EOS R7 Bird photos are backfocused

[vtforester]

I have an R7 on which I use an EF 400 5.6L and a Canon EF-RF adapter, primarily for taking photos of birds. I have noticed that most of my pictures are backfocused. It is as if the camera is not taking into account the extra distance the adapter puts between the lens and the sensor. Has anyone else experienced this problem? Is there a solution other than getting a new RF lens so I can skip the adapter? Thank you for your help.

[Peter]

You can send it to Canon to get it microadjusted. Or buy a license for a third-party service software and microadjust it yourself. Ask Canon first.

[kvbarkley]

All the adapter does is compensate for the missing mirror box the EF lens expects. 

have you tried turning on the focus point display to see what the camera is focusing on?

[deebatman316 · Accepted solution]

I would check and see if that lens is still in its service life. If not Canon is not going to fix it due to the lack of parts. Also front and back focus aren’t possible on Mirrorless cameras. The image from the lens is directly projected on the image sensor itself. Meaning back focus can’t happen like in a DSLR. Where the AF sensors sit under the mirror and in front of the image sensor. Which can lead to front or back focusing. 

[vtforester]

Yes. The focus point is on the bird's eye but the focus is sharp about 3--5 inches behind it.

[wq9nsc]

Does this happen with stationary subjects or just with birds in flight?  If it is only with moving subjects, it could be an issue with tracking adjustment rate between the R7 and the EF 400 f5.6.

The EF 400 f5.6 was one of Canon's best performance/price ratio lenses and I used mine a lot for daytime sports before moving up to a 400 f2.8.  But it appears there are significant "grey areas" in compatibility between R series bodies and EF series glass when you are pushing the performance envelope.  And I am not referring just to limits on the maximum FPS (which for most people is just encouraging greater use of the "spray and pray" crutch for photography) but rather to tracking under tough conditions.  I am currently very happy with my 1DX III bodies but if I ever make the change to mirrorless, I will accept that upgrading to lenses for that architecture from whichever camera brand I choose will be part of the process.

As Deebatman316 notes, there is no microfocus adjustment for mirrorless bodies because the image sensor is also the focus sensor.

Rodger

[Stephen]

Hi there! This is a great question, and the behavior you are seeing is a common frustration when adapting older telephoto lenses to modern mirrorless bodies.

First, to put your mind at ease regarding the adapter: The camera does not need to "account" for the adapter distance. The adapter is a passive spacer that restores the specific "flange distance" the EF lens was designed for. If the adapter were the wrong size, you wouldn't be able to focus to infinity at all—it wouldn't cause the camera to consistently focus behind a subject that it can see clearly.

Since the EOS R7 focuses using the actual image sensor (Dual Pixel CMOS AF), "backfocus" (where the mirror and sensor are misaligned) is technically impossible in the way it existed on DSLRs.

So, why are your shots back-focused? With older lenses like the EF 400mm f/5.6L, the focus motor is slower than modern RF lenses. When shooting birds, the R7's AF system is incredibly fast and may sometimes "jump" off the bird to the high-contrast background (branches, leaves, grass) just behind the subject. This looks exactly like backfocus, but it's actually a tracking issue.

Here is the fix:

1. Check your Subject Detection Go to AF Menu 1 (Pink tab):

• Subject to Detect: Set to Animals.

• Eye Detection: Enable.

• Tip: If the camera sees the eye, it won't let the focus drift to the background.

2. Adjust your Servo AF Case Go to AF Menu 3 (Pink tab):

• Select Case 2 ("Continue to track subjects, ignoring obstacles").

• This tells the camera: "If you lose the bird for a split second, DO NOT jump to the background immediately. Wait for the bird."

3. The "Heat Haze" Factor Since you are using a 400mm lens (effectively 640mm on the R7 sensor!), atmospheric heat haze can often look like focus issues. If the air is shimmering even slightly, the autofocus will struggle to lock on sharp edges, often settling for the background which might have higher contrast.

Try adjusting those tracking settings first—that usually solves the "drift" you are seeing!

Official Canon Sources https://cam.start.canon/en/C005/manual/html/UG-05_AF-Drive_0110.html https://cam.start.canon/en/C005/manual/html/UG-05_AF-Drive_0060.html

[Waddizzle]

Is it possible to post an image in the forum , the one that back focused? Is possible to also post the RAW file to a public file sharing service, too?  The EXIF data is what we need to see.  

Some settings can cause soft images with the older lenses.  I do not recommend using the higher frame rates with the older lenses.  The older lenses cannot refocus fast enough. 

The camera is supposed to wait until it gets a focus lock before it fires the shutter. But there is no guarantee that it locks focus on your subject.  This is where AF point selection can either be your best friend or your worst enemy. 

Are you handholding the lens?

[Peter]

"As Deebatman316 notes, there is no microfocus adjustment for mirrorless bodies because the image sensor is also the focus sensor."

There is. https://www.usa.canon.com/support/canon-precision-alignment

Or this:

 

 

[vtforester]

Thanks Rodger. It happens with stationary subjects, as well as BIF.