Why does everything frontfocus when using OCF?

[Viggo]

Hi guys!

I've been using Godox ad360, Profoto B1 and now I'm borrowing a ad600 whilst waiting for my Broncolor Siros 800L to arrive. My question is;

Why on earth does every picture using an Off Camera Flash result in frontfocus?? Any lens is the same. Everything is spot on as soon as I turn the trigger off and take shot without flash. Only option to get correctly focuses shots with OCF is by using LV, and I'm so tired of this.....

 

[Ray-uk]

Could it be that you have flash AF assist enabled and it is confusing the AF, try turning it off.

 

[Viggo]

Could it be that you have flash AF assist enabled and it is confusing the AF, try turning it off.

Not sure how it can affect when it's not lighting up, but just checked and it's indeed turned off in camera.

 

[Ray-uk]

In that case it must be that your ambient light levels are too low to obtain correct focus, LV focus is using a different focus system so that isn't being affected. Try increasing the permanent light level in your room apart from the flash.

 

[IglooEater]

In that case it must be that your ambient light levels are too low to obtain correct focus, LV focus is using a different focus system so that isn't being affected. Try increasing the permanent light level in your room apart from the flash.

I second that. Or, better yet, bring the whole kit and kaboodle out into the sunshine and see if it still does it.

 

[Viggo]

In that case it must be that your ambient light levels are too low to obtain correct focus, LV focus is using a different focus system so that isn't being affected. Try increasing the permanent light level in your room apart from the flash.

I second that. Or, better yet, bring the whole kit and kaboodle out into the sunshine and see if it still does it.

I AM outside, that's where I use my flash 98% of the time, and usually during pretty optimal light midday. And as soon as I turn the lamp off, everything sticks and is perfectly sharp.

 

[Ray-uk]

Ok so we are running out of things to blame, what are you using to trigger the off camera flash.

 

[Viggo]

Ok so we are running out of things to blame, what are you using to trigger the off camera flash.

I used the included trigger with the ad360, and then the CellsII-c, I used the Profoto AirRemoteTTL-c with the B1 and now the Godox X1t-c with the Ad600. It's the same, and with every lens... and with the 1dx and the 1dx2.

I'm kind of hopin git has something to do with HSS that goes away with the Broncolor that doesn't use pulses, but very long flash duration.

 

[Ray-uk]

I'm not sure the Broncolor works like that because the specs state the longest duration is 1/250 sec, the HS facility is controlled by the RFS 2.2 trigger so it must pulse it.

Anyway that aside, have you tried turning off the HSS and use ordinary synch with the shutter at 1/125.

 

[Viggo]

I'm not sure the Broncolor works like that because the specs state the longest duration is 1/250 sec, the HS facility is controlled by the RFS 2.2 trigger so it must pulse it.

Anyway that aside, have you tried turning off the HSS and use ordinary synch with the shutter at 1/125.

1/250s should anyways be long enough, since it needs the new trigger to optimize timing. The same way Elinchrom and PW does, only easier from what I read. I also contacted Broncolor and asked about this and if the HS shortens the lifespan of the tube, and they said it didn't because it was the same as using it on full power.

I have tried syncspeed also, but I can't test in the same way since I need to stop way down at the same situation. Using nd-filters will certainly make it even worse for the AF. So the thing that comes closest is to turn the lamp off, and then it works pretty great.

If I use -1 afma with soccer practice it works, but +2 doesn't , and -1 is way in front with the lamp. Otherwise pretty consistent.

I will put up an example, but my server is being worked on, so no access just now. Thanks for all the replies so far

 

[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.

 

[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.

 

[Viggo]

So I just tried every possible combination in a very dim lit room (no modellight on either), every focusing point including non-cross, in one shot and servo. Every power in the lamp at all shutters from sync to 1/8000s and every single shot is in perfect focus. So this issue is due to the surroundings and perhaps limited to faces and outdoors.

So, the gear works in a controlled situation with little ambient, but struggles big time outside in any bright light. Does that make any sense?

 

[Viggo]

Here's a fullsize example, I have many like these :-\

 

[YuengLinger]

Frustrating for you, but an interesting trouble-shooting puzzle.

Do YOU have a theory? Have you tried your Canon tech support?

 

[Viggo]

Frustrating for you, but an interesting trouble-shooting puzzle.

Do YOU have a theory? Have you tried your Canon tech support?

The only theory I had doesn't make sense anymore, that it had something to do with the picture being lit with pulses. Or that the trigger affects AF somehow, but it works with the trigger on and no lamp. And indoors in poor light everything is flawless. And I haven't seen that afma varies that much with temp changes, or at all in fact.

The one thing though is children's faces, it has always been a big struggle to focus on, but tried with my wife indoors against windows that were pretty bright, but not crazy white, and nothing worked either so. And again, if I try with no lamp it works, but backlit is more misses. I don't know :

I'll try today with the afma settings that gave the best results with lamp, without lamp to see if I can somehow split the difference and everything pretty good, or make a habit of always adjust afma to whether I'm shooting with a lamp or not...

I have contacted Canon with this and other stuff, and the answer is always the same; Contact your local service shop, and I have nothing but horrible experience with them, so they are not even looking at my camera unless it's already in pieces ..

 

[Larsskv]

Could it be that you have flash AF assist enabled and it is confusing the AF, try turning it off.

Not sure how it can affect when it's not lighting up, but just checked and it's indeed turned off in camera.

A long shot suggestion... Maybe turning on the AF assist helps?

 

[Viggo]

Could it be that you have flash AF assist enabled and it is confusing the AF, try turning it off.

Not sure how it can affect when it's not lighting up, but just checked and it's indeed turned off in camera.

A long shot suggestion... Maybe turning on the AF assist helps?

I was going to try that, and to my surprise I can't do anything, well.. when I access the Speedlite-menu in camera I can see all settings, groups, ratios etc, but when I choose a setting I can't change any of them, that also means I can't turn off the af assist beam. It doesn't work in servo anyway, but all things I can't change MAY cause any of this.

I've been thinking that all of my issues have a common denominator, TTL... Could it be that? I guess I will find out because the Siros L is not TTL in any way, if that suddenly works it might be that. So wish I had an AD600 non-TTL to try also...

 

[Valvebounce]

Hi Viggo.
Do I understand from your comment below that you are using AI Servo? Canon recommends not using AIServo for static subjects though I know many do and get perfect results, perhaps the flash is giving a false impression of movement (plus you would get the greyed out menu back in one shot).

Cheers, Graham.

Could it be that you have flash AF assist enabled and it is confusing the AF, try turning it off.

Not sure how it can affect when it's not lighting up, but just checked and it's indeed turned off in camera.

A long shot suggestion... Maybe turning on the AF assist helps?

I was going to try that, and to my surprise I can't do anything, well.. when I access the Speedlite-menu in camera I can see all settings, groups, ratios etc, but when I choose a setting I can't change any of them, that also means I can't turn off the af assist beam. It doesn't work in servo anyway, but all things I can't change MAY cause any of this.

I've been thinking that all of my issues have a common denominator, TTL... Could it be that? I guess I will find out because the Siros L is not TTL in any way, if that suddenly works it might be that. So wish I had an AD600 non-TTL to try also...

 

[Viggo]

I turned off "Af assist beam firing" in the af menu and tried about a 100 shots with a small doll head and I do not want to say anything before testing with the kids outside, but I had only two three misses out of those 100+ shots, even against a back lit window. How this could affect anything when it's not firing even if it's on, I don't know, but if it now works I REALLY don't care why, lol.

Fingers crossed...