Teleconverter Pros and Cons

[mjschocken]

I have a Canon Eos 80D and a Canon 100 - 400 mm F4.5 - 5.6 L IS USM lens and use them mostly for bird photography.  I think the 400 mm is not enough to capture small birds that tend to be skittish of humans.  Admittedly, I have lens envy when I see birds photographed with a 600 or 800 mm lens.  In generally, I really like the lens that I have but want to consider getting a teleconverter, at least a 1.4X.  I know about giving up an F stop but it's less clear to me about the effects of the teleconverter on focus points (I have 1, 9 and 45 on the camera) and on autofocus.  I would also like to know your thoughts on the pros and particularly the cons of using one.  Appreciate your feedback but if I'm asking a question that's already been asked, please let me know and I'll try to find the discussion.  Thanks.

[TTMartin]

---

@ebiggs1 wrote:

"The EF 100-400 L IS II with the 1.4X III extender still bests the image quality of the Sigma or Tamron 150-600s."

Of course this is wrong.  Even if you take published data on the three lenses mentioned, they are nearly identical in IQ.  Actually owning and using all three confirms it.  Adding a teleconverter to any one of them vs one without one, will degrade its IQ.

---

Your statement that they all have nearly identical image quality is false. The Tamron lags the other lenses in the group. That has been shown by a number of testing and comparison sites. And the used market for those lenses is the biggest indicator of that. The Tamron 150-600 now sells on the used market for well under a thousand dollars, and only about a $100 more than the Sigma 150-500 OS that you've often maligned here. 

All of the testing and comprison sites confirm that the EF 100-400 L IS II with the 1.4X III extender still bests the image quality of the Sigma or Tamron 150-600s.

The easiest way to see for yourself is at the-digital-picture.com That's at 600mm stopped down to f/8 on the Tamron, and roll over to see the Canon at 560mm f/8 at the center there isn't much difference, but, by the time you get to the corners it is clear that the Canon has superior image quality..

[ebiggs1]

Too bad you don't spend more time doing and less time reading.  You would learn a lot more.  But to each his own, I guess.

[amfoto1]

Look and decide for yourself.

[Removed link per Forum Guidelines]

Compared to the 100-400 II with 1.4X III teleconverter, it's fairly obvious ...

- Tamron 150-600mm G2 is pretty equal at the center, but slightly softer away from the center at 500mm, and more-so at 600mm.

- Original 150-600mm is softer away from the center at both 500mm and expecially at 600mm.

All the comparisons I did were on full frame (1DSIII) and "wide open" in all cases (that means effective f/8 on the 100-400 + 1.4X and 1/3 stop faster f/6.3 on the Tamron lenses). The selectable focal lengths are slightly different, too... 560mm for the 100-400 + 1.4X versus 500mm and 600mm with the Tamrons.

I'll leave it to you to compare other settings or the comparable Sigma lenses, if you wish. If you do so, just be sure to select the same camera body for the comparisons. It doesn't really matter which camera, so long as the same one is being used for both the lenses in the comparison.

Compared to the Tamrons, while the center on all of them seem pretty similar, it looks to me as if the 100-400mm II with 1.4X is slightly superior in the corners and at the edges... on a full frame camera. Using any of these lenses on crop sensor cameras, the difference would probably be pretty hard to see.

I've got the 100-400mm II... but haven't had chance to try it with 1.4X yet. Using it on APS-C cameras (7DII), I just haven't needed any more than 400mm yet. Not sure if it will work as well with the 1.4X II that I have, as it appears to with the 1.4X III. 

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2) some other cameras, various lenses & accessories
FLICKR & EXPOSUREMANAGER 

[TTMartin]

Deleted

[TTMartin]

Deleted

[mjschocken]

After a lot of reading outside and inside of this forum, talking to a few friends that have the teleconverter, and based on the image quality of photos provided priimarily by TT Maritin, I ordered the Canon extender III to go with my Canon 100 x 400 mm EF IS USM II zoom lens.  The only difference between him and me is that I have the Canon 80D and he has the Canon 7D Mark II so he has the next Canon rung up.  Hopefully I'll get good results as well.  I'm calling this lens "the kingfisher" because, if you're a bird photographer, you'll know why.  Thanks hugely for all the comments and discussion.  I'll let you all know how it goes in a few weeks.

[mjschocken]

By the way, I ordered the 1.4X extender which I failed to mention.

[ebiggs1]

Only believe 1/2 of what you see and very little of what you read.

[amfoto1]

---

@mjschocken wrote:

...difference between him and me is that I have the Canon 80D and he has the Canon 7D Mark II so he has the next Canon rung up...

---

Actually, your 80D has an excellent AF system for this particular lens + teleconverter combo. The 80D has 45-point AF, with up to 27 "f/8 capable" points.

The 7DII's 65-point AF may be superior in some other ways, but it only has a single "f/8 capable" point, at the center.

Keep us posted how you like the lens and TC combination after you get a chance to make some shots with them.

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2) some other cameras, various lenses & accessories
FLICKR & EXPOSUREMANAGER 

[mjschocken]

I used my new extender EF 1.4X III with my Canon 100 x 400 mm f4.5 - f 5.6 II yesterday at Circle B Bar Reserve in Lakeland, FL, my go-to birding spot.  (By the way, for those of you who might live in the area and don't know about Circle B, check it out.  Fantastic for Florida birds and other wildlife). For perched birds, it seemed to work very well.  Image quality was quite good at 560 mm.  I could capture birds in flight (in this case, great blue herons) but I did have a lot of trouble autofocusing on a bald eagle hovering in the air.  It seems like the speed of autofocusing is slowed in general with the extender.  Through the morning, I only used the single focusing point and have to try 9 or 27 points.  Overall, my initial experience was good for my limited sampling but the verdict is out for birds in flight.  I will report back in a few weeks when I have more experience with the extender on this lens and get a chance to photograph a belted kingfisher, hopefully both perched and in flight.  That will be my litmus test!