# EF 40mm STM Pancake Problem Acknowledged



## dr croubie (Aug 7, 2012)

http://www.the-digital-picture.com/News/News-Post.aspx?News=2822

(I couldn't find the original thread about people saying they had a problem with it, so starting a new one).

Canon have acknowledged that there is a problem with this lens, I've had it too, where the AF just stops working occasionally.
They're blaming 'pressing the lens'. I know I haven't done it purposefully, but it could happen in my bag(s), and if it takes as little pressure as 'putting a lens cap on', then that's a design flaw.
Still, i'll do what it takes to fix it, it's otherwise a good lens.

My only concern is:
"The firmware to address this phenomenon will be available for download in late August, 2012."

This problem has only happened to me on my EOS 3, not the 7D. Are they talking about lens firmware or camera?


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## Mt Spokane Photography (Aug 7, 2012)

I tried to see if I had the issue, mounted mine to my 5D MK II and pushed on the lens, and of course, it would not autofocus because the barrel could not move with me pushing on it. I removed my finger and it worked fine. I tried squeezing the barrel too, but that has no affect.
Then, it dawned on me that what they must be saying is that some cameras lock up when you do not allow the lens to autofocus by pressing the focus barrel or focus ring on the front of the lens.
Thats why the fix is firmware for the camera. nothing wrong with the lens.


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## kdsand (Aug 7, 2012)

Well heck.
I guess I had that happen on my 60D. 

I was fiddling around a bit absent minded & the lens moved inward with a fairly light pressure made by my finger. I saw it move about 1/8 inch  (oops) & thought that didn't seem right.

I had to pop the battery out & back in to get functionality back in the lens ( didn't try re seating the lens ). It seems it just froze up causing no damage . Definitely sensitive, glad their doing a fix because it could be a pain in the butt ox if it happened often.


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## Mt Spokane Photography (Aug 7, 2012)

kdsand said:


> Well heck.
> I guess I had that happen on my 60D.
> 
> I was fiddling around a bit absent minded & the lens moved inward with a fairly light pressure made by my finger. I saw it move about 1/8 inch  (oops) & thought that didn't seem right.
> ...


If you push the end of the lens barrel to put on the cap, or whatever, it will telescope in, some may take more perssure, but all of them move. 
What should noot happen is for the camera to lockup when it senses a lens movement.


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## Wideopen (Aug 7, 2012)

Haven't had any issues with mines mounted to a 7D yet.


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## kdsand (Aug 7, 2012)

Mt Spokane Photography said:


> kdsand said:
> 
> 
> > Well heck.
> ...


Yep if you put a cap on with a little to much force it could happen, although it hasn't locked up on me since that first time. I am pretty good at not interfering with AF or stripping gears in general but since its so nice to leave that lens on in a tight bag ready for a quick draw I suppose it could freeze up randomly in those circumstances.

As long as its not a hardware issue, it will be - should be relatively a simple firmware fix.


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## Kcray85 (Aug 7, 2012)

From the Canon USA website http://www.usa.canon.com/cusa/support/professional/professional_cameras?pageKeyCode=prdAdvDetail&docId=0901e02480602860


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## Mt Spokane Photography (Aug 8, 2012)

I played with mine some more today. With the lens mounted to my powered up 5D MK II, I pushed the barrel of the lens all the way back, and did a lot of other screwy things, but it kept on working perfectly. Apparently not all of them have the issue, or it is particular to certain camera bodies.


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## ageha (Aug 8, 2012)

Mt Spokane Photography said:


> I played with mine some more today. With the lens mounted to my powered up 5D MK II, I pushed the barrel of the lens all the way back, and did a lot of other screwy things, but it kept on working perfectly. Apparently not all of them have the issue, or it is particular to certain camera bodies.


Or maybe just an early batch is affected?


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## Mt Spokane Photography (Aug 8, 2012)

ageha said:


> Mt Spokane Photography said:
> 
> 
> > I played with mine some more today. With the lens mounted to my powered up 5D MK II, I pushed the barrel of the lens all the way back, and did a lot of other screwy things, but it kept on working perfectly. Apparently not all of them have the issue, or it is particular to certain camera bodies.
> ...


I think mine is a early batch.


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## dr croubie (Aug 8, 2012)

Mt Spokane Photography said:


> I think mine is a early batch.



Ditto, I had mine in hand 2 days after the announcement, before it was even available in the US.


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## victorwol (Aug 8, 2012)

Yes, mine does it....


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## thebowtie (Aug 8, 2012)

dr croubie said:


> http://www.the-digital-picture.com/News/News-Post.aspx?News=2822
> 
> (I couldn't find the original thread about people saying they had a problem with it, so starting a new one).
> 
> ...



Here's the link to the announcement on Canon Australia's support site:
http://www.canon.com.au/Support-Services/Support-News/Service-Notices/f28-STM-Interchangeable-Lens

```
To Users of the EF40mm f/2.8 STM Interchangeable Lens for Canon Digital SLR Cameras

Thank you for using Canon products.

It has been confirmed that the autofocusing function of the EF40mm f/2.8 STM lens, which was released in June 2012, may not operate correctly.

The details of this phenomenon are described below.
Phenomenon

If pressure is applied to the lens barrel while the lens is mounted to the camera (pressure can be applied even while attaching the lens cap or while carrying the camera with the lens attached in a bag), the autofocusing function of the lens may stop working.

    This phenomenon does not occur during normal shooting.
    This phenomenon does not result in a malfunction of the lens.

Workaround

When the above phenomenon occurs, detach and reattach the lens, or remove and reinsert the camera battery to restore the operations.
Market Support

The firmware to address this phenomenon will be available for download in late August, 2012.

Once this firmware is ready, we will make an announcement on our Web site.
Contact Information for Inquiries

Canon Australia Services & Support 13 13 83 (Local call)

Canon New Zealand Customer Care 0800 222 666
```


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## Mt Spokane Photography (Aug 8, 2012)

I've seen one possible explanation noting that since the lens has a stepper motor, it could lose synch with the camera body, and a remount/restart is needed to get the camera to synch up again. The fix may very well be just having the camera body do a synch when the lens position does not match rather than lockup or generate a error message.
I tried another thing after reading the comment, focusing far away, then keeping my finger on the lens barrel so it could not move out to focus closely. I could feel the stepper motor pulsing for about 5 seconds, then I removed my finger and it focused fine. I also manually pushed it in while focusing, it just keeps working fine.
Could those with a problem mention the body they are using?


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## kdsand (Aug 8, 2012)

I fairly certain its a glitch in the programing/ firmware in the lens though updating body firmware apparently is a workaround for this early batch.

On a related note its a shame the hood connects to the barrel as it does. Mounted differently it would protect vs aggravating the problem. I normally use a hood but on the 40 I'm leaning towards not using it and no I didn't buy Canons  over priced little plastic ring, I'm using a Leica one.


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## dickymint (Aug 8, 2012)

I love my canon gear....but what have they released lately that doesn't have a fault!,,,,,!


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## bkorcel (Aug 8, 2012)

Just add butter and some syrup and the problem is solved!


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## aprotosimaki (Aug 9, 2012)

Mt Spokane Photography said:


> I played with mine some more today. With the lens mounted to my powered up 5D MK II, I pushed the barrel of the lens all the way back, and did a lot of other screwy things, but it kept on working perfectly. Apparently not all of them have the issue, or it is particular to certain camera bodies.



I have the problem on a 5d Mk2.


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## drmikeinpdx (Nov 30, 2012)

I was intrigued by the data that Roger Cicala posted at LensRentals.com. He says that the 40 pancake is one of the new batch of Canon lenses that have a more accurate autofocus system which can be used to good advantage by the 5D III and 1Dx. Since they are now going for only $149 I decided it would be an inexpensive way to check out the advantages of the new technology. Got it a couple of days ago.

I immediately started putting it through my usual focus tests to see if it needed some MFA and just how consistently it focused. (MFA is not very helpful if a lens does not focus consistently.)

With the lens on my 5D3, I found that it back focused about one foot at ten feet. I call that 10% back focus. However, about one shot in five was significantly front focused, maybe 5%. I changed my working distance and the focus error changed. Grrrr....

I tried adding some MFA, but the point of final focus was too inconsistent for me to want to use the lens wide open.

I'm sending it back for another copy. Will keep you posted on the next one.

All of my other lenses work great on the 5D3. This is the first reject. Too bad, cause it's a cute lens.


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## Hillsilly (Nov 30, 2012)

Has happened to me once with an Eos 3. After a few anxious minutes and detaching and reattaching it a couple of times, it started working again. Since then its been fine. It happened while I was travelling and the camera and lens were tightly packed in a bag. I wouldn't have thought it was too tightly packed though....

I'm curious how the firmware upgrade works with a film camera.


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## Botts (Nov 30, 2012)

I have the problem on my Elan 7. I'll post an update after I upgrade it next week.


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## dr croubie (Nov 30, 2012)

Wow, i just realised I still haven't gotten around to upgrading my firmware either.
Of course, I don't have a 5D mk3, but I've got a friend who has one I should borrow.

Nice to see I'm not the only one using it on an EOS 3. I just got a PB-E2 for it the other day, looks a bit ridiculous with the 40mm mounted...


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