90D Faulty Phase Detecting AF

Hello everyone,

I've been an owner of the 90D for almost a year now and I can say with absolute certainty that that the Viewfinder Phase Detect AF is faulty, inaccurate and misfocuses with almost every image taken. This never happens when shooting with the Live-View's contrast based AF. I've tested this repeatedly several times with both various EF-S and EF lenses as well as third-party lenses like Sigma. I set up the camera on a steady tripod with a 10sec delayed shutter, took multiple images with the Live-View resulting in all of them being tack sharp, afterwards I switched the camera to the Viewfinder and again took multiple images with the same settings, focal length, one-shot AF, middle AF point resulting in almost all of them being out of focus varying in focal plane (plane of focus) which indicates that not even microadjustments can help resolve this problem.

Completely certain of this issue I made a claim last year and sent it in to an authorised Canon service center. The service technician didn't give his opinion in his report whether he acknowledged the defect or not but replaced the whole AF Sensor (Mirror box assembly, W/AF Sensor).

After receiving the camera back from the service center I tested the camera again both handheld and on a tripod to make sure that the issue was resolved. Unfortunately it was still faulty and the viewfinder unusable. I made another claim this month and a technician (or maybe the same technician) reported that defect didn't manifest itself but performed preventive measures and replaced parts regarding the viewfinder (Focus 5PCS/BOX, Pentaprism assembly, W/AE Sensor).

The camera got back to me yesterday and I performed a thorough testing to determine whether the defect was resolved. Unfortunately the defect is still persisting manifesting itself the same as before if not worse. I tested the camera again with the same settings both in Live-View and VF, tried primes as well as zooms, various focal points (subjects) and distances from subjects as well as focal lengths (from 16mm to 400mm). The viewfinder AF performs slightly better with some lenses on their longer ends such as 400mm to primer lenses with disasterous results. No matter what I do the viewfinder almolst never gets the autofocus accurate and when it does, it's a lucky image that came out accurate or is only acceptably sharp but not as sharp as an image taken with the Live-View.

I'm nost sure now how to proceed with this issue to get this junk fixed or replaced, however, I've decided to call Canon support as soon as they're availabe by phone and report my experience and after that go to the service center with my gear to show them what's going on.

Has anyone else had an issue with their copy's viewfinder AF or know of someone who has?

The list of canon lenses tried with the camera:

EF-S 10-22, EF-S 55-250, EF-S 17-55 2.8, EF-S 24 2.8, EF 50 1.4, EF 85 1.8

 

So after the fourth warranty claim, they decided to send me a new copy as they likely didn't find a solution to removing the defect.
I was told that the issue lay somewhere in the viewfinder but they didn't specify what it was, however, it's weird that they claim the defect is caused by something in the viewfinder even though they replaced the whole viewfinder and all other parts in relation to it.

 

Hi Johnsey, yeah I'm luckily through with it now. I'm not sure either why they would blame the viewfinder although they replaced the whole viewfinder assembly along with the mirror box assembly as well. I don't even think they know themselves but as you say there are more people out there.. It just could have been resolved right away after the first warranty claim but there were at least two technicians that took turns mending it and one of them was a CPS professional and neither was able to it.