Ettl question

Question.... In a party situation where only disco lights are lit, will the ettl flash zoom or adjust the exposures automatically when the subject is farther or closer to the camera?

There are times when you take a shot of a farther group of people and then some folks near you all of a sudden request for a shot.

What would be your approach in this scenario?

If zoom is working, does it need to br direct to the subject for it to be accurate or even work?


Thank you.

I have not tried it specifically, but I would imagine the ETTL is keying off your exposure metering. If you are on spot, evaluative, center weighted, it will change the ETTL functional metering.

ETTL exposure calculations are related to focus distance. Also, they are related to the focus point used.
If you focus on something that is farther away ETTL will adjust the light based on that distance. That's why, if there is something near the camera but not the focus point, it will be over exposed.

thanks guys.... started collecting answers here. That's why i love POTN.

dmward wrote in post #16533322
ETTL exposure calculations are related to focus distance. Also, they are related to the focus point used.
If you focus on something that is farther away ETTL will adjust the light based on that distance. That's why, if there is something near the camera but not the focus point, it will be over exposed.

Not quite right, Dave. The ETTL(I) used distance directly, but Canon made ETTL-II use distance in an indirect manner! In ETTL-II with flash metering Eval (the default CFn setting), the camera uses the AF point and also all the other AF zones at the same relative distance, to decide how much light to ask from the flash.

I set up this situation, with 18% grey card at 3', the flower terrarium at 5', and the Xmas tree at 11'.
First shot I choose the AF point on the grey card and shoot Evaluative ETTL; second shot I choose the AF point on the tree and shoot Evaluative ETTL; third shot I choose the AF point on the grey card but shift the frame so that AF point now lies on the Xmas tree.

sirquack wrote in post #16533307
I have not tried it specifically, but I would imagine the ETTL is keying off your exposure metering. If you are on spot, evaluative, center weighted, it will change the ETTL functional metering.

Ambient metering is Evaluative or Partial, or Spot, or Center-weighted; flash is NOT!

Flash is Evaluative or Average, as set by CFn; this is totally independent of the ambient metering mode selected.

The ambient metering mode selected has absolutely NO influence on the flash metering result!

That's correct. It took me a while to figure this out. After I did I realized why I was always afraid to use flash. In fact I hated it because if I did get good exposures I did not know why. Some type of predictability and repeatability was something I was working on.

I wish someone had told me this a long time ago. Even though flash metering uses the same exposure system your camera and flash have two separate jobs. The camera (light meter) exposes for ambient light and the flash exposes for your subject. The camera does not care what the flash is doing and the flash does not care what the camera is doing.

In ETTL the flash pre fires. In Evaluative mode the camera uses multiple metering zones, takes an ambient reading and compares it to the pre flash when you press the shutter. It measures the reflected light from the flash and isolates the closest object which is typically your subject. Now it exposes for that isolated subject. A bride in a white dress, and groom in a black tux and and the bride and groom together will all reflect light back differently. Lets think of the camera without the flash. This is similar to shooting pure white snow, black tar or and equal amount of snow and tar in the frame. Again the cameras light meter is for ambient only and has nothing to do with flash exposure.

In average the entire scene is metered. This mode does not isolate the subject so some people prefer to use this mode indoors.

As Wilt stated the 3rd way to meter flash is using FEL.

Regarding predictability and repeatability. The more you learn the more you realize ETTL, while a good tool is ball park. At least by understanding what is going on it is easier to work with. On the go shooting is - shoot - chimp - adjust FEC and shoot again.

digital paradise wrote in post #16534021
Regarding predictability and repeatability. The more you learn the more you realize ETTL, while a good tool is ball park. At least by understanding what is going on it is easier to work with. On the go shooting is - shoot - chimp - adjust FEC and shoot again.

Having the camera set for raw file recording means that all 12 bits of data per photo site are available for processing in a raw conversion software program. That means that when shooting a wedding, using raw recording, I can concentrate on getting the images I want. Its rare when more than 5 or 10 are way off during the day. A few minutes in Lightroom and all are spot one for exposure. Rarely does it take more than .5 EV to get them where I want them.

And, as said above, experience and ability to make adjustments with FEC add to success.

ETTL isn't magic, and its also not the boggy man.

i didn't know my question lead to a more technical discussion. but i learned a lot. definitely a healthy discussion. keep them coming.

thank you.

dmward wrote in post #16535155
Having the camera set for raw file recording means that all 12 bits of data per photo site are available for processing in a raw conversion software program. That means that when shooting a wedding, using raw recording, I can concentrate on getting the images I want. Its rare when more than 5 or 10 are way off during the day. A few minutes in Lightroom and all are spot one for exposure. Rarely does it take more than .5 EV to get them where I want them.

And, as said above, experience and ability to make adjustments with FEC add to success.

ETTL isn't magic, and its also not the boggy man.

I wish I was lucky enough to only need .5 EV in all the bouncing situations I shoot in . Definitely not the boogy man when you understand it but I do have to work it.

Agreed LR is spectacular for edits. It was amazing when I did some real estate work.

vinmunoz wrote in post #16535169
i didn't know my question lead to a more technical discussion. but i learned a lot. definitely a healthy discussion. keep them coming.

thank you.

if you don't hang out on the Flash and Studio Lighting page much, do so and prepare to have your mind blown on almost a daily basis. These guys are good.

I often take what I read here and go further with it. Here's a little blurb about flash evaluative vs average, much more at the link:

http://neilvn.com …sh-average-vs-evaluative/

The way I understand this to work, is that with Evaluative flash metering, the Canon camera takes the ambient light into account when calculating the flash exposure. With Average flash metering, the flash metering would appear to be de-coupled from the ambient metering, and the camera is less biased by the available light. (I’m quite willing to be corrected on this.)

hes gone wrote in post #16536566
=he's gone;16536566]if you don't hang out on the Flash and Studio Lighting page much, do so and prepare to have your mind blown on almost a daily basis. These guys are good.

I often take what I read here and go further with it. Here's a little blurb about flash evaluative vs average, much more at the link:

Yes. ETTL II is supposed to ignore reflective surfaces when in Evaluative mode.

Video #4 - ETTL II metering

http://cpn.canon-europe.com …asterclass/cano​n_flash.do

Neil's site is only one of the few places I go to learn about flash.

Forgot to mention POTN.

digital paradise wrote in post #16536582
Neil's site is only one of the few places I go to learn about flash.

thanks for sharing?