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Canon acknowledges autofocus glitch with EF 40mm F2.8 STM pancake lens

By dpreview staff on Aug 8, 2012 at 22:46 GMT

Canon has acknowledged that a glitch in the recently released EF 40mm F2.8 STM pancake prime can cause autofocus to stop working. At present, if pressure is applied to the front of the lens when it's attached to the camera (which can include re-attaching the lens cap), the autofocus may stop working. The glitch can be overcome by dismounting and re-attaching the lens or by removing the camera's battery briefly. In its product advisory notice, the company says a firmware fix will be released in late August.

Comments

Total comments: 39
CameraLabTester
By CameraLabTester (Nov 21, 2012)

Try pressing the AF-ON button at the back of the camera, if this happens.

It usually fires up the AF from here than on the shutter button.

.

1 upvote
xilvar
By xilvar (Aug 20, 2012)

It's a great lens optical quality-wise. I noticed the issue in question within a few _seconds_ of first mounting the lens. However, I actually have not triggered the issue at all in my shooting since. It doesn't always happen even when you just plain force the front lens element back in by pushing.

My habits probably help because my main prime is the 85/1.2, and I'm always careful to retract the focus all the way to infinity on that lens before putting camera into holster (to avoid pressure on it's rather expensive mechanisms).

I do the same thing for the STM so most of the time I'd be unlikely to push on it by accident.

Reattaching a lens cap would rarely if ever trigger the issue if you do it the 'careful' way where you squeeze the two triggers before putting it on. I happen to always do it that way myself to avoid wear to the lens threads and opposite bits on the cap (and the annoying sound).

0 upvotes
Jan Kritzinger
By Jan Kritzinger (Aug 13, 2012)

Only problem is I can't update the firmware on my Eos 3 - guess I won't be getting this lens after all.

Sucks.

1 upvote
ptl-2010
By ptl-2010 (Aug 10, 2012)

I love my 40mm f2.8, it's a great little lens. I haven't had this problem and I probably won't seeing as how I don't touch the front of any lens that extends/retracts when focusing, they aren't designed to be pressed or pulled when engaged. At least they are taking care of the issue.

0 upvotes
Francis Carver
By Francis Carver (Aug 13, 2012)

If you keep the pancake lens in the bedside drawer at all times, the problem with it is likely to be not too serious of an issue.

0 upvotes
sir_bazz
By sir_bazz (Aug 9, 2012)

Lucky that Canon are good at making big heavy lenses cos they suck at making small ones.

2 upvotes
nelsonal
By nelsonal (Aug 9, 2012)

I thought standard operating procedure for canon lenses was to put the lens in manual focus before replacing the lens cap.

0 upvotes
ZeusS
By ZeusS (Aug 16, 2012)

not with the STM lenses, when you switch the camera off, or remove the lens from the body, the focus doesn't move in either mode.

0 upvotes
waxwaine
By waxwaine (Aug 9, 2012)

Go Pentax!

2 upvotes
sibarkernator
By sibarkernator (Aug 9, 2012)

the same reason i read this post. why would you go for a "larger" lens with af gliches when you could have a 40mm da xs on a better camera!!

0 upvotes
xtoph
By xtoph (Aug 10, 2012)

Yes, go pentax--go on and produce a ff camera... or an f/2, 27mm pancake....

I am extremely impressed by pentax's cameras, but criticizing canon on this point is silly. Just as is brand jingoism generally.

2 upvotes
sibarkernator
By sibarkernator (Aug 13, 2012)

it was a very light hearted jab at canon, i sell cameras and use canon n nikons daily, fantastic cameras but own pentax and feel the underdog deserves more praise than is given. the canon 50mm 1.8 @ £100 is very sharp. This lens is going to be ideal with the launch of the canon m.

0 upvotes
DavesMan
By DavesMan (Aug 9, 2012)

Canon must be under heavy pressure. I cannot explain the third fail in this year otherwise. 5D Mark III light leaks, 650D grip vanishes color, 40mm STM can't be touched. What else? Probably 1D X will melt when exposed to direct sunlinght or somethig like that :)

3 upvotes
kenghor
By kenghor (Aug 9, 2012)

Happened to me last week and caused me to miss the moment and hence the entire trip!

0 upvotes
immutability
By immutability (Aug 9, 2012)

Happened to me once a few days ago too during a trip, although there was no pressure against the front element. I just took out 20D with the lens already attached from the camera bag after a few hours drive, and AF didn't work (indicated focus even if it was out of focus without any motor action). MF didn't work either - rotating the focus ring just resulted in strange STM noises but focus didn't change. Re-attaching the lens resolved the issue, as they say. Other than this glitch, I've been very happy with this lens so far - it does exactly what I would expect from a 200 € lens.

0 upvotes
Francis Carver
By Francis Carver (Aug 13, 2012)

Let me see if I follow you here, immutability:

"AF didn't work"

"MF didn't work either"

"Other than this glitch, I've been very happy with this lens so far - it does exactly what I would expect from a 200 € lens."

Wow, that's good to know. For €200, apparently you've got a Canon pancake lens that cannot do proper focusing, no matter whether in AF mode or MF mode. Cool....

Heck, at least they did not charge €500 for the thing, right? With Canon, one never really knows.

0 upvotes
abi170845
By abi170845 (Aug 9, 2012)

Can anybody please make a camera that WORKS! Where to start X10, X100, D800/e LCD, D7000, 5dmk3 light spill, and now this? No wonder here in Jakarta, Indonesia the d90, supposedly discontinued, are still selling like hot cakes and a brand new d90 price keeps going up, right now is at US800! unbelievable!

1 upvote
wlad
By wlad (Aug 9, 2012)

what's wrong with the D7000 ? oh, you mean the noobs who expect to use 1/30s shutter speeds...

1 upvote
goblin
By goblin (Aug 9, 2012)

Ever heard of Olympus ?

0 upvotes
CameraLabTester
By CameraLabTester (Aug 9, 2012)

There is the introduction of a break in circuit, due to physical means like application of pressure.

Due to the slim design, contacts between relays may be broken temporarily, but enough to introduce a glitch.

The software may try to solve this physical problem by lengthening the waiting times or standby times between commands, allotting a cache to place the software lost due to a break, etc.

The physical solution is to make the internal parts and electronic contacts more robust to withstand the pressures of normal use: Nomal things like putting on a lens cap.

2 upvotes
Kinematic Digit
By Kinematic Digit (Aug 11, 2012)

Thanks for the info. Was curious how a firmware could resolve this and this makes sense by your explanation.

0 upvotes
AbrasiveReducer
By AbrasiveReducer (Aug 9, 2012)

Every time I use the 40 I'm impressed how well it performs between my 24TS II and my 70-200/4 IS. That's all I can ask for in a $200 lens. No problems at all so far, but then I don't get white orbs either.

0 upvotes
Ruy Penalva
By Ruy Penalva (Aug 9, 2012)

As the glitch could be solved via firmware it seems caused but some malfunction in the camera-stepper motor feed back. The battery and lens removal confirm that. Could that occur in 18-135 STM lens too? To how many cameras bodies will Canon address the fix?

0 upvotes
Najinsky
By Najinsky (Aug 9, 2012)

It sounds like if contact is momentarily lost, it doesn't reinitialise software communication, hence resolved by reattaching or power recycle. The firmware fix will probably re-initialise software contact when it detects communication is lost.

1 upvote
Juck
By Juck (Aug 9, 2012)

Careful Najinsky, that much common-sense in a single post is likely to upset all these loser Canon haters.

0 upvotes
Francis Carver
By Francis Carver (Aug 13, 2012)

Apparently Canon is now doing what Fujifilm had perfected: "fixing" hardware faults via firmware upgrades. Too bad these desperate, cost-saving attempts rarely work, huh?

0 upvotes
DotCom Editor
By DotCom Editor (Aug 9, 2012)

Imagine how much less we'd be paying for our products if Canon didn't have to build into its pricing structure the cost of fixes and recalls due to AF problems, falling-off mirrors, internal lens flares, bodies that won't focus, etc.

1 upvote
Najinsky
By Najinsky (Aug 9, 2012)

I much prefer Canons open approach than Fuji's silence on much more serious issues like Sticky Aperture Blades (SAB) which means my £900 X100 now lives in a drawer. My receipt and international warenty were in a document wallet that was stolen. As Fuji don't officially acknowledge the defect and cameras with the issues are repaired as warenty issues, I'm screwed,

Comment edited 60 seconds after posting
1 upvote
samhain
By samhain (Aug 9, 2012)

They'd still charge ya the same. Maybe even more...

0 upvotes
Najinsky
By Najinsky (Aug 9, 2012)

If by they, you mean Canon, you are wrong. When they had a problem with the mirror adhesive on the 5D, they owned up and announced they would fix it free of charge.

http://www.usa.canon.com/cusa/support/consumer/eos_slr_camera_systems/eos_digital_slr_cameras/eos_5d?pageKeyCode=prdAdvDetail&docId=0901e0248004cd94

1 upvote
Francis Carver
By Francis Carver (Aug 13, 2012)

Najinsky, I read the advisory you had linked us to, thanks.

Canon-speak starts with how "in rare instances" something "may" happen. Typical camera mfr's b.s. lingo, right?

Also, which particular Canon EOS 5D camera model does this advisory even apply to -- there is nothing on that here, you know. The 5D? The 5D Mark II? The 5D Mark III?

Incidentally, I've been using MIRRORLESS digital cameras since 1995. And I had no clue that one of these old-fashioned flipping mirrors could just fall out of one of these pricey "professional" DSLR cameras, you know.

0 upvotes
Roger Knight
By Roger Knight (Aug 8, 2012)

It sounds more like a physical glitch rather than a software glitch. It's not possible, I would have thought, to get a better connection to terminals by using a software fix without severely degrading the operationality of the other component performances. It will be interesting to see if there is a massive exchange program initiated by Canon on this issue.

1 upvote
Sean Nelson
By Sean Nelson (Aug 9, 2012)

If the glitch is a physical alignment/tolerance issue that causes a momentary interruption in the data stream between the lens and the camera, a software patch could solve the issue by adjusting the timeout/retry logic in the lens/camera communication protocol.

4 upvotes
raincoat
By raincoat (Aug 9, 2012)

It's interesting how physical issues can be fixed by software.

0 upvotes
micahmedia
By micahmedia (Aug 9, 2012)

@raincoat, see: Hubble

1 upvote
Andy Crowe
By Andy Crowe (Aug 9, 2012)

If they can detect when it happens and send a reset signal to the lens then yes a hardware bug can be fixed with software.

0 upvotes
Francis Carver
By Francis Carver (Aug 13, 2012)

"a software patch could solve the issue by adjusting the timeout/retry logic in the lens/camera communication protocol."

In other words, trick the lens, thus trick the customer. It's all good, and in a worthwhile cause to boot. :-))

0 upvotes
Kinematic Digit
By Kinematic Digit (Aug 8, 2012)

It's a fantastic lens and this is the only gripe. I'm careful not to bump or put pressure on the front element. I'm curious how a firmware fixes this but if so then glad about that.

0 upvotes
ArchiDeos
By ArchiDeos (Aug 8, 2012)

Hey guys.. Canon made it again. Im glad they acknowledge the glitcn and Hoping they will fix the issue ASAP. Keep on shooting guys..

4 upvotes
Total comments: 39