough choice. Anyone any experience with those tc's?

I have an opportunity to buy a Canon 1.4 converter (version 1) at a rather attractive price, more or less the same price as the Sigma or Kenko ones would cost me second hand. Would that be a better converter? I saw that it was the same design as the version II but that the version II added weathersealing and some new coatings, not very important, no?

coatings are kind of important, depending on what their purpose is. Some coatings increase contrast, so they do improve image quality.

After spending $3200 on a lens, I wouldn't cheap out on the teleconverter to use with it.

But, I probably wouldn't buy both 1.4X and 2X. Think about it... with the lens alone you have 120-300mm covered... a 1.4X gives you 169-420mm equivalent. A 2X would give you a 240-600mm. The lens used with and without a 2X gives you every possible focal length from 120 to 600mm. A 1.4X gives you every possible FL from 120 to 420mm.

So, if I really needed 600mm, I'd just get a 2X and skip the 1.4X. A 2X might be my choice if I were using the lens on a full frame camera, for example. However, if using it on a crop camera, a 1.4X might suffice (I rarely find need for longer than about 400mm on a cropper).

Either way, I'd probably just get one TC and use it... If the other one became desirable sometime, it's easy enough to get it then.

I've not got the Sigma lens, but it appears to work well with a 2X and it's probably even better with a weaker 1.4X.

So I'd probably rent various TCs and try them out, to see which performs best with the lens, then buy whichever is best.

amfoto1 wrote in post #14300636
After spending $3200 on a lens, I wouldn't cheap out on the teleconverter to use with it.

But, I probably wouldn't buy both 1.4X and 2X. Think about it... with the lens alone you have 120-300mm covered... a 1.4X gives you 169-420mm equivalent. A 2X would give you a 240-600mm. The lens used with and without a 2X gives you every possible focal length from 120 to 600mm. A 1.4X gives you every possible FL from 120 to 420mm.

So, if I really needed 600mm, I'd just get a 2X and skip the 1.4X. A 2X might be my choice if I were using the lens on a full frame camera, for example. However, if using it on a crop camera, a 1.4X might suffice (I rarely find need for longer than about 400mm on a cropper).

Either way, I'd probably just get one TC and use it... If the other one became desirable sometime, it's easy enough to get it then.

I've not got the Sigma lens, but it appears to work well with a 2X and it's probably even better with a weaker 1.4X.

So I'd probably rent various TCs and try them out, to see which performs best with the lens, then buy whichever is best.

Thank you for your answer. I am a student and spending 2000 euro (more or less 2600 dollars) is quite a lot for me. I live in Belgium and wildlife and birds are less abondant and scared easily here. A lot of mm's is very useful, most professional wildlife photographers in Belgium I know use a Canon 500L f4 with a 1.4 teleconverter, so that is 700mm. For most applications a 2x converter would be useful, certainly when I am not in the blind. But when I am in the blind or I am photographing sports, cars etc, I won't be needing 600mm, but I might be needing 420mm, so a 1.4 converter offering better image quality at a rather small price (around 200 euro new or 125-140 euro second hand) I personally think it is worth buying.

The Canon III converters are 469 euro each, that is just a ridiculous price in my opinion, and it would only be a converter I would consider if I was buying one of Canon's new supertele's like for example a 400mm f2.8L II IS. I can get both the 1.4 and 2.0 converters of Sigma or Kenko for the price of one Canon converter...

I have found a good deal on a Kenko Pro 300 1.4 DG, so not a DGX. If I am right, this is the one you are using gabebalazs? I found some info on the internet about the body doesn't know it is on so you keep AF with lenses slower than f/4. But does it give information to the body about the aperture, so does it only trick the AF or do you get 1 stop underexposed images with it all the time, so you have to change the exposure every time?