20d + EX serries flash (IR emission)

[kawter2]

Does anyone ever notice that your IR emission (to help gain focus) on your EX flash stops working? Mine (420EX stops every 100-200 clicks.I have to reset the camera settings for it to start again. then it will stop emitting again w/o me changing anything. This is all in one shot mode of course

[robertwgross]

Is the camera just going into sleep mode?

---Bob Gross---

[kawter2]

no, the AF tries hard but cant get the focus cause the darkness

[robertwgross]

If I understand correctly from your post, the autofocus IR emitter is working correctly until it suddenly stops emitting at 100-200 clicks? Do you know that the camera is not going into sleep mode?

---Bob Gross---

[PacAce]

If I understand correctly from your post, the autofocus IR emitter is working correctly until it suddenly stops emitting at 100-200 clicks? Do you know that the camera is not going into sleep mode?

---Bob Gross---

Or more likely the flash itself is going to sleep mode.

[robertwgross]

As PacAce suggested, the 420EX goes into sleep mode after 90 seconds. That could explain a few things.

---Bob Gross---

[kawter2]

No, the flash nor the camera are going to sleep. Even if I "power cycle the flash &/or the camera, the IR still does not work. Never had this problem on the rebel so I think it is a safe guess that the flash is ok



Humm

[robertwgross]

No, the flash nor the camera are going to sleep.


Then, that is a problem. The flash is supposed to go to sleep after 90 seconds.

---Bob Gross---

[DaveG]

Does anyone ever notice that your IR emission (to help gain focus) on your EX flash stops working? Mine (420EX stops every 100-200 clicks.I have to reset the camera settings for it to start again. then it will stop emitting again w/o me changing anything. This is all in one shot mode of course

I don't suppose that you've changed the focusing from "all the rectagles enabled" to just one off-centre one? I could see where you might be inclined to do so for some reason at some point during the shoot to "help" the AF. Yet my understanding is that the flash assisted focusing only works when the "One Shot" is enabled and ALL of the focusing rectagles as well. I have heard - but haven't tried - that enabling just the centre rectagle is OK too.

[PacAce]

I don't suppose that you've changed the focusing from "all the rectagles enabled" to just one off-centre one? I could see where you might be inclined to do so for some reason at some point during the shoot to "help" the AF. Yet my understanding is that the flash assisted focusing only works when the "One Shot" is enabled and ALL of the focusing rectagles as well. I have heard - but haven't tried - that enabling just the centre rectagle is OK too.

Are you referring to specifically to the 20D or any EOS dslr in general?

[DaveG]

I don't suppose that you've changed the focusing from "all the rectagles enabled" to just one off-centre one? I could see where you might be inclined to do so for some reason at some point during the shoot to "help" the AF. Yet my understanding is that the flash assisted focusing only works when the "One Shot" is enabled and ALL of the focusing rectagles as well. I have heard - but haven't tried - that enabling just the centre rectagle is OK too.

Are you referring to specifically to the 20D or any EOS dslr in general?

10D

[kawter2]

Does anyone ever notice that your IR emission (to help gain focus) on your EX flash stops working? Mine (420EX stops every 100-200 clicks.I have to reset the camera settings for it to start again. then it will stop emitting again w/o me changing anything. This is all in one shot mode of course

I don't suppose that you've changed the focusing from "all the rectagles enabled" to just one off-centre one? I could see where you might be inclined to do so for some reason at some point during the shoot to "help" the AF. Yet my understanding is that the flash assisted focusing only works when the "One Shot" is enabled and ALL of the focusing rectagles as well. I have heard - but haven't tried - that enabling just the centre rectagle is OK too.

I am using one shot mode However....


I am using just one off-centre one, but when It is functioning proberly it works... With "all the rectagles enabled" both (the 420 has 2 emiters one for each axis) emitters work (because it is looking for focus with horizontal and vertical axis.

When I select just one off-centre one (in normal conditions), I get one emitter to work (which ever axis I have selected) When the problem occurs, I get nothing.

Next time it arises, I will have to check "all zones" and see if it is doing the same


p.s. this is 20d

[PacAce]

I don't suppose that you've changed the focusing from "all the rectagles enabled" to just one off-centre one? I could see where you might be inclined to do so for some reason at some point during the shoot to "help" the AF. Yet my understanding is that the flash assisted focusing only works when the "One Shot" is enabled and ALL of the focusing rectagles as well. I have heard - but haven't tried - that enabling just the centre rectagle is OK too.

Are you referring to specifically to the 20D or any EOS dslr in general?

10D

I just did an experiment on my 10D and this is what I found.

When the AF point is set to ALL, the flash generates vertical and horizontal scan lines.

When the AF point is set to just the center, it generates vertical scan lines.

When the AF point is set to one of the other horizontal AF points, the flash generates horizontal scan lines.

When the AF point is set to one of the two vertical AF points (not counting the middle one), there are no scan lines generated, vertical or horizontal, and I could not get a focus lock on anything in dim lighting. Interesting. Never noticed this behavior before.

[kawter2]

I don't suppose that you've changed the focusing from "all the rectagles enabled" to just one off-centre one? I could see where you might be inclined to do so for some reason at some point during the shoot to "help" the AF. Yet my understanding is that the flash assisted focusing only works when the "One Shot" is enabled and ALL of the focusing rectagles as well. I have heard - but haven't tried - that enabling just the centre rectagle is OK too.

Are you referring to specifically to the 20D or any EOS dslr in general?

10D

I just did an experiment on my 10D and this is what I found.

When the AF point is set to ALL, the flash generates vertical and horizontal scan lines.

When the AF point is set to just the center, it generates vertical scan lines.

When the AF point is set to one of the other horizontal AF points, the flash generates horizontal scan lines.

When the AF point is set to one of the two vertical AF points (not counting the middle one), there are no scan lines generated, vertical or horizontal, and I could not get a focus lock on anything in dim lighting. Interesting. Never noticed this behavior before.

I wish I know how that would translate on the 20d w/9pt sensors

I will check but I do remember seeing horiz by itself and vert by itself when I was checking it

[DaveG]

I don't suppose that you've changed the focusing from "all the rectagles enabled" to just one off-centre one? I could see where you might be inclined to do so for some reason at some point during the shoot to "help" the AF. Yet my understanding is that the flash assisted focusing only works when the "One Shot" is enabled and ALL of the focusing rectagles as well. I have heard - but haven't tried - that enabling just the centre rectagle is OK too.

Are you referring to specifically to the 20D or any EOS dslr in general?

10D

I just did an experiment on my 10D and this is what I found.

When the AF point is set to ALL, the flash generates vertical and horizontal scan lines.

When the AF point is set to just the center, it generates vertical scan lines.

When the AF point is set to one of the other horizontal AF points, the flash generates horizontal scan lines.

When the AF point is set to one of the two vertical AF points (not counting the middle one), there are no scan lines generated, vertical or horizontal, and I could not get a focus lock on anything in dim lighting. Interesting. Never noticed this behavior before.

I wish I know how that would translate on the 20d w/9pt sensors

I will check but I do remember seeing horiz by itself and vert by itself when I was checking it

I finally found my source. It's N.K Guy's "Flash Photography with Canon EOS Cameras" http://photonotes.org/articles/eos-flash/ and the operative paragraphs are:

"All of Canon’s Speedlite flash units for EOS cameras have patterned red AF assist lights - sometimes called AF auxiliary lights in older Canon manuals - built in. These are clear red panels on the front which use one or two high-brightness LEDs to project red circles of light striped with dark lines, in order to give the camera a high-contrast pattern to focus on. Red is chosen in part because high-output red LEDs are readily available, but also because red light does not cause the pupils of the eye to dilate as much as does white light. The red light is sometimes described as being “near infrared,” though it is in fact visible.

An important thing to remember is that the AF assist light works only if your camera is in One-shot mode - it will not illuminate in AI Servo or in any icon AE mode which employs AI Servo, such as the Sports mode. This is because the camera is constantly focussing and refocussing when in AI Servo mode, in order to track subject motion.

Also, if you have a camera body with multiple focussing points and your flash unit’s AF assist light isn’t lighting up in low light it’s probably because the AF light on the flash you happen to be using cannot cover your currently selected (ie: non-centre) focussing point. Many flash units have AF assist lights which can only illuminate the area around the central point. Switch to the central focussing point and the flash unit’s AF assist light should start working."

Mr. Guy seems to be the authority on Canon flashes and I certainly wouldn't contradict that view.

[kawter2]

I don't suppose that you've changed the focusing from "all the rectagles enabled" to just one off-centre one? I could see where you might be inclined to do so for some reason at some point during the shoot to "help" the AF. Yet my understanding is that the flash assisted focusing only works when the "One Shot" is enabled and ALL of the focusing rectagles as well. I have heard - but haven't tried - that enabling just the centre rectagle is OK too.

Are you referring to specifically to the 20D or any EOS dslr in general?

10D

I just did an experiment on my 10D and this is what I found.

When the AF point is set to ALL, the flash generates vertical and horizontal scan lines.

When the AF point is set to just the center, it generates vertical scan lines.

When the AF point is set to one of the other horizontal AF points, the flash generates horizontal scan lines.

When the AF point is set to one of the two vertical AF points (not counting the middle one), there are no scan lines generated, vertical or horizontal, and I could not get a focus lock on anything in dim lighting. Interesting. Never noticed this behavior before.

I wish I know how that would translate on the 20d w/9pt sensors

I will check but I do remember seeing horiz by itself and vert by itself when I was checking it

I finally found my source. It's N.K Guy's "Flash Photography with Canon EOS Cameras" http://photonotes.org/articles/eos-flash/ and the operative paragraphs are:

"All of Canon’s Speedlite flash units for EOS cameras have patterned red AF assist lights - sometimes called AF auxiliary lights in older Canon manuals - built in. These are clear red panels on the front which use one or two high-brightness LEDs to project red circles of light striped with dark lines, in order to give the camera a high-contrast pattern to focus on. Red is chosen in part because high-output red LEDs are readily available, but also because red light does not cause the pupils of the eye to dilate as much as does white light. The red light is sometimes described as being “near infrared,” though it is in fact visible.

An important thing to remember is that the AF assist light works only if your camera is in One-shot mode - it will not illuminate in AI Servo or in any icon AE mode which employs AI Servo, such as the Sports mode. This is because the camera is constantly focussing and refocussing when in AI Servo mode, in order to track subject motion.

Also, if you have a camera body with multiple focussing points and your flash unit’s AF assist light isn’t lighting up in low light it’s probably because the AF light on the flash you happen to be using cannot cover your currently selected (ie: non-centre) focussing point. Many flash units have AF assist lights which can only illuminate the area around the central point. Switch to the central focussing point and the flash unit’s AF assist light should start working."

Mr. Guy seems to be the authority on Canon flashes and I certainly wouldn't contradict that view.


That is it exactly!!!! After further testing, it seems I use my corner focusing dots after about 100 clicks :)

[kawter2]

I don't suppose that you've changed the focusing from "all the rectagles enabled" to just one off-centre one? I could see where you might be inclined to do so for some reason at some point during the shoot to "help" the AF. Yet my understanding is that the flash assisted focusing only works when the "One Shot" is enabled and ALL of the focusing rectagles as well. I have heard - but haven't tried - that enabling just the centre rectagle is OK too.

Are you referring to specifically to the 20D or any EOS dslr in general?

10D

I just did an experiment on my 10D and this is what I found.

When the AF point is set to ALL, the flash generates vertical and horizontal scan lines.

When the AF point is set to just the center, it generates vertical scan lines.

When the AF point is set to one of the other horizontal AF points, the flash generates horizontal scan lines.

When the AF point is set to one of the two vertical AF points (not counting the middle one), there are no scan lines generated, vertical or horizontal, and I could not get a focus lock on anything in dim lighting. Interesting. Never noticed this behavior before.

I wish I know how that would translate on the 20d w/9pt sensors

I will check but I do remember seeing horiz by itself and vert by itself when I was checking it

I finally found my source. It's N.K Guy's "Flash Photography with Canon EOS Cameras" http://photonotes.org/articles/eos-flash/ and the operative paragraphs are:

"All of Canon’s Speedlite flash units for EOS cameras have patterned red AF assist lights - sometimes called AF auxiliary lights in older Canon manuals - built in. These are clear red panels on the front which use one or two high-brightness LEDs to project red circles of light striped with dark lines, in order to give the camera a high-contrast pattern to focus on. Red is chosen in part because high-output red LEDs are readily available, but also because red light does not cause the pupils of the eye to dilate as much as does white light. The red light is sometimes described as being “near infrared,” though it is in fact visible.

An important thing to remember is that the AF assist light works only if your camera is in One-shot mode - it will not illuminate in AI Servo or in any icon AE mode which employs AI Servo, such as the Sports mode. This is because the camera is constantly focussing and refocussing when in AI Servo mode, in order to track subject motion.

Also, if you have a camera body with multiple focussing points and your flash unit’s AF assist light isn’t lighting up in low light it’s probably because the AF light on the flash you happen to be using cannot cover your currently selected (ie: non-centre) focussing point. Many flash units have AF assist lights which can only illuminate the area around the central point. Switch to the central focussing point and the flash unit’s AF assist light should start working."

Mr. Guy seems to be the authority on Canon flashes and I certainly wouldn't contradict that view.


That is it exactly!!!! After further testing, it seems I use my corner focusing dots after about 100 clicks :)

[kawter2]

We'll I thought that was theticket, but just now after shooting for a while. NONE of the sensors produce the IR. Not even the ALL select mode



Still noone has noticed this?

[robertwgross]

We'll I thought that was theticket, but just now after shooting for a while. NONE of the sensors produce the IR. Not even the ALL select mode

Still noone has noticed this?

Emitters emit IR, sensors sense IR.

---Bob Gross---

[DaveG]

We'll I thought that was theticket, but just now after shooting for a while. NONE of the sensors produce the IR. Not even the ALL select mode



Still noone has noticed this?

Do you have it on One Shot? I can actually see the red pulse hit the subject as I ask it to autofocus if the room is dark enough. Put the lens grossly out of focus and try it again.

[DaveG]

We'll I thought that was theticket, but just now after shooting for a while. NONE of the sensors produce the IR. Not even the ALL select mode

Still noone has noticed this?

Emitters emit IR, sensors sense IR.

---Bob Gross---

After thinking for awhile it occured to me that the AF might be shut off on you lens. Check that too. And I only use this on the M - manual setting. God knows what happens if you use one of the boob settings.

The other thing is to check Custom Function 5. Make sure it's on 0.

[kawter2]

We'll I thought that was theticket, but just now after shooting for a while. NONE of the sensors produce the IR. Not even the ALL select mode

Still noone has noticed this?

Emitters emit IR, sensors sense IR.

---Bob Gross---

Excuse me mr smart ass

I meant none of the sensors are causing the emitters to function properly

[robertwgross]

Excuse me mr smart ass

I meant none of the sensors are causing the emitters to function properly

That's not the kind of reply that we expect in this forum.

I guess that means that you don't need any more help.

---Bob Gross---

[DaveG]

Excuse me mr smart ass

I meant none of the sensors are causing the emitters to function properly

That's not the kind of reply that we expect in this forum.

I guess that means that you don't need any more help.

---Bob Gross---

We also don't need pedantic grammar corrections that are made just to make
someone feel bad. Perhaps you shouldn't offer any more "help" like this since it's
just rude, an ego trip on your part; and to be a pedant myself, the opposite of
being helpful.

[robertwgross]

We also don't need pedantic grammar corrections that are made just to make
someone feel bad. Perhaps you shouldn't offer any more "help" like this since it's
just rude, an ego trip on your part; and to be a pedant myself, the opposite of
being helpful.

That's true, but some of us were not making any pedantic grammar corrections. Nor were we trying to make someone feel bad. Some of us were trying to figure out the original poster's problem and come up with a solution that was acceptable.

---Bob Gross---