Long lens/vehicle problems

[Frank Kolwicz]

Thanks again, Bob,

I know you're trying your hardest to help me figure out how this might be addressed and I certainly appreciate it fully, BUT, I offered Canon test images and the reply I got is that they can't diagnose problems via email, that I had to send the lens, camera and 1.4x to them for evaluation. That was return #3 of 4. The initial repair and the first 3 returns went to Canon's facility in Irvine, CA, the last one went to Jamestown, NJ where they supposedly have "better equipment" after the intercession of Canon's Oregon area sales representative.

There is a happy note to all this nonsense: I didn't have to pay for shipping the last two times, but, that's the only happy thing about the experience.

Frank

Since you can borrow a good 600/4, what I'd do would be to take some calibration test shots of a distant target using both AF and MF with a good 600/4 and your 600/4, then I'd give Canon those test shots and ask them to look at them and tell you what they think is wrong with your lens. If you present them with proof of a problem you're much more likely to get it fixed than if you just send in the lens telling them that it isn't sharp.

[Bob Atkins]

I meant send along the images (both digital files and prints) from your lens and the good lens with the lens. That's what I did when I had an issue with a 300/2.8 and it did help (I used the Jamesburg office). I agree with them that they can't diagnose anything without actually having the lens on hand, but actual images and prints of the problem you are describing is much more effective then just telling them you don't think it's sharp. Without direct comparison shots they have no way to measure what you regard as "sharp" and "not sharp" and they don't know your technique is good enough to get sharp images with a different lens.

Of course they shouldn't need all this stuff. They should be able to put the lens on their test rig and see how sharp it is. I suppose there is a range which they consider "in-spec". I don't know how many focus distances they check it at either. They should do close, mid and far but I don't know what they actually do.