St-e2 + 430 Ex - I
Antonio Correia
Registered Users Posts: 6,241 Major grins
Antonio Correia
Registered Users Posts: 6,241 Major grins
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Comments
Were you holding the flash in your other hand?
Moderator of the Technique Forum and Finishing School on Dgrin
No, my friend - the one you see in the photos - was holding the flash for me when he was not in the shots. Obviously !
When he is in the photos, it was his daughter who was holding the flash.
Photos 4,5 and 6 were shot with the flash outside, through the plastic of the car, at the rear.
I think in these shots I should have used the Stofen to make it softer.
When we are in the field we, I mean I, don't see the details, or I am not aware of ...
I think it is too strong.
I take this opportunity to make you a simple question which I think I do know the answer but I am not that sure.
- Please John, does the ETTL works when the flash in turned 180 degrees (using it's vertical axis) ?
I know that it doesn't work when it is tilted, bounced.
This question is because I am "building" a reflector and the flash will be used reverted in order I can have the ETTL II.
I hope I made myself clear. The best would be with photos ...
Thank you John !
Call me Jim, that's what all my friends call me:D
Very nice lighitng on your shots. I did not notice the shadow of the steering wheel until I went back and looked a second time.
ETTL does not require the red lens part of the flash to point towards the image. I frequently find I must point the red lens portion of the flash towards the ST-E2 out of doors ( sometimes I even use my hand or a white surface to reflect the beam from the ST-E2 towards the 580ex that is facing me )
ETTL metering occurs via the cameras lens and sensor - so the flash head can point anyway you want it, even opposite the front of the flash. You can bounce can the beam from the flash off the wall behind you, and ETTL will still work.
I am not certain of the effect on ETTL II - I am sure someone will inform us quickly though.
I do use a 550ex in a Softbox on a tripod, as a portable soft light source.
Moderator of the Technique Forum and Finishing School on Dgrin
Pathfinder is, as usual correct
The main difference between Canon's ETTL & ETTL II is that ETTL II also uses the distance info provided by some (not all) lenses for it's calculations.
Where this goes astray is when you bounce the flash. ETTL II doesn't know how much further the "light" has to travel than what the lens says the distance is to your subject, and due to that, it's calculations will be off some. Canon's proprietary ETTL II matrix assumes that the flash is pointed directly at the subject.
So, even though ETTL II still works when bounced, you will have to add in the extra "light" (via FEC) that was lost due to the bounce.
Hope that helps...
I was pretty sure that I understood how ETTL II used the focusing distance from of Canon's newer lenses to calculate flash exposure, but was not sure about how bounce flash would be handled in ETTL II. What you describe about the longer light path with bounce makes sense, in that it will be underexposed in ETTL II due to the longer light path, since the algorithm assumes a direct flash, not a bounced one as that can be highly variable.
The good new for Antonio, is that it is the direction of the flash head that matters - even with a softbox diffuser, not the direction of the main body of the flash guts with the red lens that can be turned around to face the photographer and his ST-E2 trigger.
Moderator of the Technique Forum and Finishing School on Dgrin
But let me confirm in my own words because I am not sure if I have a complete interpretation due to my lack of English.
1. Assuming the flash is supported on an horizontal surface, the flash head must be at 90 degrees with the body of the flash, in order the ETTL II to work.
The horizontal angle of the rotation doesn't matter.
2. In any of these positions, the red light from the flash should (can) be pointed to the ST-E2 in order the ETTL II to work properly.
3. Does this mean that in these positions, the FEC is irrelevant ?
Thank you for your patience.
It has been brought to my attention that when a Canon ETTL II speedlight's head is moved from the 90 degree position, it no longer uses the distance info in its calculations.
I can honestly neither confirm nor deny this. The source this info came from appears very knowledgable, but I can't get past my experience with this system and the fact that when the flash is bounced, why are the results consistantly under-exposed?
If the system goes only to ETTL and doesn't use the "incorrect" distance, then the exposure should be spot on even when bounced.
Hmmm...
Maybe you guys/gals will have to come up with your own thoughts on this.
#1: No, that is not correct. ---- ETTL II will work regardless of the head position.
Edit: update; I have been informed that when the flash head is turned from 90 degrees, the distance info is not used, but the other ETTL II functions still are
#2: Well, the flash sensor has to be able to pick-up the signal from the master to work at all, but the red light does not have anything to do with the ETTL II function. It's job is for focus assist. The sensor above the red one, (and also above the name "Canon") is the one that sends/receives signals for making flash changes, IE:ratios, ETTL, FEC, etc. - but NOT what controls ETTL II. (although it does receive flash duration info via this sensor from a master, either ST-E2 or a 580EX, etc.)
#3: No - FEC is Flash Exposure Compensation - use this to either add more flash output, or less flash output
OK, now lets see if we can explain this better...
As Jim stated in the other reply, ETTL II is controlled by the camera and flash talking with each other.
When in ETTL II: When you go to take a picture, you press down on your focus button, then when you push the shutter button all the way to take the shot, your flash sends out a quick "pre-flash". The camera "sees" this light and computes it via its meter/algorithm, how long to leave the flash on (duration) for proper exposure. It sends that duration amount to the flash. The flash itself does not know how long to fire it's bulb. (using ETTL II)
All this happens so fast that most people don't even know that the flash has output a "pre-flash".
As I've heard it said "Canon's system is wicked smart & incredibly fast".
NOTE:
On a Canon speedlight, the power output is controlled by the "duration" of the flash, not how much electrical power is actually applied to the bulb, as this is constant. (this has to be constant to keep the same kelvin value - WB)
So,
Given the above info, you can see that the flash head position has nothing to do with ETTL II (directly)
There's the "Gotcha"
- ETTL II has to have some parameters to use in its calculations, right?
- ETTL II uses distance information from some of the newer lenses in this calculation.
- ETTL II assumes that the flash head is pointed "directly" at your subject.
Let's try an example:Edit: Since I've been informed that when the head is moved from the 90 degree position, distance is no longer used in the matrix.
Lets say that you are in a room and you want to take a picture of a woman in the room. You don't want to use direct frontal flash, so you decide that you will bounce the flash off of the ceiling.
Your subject is standing 6' in front of you. "If" you were to shoot her with direct flash with the speedlight in ETTL II mode (and your lens is capable of sending distance info), when the flash sends out its pre-flash, the camera then uses that 6' distance in its calculations. Everythings good, right?
But, remember, you wanted to bounce the flash off of the ceiling. Hmmm - the ceiling in this room is 8' high. So you turn your flash head up toward the ceiling. The distance that the "light" has to travel to illuminate your subject is now "farther" than 6'. 6' to subject + 2' from flash head to ceiling, then another + 2' from the ceiling back down to your subject.
So now we add the "light" distance up: 6' + 2' + 2' = 10'
10' -- How is the camera supposed to know that final number to use in its calculations? Answer: It Won't!!!
So now, even though we are using the very smart ETTL II system, we have just thrown a monkey-wrench into its calculations.
What is the result?
Your picture will be "under-exposed".
That's why when using bounce flash you have to make up the difference with + FEC. The amount will vary given the other variables. (ceiling height, reflectance, color, etc.)
Wow, I can't believe I just typed all that
Hope that helps! Have fun...
Disclaimer: The distance figures in my example are not exactly correct, and I'm sure a mathematician will correct me. It was a simple example to explain the principle.
With all the variables involved in bounce flash, how would it know what distance to factor into the calculations?
While I don't own a non-ETTL II flash (other than stobes), I've read, and it seems to make sense to me, that ETTL does a better job at bounce than ETTL II due to it not incorporating distance (or the incorrect distance) info into its calculations.
But, I can't verify that. So, take that with a grain of salt.
The best source for info on the Canon EOS Speedlite system ( which is where I learned what little I do know about Canon Flash) is here
It specifically talks about ETTL-II, and says that distance information is NOT used with bounce, or when the flash head is anywhere but straight ahead and 90 degrees from the housing.
Anyone who uses the Canon flash system, owes it to themselves, to familiarize themselves with the link above. It explains the underlying philosophy of the Canon flash system, which if understood, works quite well indeed. I strongly rec anyone wishing to use the EOS Speedlite system to give this link a gander. There are actually three separate links, but once read, the reader has a new, deeper insite into how to use the EOS speedlite system.
I am still learning the intricacies of the ETTL-II myself. I want to thank Randy for helping make the details of this topic much clearer.
Moderator of the Technique Forum and Finishing School on Dgrin
That is what I was trying to say. When the flash is not at 90 degrees, it ignores the distance information and just uses TTL metering.
I read the link PF listed and this fellow sounds like he knows all the inside details about it. I have no way to test if this is accurate or not, I'll just take it at face value that it is correct.
Like I said, I think ETTL would do a better job at bounce flash since it doesn't use distance info. If in fact when the head is turned it doesn't use distance info
GREAT!
Thanks for the info.
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Just wanted to also add here the edit I did on my earlier reply.
EDIT:
It has been brought to my attention that when a Canon ETTL II speedlight's head is moved from the 90 degree position, it no longer uses the distance info in its calculations.
I can honestly neither confirm nor deny this. The source this info came from appears very knowledgeable, but I can't get past my experience with this system and the fact that when the flash is bounced, why are the results consistently under-exposed?
If the system goes only to ETTL and doesn't use the "incorrect" distance, then the exposure should be spot on even when bounced.
Hmmm...
Maybe you guys/gals will have to come up with your own thoughts on this.
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Guess I'll do a little testing.
I'll take my 580EX set to ETTL II and use a lens that sends distance data for the test.
Tripod mounted camera - flash straight-on to illuminate subject. Record image and histogram.
Tripod mounted camera - flash bounced to ceiling at a given place to illuminate subject. Record image and histogram.
Tripod mounted camera - flash head in 90 degree (normal) position that will accept distance info. - flash is connected to camera via off-camera cord and pointed to the same place on the ceiling to illuminate subject. Record image and histogram.
I'm thinking this may tell the tale. I'll let you guys know.
I post now 2 photos done this afternoon, some hours ago.:D
I hope you all like them and the use of the off camera flash, as much as I do.
Antonio,
I don't even notice any flash =
Good job.
What flash??:D
Isn't it fun to have images that 'pop' with the light from your flash, that the viewer does not even notice that flash was used!?
Moderator of the Technique Forum and Finishing School on Dgrin
I think that - not noticing the flash - is the charm of the picture.
Refering to the pictures I posted before, the reflection on the left picture is the only sight of the flash.
You can laught, but when I saw the picture myself I had to go to the exif to see if the flash fired or not.
Why? Because many other photos were shot in a row and we don't see the flash when it fires ... well... almost.
My wife was holding the flash.
But, curiously, you can see a clear difference now.
Watch this, side by side two shots with a very small dif in time:
But I had to LOOK CAREFULLY to see it - it was not obvious, and that is a good thing.
As you say, when you look at the images side by side, the flashed shot is much better, indeed!
Moderator of the Technique Forum and Finishing School on Dgrin
And this thread is about ST-E2 and flash, right ?
I knew there was flash, but a person would really have to be looking for it.
My comments were to commend you on your flash efforts, not that I didn't really know that flash was used. It's called being nice
Enjoy, you've worked for it