Why does everything frontfocus when using OCF?

[Viggo]

Thanks for the tip Graham, but I've been alternating between AF modes from spot to face detection, and everything between, in both servo and one shot without any difference. I use Servo all the time, I just adjust the ACC-setting to -2 when shooting still subjects and it has given better results than one shot when shooting very shallow dof. When kids stand still, they're not really still enough for one shot ;D

 

[hne]

Does it still front-focus if you leave the radio-controlled flash somewhere where it doesn't affect the image at all? It should just pop on max if you do, no matter what you set FEC to. At least nothing light-related would influence the image. I could imagine a possibility where preflashes could be influencing tracking AF, now that the higher end Canons use data from the metering sensor also for AF purposes.

I've not seen it on any of my cameras, only a heavy ND with 1.8 density (6 stops, for large-aperture video) does similar things in my camera bags.

It seems like it's only when the flash lights the subject, I only use it manual, so no ETTL here at all. Interesting about the preflash, but nothing lights up before focus is locked though. And it's the same with both one shot and servo.

How do you use HSS without ETTL?

The metering preflashes are triggered just before exposure, close enough that only some individuals manage to blink. Since the ETTL II system uses differences between ambient and flash reading to figure out where the lit subject is (rather than rely on AF point placement as the previous ETTL system did), I thought there might be a back channel to the AF system for some reason if you had an AI servo mode or even more likely if you had an auto af point select mode such as zone af.

The example you showed had a bright knee in focus, closer than the face. That would have been more affected by the flash than the face would. Is this a common scenario in the images that front-focus, that there is something bright between the focus point and the flash?

Can you trigger this with speedlights too?

Can you trigger the same behaviour on a non 1-series body?

 

[Viggo]

Does it still front-focus if you leave the radio-controlled flash somewhere where it doesn't affect the image at all? It should just pop on max if you do, no matter what you set FEC to. At least nothing light-related would influence the image. I could imagine a possibility where preflashes could be influencing tracking AF, now that the higher end Canons use data from the metering sensor also for AF purposes.

I've not seen it on any of my cameras, only a heavy ND with 1.8 density (6 stops, for large-aperture video) does similar things in my camera bags.

It seems like it's only when the flash lights the subject, I only use it manual, so no ETTL here at all. Interesting about the preflash, but nothing lights up before focus is locked though. And it's the same with both one shot and servo.

How do you use HSS without ETTL?

The metering preflashes are triggered just before exposure, close enough that only some individuals manage to blink. Since the ETTL II system uses differences between ambient and flash reading to figure out where the lit subject is (rather than rely on AF point placement as the previous ETTL system did), I thought there might be a back channel to the AF system for some reason if you had an AI servo mode or even more likely if you had an auto af point select mode such as zone af.

The example you showed had a bright knee in focus, closer than the face. That would have been more affected by the flash than the face would. Is this a common scenario in the images that front-focus, that there is something bright between the focus point and the flash?

Can you trigger this with speedlights too?

Can you trigger the same behaviour on a non 1-series body?

HSS without TTL; I don't know, and that's why I also said that the Broncolor HS (not HSS) is different than the other lamps I 've used, since in fact the Bron isn't TTL at all.

It does not matter one bit if there's anything in between the point or not, and with single point or expanded or auto af point selection with face detection, they all work flawless without flash, and not with flash. Well, it works because it is consistent, only in front compared to shooting without lamp.


Anyway, after I tried turning off the AF assist beam in the AF menu things have been looking a bit better actually. I have gotten more sharp shots today then previously. Still just testing, but improved for sure.

This is sht at f1.4 with the 35 f1.4 L II.

Wide open with the 135 L.

I have only the 1dx2 to try this with so I don't know. I do know however that my 1dx didn't have any issues with the Profoto B1 or the ad360. And I know a friend who has this issue with the ad360 and the 5d4.

 

[hne]

How do you use HSS without ETTL?

The metering preflashes are triggered just before exposure, close enough that only some individuals manage to blink. Since the ETTL II system uses differences between ambient and flash reading to figure out where the lit subject is (rather than rely on AF point placement as the previous ETTL system did), I thought there might be a back channel to the AF system for some reason if you had an AI servo mode or even more likely if you had an auto af point select mode such as zone af.

The example you showed had a bright knee in focus, closer than the face. That would have been more affected by the flash than the face would. Is this a common scenario in the images that front-focus, that there is something bright between the focus point and the flash?

Can you trigger this with speedlights too?

Can you trigger the same behaviour on a non 1-series body?

HSS without TTL; I don't know, and that's why I also said that the Broncolor HS (not HSS) is different than the other lamps I 've used, since in fact the Bron isn't TTL at all.

It does not matter one bit if there's anything in between the point or not, and with single point or expanded or auto af point selection with face detection, they all work flawless without flash, and not with flash. Well, it works because it is consistent, only in front compared to shooting without lamp.


Anyway, after I tried turning off the AF assist beam in the AF menu things have been looking a bit better actually. I have gotten more sharp shots today then previously. Still just testing, but improved for sure.

This is sht at f1.4 with the 35 f1.4 L II.

Wide open with the 135 L.

I have only the 1dx2 to try this with so I don't know. I do know however that my 1dx didn't have any issues with the Profoto B1 or the ad360. And I know a friend who has this issue with the ad360 and the 5d4.

Nice shots (that I removed from the quote block to save people some scrolling).

I tried a few dozen backlit flash exposures with 35/1.4 and 85/1.8 more or less fully open yesterday on my 5D4, with my Yongnuos but couldn't find a single case of front focus. Neither with single-point spot focus nor Face priority with all points active. AF assist beam firing. This was with TTL and HSS as it was rather bright, EV 13-15 at ISO100.

When you get front focused images: Is there always an object that is in focus or could it be that nothing (or like one single twig in a corner or a slice of concrete) is in focus?
If not: Is the front-focusing amount deterministic? Proportional to subject distance?

 

[Viggo]

It doesn't matter if it's nothing in front but ground, or if the subject is the only thing except ground and or background and nothing disturbs.

The relationship between subject distance and front focus I think it's pretty constant, it's not like with the Signa's that chooses a point at random. It's pretty close to being sharp, but not quite there,
No complete misses like 20 ft in front.

 

[SecureGSM]

Viggo, I found pretty reasonable explanation to this issue on Godox website, theyu talk about Nikon version but the issue is very similar sounding at least to me. I took the liberty of providing few remarks in the text below in order to make the better sense of the information.. I hope it is OK by you.

Q:why using the AF lamp in X1N transmitter, the picture is unfocused?
A:
The AF focusing function can be only normally used with Nikon original flashes, so by using the AF lamp (AF assist beam - SecureGSM) in the camera to address the issue, turn off the AF focusing function (AF assist beam - SecureGSM) in the transmitter(C.Fn-06 set 0），and then turn on the AF focusing function in the camera( Set ON for the build-in AF lamp (AF assist beam - SecureGSM) in camera customer menu)

http://www.godox.com/EN/Q&A.html

It doesn't matter if it's nothing in front but ground, or if the subject is the only thing except ground and or background and nothing disturbs.

The relationship between subject distance and front focus I think it's pretty constant, it's not like with the Signa's that chooses a point at random. It's pretty close to being sharp, but not quite there,
No complete misses like 20 ft in front.

 

[Viggo]

Viggo, I found pretty reasonable explanation to this issue on Godox website, theyu talk about Nikon version but the issue is very similar sounding at least to me. I took the liberty of providing few remarks in the text below in order to make the better sense of the information.. I hope it is OK by you.

Q:why using the AF lamp in X1N transmitter, the picture is unfocused?
A:
The AF focusing function can be only normally used with Nikon original flashes, so by using the AF lamp (AF assist beam - SecureGSM) in the camera to address the issue, turn off the AF focusing function (AF assist beam - SecureGSM) in the transmitter(C.Fn-06 set 0），and then turn on the AF focusing function in the camera( Set ON for the build-in AF lamp (AF assist beam - SecureGSM) in camera customer menu)

http://www.godox.com/EN/Q&A.html

It doesn't matter if it's nothing in front but ground, or if the subject is the only thing except ground and or background and nothing disturbs.

The relationship between subject distance and front focus I think it's pretty constant, it's not like with the Signa's that chooses a point at random. It's pretty close to being sharp, but not quite there,
No complete misses like 20 ft in front.

Thanks for the tip! Problem is that I can't change any of the settings accessed in the Speedlite menu in camera, I can see them, but not change them...

 

[SecureGSM]

oh, schweppes! this does not sound right to me. there is v.20 (beta) Godox x1t-c firmware being discussed on the forum. just saying

Thanks for the tip! Problem is that I can't change any of the settings accessed in the Speedlite menu in camera, I can see them, but not change them...

 

[Viggo]

oh, schweppes! this does not sound right to me. there is v.20 (beta) Godox x1t-c firmware being discussed on the forum. just saying

Thanks for the tip! Problem is that I can't change any of the settings accessed in the Speedlite menu in camera, I can see them, but not change them...

It's my brothers lamp, so I'll just leave it to him to update. It's only a matter of days before my new lamp arrives and I'll have a go then. It's a similar transmitter so perhaps it will make more sense then

 

[C_Raven]

Thanks for the tip! Problem is that I can't change any of the settings accessed in the Speedlite menu in camera, I can see them, but not change them...

I think that's normal, since you don't have a flash in the hotshoe compatible with speedlite control, and the 1D series does not have AF assist lamp in the body, so there is nothing to turn OFF.

 

[Viggo]

Thanks for the tip! Problem is that I can't change any of the settings accessed in the Speedlite menu in camera, I can see them, but not change them...

I think that's normal, since you don't have a flash in the hotshoe compatible with speedlite control, and the 1D series does not have AF assist lamp in the body, so there is nothing to turn OFF.

Probably, but I can turn it on/off in the AF menu. It's a bit strange that the settings are there when they can't be changed, my other triggers only display what I can change.

 

[privatebydesign]

HSS and ETTL are not related to each other, you can do either one or both at once.

 

[Viggo]

HSS and ETTL are not related to each other, you can do either one or both at once.

I came to that conclusion also, I remembered there is a ad600 that has HSS, but isn't TTL. Hopefully the Siros is here on Friday 8)