topic Re: Canon RF 70-200 f/2.8 Front Focus issue in EF & RF Lenses

Canon RF 70-200 f/2.8 Front Focus issue

dspmax — Tue, 10 Dec 2019 17:05:57 GMT

Hi, new to the forum!

I've just purchased a Canon RF 70-200 lens, and after several days of usage appear to notice a front focus. It's not a severe issue, and mainly shows up in the shallow depth of focus circumstances, such as close-ups and portraits, where nailing the focal point is important, but it does make the lens feel soft. Given the $2700 price and the fact that I already sold my 70-200, I'm feeling a bit of buyer's remorse. I'm not the only one, seems like photography forums are beginning to get some momentum around this be a wide-spread phenomenon with this lens.

I just wanted to see if Canon is aware and anticipates this to be addressed as a firmware update or something I need to get the lens sent out.

Re: Canon RF 70-200 f/2.8 Front Focus issue

kvbarkley — Tue, 10 Dec 2019 17:14:07 GMT

We can't answer for Canon, but it does appear to be a common problem with this lens. It is discussed in the comments in the teardown article I linked to here:

https://community.usa.canon.com/t5/General-Camera-Discussion/RF70-200-Teardown/m-p/289111#M8240

I suggest you call Canon if it is still under warranty.

Re: Canon RF 70-200 f/2.8 Front Focus issue

RobertTheFat — Tue, 10 Dec 2019 21:42:53 GMT

@kvbarkley wrote:
We can't answer for Canon, but it does appear to be a common problem with this lens. It is discussed in the comments in the teardown article I linked to here:

https://community.usa.canon.com/t5/General-Camera-Discussion/RF70-200-Teardown/m-p/289111#M8240

I suggest you call Canon if it is still under warranty.

How do you get front focusing with a lens that projects its focusing image directly on the sensor? If there is a front focusing issue, wouldn't it have to be the fault of the camera, not the lens?

Re: Canon RF 70-200 f/2.8 Front Focus issue

kvbarkley — Tue, 10 Dec 2019 22:13:36 GMT

I don't know except to say that control loops are wierd things.

Re: Canon RF 70-200 f/2.8 Front Focus issue

Waddizzle — Fri, 13 Dec 2019 15:11:07 GMT

@kvbarkley wrote:
I don't know except to say that control loops are wierd things.

PID, PI, P.

Re: Canon RF 70-200 f/2.8 Front Focus issue

dspmax — Wed, 11 Dec 2019 13:54:49 GMT

I called in support and will be looking to ship the lens to the service center. I'm wondering if I should also send in my Canon EOS R as well, since perhaps it is more of a camera issue than the R? I don't have the same issue with non-RF lenses (i.e. when using EF lenses with the RF adapter). Here's an example of what i'm seeing (this is my post on dpreview): https://www.dpreview.com/forums/post/63405288

Re: Canon RF 70-200 f/2.8 Front Focus issue

Stephen — Wed, 11 Dec 2019 14:00:29 GMT

@dspmax wrote:
I called in support and will be looking to ship the lens to the service center. I'm wondering if I should also send in my Canon EOS R as well, since perhaps it is more of a camera issue than the R? I don't have the same issue with non-RF lenses (i.e. when using EF lenses with the RF adapter). Here's an example of what i'm seeing (this is my post on dpreview): https://www.dpreview.com/forums/post/63405288

If you think it's a good idea, by all means send it. Calibrating your gear with your gear is always a good idea. At the Factory Service Center (FSC) they have prescsion equipment to test and align your lenses and perform adjustments, however, if it turns out that there's a mis-alignment on your R (somehow - I don't know the ins-and-outs of the R technically speaking), then they may have to perform adjustments on the R as well.

TL;DR: When I was a tech, I always advised folks to send the camera and lens(es) that were misbehaving. Our team might not be able to recreate the exact conditions of your situation without your exact gear. 🤷‍♂️

Re: Canon RF 70-200 f/2.8 Front Focus issue

dspmax — Wed, 11 Dec 2019 14:24:09 GMT

Thanks Steven! Would I need to modify the service request to include instructions that I'm including the camera as well?

Re: Canon RF 70-200 f/2.8 Front Focus issue

Danny — Fri, 13 Dec 2019 17:10:39 GMT

You can simply include the camera with the lens. We'll check in your gear when it arrives.

We look forward to getting your equipment back to working order!