Which Canon DSLR Cameras Maintain Autofocus with Extenders at f/8 Max Aperture?

The subject of autofocus (AF) at an f/8 maximum aperture often comes up in my writings about DSLR cameras, lenses, and telephoto lens techniques for subjects like sports and wildlife. It’s an often misunderstood subject, but it also continuously raises questions about which cameras will still provide AF when used with a lens+extender combination that delivers a max aperture of f/8.

Can Canon Mirrorless Cameras Autofocus at f/8?

Canon’s RF mirrorless cameras and RF lenses use a different autofocus system than their DSLR cameras. Canon mirrorless cameras are not subject to the same f/8 autofocus limitations. Though you will see slower and less accurate autofocus performance with lenses with a maximum aperture of f/8 or smaller, Canon RF cameras will still focus. This includes using adapted EF lenses on a Canon RF mirrorless camera using the Canon EF to RF adapter.

A Two-Part Question – Lens and Camera

Whether a DSLR camera will autofocus with an f/8 max aperture doesn’t tell the whole story these days. Every year Canon is expanding the capabilities of its AF systems, and the result is that more and more DSLR cameras do feature AF at f/8 to varying degrees. Some cameras will only allow the AF to work with a central AF point, and some will allow AF with the full gamut of AF points.

The table in this guide will tell you whether any sort of AF is possible with your camera at f/8, but it will also try to provide up-to-date notes on which AF points work at f/8 and beyond. This last part has become a little more complex in recent years because some newer lenses now deliver such improved AF performance that they allow more AF points to be used at f/8 than some older lenses.

Is Your Lens f/8?

To find out the maximum aperture of your lens+extender combination, you first need to know the lens’s maximum aperture in its native form. This will be written on the lens and in the specifications. The most common is f/1.8, f/2, f/2.8, f/3.5, f/4, f/5.6, and f/6.3.

Next, you need to know that a 1.4x extender will increase the maximum aperture by one stop, and a 2x extender will increase the max aperture by two stops. For more information on extenders and the math behind this increase, you can read my ultimate guide to extenders and teleconverters.

If you are a bit rusty on your f-stops, then you can refer to my f-stop chart in order to count either 1 or 2 stops up the chart from where your lens is.


  • Canon 70-200 f/4 L IS + 2X Extender -> f/8
  • Canon 800mm f/5.6 L IS + 1.4X Extender -> f/8
  • Canon 500mm f/4 L IS II + 2X Extender -> f/8
  • Canon 100-400 f/4.5-5.6 L IS II + 1.4X Extender -> f/8

Special Note About the 5D Mark III

When this camera was first launched, it did not provide AF at f/8. This ability was added in a firmware update in April 2013, when the firmware was bumped up to V 1.2.1. If you have a 5D Mark III that does not appear to be working for AF at f/8, perhaps you have not updated the firmware. This is especially possible if you purchase a second-hand camera. Check that firmware number in the menu system!

Special Note About the 1D X

The 1D X also launched without the ability to AF at f/8, but this was quickly addressed with a firmware update in October 2012 to Version 1.1.1. If your 1D X doesn’t appear to be delivering AF at f/8, please check your firmware!

Tricking Cameras With 3rd Party Extenders

I’m aware that, in some cases, it’s possible to trick some older cameras into providing some basic AF with f/8 lens combinations. In particular, the 70D and 7D come up in conversation quite often when used with Kenko extenders or by taping over the contacts of a Canon extender, so the camera isn’t aware of exactly what is attached to it.

This non-recommended functionality is impossible to comment on because there are too many permutations. The information in the table below and the footnotes are the official words from Canon. While some other things may be possible with some fiddling and trickery, you will not get reliable AF in those situations, nor an AF speed comparable to officially supported options. I wouldn’t bother with them. Cameras that officially offer f/8 AF are available on the second-hand market for such great prices these days that it’s not worth faffing around with sub-standard options.

Which Cameras Support AF at f/8?

Camera Modelf/8 AF Possible?Which AF Points are available?
Canon 1D X Mark IIYesUp to 61 points (with version III extenders) See footnote.
Canon 1D XYesCentre cross-type AF point, or centre+ surround.
Canon 1D CYesCentre cross-type AF point, or centre+ surround.
Canon 1D Mark IVYesCentre AF point only (linear point)
Canon 1D Mark IIIYesCentre AF point only (linear point)
Canon 1D Mark II NYesCentre AF point only (linear point)
Canon 1D Mark IIYesCentre AF point only (linear point)
Canon 1DYesCentre AF point only (linear point)
Canon 1DS Mark IIIYesCentre AF point only (linear point)
Canon 1DS Mark IIYesCentre AF point only (linear point)
Canon 1DSYesCentre AF point only (linear point)
Canon 5DSYesCentre cross-type AF point, or centre+ surround.
Canon 5DS rYesCentre cross-type AF point, or centre+ surround.
Canon 5D Mark IVYesUp to 61 points (with version III extenders) See footnote.
Canon 5D Mark IIIYesCentre cross-type AF point, or centre+ surround.
Canon 5D Mark IINoN/A
Canon 5DNoN/A
Canon 6D Mark IIYesCentre AF point only, except for two lenses which can deliver 27 points. See footnote. (100-400 II and 200-400)
Canon 6DNoN/A
Canon 7D Mark IIYesCentre cross-type AF point, or centre+ surround.
Canon 7DNoN/A
Canon 90DYesUp to 27 points
(9 of which are cross-type) See footnote.
Canon 80DYesCentre AF point only, except for two lenses which can deliver 27 points. See footnote.
Canon 77DYesCentre AF point only, except for two lenses which can deliver 27 points. See footnote.
Canon 70DNoN/A
Canon 60DNoN/A
Canon 50DNoN/A
Canon 40DNoN/A
Canon 30DNoN/A
Canon 20DNoN/A
Canon 10DNoN/A
Canon 800D/Rebel T7iYesCentre AF point only, except for two lenses which can deliver 27 points. See footnote.


6D Mark II

27 active points with the 6D Mark II and certain lenses (listed below). The ones highlighted in blue continue to work as cross-type AF points.

Unlike the original 6D, the Mark II will give you some use with f/8 combinations in the same was as the 80D.

  • AF at center AF point, when any Version I, II or III Canon tele extender is used with compatible EF tele lenses
  • AF at 27 focus points, and the central 9 points acting as cross-type points, with the following lens + extender combinations:
    • EF 100–400mm f/4.5–5.6L IS II lens, with Extender EF 1.4x III
    • EF 200–400mm f/4L IS Extender 1.4x lens, used with Extender EF 2x III

1D X Mark II & 5D Mark IV

61 AF Points

  • EF 100–400mm f/4.5–5.6L IS USM (lens versions I and II) + EF 1.4x III
  • EF 200–400mm f/4L IS USM with built-in 1.4x + EF 1.4x III
  • EF 200–400mm f/4L IS USM + EF 2x III
  • EF 400mm f/5.6L USM + EF 1.4x III
  • EF 400mm f/4 DO IS USM (lens versions I and II) + EF 2x III
  • EF 500mm f/4L IS USM (lens versions I and II) + EF 2x III
  • EF 500mm f/4.5L USM + EF 1.4x III
  • EF 600mm f/4L (all lens versions) + EF 2x III

13 AF Points

  • EF 300mm f/4L USM (IS and non-IS) + EF 2x III
  • EF 70–200mm f/4L USM (IS and non-IS) + EF 2x III

9 AF Points

  • EF 70-200mm f/4L USM (IS and non-IS versions) + EF 2x I and II
  • EF 100-400mm f/4.5-5.6L IS USM (lens versions I and II) + EF 1.4x I and II
  • EF 200-400mm f/4L IS USM (with built-in 1.4x) + EF 1.4x I and II
  • EF 200-400mm f/4L IS USM + EF 2x I and II
  • EF 300mm f/4L USM (IS and non-IS) + EF 2x I and II
  • EF 400mm f/5.6L USM + EF 1.4x I and II
  • EF 400mm f/4 DO IS USM (lens versions I and II) + EF 2x I and II
  • EF 500mm f/4L IS USM (lens versions I and II) + EF 2x I and II
  • EF 500mm f/4.5L USM + EF 1.4x I and II
  • EF 600mm f/4L USM (all lens versions) + EF 2x I and II
  • EF 800mm f/5.6L IS USM + EF 1.4x I, II and III
  • EF 1200mm f/5.6L USM + EF 1.4x I, II and III

EOS 90D, 80D, 77D & 800D (Rebel T7i)

Lenses providing this broader 27-point coverage at f/8 effective maximum apertures with the EOS 80D/90D/77D/800D are:

  • EF 100–400mm f/4.5–5.6L IS II + Extender EF 1.4x III
  • EF 200–400mm f/4L IS Extender 1.4x lens + Extender EF 2x III (built-in extender not used)

If you are not using one of these combinations, you will be limited to a single central cross-type AF point. This is often a point of HUGE confusion for Canon users because Canon makes a big deal about f/8 autofocus being available for “up to 27 AF points”. They hardly mention that it only works with these two lenses, and if you don’t have either, you get one central AF point. It’s still not bad, though. It wasn’t long ago that you got no AF points at f/8 in this camera level.

Even more confusing for Canon users is that Canon appears to have removed the lis of compatible lenses from the manual for the 90D, even though it was included within the manual of the 80D, 77D etc.

Photo of author
Professional photographer based in Yukon, Canada, and founder of Shutter Muse. His editorial work has been featured in publications all over the world, and his commercial clients include brands such as Nike, Apple, Adobe and Red Bull.

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86 thoughts on “Which Canon DSLR Cameras Maintain Autofocus with Extenders at f/8 Max Aperture?”

      • Hi Dan,
        I’m thinking about changing 70D to 90D. I have a Sigma 150-600mm f5.6-6.3 lens. If I understood correctly, adding a 1.4 x converter will make the max aperture slightly higher than 8, so the autofocus should not work. On the other hand, the Sigma compatibility chart claims that this combination of lens and converter is working in good light conditions for cameras maintaining autofocus at f8. Can you please share your opinion on this matter? Thanks a lot – Gosia

        • Yeah that’s an odd one. If Sigma claim that it works then I guess it probably does, but I have never used that lens myself so I can’t be certain. That said, given that even Canon’s best of the best $10,000+ lenses often struggle to focus at f/8, using a native autofocus protocol, I would say there is no way you will get what most people would call “good” autofocus performance from this combination, even if it does technically work in some way. You can forget about using it to track fast moving subjects… And I also doubt that the image quality will be that good. These long focal range zooms are simply not designed to work in this way. Personally I would not recommend it. You have a 600mm lens on an APS-C camera already which is a HUGE amount of reach (960mm equivalent field of view). The vast majority of my own professional wildlife work has been done with a 400mm lens, sometimes with a 1.4x, on a full frame camera, so basically a maximum of 560mm. I just think the performance degradation you are going to run into is not worth the hassle or money.

          • Hey Dan,

            I have the Canon 80D, the sigma 150-600mm C, and a 1.4x Sigma APO DG teleconverter. As you mentioned there is only a single point of Autofocus through the viewfinder which I wasn’t overly thrilled about because of Canons lets call it “false advertising”. However I realized that if I switched to live mode it would give me different focus options and upto 9 focus points which is all I need. The lens would keep searching for the subject and wouldn’t regularly find through the viewfinder, but once I switched to live mode I found it to be a lot more reliable. Don’t get me wrong at certain distances (depending how small the subject was) it would continue to search and never lock on but once the subject got to a certain size it will lock on 90% of the time. I use my camera primarily for taking pictures of overhead aircraft at anywhere from surface to 45,000 feet. Live view does well tracking and capturing fast moving subjects at least in my case! I used to be a viewfinder shooter, but now I’m adapting and I believe live view is better for my shooting style especially when using an extender!

          • I have the Sigma 24-70mm f/2.8 Art, 70-200mm f/2.8 Sports, and the 100-400mm Contemporary (which is several years newer than the 150-600mm C/S. My bodies are 80D & 6DII. Both my cameras will AF with the Sigma 100-400+1.4X TC-1401. Even in broad-day, autofocus is so slow as to be un-useable (at 400mm). Unless the subject is in direct, bright sunlight, AND is a high-contrast object, the AF simply fails to lock. More over, the results are sub-par. Photos look nice enough, but there is no fine detail, which means you are using the full frame, or nothing. Cropping just amplifies the lack of detail. The photos are just not sharp enough to allow for any cropping.
            The 100-400 by itself is quite good. I’ve shot the 150-600 C; it is also quite good… without the TC-1401. I find neither of theses lenses to be of much use with the TC-1401. The results, on the rare occasion when the AF does work, are not worth the trouble.
            BTW, I am an amateur hobbyist, not a paid professional. The TC-1401 is very useful and has negligible impact on IQ with the 70-200 Sports. That lens is the ONLY reason I am keeping the TC-1401.

            • Thanks for sharing your experience. I’m not surprised to hear you get sub-par results. I have only ever been happy with teleconverter images when the TC is paired with a very expensive pro-grade lens. Sigma lenses are incredibly good value, but when you push them to the limit, as you are, they will show weakness compared to L series Canon lenses. The same goes for autofocus performance.

      • Thank you Dan. Yes it’s kind of funny that Canon didn’t mention that the 27 point AF at f/8 works only with the a/m lenses! One of the two reasons for my buying 90D today was this gimmick 27 points AF at f/8. I own none of those two lenses though have sth better in EF 70-200mm f/2.8L and EF 300mm f/2.8L IS II. But I don’t need any extra support for these two amazing glasses as they AF nicely even with 2x extender at f/5.6 on all points.

        I want to pair the new camera with my BIF lens EF 400mm f/5.6L USM. But alas, it’s limited to only the center point. Ok, I’ll have to augment my hunting skills on this one point facility. I had it already with 1DIV. With 90D there’s still some gain in weight reduction and little longer reach.

        Thank you for the valuable information.

    • Hi Dan

      I have a basic EOS 1200D which i use with a 100-400 EF mk1, i have acquired both a Canon and a Kelko 1.4x Extender, which dont AF on the body
      I was considering either a 5D mk3 or a 80D, to use with either extender, will the 80D AF, i believe the 5D will, which is the better body, im pure amateur, shooting aviation
      I will be looking to purchase S/H

      • I think for your type of shooting I would go with the 80D. The crop-factor will give your lens more reach, and mean that you don’t need to use the 1.4x extender nearly as often. If you do put an extender on the lens with the 80D, I believe with that lens, you will get centre-point AF only, and I think the same thing can be said for the combination on the 5D Mark III.

  1. Hello,
    This is the first time seeing your site. Very nice and I love the way you explain EVERYTHING. I will be the first to admit I don’t understand everything about cameras but photography is one of the great loves of my life. So I keep thriving and I keep buying. It seems as though overtime I buy “the latest addition” something new comes out. I live in South Louisiana. I am not sure if you are familiar with Lake Martin, but the birds and other wildlife are amazing. I live on the Intracoastal Waterway. Needless to say I am surrounded by wild life. People post pictures they have taken at Lake Martin. I know several of them. I can’t tell you the amount of money I have spent on cameras and I will admit my photographs are not bad at all. But last week I noticed a photo that took my breath away. I messaged the man and asked what camera he is using. 7 D Mark II with the 100-400 Lii. Now I am reading on your site about the 860 zoom. I am getting older now so the time it takes for me to drag every thing around is getting more and more precious. When I make the effort to travel I want the best photos I am capable of getting. I am willing to spend the money. Please let me know what I need and the approximate cost. The camera, the lens, the extender. Not that I am not already very proud of the photos I have been taking, I am certainly not blown away the way I am when I can see every little feather on the beautiful egret, heron and eagles not to mention the other wildlife out there. I am very detail oriented and I love seeing every detail of what there is to see. I hope to God this email doesn’t sound crazy or ridiculous to you but Help, tell me what to buy and where to get it. I usually buy from Adorama but I see you have a store….I want beautiful photographs for my effort. HELP ME..PLEASE! And by the way, if you are ever in South Louisiana I can show you some “dynamite” places in South Louisiana, I will even take you. Claire Whitaker

  2. Dear Dan, Thanks for such an informative detail, a simple question, Will the lens 100-400, other than AF, perform accurately on cameras like 60D and 70D, with 1.4 TC

    • There’s very little effect. A polarizing filter does cut some light, maybe 1-stop in some filters, so in very dark scenarios it might slow things down a little. AF systems work better when more light comes into the lens, but I don’t think I’ve ever really noticed a difference in a real-word scenario.

  3. Hello Dan,

    I was thinking about to buy canon 70-200 f2.8 ii + 1.4x iii canon with canon 80d (I won the body now). It will give around 450mm (if I’m right) which is fine for me. Also sometime I can use portrait with f2.8. This is my hobby and I don’t earn any money from photography.

    I loved to take birds pictures and portraits sometime.
    Any suggestions? Thnkas

    If I use 70-200+1.4x how many points will work? All 45?

    Canon 100-400mm mark ii + 1.4x? Maybe


  4. Hi Dan,

    Looking at getting the EF 400mm f/5.6L USM for use with my Canon 80D and the 1.4x III, will Autofocus still work and how many focal points will there be?

  5. Hi
    Thanks for the useful information. I’m in the market for a 100-400 II lens. Does the type of 1.4 TC matter for autofocus with a 5D markIII? What’s the difference in the various versions eg III vs earlier?

    • Stay away from version 1, optically inferior. Version 2 and 3 are optically extremely similar, but version 3 delivers faster AF with Canon’s Mark II super telephoto lenses: 300,400, 500, 600, and also 200-400 if memory serves me right. As for the difference with the 100-400 II… according to Chuck Westfall, a canon spokesperson, there will be little difference. I should point out that he did not tell me this directly, I have just seen someone else quoting him on this and that’s all I have to go by.

  6. Hi Dan,
    Thanks for the valuable compatibility details, very useful indeed. I do have a Canon 5Dsr camera and planning to buy a Canon 100-400mm is II lens. But interested in using the new Canon 2X teleconverter with. Is this possible.

    • Yes, as it states in the table, you will have Centre cross-type AF point, or centre+ surround af points with the 5Dsr and the 100-400 + 2x.

  7. Hello. I have a Canon EOS 7D and a Canon EF 100-400mm f/4.5-5.6L IS II USM lens which I use for bird photography. Truthfully, Im a novice at this. Well, Ive been contemplating buying a Canon 1.4 extender for the above unit and stumbled on your website today. According to your chart, the 1.4 extender won’t work on my setup? I thought I would double check with you to make sure this is true.

    If it won’t work, I assume you would recommend the Canon 7d Mark II? Or is that an “older” model now and I need to look at something else.

    Also, I would like a Canon lens to use indoors at ballroom competitions where I could video the dancers. The distance would be about 50-60 feet. What lens would you recommend for that?

    Thank you.


  8. I realize this camera was released after you created this but the T7i functions the same as the 80d with regards to autofocus. It will auto focus with the 1.4x ii center point only on the 100-400 is ii. When using the 1.4x iii on the 100-400 is ii you get 27 point coverage.

    • Thank you for pointing this out! I’ll update the post 🙂 Yes sometimes when a new camera comes out I miss them. To be honest I never new a Rebel series could do af at f/8. That’s actually pretty cool.

    • Well that lens has a variable aperture and part way through the aperture range it goes to f/5.6. At that point, with a 2x extender on it, your aperture would be a minimum of f/11 which is beyond f/8. So no, if you are zooming the lens to 400mm with the extender on it, it would not autofocus on a T7i.

  9. Thanks for the great, detailed information on the Canon 100-400ii + 7D Markii + 1.4x extender. Have the lens and body which I love and now am looking to buy the extender. Do you think paying a little less for a used copy would be ok or would you ante up for a new one?

    • If you can find a used one in good condition it’s an excellent way to save some money. Since they have no moving pieces like a focus or zoom ring, it should be easy to find a nice one 🙂

  10. hey Dan, this is an awesome article thank you. I have the Canon Rebel T6i with a Tamron 150-600mm, but I feel convinced that the quality of the Canon 100-400mm II paired with a 1.4x Extender III will give me better results (going on a safari in a couple of months). Your article says that the Rebel T7i will autofocus with this combination but I wasn’t sure if there were any differences with my Rebel t6i. Can you help? Thanks!!!!!

  11. Hi Dan, i want to know how well does the 1.4x iii function with 300mm 2.8 Is ii canon on a 5d mark iv? Has anyone used this combo?

  12. Yeah actually I have used this combo myself and I often use the 1.4xIII on my 400mm f/4 DO IS II which has similar AF performance to the 300 II. It’s good, very good in fact, as long as you take the time to understand and adapt the rather complex AF settings on the 5D Mark IV. Understanding the various options in the AF menu will get you a long way. The only time I have some trouble is when a subject suddenly rapidly accelerates towards the camera. If it’s a constant speed approaching camera, no problem. But if something changes direction and accelerates at you it might miss a few shots. To be fair though, that’s more of a Canon issue in general, and not limited to that combo. But all issues are easier to spot when you add a TC. It’s a solid pairing though!

  13. Hi Dan, would a 1.4 or 2.0 extender be compatible with my Canon EF 75-300mm f/4-5.6 III Lens? also, would I be able to use auto focus still?

    • No I don’t think you can mount an extender on that lens. The rear glass element is too close to the mount so the extender’s protrusion had nowhere to go.

  14. Hi Dan I’ve got a Canon EF 100-400mm f/4.5-5.6L IS ii USM lens on a 700D body and I was blown away by the quality of the lens after previously using a Tamron 150-600mm on the same body. That said I am about to upgrade the camera to an 80D and to also get a 1.4 extender mkiii. Would this be a good combination and would I lose any or all of the AF in this set up? Sorry if this has been asked previously. Thanks

    • You’ll get 27-point coverage with that lens and your 1.4x extender attached to it. There’s a diagram right at the bottom of the post that shows exactly which points will be available on the 80D with that lens. Great combo! Cheers!

  15. Hi Dan, I’ve read this entire post at least twice and first off THANK YOU for all the great information. I want to clarify my analysis before I make a purchase and hope you don’t mind what might be a redundant question. 🙁

    I currently have a Canon 7D mark I, 5D Mark II and the EF 100-400mm USM IS I, and have always wanted to add an extender. After seeing the comments and results about the EF 100-400mm USM IS II and the pairing with the 1.4x III extender I cannot get them fast enough. However, my 7D I body isn’t going to work with auto focus and I would really like to use a body that isn’t a full frame sensor so that I can get even stronger magnification on occasion.

    So my question is, what body with a cropped sensor should I buy? I’ve seen lots of references to the 7D Mark II and the 80D. I’ve read reviews that overall recommend the 80D over the 7D II—but they didn’t factor in the use of the 100-400 and an extender.

    Do you have a recommendation regarding which body I should buy 7D II or 80D or another option?

    Thanks in advance!


    • Hey Dave. Personally I would go for the 7DII if you want to shoot wildlife. It has more processing power and more AF points and a faster burst rate. If you were not shooting wildlife it wouldn’t be such a clear answer, but I think you’ll appreciate the 7D Mark II. There are many excellent examples on the second hand market these days if you want to save some $$.

      • Thanks Dan. Immediately after I posted my question I continued my internet search and found some other conflicting information. Now I’ll preface my question by saying some of the posts I saw were just in the “comments” section and I’m not sure who they are and they certainly don’t provide all the detail that you go into here…so I don’t put as much faith in what they have stated…however, here are a sample of some of the comments indicating that the 80D has more AF points when combined with the EF 100-400mm IS USM II and the extender 1.4x III and I just want to make sure I’m not missing something?:

        “The 7D2 has only one AF point that is sensitive at f/8, while the 80D has 27 f/8 AF points.”

        “With F8 lenses (like your 100-400/1.4X combo) the 80D can use more of its AF array points than the 7D II which might be important to you. With that combo the 7D2 can only use the center point for AF along with up to 4 points around it while the 80D can use 9 points in the center and 9 points to each side.”

        “With the 100-400 Mk II + 1.4x extender, you can use 27 AF points on the 80D, but only the center AF point on the 7D Mark II ”

        So there’s some confusion about which has more AF points, and whether the 7D II has 1 or 1+4 or even more AF points and I’m just trying to make an informed decision.

        To clarify, I will be taking some wild life shots and some landscape and some of my kids on the beach or doing sports. I have little kids and while my son doesn’t like having his pic taken, my daughter loves hers taken too much and often becomes a ham and spoils shots making extremely silly faces. So I find using a super telephoto lens or equivalent set-up like this is ideal as it allows me to get more awesome candid captures.

        Money and weight of the body isn’t an issue. I like the idea that the 7D II has potentially double the shutter like at 200K, more rugged. Seeing comments elsewhere that the 80D might take better video is the only reason I’d consider it except the question as to which body is best with the lens and extender combo already referenced. I was leaning towards the 7D II until I saw the quotes about AF points shared above that made me second guess myself? Are these people incorrect? Is there perhaps more AF points with the 80D but somehow it’s not relevant with the lens/extender combo? What am I missing? THANKS AGAIN!

        • H Dave. “80D has more AF points when combined with the EF 100-400mm IS USM II and the extender 1.4x III”

          This statement is true, as indicated in the table on this page. When I said that the 7DII has more AF points, I was talking about regular shooting situations. Not f/8 situations. Since I’m sure you would not be planning on shooting all your photos with the 100-400 and the 1.4X III, this seemed like a better way to examine the situation. In other words, yes the 80D has more AF points if you’re using the 100-400 and the extender, but given this is likely an outside case, I wouldn’t base a purchasing decision on that. The 100-400 on the 7DII is a killer combo for wildlife without needing to use the extender all the time.

          If you put the 100-400 on its own on a 7D II you would have 65 AF points.
          If you put the 100-400 on its own on a 80D you would have 45 AF points.

          The ONLY time the 80D gets more AF points than the 7DII is when you use the 1.4xIII on a 100-400 II.

    • Hi Dan,
      I have 80D and 100-400 version 1, i’m thinking to buy the extender 1.4x ii.need your suggest for that before i buy the 1.4x ii

      • The Mk1 version of that lens doesn’t work all that well with an extender. Personally I would not bother. I would put that money aside and save up for a second hand version of the MkII lens instead.

  16. If i am using Canon 5dm4 with 1.4x with Tamrom 150-600mm, will it works ? how many focus points should i go ? pls advice

    • No it won’t work once you zoom to 600mm. The native aperture at 600mm is 6.3. The extender adds one more stop of light so that would make it f/9 so it won’t work.

  17. Hi! First I wanted to say thanks for such a useful, succinct breakdown of how the extenders work with specific lenses and cameras. I just bought a refurbished 2x vIII extender that I was going to use on my 7D with my f4/70-200L lens, and when it didn’t autofocus I searched Google and yours was one of the first results. So I guess the extender won’t work with the 7D, but all was not lost! I have an M5 with the EF-M adapter, and autofocus works fine on that camera, plus it’s less bulky than the 7D-extender-70/200 combo. It also works on my RP with the RF-EF adapter, so you can add the M5 and the RP as working (and probably the R). Both cameras had no problems focusing anywhere I put the focus point, and the object tracking worked flawlessly as well.

    So now instead of the RP/7D combo as my carry-around duo, I will have the RP/M5 combo, which actually will be lighter overall, and means I only have to carry one kind of battery.

    • Thanks for the real-world testing results! Mirrorless cameras do open up some opportunities with more lens/extender combinations! That’s great news for everyone.

  18. Dan- I’m enjoying reading about all the possible combinations of lenses and extenders but I think I have one that I have not seen. What would you prefer for wildlife, the 70-200 2.8, with a 2x extender or just the flat out 100-400 lens? Each combo would us the same 6D camera body.

    Thanks for the time and info.

    Todd S.

    • That’s easy! 100-400 every time. 70-200 with a 2x is slower to focus and the image quality is nowhere near as good.

      • Thanks loads Dan. Heading to the Tetons and Yellowstone in the fall so hopefully I’ll get some winners. Appreciate your tips.

          • I will do that, heading out Labor Day weekend. One last question, when shooting with sun down/dusk would you rather increase ISO or increase expose a couple of stops?


            • This doesn’t really make sense. Increasing ISO will also increase your exposure. So I guess you mean increase ISO or set a wider aperture.

              The answer to that depends on what you are shooting and what your priorities are. If you widen your aperture, you’ll sacrifice some depth of field. I can’t say whether that will be important to you or not. You have to weigh the pros and cons as you examine the situation.

  19. Hi Dan, I spend a lot of time photographing wildlife in South Africa. Current equipment : 5D4 and the 100-400 ii, would you recommend the 1.4 converter? I would ultimately like to buy a 400 2.8 just need to save for a little longer (what might feel like an eternity) so would this be a good short term solution?

    • I think it’s worth having, yes. They aren’t that expensive, and surely a minor cost compared to “a lot of time photographing wildlife in South Africa”. I would not keep it on all the time, but occasionally you will find it useful, especially with relatively static subjects such as big cats lounging around.

  20. Hi Dan,

    Two questions:

    1) I am now in the possession of a 7D mk2 + 100-400 mm mk2 using a 1.4 converter mk3. Indeed as you were indicating I only have 1 autofocus point which is in the center. However, when I use Liveview I see multiple “green squares” fixing on the subject. What is that then?

    2) What exactly is this “centre surround+” ?



    • 1. Liveview uses Contrast Detection as an autofocus method. It’s able to be more accurate in some situations but it’s slower so not really useful for moving subjects and not what people would consider the “normal” AF mode for the camera.

      2. This is just the name for a specific group of AF points. For a diagram, check the camera manual and it’ll show you all the clusters and their names.

  21. 90d vs 7D2? my AF hit rate for birds in flight with the 7D2, 100-400ii & 1.4xiii isn’t great (the 5D4 is better but often doesn’t have enough reach). If the 90D is at least equal, the extra pixels would be useful.

    • Tough call. I can’t be certain right now as I have not used the 90D, but in general Canon is a bit hit and miss with BIF at the best of times, and that is exacerbated when using an extender. Particularly if you have birds flying towards you and away from you as I’m sure you know. I personally do not think that if the 90D is any better, it will be better by very much at all. But with the extra pixels you could shoot without the extender and then crop in afterwards if you needed to.

  22. Hi Dan, I’m using Canon 6d Mark ll with a Tamron 100-400mm (A035) and am considering the Tamron extender 1.4 and looks like I Will get autofocus at f/8. Not sure how many points, mainly used for aircraft spotting. Do you think it would be Okay.?

  23. Hi Dan,

    I am using Canon 600 mm f4.0 version II with 1.4 Extender III. Theoretically, I can autofocus @f5.6. However, it’s slow.
    In addition, when checking the metadata in PS, it shows the f max is 5.7. That means we can’t use it at f5.6? Or if my lens needs a calibration. NOTE: my lens is brand new.
    Please advise.


  24. Hi Dan,

    I own 6d mkii with 100-400mm mkii. For a long reach what would you recommend between a TC 1.4x III or another body like 7d mkII? Thank you!

  25. Best explanation ever !
    Can’t tell you how many Google searches I have done on this subject.
    Really don’t understand why Canon does not make this information available.

    Dan, just to check that I read the footnotes correctly:

    With the 100-400mm mkii lenses, even the 5D MK iv body, can’t take the 2x converter ? Only the 1.4x ?


  26. I have the 90D and the 100-400 IS ii and when I add the 2x iii extender it will not autofocus, but will if in live mode. Does that make sense?

  27. Hello. Very good explanatios…Thanks. Now, could you please help me: I have an Extender 2X and a 7D camara. I woul like to buy a camara to replace de 7D. What camara would you recomend to make the replacement and that will maintain the autofocus with that extender. Greetings.

  28. Will the auto focus work with Canon’s 2x II extender paired with the T8i and the EF 100-400mm 1:4.5-5.6 L IS lense? Looking to find a new body and was hoping the T8i would work for this. Thanks in advance

  29. Hello Dan –
    Thank you for your generosity with time and information on this and other topics. Your article and this conversation have contributed enormously to my understanding of this technically challenging aspect of photography.
    In an ironic twist, playing with a Canon M100 whose primary purpose is to replace my phone camera for better image quality, I was astonished to discover that with my EF 100-400 Mk2 with 1.4x Mk3 (= 560mm f/8), the absurdly tiny mirrorless would quite swiftly focus on and accurately track subjects selected (with the touch-screen) way out from the centre of the frame. Much as I love my 7D Mk2 and appreciate that it will AF this combination at all, it’s limiting not being able to focus at say the golden section without recomposing, or track subjects around the frame. I guess this *is* available in live-view (I haven’t tried) but without the intuitive and swift touchscreen interface and with a pound and a half more camera body in hand! Whilst for serious work one of course needs a viewfinder, I don’t find the M100/100-400/1.4x combo too dire. I quickly adapt to holding the lens, not the camera!
    So I’m not really asking a question so much as sharing a slight perplexity that in this one respect a pocketable budget mirrorless can apparently out-perform its still-awesome pro DSLR sibling. It just makes me wonder if I’m missing something in how I use my 7D2! Or whether I should be considering an 80D or 90D, the only APS-C bodies, apart from these mirrorless gems, that allow escape from the central point(s) with this particular lens combination. Meanwhile I found a used M5 at a great price, to extend my experimentation, whilst knowing it doesn’t cut the mustard for pro wildlife photography.
    Thanks for reading!

    • No, you’re not missing anything. This is an inherent difference between the way autofocus systems work with DSLRs and mirrorless cameras. The active AF area is simply much wider in mirrorless cameras than in any DSLR, and this includes f/8 combinations. The 7D2 is still a wonderful camera, but the world has moved on since its launch. I don’t think Canon even bothers to specify max aperture AF cutoff with their mirrorless cameras. At least not that I have seen.

      • Well thank you for that swift and encouraging confirmation of those thoughts Dan. Perhaps for EF folk like me not quite ready to embrace the R system, but sometimes wanting some mirrorless benefits along with the APS-C crop factor, the M5 / 50 models can provide an affordable, if imperfect, toe-hold in that technology. Not quite the ‘R-system 7D’ that some are asking for, but a reasonable stand-in for less demanding applications. Now I look forward to seeing what I can achieve with my M5 mounted on the 100-400 II with 1.4x extender. 😅


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