How Do You Test a New Lens?

[HDNitehawk]

A bubble?
Probably no effect at all on IQ but that would drive me nuts.
I couldn't handle the mental stress.

[Kayaker72]

Thanks Rick and JRW....

I figured that the main way that the bubble might hurt IQ would be for dark images with bright lights, creating a "star burst.". So I did about 30 test shots last night with a flashlight hitting the bubble at different angles. I varied the conditions to include: f/2.8, f/11, 24 mm and 70 mm, MFD, and focus set to infinity.

I didn't see anything other than normal lens flare. I may try the test again tonight, but, as JRW said, I don't think this will have a noticeable impact on IQ. Actually, your post made me recall all the references to scratched front elements I've see that supposedly don't impact IQ and also my 10 stop ND filter has a gouge right in the middle. I have never noticed any impact.

It does seem I am not alone with having issues with this lens. There is this thread over at CR with 11 pages of people with different issues ranging from clicks, to softness, to squeaks to bubbles. There seems to be production issues with this lens at least form February through June 2013. I have to say, this is the first time I've been disappointed with Canon. I know perfection is a concept, but this many production issues is disappointing for any lens especially a premium lens like the 24-70 II.

At this point, I am going to give myself a bit more time to see if I can handle the "mental stress." I have been telling myself that "nothing is perfect" and that seems to be working. If I don't keep it, I may send it into Canon to replace the front element or I'll return it to Adorama for a refund. I don't see exchanging it for a fifth copy. I'd be too worried about what issue I would find with the next lens.

BTW, for those keeping track: copy 1: 032-loud clicking while operating the zoom ring; copy 2: 032-loud clicking while operating the zoom ring; copy 3: 062-AFMA issues at 70 mm; and copy 4: 062-very small bubble in front element.


Thanks for your help,
Brant

[HDNitehawk]

If it checks out every other way I would be tempted to call Canon send it and have the front element replaced.
One thing to keep in mind though is that under the Canon warranty they do not have to send you the same lens back, and you may end up with another copy.

My concern would be sunsets and your long exposure waterfalls. I think if it was going to be noticeable it would be then.

Another consideration is resell. If I were buying a lens and looked it over and saw this I might pass on it.

[Kayaker72]

If it checks out every other way I would be tempted to call Canon send it and have the front element replaced.
One thing to keep in mind though is that under the Canon warranty they do not have to send you the same lens back, and you may end up with another copy.

My concern would be sunsets and your long exposure waterfalls. I think if it was going to be noticeable it would be then.

Another consideration is resell. If I were buying a lens and looked it over and saw this I might pass on it.

I actually called and talked with Canon today. They said that they would simply change out the front element. I've been taking actual pictures tonight around the house. It reminded me that optics isn't the only reason I wanted this lens. The AF is noticably faster, and I am getting focus lock in conditions I normally wouldn't.

Thanks for your continued input. Just so you have an idea of what I am looking at. It is slight above and to the right of center. I am shining a flashlight on it to make it more obvious.

Like I said, tiny, and I haven't been able to get it to impact IQ. But, it still shouldn't be there.

[Busted Knuckles]

I actually called and talked with Canon today.
Like I said, tiny, and I haven't been able to get it to impact IQ. But, it still shouldn't be there.

Thanks for the pic. I don't mean to overly harsh but.......

I would not hesitate to send it back - how in the world did that get past QC and out of the factory. How dark is the room where they inspect these things????

Think about exactly what this assemblage of parts really is and how much attention detail there is supposed to be. At least two inspectors missed this - component and final assembly.

This isn't a "nifty fifty" it is their flagship "normal range" zoom. This is a professional product, not a cheap consumer event. If this weren't a "L" and was $500 maybe, just maybe but probably not even then.

There is no reason in my book that the lens shouldn't have been set aside to the rework line and the front element replaced before it left the factory.

[Kayaker72]

There are a couple of ways to look at this. First, I agree, no lens, much less a premium lens, should have a defect like the small bubble that resides in my current copy. This has actually damaged Canon's reputation with me. Not much. But a little. I would normally be concerned it is just me, but I've read enough about other people having similar issues that I think it is Canon. And the bubble is hard to argue with.

So, the second way to look at this issue...does this lens accomplish my goals? Practically speaking, I want a lens that accomplishes my photographic expectations of the 24-70 II. Great IQ, fast AF, etc. This copy, while it shouldn't have the defect, does seem to accomplish my practical needs. So, there is a chance I still keep this lens as I am concerned that what may be sent to replace it will have a problem that does impact my practical goals (such as copy 3). The other factor playing into this is time. I've been at this almost two months. I was really getting this lens with the holidays in mind and I am headed out west for an early Christmas with my family later this week. So, I want this resolved and keeping copy 4 would resolve the situation.

But, the chances of me keeping it are low. What I have done is contact Adorama and ask them for multiple copies to evaluate and for a return slip for this current lens. They haven't yet responded, and I expect them to decline on the multiple copy request but send me the return information. I also noticed that Amazon still had the sale price (B&H and Adorama no longer did). So I ordered in two copies from Amazon. They should arrive today. I am planning to spend tonight evaluating the two copies from Amazon against the current copy I have from Adorama. I'll probably keep the best of the three and return the other two. If Adorama gets back to me that they'll send me multiple copies, I may wait to evaluate all the lenses together.

On a side note, my recent call with Canon was interesting and did make me think about this in a slightly different light. I pressed the Canon rep to see if they were having issues with this lens and the response was essentially nothing out of the ordinary. They checked, but there were no advisories on the 24-70 II. I mentioned the threads I've seen, and I got what I should have expected, there is a lot out there on the internet. It was a brief glimpse into a very large organization. Returns are ordinary. Flaws are ordinary. If they weren't, no one would ever be selling refurbished lenses. The fact that this was so much in stride for them, really brought home the point that each of us really needs to be our own advocate. They are prepared for it.

[Kayaker72]

Quick update. Just received the two new lenses from Amazon. Both 042 (April 2013 construction)...

Both with the clicking when zooming issue.

[HDNitehawk]

Huh??
You just bought two more off Amazon to test out? I thought I went to extremes.

[neuroanatomist]

Really, really, really glad that I bought mine back in March of this year...

[HDNitehawk]

On a positive note Brant, you now have the skills to work for Canon as a QC inspector.
It seems obvious that they may have the position open.

Don't loose faith though, this lens is worth the time it takes to get a good copy.