POVDOV

I want to check and see if the focus of my Canon 100-400mm Mk II is correctly focusing or is it back focusing or forward focusing. This is with my new R 6. The Canon 7D MkII has a menu item to do this but I cannot find one on the R6 menu. The distance from the lens back element to the sensor has got to be different because of the Canon adapter EF to R between lens and camera. Any ideas would be greatly appreciated

Eblong Loc: Colorado

Since the same sensor is used for both focus and imaging. There is no need to do the focus compensation we used to do with our DSLRs. I noticed the delta immediately when I went from my 6D to my R6.

POVDOV

I guess the topography of the mirrored vs no mirror somehow compensates for this. I accept what you are saying but do not understand fully what you mean. Thank you for your answer

User ID

The R6 is not an SLR. The parts within an SLR that lead to inaccurate AF are not present in a live view camera ... likewise those parts are not in use when an SLR is used in its live view mode.

Your remark that the adapter must have changed the rear element to sensor distance show that you need to study up. The job of the adapter is to maintain the original distance despite the different depths of SLR bodies vs R bodies. The adapter is a corrector, not a disrupter.

Any small error in the depth of a lens adapter has absolutely zero effect on the AF accuracy of any camera, SLR or live view. So your adapter shouldn’t cost you any sleep :-)

POVDOV

Thanks so much for the clarification. yes indeed sleep will come easy now.

User ID

Realizing that the job of an adapter is to restore the missing body depth when mounting SLR lenses on LV bodies, you can see why adapting is a oneway street. You don’t adapt LV lenses to SLR bodies.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

It can't back/front focus - and the adapter is correctly sized to make the lens match up so that it will focus at infinity, but being a zoom there is a little "wiggle room" at maximum focus distance anyway.

The only time you will need to calibrate focus is when you have Phase Detect Auto Focus (PDAF), where there is a main mirror, semi transparent areas on that mirror that permit image information to travel to a second mirror which in turn sends the light to focus sensors. Everything has to be in alignment and situated at the correct distances in order for everything to work correctly. The AF sensors and the firmware that interprets what they see can detect when each one of a pair of sensors (or more) see the two images that should conicide (in focus) or see two different images that do not coincide - (out of focus). This is an oversimplification, but you can get a better visual explanation here.

https://photographylife.com/how-phase-detection-autofocus-works

And you can see why mirrorless cameras, which don't have this elaborate system cannot be out of focus. However, proper mapping of focus points may be a factor with mirrorless - I do know this to be a factor with PDAF systems - where the focus box you see in the viewfinder does not match what the camera is actually focusing on. I am not sure if this affects mirrorless or when one uses live view on a DSLR.

bleirer

You should check your camera menu to see if your R6 can use the dual pixel raw system. I know the R5 and the 5D mark 4 does, but my RP doesn't. It would be in the camera menu under the camera icon, look for a dual pixel raw setting with enable or disable as the choices. What this does in Canon DPP4 software is to let you adjust focus to a degree after the shot is taken. You can adjust sharpness a little or change bokeh a little, etc. Be worth checking out. In DPP4 the menu is tools/start dual pixel raw optimizer. This is different from lens fine tune that you find on a mirrored camera.

CHG_CANON Loc: the Windy City

Member Photolady2014 was having focus problems with her 100-400L II and EOS R5. The linked post discusses the final resolution. If you're too having issues, consider reading the details, seeing if there are any firmware updates for your camera / lens or whether her earlier examples (see her topic list) are similar to yours and maybe you need to call Canon Technical support. see: https://www.uglyhedgehog.com/t-681779-1.html

POVDOV

Thanks

POVDOV

Thanks, Appreciate your thorough explanation.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

With the R6 there is no need to check focus. Your lenses now focus directly on the sensor. Congratulations, you graduated.

CHG_CANON Loc: the Windy City

Please note, this is a factually incorrect assumption.

The purpose of the EF to R adapter is to set the EF / EF-S lenses to the exactly correct distance for the legacy EF/EF-S to operate exactly and accurately on the RF-mount body as an EF-mount body.

POVDOV

I stand corrected correctly. Amazing what you can learn on UHH. Thanks

Picture Taker Loc: Michigan Thumb

CALL CANON (800) 652-2666 the will walk you thru it.