Image from the manual:
.....
Note by © cgardner: HS Sync will not work in auto mode because the sensor controls the flash exposure in real-time vs ETTL which sets flash power in advance of the actual shot based on the pre-flash calculation.People, even very skilled ones, tend to dismiss techniques they are not very familiar with. "Stobist" for example completely dismissed TTL flash on silly "ethical" grounds and thus never really used it enough to learn how to use it effectively, but is apparently starting to warm to the idea since he used a set of radio popper radio triggers. I started with completely manual flash in the early 1970s used "auto" flashes (Vivitar 263, 283 and 285HV) for many years. The idea of using a tiny sensor window on the flash worked OK in the days when prime lenses with identical FOV and negative film with 1-2 stops latitude for overexposure were used, but that 30 year-old technology isn't ideal for digital which requires precise exposure for highlights. Auto mode reacts to the overall scene and while it handles "average" and static scenes well it can't correctly expose highlights correctly many situations with the precision needed for digital. When I bought my first Canon 20D in 2004 I initially used my pair of Vivitars but soon switched to a pair of 580ex, primarily for the HS Sync outdoors. I found that I had to completely relearn flash exposure to use ETTL flash effectively. The key was understanding how the camera evaluative flash metering works in Canon cameras. The Canon evaluative metering introduced around 2004 (20D and later models) evaluates ambient and pre-flash across 35 different zones between the time you mash the shutter button fully and the shutter opens. By comparing ambient and pre-flash reflection it can make a logical guess how far things in each zone are from the camera (nearer objects will reflect more light) and their relative importance (more weight given to zones in the middle of the viewfinder). The camera then will try to preserve the detail in the brightest highlights. The biggest problem people starting with flash seem to have is relearning how to compose for flash. Flash exposure is only correct at one distance. It is physically impossible to put something in the foreground to frame a shot, as you can with ambient light, and not have it fool automatic metering, which simply reacts to the reflected light. Obviously if you have something very reflective in the foreground the flash adjusted for it will underexpose the background, so the best way to compose for flash is to ensure what you need correctly exposed is in the foreground and that everything you want correctly and identically exposed is the same distance, including body parts when setting up a pose. For example with flash if you set a pose where the shoulder is closer to the flash than the face either the shoulder will be correctly exposed and face underexposed, or the face correctly exposed and the shoulder overexposed.ETTL does a fine job of fill flash. You simply need to adjust FEC as needed for each different scene reflectance.Evaluating exposure based on what the camera actually recorded in the last shot is much better than relying on a sensor in the flash. Learn to use the overexposure warning (OEW) to monitor exposure . It will tell you both when and exactly where the highlights are overexposed. My workflow is quite simple: Point and shoot, evaluate the OEW in the playback and adjust FEC as needed on a ongoing basis. In static shooting situations such as portraits where the subject / flash distance does not change it is more effective to use M mode rather than ETTL. The workflow is exactly the same - shoot, evaluate, adjust - but what is adjusted is power level directly, not via FEC setting. But once set the exposure will not change because the camera metering isn't involved. If you click the WWW button below it will link you to my tutorials which explain Canon flash. In one of them I compare the 18 different ambient / flash metering combinations my 20D offers.
......
...
Note by © dmward: A friend who uses Nikon made the same comment about WC regarding TTL.
...
I think your problem is that Auto on Nikon speedlights is essentially the same function as High-speed synch on Canon speedlights.
...
For both the concern is finding a way to get the speedlight to illuminate the whole image when the shutter speed creates a moving slit across the sensor.
....
For Canon its High-speed Synch, for Nikon its, Auto. The result is the same, a "flashing" of the speedlight to ensure the image is evenly illuminated by the flash when the shutter speed causes a shutter curtian slit.
....
I use Canon, and the High-speed setting on the 580EX does a good job filling shadows outside.
...
It is possible to use a combination of EV compensation adjustment in the camera with FEC on the speedlight to "darken" a sun lit background while "popping" the subject with the flash.
....
It is important to remember that the effective GN is reduced because of the high-speed synch so you have to be closer to the subject.
...
...
...
" I'll have to review Will Crockett's DVD, but I believe he was claiming the ETTL is not as consistent in getting proper exposure and suggested auto flash as a better alternative. I don't recall if he was speaking of shooting outdoors or indoors. I'll have to check."
..
Note by © cgardner: Both ETTL and Auto (sensor on flash) both react to the light reflecting from the scene. The difference is evaluative flash metering reacts to it zone-by-zone over 35 metering zones then uses deductive programmed logic to try to prevent any of the highlights from blowing out. The "auto" sensor on the flash will also react to changes in overall reflectance of a scene but not to where in the frame the change is occurring. For example, you are shooting a table photo. People are standing behind the table covered with a white table cloth with an open space behind them. Evaluative flash metering will react to the fact there is a big white thing very close to the camera and reduce the amount of flash output to avoid overexposing it resulting in the people 4 feet further back being underexposed. Auto metering will see the same scene as an even balance of light and dark tones and give it more flash output. But since regardless of metering method the flash exposure is only correct at one distance if auto correctly exposes the faces it will blow out the detail in the table in the foreground. With ETTL an FEC adjustment can be used to expose the faces correctly but it will also blow out the detail in the foreground. This example reveals a fundamental difference between ambient and flash photography: distance to the flash matters when composing the photo.Regardless of how flash is metered and controlled only things at the same distance will be correctly exposed. Since digital requires exposing for the highlights the only way to ensure that no highlights in the photo are blown is to make sure what needs to be correctly exposed is closest to the flash and everything you want to be correctly exposed is the same distance from the flash. Not surprisingly if you start composing your flash shots with that in mind you will find that ETTL metering does a much better job of getting the exposure correct. If you see there is something reflective in the foreground which is unavoidable you can anticipate the ETTL metering will react to it and you will need to dial in more FEC than normal.Setting the CF.n for average flash metering in the camera works similar to auto in that it averages the overall scene, but the difference is that is averages what the camera sees, not what the flash see. The difference is significant if a zoom lens is used.One of the advantages of working with two flashes is that the distance of the key light which creates highlight exposure can be controlled separately from the camera distance. With ETTL metering the camera will automatically compensate for differences in distance of both key and fill on camera if either light moved. That is ideal for situations where the flash - subject difference can't be predicted or controlled.Its also worth noting that auto flash (sensor on flash) does not work with multiple flashes because the light from one flash will fool the other into thinking the scene is brighter than it actually is. That leaves manual power mode as the only option, which in turn means the exposure will only be correct at a specific distance. That works fine for static situations like portraits, but not well at all if the subject-flash distance is dynamic.When I used a pair of manual flashes it was with a simple distance differential technique. Both flashes were identical. If shooting at 8ft the off camera light would be placed at 6ft to get a one stop incident power differential and 3:1 lighting ratio. Finding the correct exposure was simply a matter of a one time test. Since the distance and power was the same the exposure at that distance combo was always the same also. If moving back to 11ft for a wider shot the off camera light moved to 8ft to maintain the ratio and the aperture was opened one stop. The technique was very simple but required shooting from pre-tested distances. In this photo of one of my early diffuser prototypes you can see the "cheat sheet" for manual flash. The flash in the photo is a 580ex but the exposure chart was for my Vivitar 285HVs.
..
....
Note by © markle: well said Chuck but there is one more important aspect to consider: the fact that auto flashes give more predictable results, so the photographer can adjust knowing what is going to happen with no "surprises". Also any automatic flash (being e-ttl or thyristor) will try to compensate when there are other flashes illuminating the same scene . (obviously)
...
Now It's up to us to decide which is better (for us): I'd rather have a thyristor flash giving predictable emissions rather than TTL flashes trying to make an interpretation where there is not much I can do about it.
...
Of course if I shoot on the street and I have no time to think then I'll use some automatic flash praying for the best, but that's not the topic here (as I understand) because if I have time to set the shot then I wouldn't use any automatism (maybe the thyristors, but only those if I really have to) hehehehe
....
But FEC on TTL flashes is (in my opinion) a contradiction in terms: mainly because it's a patch to compensate the "interpretation" pretty much unpredictable (from the start) and it may change once the scene is re-composed to apply the compensation. The FEL makes more sense but again is in contradiction with the "spirit" of the technology. In my opinion. Once again the thyristor system is hard to beat... hehehehe
...
Automatic should be automatic: it's like you buy a car but the auto-transmission needs to be adjusted by you often: if I have to do that then why I bought an automatic car, plus if I have to switch to standard then the auto-transmission doesn't really work as it should because when you know that it changes the gears by itself then you don't expect to do it manually and then it does whatever the transmission likes anyway (after you manually adjust it) . I'm sorry but it doesn't work both ways: either you use an automatic flash or you don't. The auto-thyristors are now well proven, in automatic, indoor and outdoor. They are straight (with the instructions) consistent , honest, don't promise the moon and always do what they have to do, shot after shot, always the same.
...
On the side of the topic I want to tell a real story happened few days ago: we were playing around with a couple of photographers waiting for a ceremony to start and we were discussing about fill flash , outdoor, sunny day. To cut the story short we made a test between my sunpak 383 and a nikon SB-800.I took one shot with the sunpak (1 stop difference from the ambient, F/11 auto set) and they took 8 shots with the SB-800 in aperture priority.The (one and only) shot from the sunpak was perfect and beautiful while the 8 shots with the Nikon were randomly over-exposed (all 8!)
...
hmmm
...
talking about fill flash outdoor and the limitation of the auto thyristor flashes.. hehehe
....
sorry about the OT slip
...
...
...
...
Note by © markle: cgardner said it all, correctly.
...
I just wanted to add that the external metering of the 580EXII works with limitations with all the cameras before the 40D and mark IIIs and in automatic with the 40D and mark IIIs
...
Basically with the 5D will underexpose 2 full stops and you have to enter the ISO manually. Plus you can't correct the under-exposure because the FEC won't work. The only thing you can do in order to get correct exposures is to cheat with the ISO (400 instead of 200 for example) but then it also depends on the distance and if you bounce the head or not.
...
With a 1DIII you can (at least) set a permanent +2 FEC
.......
Just like the Metz 58 the auto thyristor sensor will suffer (being therefore inaccurate) at small apertures and with a subject close to the flash.
....
for the rest it works pretty much like a Metz (again in AUTO mode or external metering like Canon likes to call it) but with the above limitations.
......
...
Note by © cgardner: When I learned to use flash in the early 1970s it was with a single power Graflex flash with a head the size of a car headlight and 410V battery back that seemed as heavy as a car battery. There was only one option for exposure control: distance and aperture. Fortunately color negatives where more tolerant of over-exposure than digital so correct exposure was defined by making sure there was density in the shadows and letting the lab sort out the rest.
....
I bought my first Vivitars, a pair of 263s, around 1975. I still have them and they still work. I initially thought the auto thyristor mode a great leap forward over manual, but found it was necessary to compensate with aperture when a scene was brighter or darker than normal. The fact I used two flashes most of the time in a key / fill arrangement also made it impossible to use auto mode in most situations and all things considered I found manual far more consistent and predictable and used it far more than auto mode.
...
Prior to making the jump to the 20D I used a Minolta D7Hi which has a EVF and no x-sync limit which was a blessing for outdoor fill situations. By then I had upgraded to a pair of 285HV flashes which I used in manual mode. They were sufficient for most things, but to was real PITA to have spend thousands on a DSLR and fast glass only to be stuck shooting at f/11 because of the *&%$ x-sync limit. Thats really what motivated me to switch to the 580ex.
...
My first reaction to ETTL flash exposure was that it sucked. Most shots were underexposed. With a bit of research and experimentation I figured out mastering ETTL flash was mostly a matter of understanding how the camera interpreted scenes. Results can get confusing because the 20D has 18 different ambient/flash metering combinations. Cameras with spot metering have 21. One winter day a few years ago I put the camera and flash on a tripod and shot wide, medium and close-up views of a complex indoor scene in all 18 modes using Av and ETTL with EC and FEC set at zero. The goal was to see how each combination handled the exposure differently. The results of the test are here: http://super.nova.org/DPR/Canon/TTL/ I concluded that none of the modes got the flash and ambient exposure perfect, but all things considered I thought the evaluative ambient + evaluative flash combination did the best overall job. I think that sticking with any combination of ambient and flash metering options will produce consistent results if used consistently enough to understand how the camera handles the more challenging flash metering situations such as brightly lit backlit subjects.
....
That test confirmed the practicality of the workflow I'd been using. When confronted with a new scene I will most often put the camera in Av mode with evaluative metering and flash in ETTL with EC and FEC set to zero: the camera baseline. I lock AF with the * button then recompose and shoot. I evaluate the results then adjust EC and FEC as necessary to get to the correct exposure. I've done enough systematic testing to look at the scene and correlate the brightest thing in it to where the right edge of the histogram should be to reproduce it correctly. I've also learned to correlate the clipping warning in the playback to the point where texture starts to disappear in the highlights. When practical, such as with portraits, I use a white terry shop rag as an exposure guide, both visually and in conjunction with the clipping warning. It never takes more than a couple frames to zero in the exposure. For candid shooting I use ETTL and evaluative metering. I constantly monitor the playback and clipping warning as I shoot and correct FEC downward if the clipping warning occurs or raise it if a gap appears on the right of the histogram. Because of the way I evaluate and adjust there isn't much difference when I switch and shoot in M mode in static situations. I simply adjust flash power directly instead of playing the cat-and-mouse game with ETTL guessing and then overriding with FEC.
....
Given the way I shoot and the fact I don't have a problem getting correct exposures consistently, there really wouldn't be any advantage to using auto mode vs either ETTL or M. As mentioned previously simply putting the flash metering in average mode would result in the camera doing the same type of broad average metering that the auto flash in the sensor does, and I can see no inherent advantage of having the flash sensor meter the exposure rather than the camera because what really matters is what the camera records, not what the flash sees.
....
With regard to outdoor fill flash its important to realize that in most scenarios the sun is typically used as rim light and the flash as fill will not affect exposure of the highlights much. The shadow side of a head in the direct sun meters 3-stops below the sunny side. There is actually plenty of very soft fill light there created by the light bouncing off the sky, but the 3 -stop deferential puts in the face down in the middle of the camera sensor range making it very dark. Since fill is typically kept a stop below the ambient highlights on the hair and body when fill flash is added it only is lifting the soft sky fill about 2 stops there isn't as much risk variation in flash output fill blow the highlights as with indoor shooting.
....
A mistake neophytes make with flash outdoors is shooting in Av mode and failing to heed the x-sync warning. In Av mode the camera automatically limits shutter speed to the x-sync speed. If aperture selection in sunlight is wider than f/11 the locking of the shutter at 1/200th or 1/250th may cause it to become overexposed. I've seen more than one person think overexposure in that situation was due to too much flash and not understand why a minus FEC adjustment had no effect. Using HS mode in Av is simpler because the flash which switch to HS mode whenever aperture selection and scene brightness push the shutter faster than x-sync. But regardless of flash mode I find it is less confusing and error-prone to shoot in M mode if the ambient light level is consistent. Starting with flash off and adjusting ambient exposure until there is no clipping provides a good baseline for evaluating the effect of the flash when it is added and will keep the background exposure consistent shot-to-shot as you reframe.
...
...
..
Note by © markle: Chuck, it's a pleasure to read your posts!!
....
I believe that the main point is this:
....
" That test confirmed the practicality of the workflow I'd been using. When confronted with a new scene I will most often put the camera in Av mode with evaluative metering and flash in ETTL with EC and FEC set to zero: the camera baseline. I lock AF with the * button then recompose and shoot."
...
The old ETTL used to compensate exposing correctly once you recompose and move the focus point .
...
that was the key for success
....
The new ETTLII performs some additional compensation resulting in erratic emissions. If you leave the AF with the shutter then it will try to "remember" where the focus was measuring in prevalence from there, even if you recompose moving the focus away.
....
In any case having the AF with the "*" is another contraddiction in terms you are rejecting (or trying to) the entire ETTL philosophy doing that so basically another flash (metz or better a sunpak/vivitar 285HV) will make more sense. (in my opinion)
...
There is no doubt that the most "consistent" flash will be in manual (the flash I mean).
...
Bottom line ETTL has too much brain that I want to deal with. In the end we have two different practices: either you adjust your photography trying to anticipate or predict the flash system or you use the most predictable automatic system you can find and make the flash adjusting itself to your photography. because we're talking about portable flashes, not studio or location setups.
....
I gave up on ETTL I&II because I was tired of chasing the "moods" of whoever wrote the software for it.
....
Because at the end of the day what really counts are the pictures and if I have to concentrate anticipating or trying to predict a flash system then I'll be losing too many shots.... hehehehe
...
..
..
Note by © cgardner: Markle, NK Guy's site explains the differences between E-TTL and E-TTL II. http://www.photonotes.org/articles/eos-flash/#ettl
...
At the default settings both E-TTL and E-TTL II meter ambient AE when the shutter is half-pressed and fire and measure pre-flash when the shutter is fully-pressed. The primary differences is are that E-TTL uses the active AF point for exposure weighting and has the auto-fill reduction function, while E-TTL II bases its flash weighing on algorithms based on zone-by-zone comparison of ambient and pre-flash and focus distance information if available. E-TTL II also has the ability to detect and eliminate exposure errors cause by direct specular reflections of the flash, such as when there is a mirror in the background -- try that with your auto thyristor flash
....
Composition habits and camera CF.n settings will affect metering. With ETTL-II when CF.n 04 is set to 0 if I point the camera at a dark area in Av mode and half-press the shutter, then recompose to a lighter area the ambient shutter time will be incorrectly based on the darker area I locked AE on with the half press, but flash will be based on the area being photographed, resulting in gross over-exposure. Setting CF.n 4 to 1 separates the AE and AF independently, shifting the AF lock to the * button, allowing me to press * to lock AF, recompose, then half press the shutter to lock ambient AE. The pre-flash and flash metering doesn't occur until after the shutter is fully pressed but if I don't change the framing between the time I half-press and fully press the shutter both ambient and flash metering are based on the final photo composition. Most significantly with E-TTL II the recomposition after AF lock does not affect exposure as it did with the AF-point-weighted E-TTL system.
....
My day job for the past 30 or so years has involved designing and programming database information systems so perhaps I have a better understanding and more patience for the "moods" (logic) of the software than you do. I concluded that the best approach not to even try to out guess ETTL-II in advance, or expect the camera to get the exposure correct all the time. I do the opposite: I first let the camera take its best shot at getting the exposure correct before trying to second-guess it. I eliminate variables in the workflow by always using the same metering mode and taking initial test shots from a consistent baseline of EC = 0 and FEC= 0 rather than whatever the camera was set at previously. Only after I evaluate the results of default metering setting of the camera is do I intervene and override it with EC or FEC. Working with E-TTL II systematically from a consistent baseline is what has helped me understand how to make it work effectively.
...
...
...
Note by © markle: Yes but come on there is always some new "excuse" for E-TTL to illuminate is some strange manner. Now is the focus area too bright, now is the camera position too high, now is some CF on both the flash and the camera, now is because the ambient was too bright, now is because I supposed to lock fel fec adjust re-measure, compose and don't shoot, re-compose and shoot.
....
Can I tell you what I do on weddings?
...
- I bring two sunpak 383 and a tinycycler
- I set the camera in manual f/5.6
- I check the flash settings (ISO 200 , F/5.6 in auto)
...
and that's it
.....
no.. seriously.. that's it
....
thanks for the link, it was interesting but like I said the system shows too much brain.
....
P.S. : not to be redundant but I see that e-ttl works only when the subject is tight up, close ups for example, not too much graduations of colors or luminosity: then it gets it right (maybe). But in similar conditions the sunpak/vivitar flashes in auto ALSO get it right. but all the time. not just most of the time.
...
...
...
by © Fred Miranda
