Tom70 Loc: NY

Need some HHG help can't fix this alone.
Current system 7dmk ll, Canon 100-400 MK ll, 1.4 Canon MK ll extender. Purchased used from reliable camera store. Extender worked well (did what it was made for) for approx 6 months, was out shooting for several hours in approx 20 degree weather, all of a sudden when lens fully extended in AF mode it does not focus, image in viewfinder is completely blurred. Cleaned all contact points, did not change results. If I switch to Manual Focus, get approx focus, then switch to AF focus, AF will do its job & make final adjustments and achieve focus, works while shooting that subject only, when I move on to another subject have to repeat process.

As you can see I need some help/advice. Has something been done to extender (like me hitting wrong button or
something) is this a normal problem with this product, can I fix this or should I send to Canon to fix.

I treat my equipment with TLC, never dropped or banged, now at a loss

Thanks in advance

CHG_CANON Loc: the Windy City

Now that all the equipment is indoors and warmed to at least room temperatures, how does the AF operate? If still a problem, can you isolate the problem to the extender, as in AF is fine at all focal lengths without the extender?

I had a used lens arrive from KEH that behaved like you described, could only focus if I got the focus 'close' to where the camera could finish. That was a bad motor on the lens, no extender involved, quickly returned / rejected. That's not the kind of thing you'd like to find with your new 100-400L II. Again, see if you can isolate the problem to the extender and / or cleaning the contacts or the temps for usage.

robertjerl Loc: Corona, California

There is a focus limiter on the lens. Pushed forward it will auto focus from it's closest AF to infinity, to the rear it will only AF 3 meters to infinity.
But it was probably the cold turning the internal lubricant to glue.

imagemeister Loc: mid east Florida

Yes, look at the focus limiter switch ......
.

olemikey Loc: 6 mile creek, Spacecoast Florida

Generally - Switches and contacts are likely suspects ....and focus limiter switch operation could be a culprit....cold affecting movement is also possible. Look at externals first, check and clean all electrical contacts on each component, work switches, you can even place a drop of alcohol on each switch and work them (on items that aren't "weather sealed" - alcohol might not make it into the switch contacts on a sealed lens) and give it plenty of time to dry (alcohol) prior to powering up.

If the lens does perform as intended in a warm environment, then cold causing tightening or causing lubricant to firm up are possibilities.

I do not have that lens, but on many you can service the switches without disassembly, or minor disassembly at the mount end (most/many folks would not want to try anything involving opening up the mount end, and do not if still under warranty). Note: Again, If still under warranty, do not open anything up) If none of this works I'd call Canon. Good luck in your quest...

Tom70 Loc: NY

Thanks UHH'ers (CHG-CANON, Robertjerl, Imagemeister & Olemikey) for all your timely (very fast) response to my question/situation. You guys all pointed me in the right direction, my thoughts were all pointing to the extender but your comments (correctly) brought me to the lens focus limiter switch. Weather warmed up a bit from 20's to 50's, so went out shooting. I did clean all contact points again, just to make sure. I did move the switch back and forth a bit and shot with and without extender. Shot at full range of settings (100mm, 400mm, no extender, 160 & 560mm with extender) Had NO problems, AF was working well. Can't control the weather but now knowing what the problem is I can find a way to work around it, maybe just go out on nice days.
Again thanks to all, help is much appriciated.

CHG_CANON Loc: the Windy City

Hooray!

robertjerl Loc: Corona, California

Enjoy your shooting. I have among others the 7DII and the 100-400L mk2 with the1.4x III (also 5DIV, 80D & 90D and for telephoto zooms I also have the Tamron 150-600 G2 and Canon 70-300L w/Kenko MC4 1.4x-the only extender that lens has all functions with)

Tom70 Loc: NY

yes I agree, Hooray, situation threw me for a loop, i love easy fixes

Tom70 Loc: NY

I do enjoy shooting, try to get out every day. Very happy with my set up (better be it's the only one I have)
Reviewing your equipment list leads me to another question. When fully extender with the extender on of course a good number of my shots are a bit soft, I like subject to be perfectly sharp all the time (the impossible dream with BIF), I realize my technique is probably 90% of the problem (I'm working on that) but do you think if I backed off, say to 540/550mm or
so might help give me more keepers.

TriX Loc: Raleigh, NC

I shoot my MK I with a Canon 1.4x MKII at full length often and can’t see any difference if I back off a little, but no idea if that’s applicable to the MKII since it’s a different design. I can tell you one thing to try though. Assuming your lens isn’t front or back focusing, you might download a trial copy of Topaz AI sharpen and give it a try. It doesn’t work on every image, but when it does, the improvement in sharpness is quite pronounced.

amfoto1 Loc: San Jose, Calif. USA

I have the exact same combo. While I don't use the 1.4X II on the 100-400 II a lot, I've never had any problem with it when I do. It is very sharp with little to no loss of image quality, the way there usually is using teleconverters. I was surprised how good the IQ was.

It sounds as if you've solved the problem. Good! Likely there was a little oxidization in the switch. That can happen when a switch isn't operated for a long time. Many of the switches used in cameras are "self-cleaning"... Essentially they "wipe" the contacts each time they're used. But if left unused for a long time, oxidization can form and cause a break in the circuit.

Something else to remember is that the 7DII only has one "f/8 capable" AF point, at the center. When I use the lens/TC combo I always try to remember to set the camera's AF to Single Point and select that center one. The other 64 AF points are "f/5.6 limited", so AF will fail if any of them are used with the 1.$X on that lens.

I honestly don't know what might happen if I didn't set the camera to Single Point... What it would do if I left it set to any of the other seven focus patterns the 7DII offers. I don't think I've ever tried it. Maybe the camera would override and force the AF to use only that center point. Or maybe not. I suppose I should experiment with it and see what happens.

The image below was shot with my 100-400 II, 1.4X II and 7DII. (ISO 1600, lens maxed out at f/8 and 560mm). It's had little sharpening... just the default Lightroom applies. Besides some slight exposure tweaks, it was just resized with little to no cropping to my standard 300 ppi print resolution and 8x12" size. Looks pretty sharp to me. (I've uploaded this image here before, to illustrate how well the zoom and TC work together... apologies for the repetition!)

(Download)

robertjerl Loc: Corona, California

With long lenses, unless the lens is not sharp (not the case with the 100-400L) the most common culprit is camera/lens movement. The longer the lens the harder it is to avoid some movement. Even wind causing vibration can do it. A tripod, camera + long lens and lens hood offer a lot of surface for wind to vibrate. And of course hand held for BIF unless the light is so bright you can use ridiculously high shutter speeds there is even higher probability of motion blur for several reasons. For really long lenses or macro lens very close even mirror slap can do it.

Topaz Sharpen AI does have motion blur settings, in fact the highest of the three can go to over sharpened very easily.
Look here for a comparison list of apps to fix blur: https://capturetheatlas.com/how-to-fix-blurry-pictures/

rlynes Loc: Wisconsin

I shoot a lot of outdoor during the winter and condensation from temperature variations can be a problem if you don't prepare for it. I leave the lenses and body unassembled (and in the camera bag or pack), then in the cold truck for at least four hours prior to shooting. I will then wipe the contacts with a microfiber cloth to remove residual condensation before assembling. The contacts are important as they carry the power for the focus motors and stabilization controls. Low current flow due to poor electrical connections does make those functions very sluggish in the cold. Also, I take an extra battery or two (or more depending on the length of my shoot) that are kept warm. Batteries discharge quickly in the cold.

The above works for me and my 16-35, 24-70, 100-400 and primes down to about -15F. Below that there are other things you must consider (like constant warm battery swaps).

A TC would add two extra sets of contacts into the mix, so just more bits of electrical resistance for the stabilization and focus motor power if they're not clean.

scsdesphotography Loc: Southeastern Michigan

Hi Tom, I had a similar problem with my D7000. I was in downtown Detroit to photograph the blues band that my brother is in. It was the annual Winterfest in February, and the outside temperature was around 9 degrees with a 15 mph wind. We were in a heated tent. Without thinking I had placed my camera bag down along the edge of the tent. Bad idea! When I pulled my frozen camera out, the autofocus was so agonizingly slow, it was nearly unusable. After about 15 minutes it had warmed up enough to start working again. Lesson learned, keep your gear as warm as possible before you use it in subfreezing temperatures!