WJShaheen Loc: Gold Canyon, AZ

Blair Shaw Jr Loc: Dunnellon,Florida

Wonderful results Blurryeyed.......love it !

robertjerl Loc: Corona, California

I have the Pro 300 1.4 and 2.0, my first extenders. I used to use them a lot but the last few years I only use the Canon 1.4x III on my 100-400L. Once in a while I will use the Kenko Pro 300 1.4x with my Tamron 180 macro. I use it in the yard for bees, butterflies and hummingbirds on an 80D or 7DII it gets the angle of view of a 403 mm lens and being a really good macro to start with it still has very good IQ with the extender. Great detail in the subjects if I do my part. AF is a bit slow, but pre-focus and ambush the subject works great. (the Tamron 180 macro doesn't have fast AF to begin with, but neither do most macros as the usual subjects for macro don't need fast AF)

Architect1776 Loc: In my mind

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

F4 is about the limit for decent AF performance. If it is a dedicated TC it is usually not a problem. I have a friend that shoots the 100-400 II with a 1.4x TC III on a 5D MkIII - and while the image quality is exceptionally good, the AF performance does suffer a lot, especially in lower contrast situations. It did not seem as snappy as my 150-600 Sigma Sport on a D810, and the image quality was about the same. It's hard to compare since the 5D has fewer pixels than the D810.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

The 300mm F2.8 and a 1.4X is excellent! Nice shot.

Blurryeyed Loc: NC Mountains.

Yes I am shooting the 300mm f/2.8 II, possibly the sharpest lens that Canon makes with MkIII extenders. I do use the 2X quite a bit with that lens, it works very well delivering very sharp images, what bill does not take into account is that an image shot at 600mm even with the extender will allow for more flexibility in post such as tighter cropping than an image shot with the same 300mm lens. All birders know that much of the time you just can't get close enough and have to crop, even with your 600mm lens. Below are two versions of the same image taken with the 300mm and the 2X extender from some 300 ft or so, distance was hard to tell, the bird was collecting nesting material on an island on the other side of the channel.

The crop would probably support a 10X14" print, had I taken this image with the 300mm lens without the extender it would hardly have supported the crop on a computer screen as the enlargement on screen would begin to pixelate before filling a 21 inch screen. My ability to crop so tight is a combination of all three, camera, lens, and extender, but this setup would perform about the same on a crop camera as it does the 5DSr. The pixel densities of the 80D and the 5DSr are very similar

When I purchased this lens I exchanged PM's with Regis who has some pretty impressive Canon gear over the last few years but this is his current setup. He convinced me it was a good investment so I went ahead with it, really wondering if a 300mm lens and extender could out preform the 500mm f/4 L IS I had at the time, well to make this story short it did, better results than the 500mm even with the 1.4 extender attached to it. Packed that 500mm up and sent it out to Montana.... I am sure that MT has sold it by now.

This is not the best image to show this with because it is a bit front focused so the bird is not as crisp as it should be but the grass in front of him is, but the point was that the bird resides on many more pixels with the extender allowing for more flexibility in post.

Downsized Image

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robertjerl Loc: Corona, California

I believe I need to add a warning to what I posted about the Kenko 1.4x and Tamron lenses.

Though I used it with very good results with a Tamron 150-600 G1 lens, it becomes manual focus of course, I just check today after posting and the G2 version of the lens gives an error message that the lens and body are not communicating. Since the Tamron 100-400 is the same design generation you had better check with both Tamron and Kenko to see if their extenders will work with the newer Tamron lenses. You may have to use a Tamron extender.

While I was at it I tried my other 1.4x (Canon 1.4x III) and it not only communicated but the image was clear, crisp and manual focus seemed to "snap" in very well. I am about to import and go over the test shots I did and will post some of them if they look as good as I think they will.

Now, I didn't say anything before, I am assuming you got the Tamron because of cost, but why not the Canon 100-400? I used to own a mk 1 and now the mk 2 version and my Canon 1.4x III has been used with both versions, getting outstanding results with both. On the mk2 it does AF faster and the IQ is a bit higher at some zoom settings. However pictures in my files done with the mk1 are very very good IQ and if I still had it I would be able to get by without too many regrets.

rehess Loc: South Bend, Indiana, USA

Back when I was a Canon Rebel user I purchased an older Kenko 2X converter from Roberts. The combination should have reduced light enough to make focusing iffy, but the converter didn't report itself, so the camera didn't know it was supposed to have problems.

bwana Loc: Bergen, Alberta, Canada

Look at the Kenko 1.4x or 2x. I have both and they fit every lens I own. Not the same with the Sigma 1.4x or a no name Chinese one I bought.

The above said, I wouldn't recommend any 2x extender.

bwa

tommyII Loc: Northern Illinois

Always get the extender that is meant for the lens you have. Get the Tamron.

Scruples Loc: Brooklyn, New York

I purchased a 2x extender for my 100-300mm lens. I thought that this was the greatest thing since sliced bread. Even though both were Canon labeled, I was confused as to why it was cheaper than an off market manufacturer like Tamron or Rokinon. Great, I thought that I was getting two lenses for less than the price of the larger lens. I also wasn't carrying as much glass. No worries here. I used them in conjunction for two months. Now, not so much. For the most part it takes up space on my bag. As for its weight, it's nominal and hardly noticable. What was disturbing was the fact that I needed to use slower shutter speeds and wider f/stops. I was forced to increase my ISO which would otherwise "bleach out" many photographs. I also didn't like the density of the photographs. They appeared to have more "noise."

There are several caveats when using an extender. Expect to lose two f/stops to compensate. And no, it is not a multiplier as many believe. With the three or four elements it will extend the zoom lens even further from the sensor than before.
It may or may not be a good idea. With that being written, save the money on an extender and use it elsewhere, like taking your spouse out to a nice dinner and a show. It will be appreciated.

Happy Shooting!

rehess Loc: South Bend, Indiana, USA

If it isn’t a “multiplier” what is it? It turns a true 300mm lens into a true 600mm lens.

amfoto1 Loc: San Jose, Calif. USA

It is accurate to say that any teleconverter reduces image quality to SOME extent. It really depends upon the lens/TC combo though. Some work very well together, so that there's no significant loss. Others, not so much.

Generally speaking, prime lenses work better with TCs than zooms do. This isn't a hard and fast rule. Just a generality. You need to find someone using the exact same lens with the exact same teleconverter... or just buy and try, from a place that allows returns in case the results aren't up to your expectations. I can't tell you how well the Tamron 100-400mm works with teleconverters. I can tell you that the Canon EF 100-400mm IS USM "II" works extremely well with a Canon EF 1.4X II. That's a combo I sometimes use together. (I also use that 1.4X II on EF 135mm f/2L, 300mm f/4L IS, 300mm f/2.8L IS and 500mm f/4L IS lenses. I've also got Canon EF 2X II that I occasionally use on EF 300mm f/2.8L IS and more rarely on 500mm f/4L IS lenses, but not on any zooms.)

1.4X teleconverters generally have a lot less impact on image quality than stronger 2X teleconverters.

One thing you need to watch out for is that the Canon teleconverters have a protruding front element. That needs to fit inside the rear barrel of any lens they are used upon. Many lenses don't have large enough rear barrel OR have rear elements that might interfere with the teleconverter. The current Tamron and Sigma APO 1.4X teleconverters also appear to have slightly protruding front elements, although there's less protrusion than the Canon.

If it will fit, you might consider the Canon 1.4X II... the older version... used. It can be found for considerably less than the current III sells for new. The optical quality of them is very similar. I'd challenge anyone to tell apart images made with these two versions of Canon 1.4X. I just found a used 1.4X II at B&H Photo in top condition for $219. That's half the price of the 1.4X III new.

The earlier Kenko 1.4X TCs I've had some good experience with. They are much more affordable, yet are pretty good... and they don't use a protruding front element, so can be fitted to a wider variety of lenses. I have had no experience with the current "HD" Kenko, which prime claim to fame is that they can accommodate both EF and EF-S lenses. (They're the first TCs that can do so, I think... though IMO there aren't any EF-S lenses that it would make sense to use with a TC... maybe the EF-S 55-250mm, though I would expect a pretty strong hit to IQ and pokey autofocus.)

If you can find the previous version Kenko Teleplus 1.4X "Pro 300" DG (or DGX), those are quite good and affordable.... sold for around $160 new. The "Pro 300" version has good image quality from corner to corner, so might be a better choice for a full frame camera such as you're using.

On most lenses, the even less expensive Kenko Teleplus 1.4X "MC-4" DG (or DGX) is actually one of the sharpest TCs I've seen... at the center of the image. In fact, it rivals the IQ of the Canon TC's, but the Kenko MC-4 goes a little "soft" out toward the corners of the image area. This wouldn't be very noticeable on an APS-C crop-sensor camera, but may be on full frame. Of course, in many cases some corner softness also doesn't matter. It might even be desirable in many images. I don't know current pricing, but the Kenko 1.4X MC-4 originally sold for around $125.

The Kenko teleconverters' "DG" and "DGX" designations represent some slight changes in the electronics. The DGX is a later version that might offer some slight improvement in autofocus performance... but not enough to worry about, IMO. With a 1.4X teleconverter on a lens that's already f/6.3 (so becomes an f/9 combo), I wouldn't expect great AF performance anyway. It's probably going to need good light. I don't have the Tamron 100-400mm and don't currently have any of the Kenko TCs... so can't really say how specific combos might work together.. But, for the money it might be worth trying one or the other of the Kenko.

Here are links for info about the Kenko 1.4X Pro 300 and MC4... The Pro 300 is still available new, but the MC4 isn't (if you want one, you'll probably have to track one down used)....

Kenko Teleplus 1.4X MC4 DGX: https://www.bhphotovideo.com/c/product/674589-REG/Kenko_MC4AF1_4DGXC_TelePlus_MC4_AF_1_4X.html

Kenko Teleplus 1.4X Pro 300 DGX: https://www.bhphotovideo.com/c/product/674565-REG/Kenko_PRO3001_4XDGXC_Teleplus_PRO_300_DG.html

This is the Canon 1.4X II that I use now: https://www.bhphotovideo.com/c/product/801956188-USE/canon_6845a004_1_4x_ef_extender_ii.html

imagemeister Loc: mid east Florida

Optically, they are VERY similar - the biggest difference is with AF control on series II lenses.....
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