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16

Canon E-TTL E-TTL stands for "Evaluative Through the Lens" and was introduced in 1995. A low power preflash is fired immediately before shutter opens and its reflectance is measured to determine correct flash exposure. Entire frame is analyzed by the same evaluative exposure metering system as ambient exposure, area under active AF point is given more ...


12

The way TTL works is to measure the exposure of the scene when the aperture of the lens is wide open, and then when the picture is taken, it stops down to the correct aperture. With a manual lens, oftentimes you have manually stopped the lens down already to the aperture you want, or because that is where the exposure reading is telling you it is correct. ...


12

The first flash is part of the eTTL system. The camera is using it to establish the exposure. If you switch to manual flash mode it will not happen (but you will have to fix the exposure yourself). This initial flash occurs before the shutter opens and does not affect exposure, but is rather used to measure the light as part of the metering processed. You ...


10

The camera doesn't know the distance of all subjects - only a rough estimate of the distance to which the lens is focused. The camera also does not know the exact flash head angle, it may be the case that you are bouncing the flash of the ceiling, or there may be other surfaces in the scene that reflect light back onto the subject. Flash exposure ...


8

If you're setting up the lights, and they're a fixed distance away from your subject, then use manual. Other than if you fire your flashes with insufficient power, your exposure will be consistent from frame to frame. That's the boring example. Nothing is moving. TTL doesn't gain anything over manual. If the distance isn't fixed, then it's still ...


8

Yes. This is an advantage of through-the-lens metering, as the effect of the flash is judged based the light that, well, actually comes through the lens. It doesn't need to know anything fancy about angles; it just measures the effect on exposure. (on modern systems, using a low-powered "preflash" to test, and calculating from that). This can be fooled by ...


8

What you want to do will not work. Here's why: The way TTL operates is that your camera meters a pre-flash to determine the amount of power to use when the shutter is open. This pre-flash is a low power burst of light that reaches the camera through the lens (thus, TTL) an instant before the shutter begins to operate. The camera knows how much power it used ...


7

The same is true when the flash is on the camera, facing away from the subject into empty space with nothing to reflect it back to the subject. The point of TTL is to adjust flash power automatically under the assumption that it has an influence on the scene. If the flash is on camera or not is not too relevant. In event photography or photojournalism for ...


6

I have used P-TTL flash on some events, and have generally been quite satisfied with the results. I don't like the "deer in headlights" look of a direct on-camera flash, so I've only used bounce flash, or off-camera flash. That said, here are some ideas why underexposure might be experienced and how to avoid it. In exposure modes where shutter time is not ...


6

The problem that is solved via high speed sync has nothing to do with the power of the flash and everything to do with the curtain transit time of the camera. Above a camera's sync speed the second curtain begins to close before the first curtain is completely open. Therefore very precisely timed multiple flashes must be emitted from the flash as the open ...


6

Is E-TTL Universal? No, it's the opposite of universal. It is proprietary and specific to Canon. Each brand has their own specific flash/camera communication system. The only thing that's universal is the sync (fire) signal [which is a short between ground (rails) and the center contact of the hotshoe], because that's part of the ISO standards for flash ...


6

Nikon doesn't tell Sigma how their TTL protocol works (and Sigma does not pay to license it). The communication is reverse engineered. Sometimes, the protocol used varies slightly from camera body model to model — and sometimes, that variation means that the guesses Sigma made are out-of-spec and communication breaks. Sometimes, Sigma updates the firmware of ...


5

You triggered a distant memory. It appears to have been a genuine one :-) - TTL (through the lens) metering was invented by Olympus in 1975. My memory says that they measured light reflected from the film surface to determine the light level and that they obtained a large number of film samples from many countries to arrive at a typical reflectance value to ...


5

This behavior is perfectly normal for a Canon 60D, and most other Canon EOS bodies. When you select Av Mode with E-TTL in lower light environments, the camera assumes you want to expose the entire scene correctly for the ambient light and then use the flash to illuminate your subject in the foreground. If you wish to disable this slow sync feature, use ...


5

The camera will calculate the amount of flash to use in one of two ways, depending on the conditions. The first case is when the flash is the primary light source. In this case, the shutter speed is irrelevant. The target exposure is still the standard 18% gray, but flash power effectively replaces shutter duration in the calculation. That's because the ...


5

The first flash is a metering flash done just before the shutter opens when you are using E-TTL to automatically compute the amount of power used by the flash. With E-TTL II this allows the camera to combine the distance info from focusing with the amount of light returned from the metering flash. This allows the reflectivity of the subject to be taken into ...


5

No. E-TTL is a proprietary part of Canon's EOS flash system. Some third parties (e.g. Metz, Sigma, Yongnuo) have reverse engineered it, but to my knowledge it is not licensed to anyone else. Most of the third-party flashes are of the hotshoe type, but a few (again e.g. Yongnuo) offer AC-powered studio strobes as well. It looks like Profoto is included in ...


4

The way Flash Exposure Lock works is that it locks the power level of flashes to what is metered to be a correct level during preflash. In manual mode, the power level of flashes is locked all the time anyway (to the level you have set it to) and there's no preflash to meter, so Flash Exposure Lock is just not relevant. What you seem to be trying to achieve ...


4

There are many flashes across many brand lines that exhibit what you have discovered concerning your 430EX II. Although I don't think there is a great conspiracy amongst the flash manufacturers, the "Truth" is that the manual minimum setting is actually the minimum manual setting. In other words, many flashes that can be controlled both manually and via TTL ...


4

The following radio-based flash triggering systems can communicate TTL for Pentax: The Cactus X-TTL system with their V6II/IIs triggers can give you remote power control over TTL Pentax flashes, HSS sympathy triggering, and full TTL passthrough to an on-camera flash mounted on top of the trigger, as well as P-TTL with remote flashes. Phottix's Odin II ...


4

If you are using a non-Canon flash that does not support the E-TTL standard, then the camera is writing "Flash: Did not fire" to the EXIF data. This is also true when using non E-TTL compliant triggers or when using the PC connector on Canon bodies that have one.


4

This is a known problem with Pentax's wireless flash system. Or rather, it's a common problem with all such systems. (See similar complaint with Nikon.) Even though the manual states otherwise, at least portion of the control flash fires during the actual exposure, and you can see it in the image, particularly if there are reflective surfaces or if your ...


4

Before we can understand what happens during TTL flash metering, we must first understand how metering works in general. There is no single "correct" exposure value for an entire scene, there are only correct exposure values for objects with a specific luminance value within that scene. If "correct" exposure is equivalent to 18% gray, then only one luminance ...


4

There isn't nearly as much to figure out as you seem to think. Let's say that you have a scene in front of you that is nicely illuminated and doesn't really need flash at all, and you meter for, and set a manual exposure for, an ambient exposure that would have been absolutely perfect. Then, for some inexplicable reason, you decide to add manual flash (...


4

Godox has several lines of flashes (everything from speed lights to studio strobes) that are manual with HSS. The challenge is HSS requires the trigger interface with the cameras proprietary flash protocols and so if you're doing all that you might as well do TTL. Godox gets around this by making HSS an off-camera only function. So the flash has a single ...


4

If you are using your flashes in full auto TTL, then there is no point in having a LightMeter, however, if you wish to have better control and more accurate tone, colour, brightness, contrast, shadows and highlights, then manual is the way to go and the Sekonic Lightmeter is a great tool to have. Apologies if I happen to go over anything too basic with my ...


4

The first thing you want to do is to check that the pins on the foot of the flash match the contacts on the hotshoe of your camera. They need to match in both the number of pins and placement so that the pins will touch the contacts exactly. Most sellers will show a picture of the foot of the flash. See also: Is flash brand X compatible with camera brand Y?...


4

With my long exposures, I meter for the scene and then add whatever ND amount needed and disregard the camera’s meter from there on out. That being said, it wouldn’t hurt to do some testing to determine more about your particular filter’s characteristics (I’d recommend using a digital camera for the testing). Take a regular exposure, manually adjust 10 stops ...


3

Even if you knew the distance (some cameras will transmit focus distance info to the flash system), you still don't know how much reflected light is being bounced back on the subject. The flash exposure needed would be greater outside than in a small room with white walls.


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