I need to understand ETTL better.

[Derrel]

Okay, the "NEW" Canon flashes use the E-TTL II protocol, which is supposed to be better than the earlier protocol, E-TTL, when using newer flashes like the Canon 580 EX II, the "II" meaning the newer, second-generation Mark II variant of that flash, and with the very latest RT 600 flash.

Newer Canon cameras, like the 7D, and the later EOS 1-series cameras, have color-evaluative light metering capabilities, whereas the earlier cameras were color-blind, and went STRICTLY by reflectance value (18% gray).

So, a few questions: in the early days of digital, I read about a LOT of very inconsistent E-TTL results with the pre-II flashes like the 580, and the "older" cameras.

But then, E-TTL II came out, and well, it was alleged to be better, and on the 20D and 5D, I found E-TTL flash with the 580 EX-II flash was sort of okay. What I am wondering now is how E-TTL II flash protocol, and an E-TTL II flash unit, work together with the color-aware, latest generation Canon bodies, like the 7D and 70D, and the 5D-III,and so on.

At one time, E-TTL flash was HYPER-SENSITIVE to the AF point that was in use, and the subject that was underneath that AF point. I'm wondering how much that is true today, with the latest flash and cameras, or if the focus point in use weighting is still as strong as it was, and if it's still as prone to blowing things out as it used to be, or if they've managed to get that issue more under control now that the newer bodies are measuring not just reflectance, but also are reading color values.

 

[runnah]

Derrel I have had great success using the mark 3 and 600 ex rt in ETTL mode. In all camera mode it evaluates the scene and delivers great results.

 

[table1349]

Ok, well if you really want to understand ETTL - your going to need a live chicken, a red candle and a white candle, the eye of a newt and some paprika. Hmm.. wait.. that doesn't sound right. Oh.. sorry, that's for a voodoo curse. Nevermind.

Nooooo......that was not a voodoo curse, with the paprika in it that was a love spell to get e.rose to marry you. You need the feet of a frog not paprika for it to be a voodoo curse. Jeeze did you flunk basic Voodoo 101 or what?

Ok, well technically I didn't flunk Voodoo 101 - I got an incomplete. The teachers eyebrows did grow back... eventually. I don't think there is enough Paprika on the planet to convince E.Rose to marry me, she doesn't strike me as being that foolish.. lol.

Well there is that plus if my remember is working correctly ( at my age it don't always) e.rose is MARRIED already.

I realize that she is in Tennessee, but lessen you be her brother or daddy I doubt that you two could legally get hitched anyhow. :lmao:
The previous description don't count cause I believe she was married up north and then moved down south where the new marriage laws now take effect.

 

[Derrel]

Derrel I have had great success using the mark 3 and 600 ex rt in ETTL mode. In all camera mode it evaluates the scene and delivers great results.

Just wondering if the flash exposure compensation or FEC is "tied to" the exact AF point in use like it was before. Last time I really read up on the issue of E-TTL was well before the 5D-III was out, and a group of wedding photographers were discussing how sensitive the flash metering was with regard to active AF point. It's been a long time ago. I know that Nikon had a heck of a time developing it's D-TTL protocol with the first d-slr's; it was very erratic at times. Then they came out with i-TTL. Canon had pretty much the same issues; e-TTL had issues, e-TTL-II is supposed to be better (it seemed okay to me).

I'm just sort of thinking the "newest" technology, the iFCL metering might be the last, final,critical piece for really good automatic flash control in run-n-gun type use.

Canon Professional Network - iFCL metering

 

[robbins.photo]

Nooooo......that was not a voodoo curse, with the paprika in it that was a love spell to get e.rose to marry you. You need the feet of a frog not paprika for it to be a voodoo curse. Jeeze did you flunk basic Voodoo 101 or what?

Ok, well technically I didn't flunk Voodoo 101 - I got an incomplete. The teachers eyebrows did grow back... eventually. I don't think there is enough Paprika on the planet to convince E.Rose to marry me, she doesn't strike me as being that foolish.. lol.

Well there is that plus if my remember is working correctly ( at my age it don't always) e.rose is MARRIED already.

I realize that she is in Tennessee, but lessen you be her brother or daddy I doubt that you two could legally get hitched anyhow. :lmao:
The previous description don't count cause I believe she was married up north and then moved down south where the new marriage laws now take effect.

Well honestly I think that might be a little short sighted. I mean think about the possibilities here. "Honey, I'm watching the game right now. Don't you have another husband you can discuss your 'feelings' with?" - Lol

 

[runnah]

Derrel I have had great success using the mark 3 and 600 ex rt in ETTL mode. In all camera mode it evaluates the scene and delivers great results.

Just wondering if the flash exposure compensation or FEC is "tied to" the exact AF point in use like it was before. Last time I really read up on the issue of E-TTL was well before the 5D-III was out, and a group of wedding photographers were discussing how sensitive the flash metering was with regard to active AF point. It's been a long time ago. I know that Nikon had a heck of a time developing it's D-TTL protocol with the first d-slr's; it was very erratic at times. Then they came out with i-TTL. Canon had pretty much the same issues; e-TTL had issues, e-TTL-II is supposed to be better (it seemed okay to me).

I'm just sort of thinking the "newest" technology, the iFCL metering might be the last, final,critical piece for really good automatic flash control in run-n-gun type use.

Canon Professional Network - iFCL metering

I have no idea. I use single point AF 99% of the time and with ettl i haven't had a blown out wonky photo. The wedding I shot I used that combo the entire time and never had any issues.

 

[Big Mike]

In a nutshell...

E-TTL uses a preflash to determine how much light/power to use. Before the shutter opens, it pops a small flash and reads how much is reflected back Through The Lens (TTL). By doing that, you can shoot straight, bounce and/or use diffusers & filters etc., and the process will account for that.

Note that E-TTL metering doesn't use the camera's primary metering mode...it's completely separate. So if you are in say, spot or partial metering mode, the E-TTL metering is still going to be 'Evaluative'. You can change it to 'Average' but the recommended setting is 'Evaluative' for most scenarios.

So the camera receives the light from the preflash and determines how much power it should use, to expose what it thinks is the subject, to a middle grey level. In other words, just like the camera's ambient light meter, the flash metering will only expose correctly when your subject is the same tone as a grey card. If the subject is brighter, the metering will under expose it. If the subject is darker, the metering will over expose it.

This is why you have FEC...Flash Exposure Compensation. So when you are shooting someone like a bride in a white dress, the metering will naturally under expose, so in order to get proper exposure, you must dial in positive FEC. It's pretty much the same principle as getting proper exposure with ambient light. You can dial it on either the Camera or the Flash, I've always liked using the camera controls.

The main issue with E-TTL, is that it's still an automatic function. It tries to determine what your subject is, and tries to give you enough light to expose that subject to a 'middle grey' level. It's metering will change when the brightness/reflectivity of the scene/subject changes. For example, if you go from shooting a bride in a white dress, to a groom in a black tux, the TTL metering will give you different amounts of light.
In other words, it can be inconsistent.

But if you know and somewhat expect that it will sometimes be inconsistent, then it's still a great tool.

This actually makes the most sense to me.

Maybe it's the state of mind I'm currently in, but this made the most sense.

I'm mostly curious about it in the setting of a reception hall.

When I'm forced to use on-camera flash in other situations, I usually still switch it to manual to keep things consistent. However, in a reception setting, when I'm moving about in the middle of a very tight crowd, flash on manual doesn't work. Because if I set it to light someone well 6 feet away from me, but then I'm suddenly 3 feet away from someone else and catching a moment that's happening, they're SUPER bright. ETTL helps in that situation, but then I deal with the very opposite problem. When I'm lighting for someone 3 feet away from me in a reception hall, but I see something happening 6 feet away I want to catch, they're super dark. I notice a lot of the time that there's usually someone on the edge of the frame with a white shirt who is light brightly, which made me start wondering what exactly the "flash" is seeing when it meters, because I assume the reason the people 6 feet away were dark is because, even though I had my spot meter pointed at them... the flash somehow took into account the dude on the very edge of the frame, closer to the camera, that had a white shirt on.

Basically I'm trying to figure out how to speak this damn thing's language so I can make it do what I want it to do when I want it to do it.

Yes, that is one of the inherent problems with using flash, whether manual or TTL. People/objects at different distances are hard to light evenly.

What we need to keep in mind, is a property of lighting (specifically, a property of diffuse reflection) called the Inverse Square Law. It states that the amount of light being reflected (the brightness) of something, is inversely proportional to the distance it is from the light source.
Basically, if you are shooting your flash straight ahead and you have two people in frame, one at 5 feet and one at 10 feet....the person at 10 feet will up roughly 4 times darker. (5:10 is a factor of two, two squared is four).
If the close person moves to only two feet away, and the other person is still 10 feet away, now you have a factor of 5, and the further person will be 25 times darker (or you could say that the close person would be 25 times brighter).

So what I'm trying to say is that the distance, from light source to subject(s), is very important....but what we really need to pay attention to, is when the distance to multiple subjects is different by a larger factor.

If you're shooting two people who are two feet (further from you) away from each other.....if they are 14 feet and 16 feet away, they would be lit relatively evenly...but if they were 4 feet and 6 feet, they would be rather unevenly lit.

Do you get where I'm going here?

So the key to avoiding super bright or super dark people/objects, is trying to even out the distances (from the light source). Shooting straight ahead, this can be tough. But this is one of the reasons why bouncing the flash works so well. If you bounce the flash off of a wall that is 10 feet away, then the path of light might be 24 feet to the first person and 25 feet to the second person, the difference is negligible.

So not only does bouncing give you a softer light (the spot of light on the wall is much larger than the flash, thus you get softer light), and not only is it directional (it doesn't come from the direction of the camera), but bouncing off of walls/ceilings allows you to even out the distances to multiple subjects which evens out the lighting.

Of course, not every location allows for good bouncing, but with a powerful flash and helpful settings (larger aperture and higher ISO) you'd be surprised how well it can still work, even when the bounce surfaces are dark and/or far away.

 

[e.rose]

Nooooo......that was not a voodoo curse, with the paprika in it that was a love spell to get e.rose to marry you. You need the feet of a frog not paprika for it to be a voodoo curse. Jeeze did you flunk basic Voodoo 101 or what?

Ok, well technically I didn't flunk Voodoo 101 - I got an incomplete. The teachers eyebrows did grow back... eventually. I don't think there is enough Paprika on the planet to convince E.Rose to marry me, she doesn't strike me as being that foolish.. lol.

Well there is that plus if my remember is working correctly ( at my age it don't always) e.rose is MARRIED already.

I realize that she is in Tennessee, but lessen you be her brother or daddy I doubt that you two could legally get hitched anyhow. :lmao:
The previous description don't count cause I believe she was married up north and then moved down south where the new marriage laws now take effect.

All of this is accurate.

And hilarious. :lmao:

 

[e.rose]

In a nutshell...

E-TTL uses a preflash to determine how much light/power to use. Before the shutter opens, it pops a small flash and reads how much is reflected back Through The Lens (TTL). By doing that, you can shoot straight, bounce and/or use diffusers & filters etc., and the process will account for that.

Note that E-TTL metering doesn't use the camera's primary metering mode...it's completely separate. So if you are in say, spot or partial metering mode, the E-TTL metering is still going to be 'Evaluative'. You can change it to 'Average' but the recommended setting is 'Evaluative' for most scenarios.

So the camera receives the light from the preflash and determines how much power it should use, to expose what it thinks is the subject, to a middle grey level. In other words, just like the camera's ambient light meter, the flash metering will only expose correctly when your subject is the same tone as a grey card. If the subject is brighter, the metering will under expose it. If the subject is darker, the metering will over expose it.

This is why you have FEC...Flash Exposure Compensation. So when you are shooting someone like a bride in a white dress, the metering will naturally under expose, so in order to get proper exposure, you must dial in positive FEC. It's pretty much the same principle as getting proper exposure with ambient light. You can dial it on either the Camera or the Flash, I've always liked using the camera controls.

The main issue with E-TTL, is that it's still an automatic function. It tries to determine what your subject is, and tries to give you enough light to expose that subject to a 'middle grey' level. It's metering will change when the brightness/reflectivity of the scene/subject changes. For example, if you go from shooting a bride in a white dress, to a groom in a black tux, the TTL metering will give you different amounts of light.
In other words, it can be inconsistent.

But if you know and somewhat expect that it will sometimes be inconsistent, then it's still a great tool.

This actually makes the most sense to me.

Maybe it's the state of mind I'm currently in, but this made the most sense.

I'm mostly curious about it in the setting of a reception hall.

When I'm forced to use on-camera flash in other situations, I usually still switch it to manual to keep things consistent. However, in a reception setting, when I'm moving about in the middle of a very tight crowd, flash on manual doesn't work. Because if I set it to light someone well 6 feet away from me, but then I'm suddenly 3 feet away from someone else and catching a moment that's happening, they're SUPER bright. ETTL helps in that situation, but then I deal with the very opposite problem. When I'm lighting for someone 3 feet away from me in a reception hall, but I see something happening 6 feet away I want to catch, they're super dark. I notice a lot of the time that there's usually someone on the edge of the frame with a white shirt who is light brightly, which made me start wondering what exactly the "flash" is seeing when it meters, because I assume the reason the people 6 feet away were dark is because, even though I had my spot meter pointed at them... the flash somehow took into account the dude on the very edge of the frame, closer to the camera, that had a white shirt on.

Basically I'm trying to figure out how to speak this damn thing's language so I can make it do what I want it to do when I want it to do it.

Yes, that is one of the inherent problems with using flash, whether manual or TTL. People/objects at different distances are hard to light evenly.

What we need to keep in mind, is a property of lighting (specifically, a property of diffuse reflection) called the Inverse Square Law. It states that the amount of light being reflected (the brightness) of something, is inversely proportional to the distance it is from the light source.
Basically, if you are shooting your flash straight ahead and you have two people in frame, one at 5 feet and one at 10 feet....the person at 10 feet will up roughly 4 times darker. (5:10 is a factor of two, two squared is four).
If the close person moves to only two feet away, and the other person is still 10 feet away, now you have a factor of 5, and the further person will be 25 times darker (or you could say that the close person would be 25 times brighter).

So what I'm trying to say is that the distance, from light source to subject(s), is very important....but what we really need to pay attention to, is when the distance to multiple subjects is different by a larger factor.

If you're shooting two people who are two feet (further from you) away from each other.....if they are 14 feet and 16 feet away, they would be lit relatively evenly...but if they were 4 feet and 6 feet, they would be rather unevenly lit.

Do you get where I'm going here?

So the key to avoiding super bright or super dark people/objects, is trying to even out the distances (from the light source). Shooting straight ahead, this can be tough. But this is one of the reasons why bouncing the flash works so well. If you bounce the flash off of a wall that is 10 feet away, then the path of light might be 24 feet to the first person and 25 feet to the second person, the difference is negligible.

So not only does bouncing give you a softer light (the spot of light on the wall is much larger than the flash, thus you get softer light), and not only is it directional (it doesn't come from the direction of the camera), but bouncing off of walls/ceilings allows you to even out the distances to multiple subjects which evens out the lighting.

Of course, not every location allows for good bouncing, but with a powerful flash and helpful settings (larger aperture and higher ISO) you'd be surprised how well it can still work, even when the bounce surfaces are dark and/or far away.

Yes that definitely makes sense, and I do already bounce my flash, but the issue isn't that I'm trying to shoot 2 different people at two different distances at the same time...

It's that the people I AM shooting are further away, and there happens to be this random dude on the dance floor (who I'm not focusing on and trying to ignore/avoid) who happens to be closer to me and in frame at the edge of the frame that seems to be throwing my exposure off, because *he's* well lit, but the people I'm focusing on are not...

Does that make sense?

So I guess I'm trying to figure out what the camera/flash is seeing when shooting on camera ETTL so that I can trick it into lighting the further people correctly, when I'm focusing on them, vs. people who are closer to me (when I'm actually focusing on the people closer to me).

 

[pgriz]

Emily, as Mike has already said, you're working against the inverse-square law in terms of light fall-off. If both people are the same distance from the (single) flash, then you'll have the right amount of light. If they are at different distances, then it's gonna be hard to get an even exposure for both. The method I've used in situations where people were at different distances from the "main" flash, is to set up additional "slave" flashes that would provide more-or-less even light in the "interior" area delimited by the four perimeter flashes. This can work if you're in a rectangular room with 9-12 ft. high ceilings. If you put the flashes at the corners, illuminating the ceiling, they will give a more-or-less even light throughout the enclosed space. Of course, if you do this, you need to be sure that your camera angle doesn't catch the illuminated ceiling as part of the image. This approach has worked for me in shooting family events where everything was happening in the same room.

If you're shooting in a reception hall, then this approach will probably not work, as the amount of light needed to light up the area evenly becomes more than what speedlights can provide.

As for the scenario where a foreground person is throwing off your flash exposure, I know that my camera's ETTL processing looks at the entire frame, and will not get the right exposure for the back person. However, maybe Runnah's experience with his 5DIII shows that the newer cameras have more intelligent handling of the exposure calculation.

 

[Big Mike]

This actually makes the most sense to me.

Maybe it's the state of mind I'm currently in, but this made the most sense.

I'm mostly curious about it in the setting of a reception hall.

When I'm forced to use on-camera flash in other situations, I usually still switch it to manual to keep things consistent. However, in a reception setting, when I'm moving about in the middle of a very tight crowd, flash on manual doesn't work. Because if I set it to light someone well 6 feet away from me, but then I'm suddenly 3 feet away from someone else and catching a moment that's happening, they're SUPER bright. ETTL helps in that situation, but then I deal with the very opposite problem. When I'm lighting for someone 3 feet away from me in a reception hall, but I see something happening 6 feet away I want to catch, they're super dark. I notice a lot of the time that there's usually someone on the edge of the frame with a white shirt who is light brightly, which made me start wondering what exactly the "flash" is seeing when it meters, because I assume the reason the people 6 feet away were dark is because, even though I had my spot meter pointed at them... the flash somehow took into account the dude on the very edge of the frame, closer to the camera, that had a white shirt on.

Basically I'm trying to figure out how to speak this damn thing's language so I can make it do what I want it to do when I want it to do it.

Yes, that is one of the inherent problems with using flash, whether manual or TTL. People/objects at different distances are hard to light evenly.

What we need to keep in mind, is a property of lighting (specifically, a property of diffuse reflection) called the Inverse Square Law. It states that the amount of light being reflected (the brightness) of something, is inversely proportional to the distance it is from the light source.
Basically, if you are shooting your flash straight ahead and you have two people in frame, one at 5 feet and one at 10 feet....the person at 10 feet will up roughly 4 times darker. (5:10 is a factor of two, two squared is four).
If the close person moves to only two feet away, and the other person is still 10 feet away, now you have a factor of 5, and the further person will be 25 times darker (or you could say that the close person would be 25 times brighter).

So what I'm trying to say is that the distance, from light source to subject(s), is very important....but what we really need to pay attention to, is when the distance to multiple subjects is different by a larger factor.

If you're shooting two people who are two feet (further from you) away from each other.....if they are 14 feet and 16 feet away, they would be lit relatively evenly...but if they were 4 feet and 6 feet, they would be rather unevenly lit.

Do you get where I'm going here?

So the key to avoiding super bright or super dark people/objects, is trying to even out the distances (from the light source). Shooting straight ahead, this can be tough. But this is one of the reasons why bouncing the flash works so well. If you bounce the flash off of a wall that is 10 feet away, then the path of light might be 24 feet to the first person and 25 feet to the second person, the difference is negligible.

So not only does bouncing give you a softer light (the spot of light on the wall is much larger than the flash, thus you get softer light), and not only is it directional (it doesn't come from the direction of the camera), but bouncing off of walls/ceilings allows you to even out the distances to multiple subjects which evens out the lighting.

Of course, not every location allows for good bouncing, but with a powerful flash and helpful settings (larger aperture and higher ISO) you'd be surprised how well it can still work, even when the bounce surfaces are dark and/or far away.

Yes that definitely makes sense, and I do already bounce my flash, but the issue isn't that I'm trying to shoot 2 different people at two different distances at the same time...

It's that the people I AM shooting are further away, and there happens to be this random dude on the dance floor (who I'm not focusing on and trying to ignore/avoid) who happens to be closer to me and in frame at the edge of the frame that seems to be throwing my exposure off, because *he's* well lit, but the people I'm focusing on are not...

Does that make sense?

So I guess I'm trying to figure out what the camera/flash is seeing when shooting on camera ETTL so that I can trick it into lighting the further people correctly, when I'm focusing on them, vs. people who are closer to me (when I'm actually focusing on the people closer to me).

A couple things come to mind.

Firstly, try to avoid having someone get in between your flash (bounce path) and your subject. Easier said than done, I know. Maybe using a longer focal length, would help prevent people from sneaking into the edges of your shot.

Another option might be to use FEL, Flash Exposure Lock. With FEL, you tell the camera to fire the preflash and then wait until you open the shutter, before it fires for real. So you could use FEC to lock in the (hopefully) correct flash power for your subjects, then wait until just the right moment to snap the shot.

 

[e.rose]

Emily, as Mike has already said, you're working against the inverse-square law in terms of light fall-off. If both people are the same distance from the (single) flash, then you'll have the right amount of light. If they are at different distances, then it's gonna be hard to get an even exposure for both.

Right. I get that. But I'm not *trying* to evenly lit both people. I only want to light up the people in the back, and if the drunk dancing dude, frame right, is totally blown out... no biggie, because I'm probably going to try and crop him out anyway. Haha.

The method I've used in situations where people were at different distances from the "main" flash, is to set up additional "slave" flashes that would provide more-or-less even light in the "interior" area delimited by the four perimeter flashes. This can work if you're in a rectangular room with 9-12 ft. high ceilings. If you put the flashes at the corners, illuminating the ceiling, they will give a more-or-less even light throughout the enclosed space. Of course, if you do this, you need to be sure that your camera angle doesn't catch the illuminated ceiling as part of the image. This approach has worked for me in shooting family events where everything was happening in the same room.

That sounds great, however, I don't shoot weddings on my own. I hate weddings.

I'm a second shooter for other people, so I'm working with what they have set up.

If they have the floor evenly lit with studio strobes about the room... they're tied to them. I'm not. So I'm still having to use on camera flash.

And if they DON'T have the floor evenly lit... I'm still having to use on camera flash.

Which is why I want to better understand the way on camera flash see things so that I can be a better *SECOND* shooter... haha.

As for the scenario where a foreground person is throwing off your flash exposure, I know that my camera's ETTL processing looks at the entire frame, and will not get the right exposure for the back person. However, maybe Runnah's experience with his 5DIII shows that the newer cameras have more intelligent handling of the exposure calculation.

I think I need to bust out my manuals again to see what they say about that.

A couple things come to mind.

Firstly, try to avoid having someone get in between your flash (bounce path) and your subject. Easier said than done, I know. Maybe using a longer focal length, would help prevent people from sneaking into the edges of your shot.

Another option might be to use FEL, Flash Exposure Lock. With FEL, you tell the camera to fire the preflash and then wait until you open the shutter, before it fires for real. So you could use FEC to lock in the (hopefully) correct flash power for your subjects, then wait until just the right moment to snap the shot.

Problem with using a longer focal length (at least at the wedding I was just at) was that the dance floor is PACKED... and I have a 28... a 50... and a 70-200. The 50mm is too long for most everything I was trying to capture that night, let alone the 70-200.

The 50mm would have come in handy FABULOUSLY in the situations I'm talking about... but it's a prime... and my 28 is a prime... and I can't switch back and forth while I'm on the floor and all that action is happening.

So if I see something happening a little further away I shoot, and crop.

Not ideal, but until I sell my 50 and 28 and trade it in for a 24-70 (HAR. HAR. HAR. That's really funny because I don't have enough money to pay the balance of that even after I sell the first two lenses...), that's kind of how it has to work.