EF 24-70 II returned from service - need advice

RCicala wrote:

NineX wrote:

Thanks Roger for advice. I will bring lens back to service and will ask them to adjust it further. Only thing which i dont understand is how is possible that they let lens which is not adjusted properly. But obviously it is how it is, regardless service center.

People massively overestimate the amount of time spent and the amount of testing done at service centers. Everything is on the clock - a given repair should take xx minutes. If that time includes 12 minutes for optical adjustment, you generally get the best adjustment that can be done in 12 minutes.

And it's not like the lenses get put on an optical bench for testing after repair. Some shots are taken of a test chart most of the time, sometimes some computer generated projection tests are done. Less frequently some true optical testing is done. It varies depending on the brand, the center, the lens in question, and the repair type.

Hello,

I just received lens from 3rd service iteration. Now perfectly adjusted. They told me that on the end they needed to replace complete rear lens group and rear group fitting with all that shims and adjustable collars. My lens was bought in 2015, and that element was originaly placed in piece which didnt have some springs which are needed to adjust element. It seems that canon has changed that in newer production batches and new lenses are now shipped with more adjustable rear element. so they ordered that part and when they tryed to fix old rear lens group inside they concluded that when lens is open would be cheaper for them to play on safe side and they ordered rear lens element group as well. All was fitted and adjusted and now is perfectly fine. All job and parts were done and replaced free of charge. It took some time but is sorted out finally.

Maybe Roger will know what i am talking about part of lens which is changed from early production batches till now.