EF 24-70 II returned from service - need advice

Hello,

My EF 24-70 II was returned from Canon service where they have done blade assembly replacement. I think that bottom left and bottom right corners are bit off. I suspect that lens is slightly decentered.

what do you think (examples below)

Attached pictures

focus is at infinity images attached are from center and all 4 corners. Subject distance around 200m, picture taken at 70mm f2,8

up right corner

up left corner

bottom right corner

bottom left corner

center

There is also picture taken from tripod at 70mm f2.8 5 meters from wall (look difference between up corners and bottom corners)

Thanks for answer.

I have seen Rogers posts

These are 100% crops, and extreme corners. Im not sure if this will have visible impact in real life photography (definitley shooting brick wall and chimneys positioned in extreme corners are not examples of how this lens is used)

Im not sure should i return lens back to service and insist that they make all 4 corners look equaly or just leave it as it is now. I know that maybe fixing bottom corners can bring down overall resolution.

Is it worth it?

unfortunatley i dont have examples from before service, but i doubt that they returned me lens which is not "in spec".

We want to think that Canon Repair tests everything before they ship a repaired item, but I've had to return my last two repairs because of things they had broken during their repair.

NikonHaoleboy wrote:

Roger frequently comments on DPR forums, why not shoot him an email with images?

That one needs to go back to Canon for an adjustment, it's a bit off. And as mentioned above, this isn't shockingly unusual after a repair.

Roger

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.

I don't use canon service anymore but luckily I have repair shop only blocks from my house.

I see....

Unfortunatley it looks that bringing lens which is for little more complicated repair than replace red ring or rubber, and expect that that lens will be in depth observed and returned back in 100% working condition equal to playing lottery.

as consumer i would expect that they send me back lens which is 100% repaired. repair and hours which we are all paying to authorized service centers are not cheap.

I have contacted Canon service center and they told me that they will call me back to bring lens after they escalate issue to service center in Italy where more experienced staff is located. They need to consult with them....

will post further to this topic when i will have my lens back from 2nd shoot service

thank you all for contributing

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.

Corners after repair

Bottom right

Bottom left

Up Right

Up Left

If the lens was purchased in 2015, its out of warranty. Why did Canon do the extensive repairs for free? Congratulations! I'm glad everything worked out to your satisfaction.

Great to hear. Happy shooting with this lens