The Curious Case of the EF 28-300L IS USM...

[Tronhard]

I have the venerable, and unique Canon EF 28-300L IS USM super-zoom lens.  It seems to be in perfect condition and has been so for some time since I bought it about 10 years ago.  Recently, when I began shooting with it using my FF cameras: EOS 5DMkIII, MkIV, 5DsR, and in each case it takes one or two images and displays the dreaded 01 error: Cannot communicate with the lens, clean contact. Because the lens displays the same issue on several cameras, it is logical to assume that the lens has a fault.

So that is what I have done (several times) is clean the sensors on both camera and bodies: they don't seem particularly worn and are bright and shiny. 

HOWEVER!  If I put the lens on my crop sensor cameras: 60D, 7DI, 7DII, 80D, 90D, M5 (with adapter), and the FF R5 (with adapter) it performs perfectly, working through the various zoom and shutter speed ranges and at high speed continuous shots.

That, I find somewhat confusing.  I looked at the contacts and compared them to other lenses, and there are exactly the same number of contacts and in similar condition, yet they work fine! 

I am throwing this out there to the brains trust and any Sherlock Holmes!!!

[Tronhard]

Hi Ernie and thanks for you input. 🙂 This lens is part of my "legacy" collection and not used for my day-to-day photography, but I like to use this gear from time to time for the enjoyment and to make sure it works - obviously, I have found an issue.
I think the next step, as you say, is to consider sending it to Canon: if they will even take a look at it...  The thing is, that even if they refuse, I can still use it on my crop bodies and my new gear, so it's not like I can't use it at all - it's more of a slightly annoying itch I want to scratch! 

[kvbarkley]

I am going to take a WAG and assume it has something to do with signal level and buffering. When connected directly to the camera the lens does not have enough oomph to drive the interface. The adapter has a buffer and does not load down the lens as much so that it amplifies the signal as it goes through.

[Waddizzle]

Here’s my two cents.  Your observations are consistent with a possible firmware issue.  It works with APS-C bodies of various vintages but not with some full frame bodies that are more recently released   

[Tronhard]

Thanks Bill, but I tried looking for a firmware update when this started and there is none available for this lens, and my cameras are all up to date with their firmware according to the sites.  Good try though! 🙂

[ebiggs1]

"Your observations are consistent with a possible firmware issue."

I like that thought. Still requires a trip to Canon service.

[Waddizzle]

It may only require camera firmware updates. 

[ebiggs1]

"It may only require camera firmware updates."

Oh yeah, right, now I don't like the idea so much.

[ebiggs1]

"I think the next step, as you say, is to consider sending it to Canon: if they will even take a look at it... "

It' still for sale on the market, isn't it? I would assume Canon has to still service it.

[Tronhard]

Canon NZ is not as forthcoming as the US version.  I asked them and they simply said that they would look at it but would not commit to fixing it, rather disappointing I thought.  They said it could be dirty contacts (already cleaned) or anything, which is rather vague.  I will likely send it in to them for evaluation, but if they refuse to service it, at least I know it works with a lot of cameras!

[Tronhard]

Well, a footnote to this post.  Initially, when I contacted the Canon NZ service desk they said to bring it in for an evaluation.  Then they declined to do so.  It turns out that while the Australian branch sells and supports the 28-300 currently, NZ does not - which is odd considering the warranties issued for gear sold in this region apply to Oz and NZ.  So, I shall stick with using the lens of APS-C and via the adapter on my R5 and R6 units.  Not impressed with Canon NZ though...