Canon 70-300 DO IS with sticky zoom

[RedRebel]

I just got back from a two week holiday from Tuscany, Italy where I used my 5D, 24-105IS and 70-300 DO IS for the first time.

As far as I have viewed the images on my computer, the 5D and the 24-105 L IS perform very wel as expected. This is a real quality combo.

The optical quality from the 70-300 DO IS, also seems to be Ok, however during this holiday were I used it for the first time, I noticed that the zoom ring often operates very sticky. At home I already noticed that it didn't operate as smooth as the L lens. I also new this from other reviewers that it can be a bit sticky. But during this holiday, at temperatures from about 30 Grc it became a lot worse. Often I had to retract (70mm) the zoom completely (while pointing the lens up) and try again (pointing the lens down) to zoom in to about 200mm. When zooming in and out a few times firmly, it becomes a bit better, but a few moments later the problem is back.

When I was at the Fiorano (Maranello ~ Ferarri) race track, it was virtualy impossible to catch up a moving car (even when it was far away) because the zoom simply blocked, or didn't move smoothly. Also when shooting still images such as a church tower, the zoom blocked, especially when the lens was pointed a bit upwards, but also when it was kept almost horizontally.

At home at room temperatures, the problem seems much less (acceptable -but nothing more then that- ). I have a feeling that the plastics become softer at higher temperatures making the problem worse. The lens consists of two telescopic sections that move in and out. These sections contain quite some heavy lens elements that causes the rather heavy zoom operation.

I wonder if other users from this lens have noticed simmilar problems, because I consider this not to be acceptable from a lens in this price class. Operating a 24-105L IS lens or a 17-85 IS lens is a joy, but the zoom mechanism from my copy of the 70-300 DO IS is often a real pain. I do not consider it a problem when the zoom operates a bit heavy, but it should operate smooth...

If this behaviour is typical for this lens, I consider it as a design flaw and a serious shows stopper, because it spoils the plessant use from a lens like this.

Does anyone have experience with this problem?

[Gary Ferguson]

The zoom on my 70-300 DO isn't as smooth as some others in the Canon range, but I've been using one for some while now, and in a broad range of temperature and humidity conditions (Moscow in January, Shanghai in August), and I've never had it stick in the way you describe.

[jimhuber]

I've had my 70-300 DO since June 2005 and used it in weather from 23F (-5C) up to over 100F (40C) and humidity ranges from near 100% down to under 10%. Initially mine was much stickier than it is now - it worked out some with use, but it isn't as smooth as an L zoom and probably never will be. But mine has never been quite as stiff as you report. I've been very pleased with it's optical quality as long as I'm not shooting anything that has to preserve straight lines really well, like architecture, though DxO Optics helps considerably with that.

[Paul2660]

It's my understanding that the fix for the Portrait focus issues also makes the zoom stiff or sticky as you mentioned.  Also new lenses that have the fix, can also have the same stiffness.  This based on a conversation I had with Canon while my lens was in for repair.

Before on early versions, it was just the opposite, way to free.  At least mine was.  

Paul C.

[boku]

It's my understanding that the fix for the Portrait focus issues also makes the zoom stiff or sticky as you mentioned.  Also new lenses that have the fix, can also have the same stiffness.  This based on a conversation I had with Canon while my lens was in for repair.

Before on early versions, it was just the opposite, way to free.  At least mine was. 

Paul C.
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I don't think you are talking about the DO lens. Please clarify.
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I have the DO. It is stiff/sticky, and improves with age. I don't feel that this hampers usage. It is apparent to me that this is caused by a steep angle on the focusing helix and the choice of materials. If they designed it otherwise, you would be making to many turns to get from close to far focus. Or, it would use metals that would add extra weight.

Everything in life is a comprimise.

[RedRebel]

Today I have send it back to Canon for a checkup/repair. At room temperatures everything seems alright, but in the sun it gets very sticky. I contacted Canon over here in the Netherlands, but to them it's not a known issue.

The mechanism is very sensitive, using the hood already causes a noticable more heavy operation of the zoom. Since the lens is quite prone to flare, I always use it with the supplied hood.

I just wait and see, the only downside is I have to wait for 3-4 weeks.

[Paul2660]

Boku,

You are right, I was referring to the wrong lens. I missed the DO portion of the post.

Thanks
Paul C.

[Craig Arnold]

I've had my DO for nearly two years now and although it's not silky smooth I have certainly never had problems such as you describe, used sometimes in some very hot conditions in Africa and Europe.

Good luck.

[isaacsdad]

I've been using the 70-300 DO for more than a year. It's always had a sticky zoom. My work-around is to ignore the zoom collar and simply pull or push the lens to the desired range, holding the lens hood. This way, it moves smoothly.