Lenses on mirrorless body need Focus calibration ?

I got this brand new Sigma 100-400MM F5-6.3 DG OS HSM | C a few weeks ago.

Using it with the Canon R10 body it won't achieve critical focus most of the times even in AF single shot, single area mode.
My camera is already in Focus Accuracy priority and also this lens.

So, this left me wondering if this lens needs focus calibration using the Sigma app ?
I already check and everything was on default.

I assumed focus calibration was only necessary with SLR AF systems, am I right ?

I've achieved critical focus using Manual focus so is not an optical defect.

What is going on here, any clues ?

Thats one of  big selling points of  the R system   I would send it in for exchange for the RF100-400.  The focus is faster and dead on every time.  I had both the tamron and Sigma 100-400 and was never really happy with the focus.  RF 100-400 is dead on every time.

Best of luck.

Is that an EF mount lens your using on an R body via an adapter?

If so , which adapter?

You sometimes find using lenses via an adapter perform much better in AF-C mode than AF-S .

Also , is the lens focussing with the aperture wide open , then stopping down on exposure?

If so , there could be some focus shift .

davel33 wrote:

Thats one of big selling points of the R system I would send it in for exchange for the RF100-400. The focus is faster and dead on every time. I had both the tamron and Sigma 100-400 and was never really happy with the focus. RF 100-400 is dead on every time.

Best of luck.

I already ordered the RF 100-400 and yes, it nails the focus every time. Its only issue is the 1EV darker apertures, compared to the Sigma.

Almost certain I am keeping the Canon and returning the Sigma but wanted some confirmation before doing so.

neilt3 wrote:

Is that an EF mount lens your using on an R body via an adapter?

It is a third party adapter Ykeasu, which has worked well with a Tokina EF lens, or other Canon EF lenses, no AF issues.

If so , which adapter?

You sometimes find using lenses via an adapter perform much better in AF-C mode than AF-S .

Did not know. But AF-C fdpepletes the battery faster and takes a toll on the focus motors over time when no needed.

Also , is the lens focussing with the aperture wide open , then stopping down on exposure?

If so , there could be some focus shift .

But that is how AF is supposed to work, it opens up temporarily then return to the set aperture when taking the shot, the focus plane should not change.

Photato wrote:

neilt3 wrote:

Is that an EF mount lens your using on an R body via an adapter?

It is a third party adapter Ykeasu, which has worked well with a Tokina EF lens, or other Canon EF lenses, no AF issues.

I'm using Canon EF lenses on E mount cameras with a Sigma MC-11 adapter with no problems.

Apart from a Sigma 15-30mm lens , all my EF lenses are Canon , mostly "L" lenses .

I did have a Commlite adapter that I used on a NEX 7 , but this doesn't work well with my a7Riv or a6600 .

Some lens/camera/adapter combinations don't always work well together.

If so , which adapter?

You sometimes find using lenses via an adapter perform much better in AF-C mode than AF-S .

Did not know. But AF-C fdpepletes the battery faster and takes a toll on the focus motors over time when no needed.

Not really .

AF only functions while you press the shutter button to obtain focus , when your focussed , you take the picture . When your not wanting to focus on anything, you take your finger off the shutter release and to camera stops using the AF motors .

You don't really wear the motors out any more as your using them the same amount to obtain focus .

Your only adding unnecessary wear if your holding the shutter button half way down when your not tracking anything.

If you are tracking something, then the camera needs to be set to AF-C anyway. Otherwise you'll lock focus somewhere other than what your shooting.

If you want to prefocus on a point while you wait for the subject to be there  ( sports , racing etc ) then you can prefocus in whichever mode works best .

Also , is the lens focussing with the aperture wide open , then stopping down on exposure?

If so , there could be some focus shift .

But that is how AF is supposed to work, it opens up temporarily then return to the set aperture when taking the shot, the focus plane should not change.

Do a search on "focus shift" . Some lenses suffer more from it than others .

Yes that's how DSLRs work , but most mirror less cameras focus with the lens stopped down with native lenses so you should have 100% accurate focus every time , preventing focus shift .

When adapting lenses , they mostly seem to focus wide open , then stop down after AF is locked , before taking the image .

Try taking some shots wide open with a stationary target ( a wall for eg ) and see how it behaves .

Then do the same shot stopped down , and see it behaves differently.

neilt3 wrote:

Photato wrote:

neilt3 wrote:

Is that an EF mount lens your using on an R body via an adapter?

It is a third party adapter Ykeasu, which has worked well with a Tokina EF lens, or other Canon EF lenses, no AF issues.

I'm using Canon EF lenses on E mount cameras with a Sigma MC-11 adapter with no problems.

Apart from a Sigma 15-30mm lens , all my EF lenses are Canon , mostly "L" lenses .

I did have a Commlite adapter that I used on a NEX 7 , but this doesn't work well with my a7Riv or a6600 .

Some lens/camera/adapter combinations don't always work well together.

If so , which adapter?

You sometimes find using lenses via an adapter perform much better in AF-C mode than AF-S .

Did not know. But AF-C fdpepletes the battery faster and takes a toll on the focus motors over time when no needed.

Not really .

AF only functions while you press the shutter button to obtain focus

Perhaps on  Sony, but not on a Canon.

I suspect that you are thinking that AF-C is referring to what Canon calls Servo AF, when the camera continues focusing as long as you hold the button down.

In Canon world, AF-C is Continuous AF where the camera will continue trying to focus when it is sitting on a table with no-one touching it (or hanging around your neck). The theory behind this is that the lens is always very close to being focused when you touch the shutter (or back button focus) to take a shot. It does, however, mean that the camera is focusing almost continuously (as long as the camera is turned on) and does consume more battery doing so.

, when your focussed , you take the picture . When your not wanting to focus on anything, you take your finger off the shutter release and to camera stops using the AF motors .

You don't really wear the motors out any more as your using them the same amount to obtain focus .

See above.

Your only adding unnecessary wear if your holding the shutter button half way down when your not tracking anything.

If you are tracking something, then the camera needs to be set to AF-C anyway.

See above.

Otherwise you'll lock focus somewhere other than what your shooting.

If you want to prefocus on a point while you wait for the subject to be there ( sports , racing etc ) then you can prefocus in whichever mode works best .

Also , is the lens focussing with the aperture wide open , then stopping down on exposure?

If so , there could be some focus shift .

But that is how AF is supposed to work, it opens up temporarily then return to the set aperture when taking the shot, the focus plane should not change.

Do a search on "focus shift" . Some lenses suffer more from it than others .

Yes that's how DSLRs work , but most mirror less cameras focus with the lens stopped down with native lenses so you should have 100% accurate focus every time , preventing focus shift .

When adapting lenses , they mostly seem to focus wide open , then stop down after AF is locked , before taking the image .

Try taking some shots wide open with a stationary target ( a wall for eg ) and see how it behaves .

Then do the same shot stopped down , and see it behaves differently.

Andy01 wrote:

neilt3 wrote:

Photato wrote:

neilt3 wrote:

Is that an EF mount lens your using on an R body via an adapter?

It is a third party adapter Ykeasu, which has worked well with a Tokina EF lens, or other Canon EF lenses, no AF issues.

I'm using Canon EF lenses on E mount cameras with a Sigma MC-11 adapter with no problems.

Apart from a Sigma 15-30mm lens , all my EF lenses are Canon , mostly "L" lenses .

I did have a Commlite adapter that I used on a NEX 7 , but this doesn't work well with my a7Riv or a6600 .

Some lens/camera/adapter combinations don't always work well together.

If so , which adapter?

You sometimes find using lenses via an adapter perform much better in AF-C mode than AF-S .

Did not know. But AF-C fdpepletes the battery faster and takes a toll on the focus motors over time when no needed.

Not really .

AF only functions while you press the shutter button to obtain focus

Perhaps on Sony, but not on a Canon.

I suspect that you are thinking that AF-C is referring to what Canon calls Servo AF, when the camera continues focusing as long as you hold the button down.

Correct .

In Canon world, AF-C is Continuous AF where the camera will continue trying to focus when it is sitting on a table with no-one touching it (or hanging around your neck).

I don't have an "R" camera , so can't comment on how you set them up .

The Canon cameras I have are a 5d and 60d which are DSLRs and several 35mm SLRs such as the EOS 1n , 3 , ELAN 7NE and several of the smaller type bodies .

The theory behind this is that the lens is always very close to being focused when you touch the shutter (or back button focus) to take a shot.

I typically have my cameras set to AF-S ( call it what you will ) , as in you half press the shutter button to focus , when it locks focus , it stops moving , regardless of if you move the camera or the target moves , then you take the shot .

I'm sure I've had my cameras set up so that I can press either the back button or top shutter release button to start AF-C ( servo ) and until I press and hold it nothing happens .

I'm not at home to check at the moment , but would be amazed if you can't set a new camera with all those custom functions up to work in such a conventional manner .

It does, however, mean that the camera is focusing almost continuously (as long as the camera is turned on) and does consume more battery doing so.

I shall check my cameras when I get home .

, when your focussed , you take the picture . When your not wanting to focus on anything, you take your finger off the shutter release and to camera stops using the AF motors .

You don't really wear the motors out any more as your using them the same amount to obtain focus .

See above.

Camera usage tends to be different between DSLRs and mirror less .

When you let go of the grip of a typical dSLR it tends to go to sleep . No AF , no metering , and as it has an OVF rather than EVF , no constant live view .

With my mirror less cameras when I let go of the grip to hang around my neck , the EVF is still on , using power . I don't have the camera go into energy saving sleep mode , as it's a PITA when your working on a tripod .

So when I take a shot and won't be taking another straight away , I turn the camera off .

No energy to wast , no AF , no EVF etc .

Your only adding unnecessary wear if your holding the shutter button half way down when your not tracking anything.

If you are tracking something, then the camera needs to be set to AF-C anyway.

See above.

In the user manual for the R10 it states ;

"Pressing the shutter button halfway tracks moving subjects to keep them in focus.

Keep the subject on the screen as you hold down the shutter button halfway, and at the

decisive moment, press the shutter button completely." .

End quote .

If the AF is always active in "Servo" mode , why would you need to keep the shutter button constantly half pressed down to keep AF going until you take the shot ?

Your saying even if the camera was just sat on a table still switched on , it would continue to focus ?

• In which case , why keep the button held down?

Otherwise you'll lock focus somewhere other than what your shooting.

If you want to prefocus on a point while you wait for the subject to be there ( sports , racing etc ) then you can prefocus in whichever mode works best .

Also , is the lens focussing with the aperture wide open , then stopping down on exposure?

If so , there could be some focus shift .

But that is how AF is supposed to work, it opens up temporarily then return to the set aperture when taking the shot, the focus plane should not change.

Do a search on "focus shift" . Some lenses suffer more from it than others .

Yes that's how DSLRs work , but most mirror less cameras focus with the lens stopped down with native lenses so you should have 100% accurate focus every time , preventing focus shift .

When adapting lenses , they mostly seem to focus wide open , then stop down after AF is locked , before taking the image .

Try taking some shots wide open with a stationary target ( a wall for eg ) and see how it behaves .

Then do the same shot stopped down , and see it behaves differently.

neilt3 wrote:

Your saying even if the camera was just sat on a table still switched on , it would continue to focus ?

• In which case , why keep the button held down?

This is only if the AF-C (Canon's Continuous AF feature used in the M series and R series mirrorless cameras) is turned on. Technically it wouldn't continue trying to focus if it was sitting on a table without being touched - as long as it was able to lock focus on something.

But if it was hanging around your neck (as you rightly say the mirrorless tend to stay on because the EVF proximity feature keeps them "alive") and this AF-C was turned on it could keep trying to focus on the new subject as the camera kept moving.

I suspect that if you did a poll, most Canon mirrorless users generally have this Continuous AF turned off and use One Shot (your AF-S perhaps ?) or Servo (your AF-C perhaps ?).

Photato wrote:

davel33 wrote:

Thats one of big selling points of the R system I would send it in for exchange for the RF100-400. The focus is faster and dead on every time. I had both the tamron and Sigma 100-400 and was never really happy with the focus. RF 100-400 is dead on every time.

Best of luck.

I already ordered the RF 100-400 and yes, it nails the focus every time. Its only issue is the 1EV darker apertures, compared to the Sigma.

It's actually only a 1/3-2/3 stop difference, depending on the focal length. At 100, Sigma is F5, Canon F5.6. At 400 Sigma is F6.3, Canon F8.

Almost certain I am keeping the Canon and returning the Sigma but wanted some confirmation before doing so.