The order of attaching a teleconverter, lens, and body for Canon EOS

Is there a specific order that must be followed to attach a TC/lens/body?


This came up in another post. One user said not following Canon’s exact pattern can mess with the EXIF information and/or mess with AF (he read this somewhere) because the camera doesn’t know the TC is there.

That canon states the following in it direction page for extenders. “Mounting and dismounting the Extender First attach the Extender to the lens, then attach it to the camera. To detach it, follow the same procedure in reverse. To detach the Extender from the lens, slide the lens release lever as shown by the arrow, then turn the Extender counterclockwise.” I believe this is just one way described and Canon to perform the action. Canon has no real reason to explain every possible way to connect/disconnect the components. It to me isn’t a must and there is no warning of issues if this is not followed.

I didn’t think so, and tried it following the directions – obviously no problem. I then attached the TC to the body first, followed by the lens – also no problem. Plus either way gave basically all the same information EXIF-wise. But this was basically one test.

I have been doing opposite canon’s directions when the lens that I want to use a TC with is currently mounted to the camera. I find the change to be faster, plus the insides of the camera are exposed for a shorter period of time (less chance of dust and other crud getting in) if the TC gets immediately put on the body. I have been doing this since EOS film bodies without issue.

I do not want to mess anything up with my equipment (or images), so my questions!
1) Have I been just been lucky having no problems for decades?
2) Must you attach the TC to the lens first or risk EXIF and AF issues? (less of an issue compared to the next one)
3) If I don’t connect/disconnect as mentioned in Canon’s manual do I risk physical/electrical damage to the camera body, lens, and/or TC? (my main concern)


Or am I right? The order the parts are attached and unattached makes no difference at all - so don't worry about it.


Thanks in advance!

I've been doing it both ways for years and have never had an issue. I also don't keep a certain order when using extension tubes and haven't had any problems.

I generally do it the way they suggest, but I am sure I have done it the other way as well. I always try to remember to turn off the camera before changing lenses, and it seems to me that in that case, it can't matter: there is nothing going on electrically until everything is connected.

I've never heard that mounting the extender to the body first causes any issues with AF or messes with EXIF data.

But I do follow Canon's recommendation for a practical reason - because my Canon x1.4 has a protruding front element with a matted barrel, I find it easier, more wieldy, to offer it up to the lens first - thus ensuring that the black matting on the extender and inside the lens throat stay unscuffed. The semi-precision required is easier to handle than first mounting the extender, then offering up the lens. But YMMV; it's just my preference.

paddler4 wrote in post #14715686
I generally do it the way they suggest, but I am sure I have done it the other way as well. I always try to remember to turn off the camera before changing lenses, and it seems to me that in that case, it can't matter: there is nothing going on electrically until everything is connected.

Unfortunately that may not be true. For example, when I put a CF modified for my XTi to be hacked in (camera turned off), you can see a light flash. I can't remember if it does this with a normal card. Therefore, some electrical contact can still be going as long as there is power (ie. with battery). This works with other electrical devices too, think of a "turned off" cell phone.

That is why I worried a little. As I had not consiously thought of that, until I was reminded.

I have done it both ways without any problem.
If the lens I want to use is on the camera, I usually take off the lens and put the extender on the camera before attaching the lens. This is to avoid too much time with the camera open. If the lens is not on the camera, I put the extender on the lens first before attaching the set to the camera.

sebr wrote in post #14715808
I have done it both ways without any problem.
If the lens I want to use is on the camera, I usually take off the lens and put the extender on the camera before attaching the lens. This is to avoid too much time with the camera open. If the lens is not on the camera, I put the extender on the lens first before attaching the set to the camera.

Yep, that is what I've always done too. I didn't (don't) think it mattered but someone said it did. I'm just trying to be sure (and safe) with my equipment. Thanks.

99% that order is to address attaching lens with the converter while the camera is on so it would register properly. Most professionals do not turn camera off when changing lenses.

Andrew_WOT wrote in post #14716982
99% that order is to address attaching lens with the converter while the camera is on so it would register properly. Most professionals do not turn camera off when changing lenses.

I'm no professional, and I usually turn off my camera before changing the lens. That said, I have forgotten to turn off the camera while changing the lens and while changing for a TC. Plus when I tried the change with the TC, I also tried it both with the camera off but also while it was on. No difference and everything still registered just fine.

So are there any pros that have changed by putting the TC on the camera first and then adding the lens? Again especially when the lens you want the TC for is currently on the camera.

So still my question remains somewhat unanswered.

wow, never knew these things had instructions. i've been hooking mine on the lens, and then attach it to the camera.

I never bother to turn my camera off while changing lenses, just pop the TC on the lens and then lens+TC on camera.

its just easier to that one handed than the other way around.

takai wrote in post #14718319
I never bother to turn my camera off while changing lenses

Nope. No point, as turning the switch to 'Off' doesn't actually do anything apart from disabling the other switches and turning off the LCDs. Power is still flowing through the camera.

takai wrote in post #14718319
I never bother to turn my camera off while changing lenses, just pop the TC on the lens and then lens+TC on camera.

its just easier to that one handed than the other way around.

I agree, except when the lens you want to use the TC with is currently on the camera. How do you do it then?

I always remove lens and TC as a single unit. Much easier to hit the camera lens release button with one hand than it is to fiddle with the little slider on the TC.

I've never thought about it and have no idea... probably do it both ways. I usually don't turn off the camera, either.