Lens extenders

Forums Forums Get Technical Hardware Lens extenders

Viewing 7 posts - 1 through 7 (of 7 total)
  • Author
  • #1596

    So, what’s the verdict on these things? From what I have read, they have their niche. I can see trying them on my 100mm f/2.8 macro and my 70-300mm f/4.5-5.6 DO IS zoom.

    Will auto-focus work with the slower tele-zoom?



    I have the Canon 2x and I use it with my 70-200 2.8. In my opinion, this extender – and probably the other one as well – is a mediocre but necessary solution to a problem. The problem is, there’s no way to get that kind of length out of a lens that’s in any way practical. A 400 (or 500 or 600) just isn’t a realistic purchase for a hobbyist when rentals are available. That said, my 70-200 with the 2x extender turns out pretty mediocre results considering the cost of the equipment involved. They’re not bad, they’re just not great. Hand-holding is almost out of the question (though I’ve done it) and the IS is not as good but still works. The autofocus is noticeably slower, but not slow enough to cost me too many photos. Using it on a tripod with the IS turned off and focusing manually seems to produce the best photos.

    One thing to note, I don’t think the 2x extender will work with your 70-300 and I’m not sure about the 100. Many Canon lenses simply don’t mount up to this thing (regardless of aperture) and it seems to be a source of consternation for everyone who looks at buying one. Research carefully.

    My advice would be that if you have a specific project or photo in mind, save the money you would spend buying one of these and use it to rent a 400 2.8 for a week or two. If you just want to have the ability to throw it on when you see something a long-ass way away (and it will work with the lenses you already own) then it’s probably not a bad thing to have in your bag. If you have to buy a new (and probably more expensive lens) just to make it work, don’t bother; it’s not worth it.

    Hope that helps!


    Replace Canon with Nikon and Kenko, and my comment would be a carbon copy of Miller’s.

    One additional point though, is that I went with the tele-extenders for solar shots and general reach-out-and-touch, so I was not terribly concerned with the increased f/number or the downright lack of auto-focus (when using a 2X and a 3X in series with my 70-300mm). What kills me is the incredibly shallow DOF. You’d think at 93,000,000 miles, something as wide as 100 or so Earth’s would be easy to focus on, but not so much.


    I’ve got (somewhere) a Tamron 1.4x extender, and I really can’t stand the results it gives on my 100-400. However, I have a friend who uses a Canon extender on his 500mm prime, and it gives lovely results. I think a lot has to do with the lens they are used on.


    I think part of the problem is that you’ve got to stop down a bit to get anything resembling decent quality unless the lens you’re using is incredibly good. When you’ve got a F4 or 5.6 zoom that loses 2 more stops to the converter, you need a lot of light to stop down a couple of stops to get decent results.


    I read a bit more after my initial post. That reading goes along with what you all have shared. They are in the not so great category.

    /Thanks for the input.


    Any ideas on if the 2x works with the Sigma 70-300mm ? I was considering getting one to use with that lens. Could be interesting to stick it on my nifty fifty assuming it would fit.

Viewing 7 posts - 1 through 7 (of 7 total)
  • You must be logged in to reply to this topic.