2x Teleconverters??

I want to purchase a 2x digital teleconverter for my 70-300mm lens. I lassalready know that adding extra glass will reduce some quality. My question is of the ones you guys have used, what am I better off going with: Tamron, Vivitar or Bower. The Bower was the most expensive, BUT if the optics are going to be much better, I'm willing to pay it. So what do you guys use and advise to use in the price range of $75-125??? Thanks guys!!

I'd save my money and use that for a possible upgrade in the future.

I'd only recommend a 2x teleconverter for the best of lenses (the "L" telephotos, especially the super-telephotos and the 70-200 2.8). For a 70-300 I'd imagine the results wouldn't be worth the money. As well, I don't know if I'd trust any of those brands, especially the latter two.

Here's a shot with a 2x II on a 500/4:

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I agree with birder-herper, 2x TCs are best on already very good lenses (preferably 2.8 or faster).

However, if you want to try one without investing much, I have one for sale, a Kenko MC7 2x, it is pretty sharp.

https://photography-on-the.net …861&highlight=k​enko+2x+tc

Here's an image with the Kenko 2x TC + Sigma 120-300 OS at 600mm:

IMAGE LINK: http://www.flickr.com …/29108710@N04/6​351097935/

I was looking at the Kenko one but it was so cheap (money-wise) that I didn't think it'd be a good one. I'll have to rensider that one now. That's why I wanted opinions from others to get ideas. Thanks guys!!

I'd all so save my money and use that for a possible upgrade of the lenses in the future. Personally I think the lenses you now use will disappoint you with an 2x extender.

Hi Shelly,

Unfortunately, when it comes to long lenses and teleconverters, you get what you pay for and there really aren't any cheap solutions that have any kind of very usable image quality.

As a rule, with 2X you want a 7 element (or more) design to have any hope of decent image quality. But it's going to be extremely dependent upon what lens it's matched up with, too.

Your lens won't autofocus with a 2X on it and the viewfinder will be extremely dark to try to manually focus. A 70-300mm f5.6 will be an effective 140-600 f11. It will also be a lot harder to hand hold steady... I hope you have a tripod or at least a monopod.

In fact, your lens isn't supposed to auto focus with even a 1.4X teleconvter on it (making it an effective 88-420mm f8)... but there are some ways to trick the AF into at least trying to work, when using third party teleconverters on f5.6 lenses.

The Canon teleconverters won't even fit on your lens, so are completely ruled out. All the Canon have a protruding front element design, and that won't allow them to mount on any of your lenses. (Note: the shortest Canon lenses that can be fitted with a Canon TC are the 135/2L and the 70-200mm zooms. Also, Canon calls their TCs "Extenders". That's sometimes confused with macro extension tubes, which are an entirely different animal.)

I also agree with previous response... few zooms work very well with 2X (the newish 70-200/2.8 IS Mark II and Canon 2X Mark III teleconverter are exceptions.... another is the Sigma 120-300/2.8 with a quality TC).

I'd suggest putting the money aside and start saving for a longer lens, such as Sigma 150-500 OS, which sells for roughly $1000 new. It can't really be used with teleconverter, either... But will give you more reach with good IQ for the money.

A bit more expensive alternative would be the Canon 400/5.6L... would likely give better overall image quality than a zoom, but it lacks any kind of stabilization so would largely be a tripod or monopod lens. Some 1.4X teleconverters would be usable with this lens, to give you an effective 560mm f8 lens, though in general you'll lose auto focus (there are some tricks to make AF work to some degree in good light).

For handheld shooting, I use 300/4 IS a lot, both with and without 1.4X (Canon, Mark II... giving me an effective 420mm f5.6). There's a little loss of IQ with the teleconverter... for example the 400/5.6L without any TC would be sharper... but the 300/4 IS and 1.4X is still a very good combo:

I just sold a Kenko MC7 2x TC to replace it with a Kenko DGX 1.4x as my lenses were mostly f4 and with the 1.4x I could still retain AF with them. When I had the 2x MC7 on my 100-400 L, set up with a tripod and focussed manually I could get photos of the moon that were far too big for my 23" monitor to show. Great IQ when focussed properly too, and for a price around £90 you cant go wrong.

what are you trying to shoot that you need a 2X TC?

Birds, moon, wildlife...

you do realize you'll have to manual focus, right?...that may be a bit difficult for birds/wildlife...

the reality is that with those TCs and the lenses you have that you will get better quality by not using a TC and cropping to get the FOV you want rather than by using the TC.

robonrome wrote in post #13630948
the reality is that with those TCs and the lenses you have that you will get better quality by not using a TC and cropping to get the FOV you want rather than by using the TC.

This is the truth of it. With the resolving power of today's cameras, cropping an image taken with good glass will do you better than trying to magnify an average lens with an average TC.

I did a bit of research when I was shopping for a TC, and ended up going with Canon's 1.4 mark II. The only lens I have that it works with is my 70-200 f4 L IS, and the IQ is still very good and the autofocus still works. I have made a 50% crop of a closeup image taken with that combo, and even the cropped image is very sharp.

It's a much better plan to just skip the TC and concentrate on taking the sharpest image you can with what you have, then crop to size in post.

@OP...do you know if a TC will even fit on your lens? Better make sure before you buy.

40D; Sigma 120-300 f/2.8 w/2xTC

...don't forget that a 2X TC is 2 x the focal length, 2 X the aperture, and 2X THE FAULTS OF THE LENS YOU MOUNT IT ON HAS.

People love to complain about losing IQ with TCs without considering the IQ of the lens they have mounted. Acceptable at 1X, borderline at 1.4X, truth at 2X.

Vivitar x2 TC,
https://photography-on-the.net/forum/showthre​ad.php?t=962469