550EX & 300D FEL

[CanonUser]

Please correct me if I'm wrong...
When using the 550EX on a D-Rebel, according to the user manual, the following happens if you want to control the flash level:

- Turn both units on.
- Focus your subject.
- Aim the CENTER focus point over the area where you want the flash exposure to be locked.
- Press the "*" (FEL) button.
- The 550EX (or built in flash) will emit a pre-flash to evaluate the exposure.
- Release (or hold? This is where I'm not certain!) the FEL button.***
- In the view finder, you should see the FEL indicator "*" next to the "flash on" indicator.
- Recompose and shoot. The flash exposure of this shot should be based on the previous pre-flash evaluation stored in camera's memory.

***According to some article (http://bobatkins.photo.net/info/faq30/flashfaq.htm), the FEL value is stored in the camera's memory for up to 16 seconds. You can release the FEL button after the the pre-flash is fired, recompose and shoot. The flash exposure value will be based on the value stored in the camera's memory. However, the D-Rebel manual stated that the FEL button should be pressed untill the picture is taken. I took some quick & dirty shots using the above steps, including releasing the FEL button after the pre-flash, and it seemed to work. I pre-flashed a hi-key area next to a window, recomposed and shot a dark closet. The closet was underexposed with the 550EX fired.
I'd like to see some confirmation that you don't have to press the FEL button continuously on the D-Rebel, and that the pre-flash eveluation is done using the central area of the metering pattern.
If the above is true, then I can use the center focus point to focus my subject, pre-flash his/her skin tone (while zoomed in) or other tones, recompose and shoot. The critical area will be properly lighted by the flash, while I can control the ambience light with the shutter value in the Tv mode. The result is repeatable.

Any input would be greatly appreciated. Thanks.

Regards,
Alan

[robertwgross]

Alan, based on what you determine here, try to describe how you would follow your process in these two cases, and what you would expect to get:
(1) Very black subject. Let's say a groom wearing a black tuxedo, or else a black cat eating licorice in a coal bin at midnight. Distance ten feet.
(2) Very white subject. Let's say a bride wearing a white gown with shiny sequins. Distance ten feet.

Note: I don't have a Digital Rebel.

---Bob Gross---

[CanonUser]

Bob,
I think E-TTL works the same way in all EOS camera. I come from Olympus OM and Minolta Maxxum film cameras, so E-TTL is a strange beast to me. Anyway, this is what I gathered after reading all of what I could find about the subject:

- FEL will use center weighted evaluation, always.
- Manual focus flash will default to center weighted evaluation.
- Auto focus flash will bias toward the area surrounding the active focus point.
- Focus, then hold the focus and recompose technique WILL produce inconsistencies, depending on where the active focus point moved to.
- User selected focus point will result in center weighted flash eveluation.

Canon recommends FEL for situations where you have time to set up and auto E-TTL for everything else. The problem is the DR's auto focus is not reliable and doesn't always select the subject that you'd like to be the focal point. So auto focus flash results at a fast moving wedding are unpredictable.

For the scenarios you described, the camera has no problem in lighting a scene that's all low-key or hi-key. It's the mixed contrast or ambience/flash balance that gives E-TTL troubles. I plan to test the following for a wedding in 2 weeks:
- Read the ambience or gray card value.
- Use Tv mode to set up the camera.
- Zoom in, do a FEL evaluation & lock on the skin tone, neutral tone, or a shadowed part of the gown.
- Recompose & complete the shot.

Hopefully, I'll get these:
- Close to properly lit faces. May be a bit under exposed.
- Minimal blow out on the bride's white gown.
- Underexposed tuxes.

By shooting RAW, I can salvage the pictures this way:
- In C1 I can adjust the exposure/contrast/saturation/sharpness for the most pleasing look. Customer tends to forgive lost shadow details in the tux but blown whites and facial shines are unacceptable.
- I'll use C1's linear exposure mode to extract all the hilite details into another version of the same photo.
- In Photoshop, I'll combine the 2 versions and fix the crowfeets/red eyes/stained teeth/pock marks/tux details and blown hilites.

You'd be supprised by the amount of hilite data contained in a RAW file, even when you see blown whites on the monitor's screen. If you drop into the "linear response" mode in the RAW converter, you can use the curve/lenel to bring back alot of the lost hilites.

Regards,
Alan

[scottbergerphoto]

canonuser wrote:
Please correct me if I'm wrong...
When using the 550EX on a D-Rebel, according to the user manual, the following happens if you want to control the flash level:

- Turn both units on.
- Focus your subject.
- Aim the CENTER focus point over the area where you want the flash exposure to be locked.
- Press the "*" (FEL) button.
- The 550EX (or built in flash) will emit a pre-flash to evaluate the exposure.
- Release (or hold? This is where I'm not certain!) the FEL button.***
- In the view finder, you should see the FEL indicator "*" next to the "flash on" indicator.
- Recompose and shoot. The flash exposure of this shot should be based on the previous pre-flash evaluation stored in camera's memory.

***According to some article (http://bobatkins.photo.net/info/faq30/flashfaq.htm), the FEL value is stored in the camera's memory for up to 16 seconds. You can release the FEL button after the the pre-flash is fired, recompose and shoot. The flash exposure value will be based on the value stored in the camera's memory. However, the D-Rebel manual stated that the FEL button should be pressed untill the picture is taken. I took some quick & dirty shots using the above steps, including releasing the FEL button after the pre-flash, and it seemed to work. I pre-flashed a hi-key area next to a window, recomposed and shot a dark closet. The closet was underexposed with the 550EX fired.
I'd like to see some confirmation that you don't have to press the FEL button continuously on the D-Rebel, and that the pre-flash eveluation is done using the central area of the metering pattern.
If the above is true, then I can use the center focus point to focus my subject, pre-flash his/her skin tone (while zoomed in) or other tones, recompose and shoot. The critical area will be properly lighted by the flash, while I can control the ambience light with the shutter value in the Tv mode. The result is repeatable.

Any input would be greatly appreciated. Thanks.

Regards,
Alan

1.Flash Exposure Lock uses the Active Focus Point in Evaluative mtering. In Center Weighted and Partial metering it is based on the Center Focus Point. Source:" A Short Course in Canon EOS 10D Photography", by Dennis Curtin.
2. You don't keep the the * pressed. It is good for 16 secs then is deactivated.
3. You said that you FEL'd a high key area. Why are you surprised that the closet was under exposed? You told the camera you were taking a picture of a bright area. Are you trying to say that that proved FEL was working? If so then, yes, it did what it was supposed to.
Flash On!
Scott

[scottbergerphoto]

canonuser wrote:
Bob,
- FEL will use center weighted evaluation, always.
-Alan

Sorry Alan, this is not correct. Canon's FEL in Evaluative metering uses the active focus point.
Scott

[CanonUser]

Scott,
Perhaps there is a misconception on my part or miswording on Canon's part. That's what I try to clarify by asking these question.
The steps provided by Canon for FEL on page 83 of the manual specified:
1. Verify that the flash is ready.
2. Focus on the subject. Keep the shutter button half pressed until step 4.
3. "Aim the viewfinder center over the subject where you want to lock the flash exposure, then press the button. A preflash will fire and the icon will light in the viewfinder. Hold down the button."
4. Shoot. Press the shutter button fully.

Clearly, there is a difference between the printed instruction and the actual behavior of the camera. In step 3 (Canon's wording), why would the "viewfinder center" used instead of the active focus point? That lead me to believe that center weighted metering is used in this particular technique.
Also, I was not surprised by the underexposure. I expected the result to be dark, which it was.
My DR just ran out of juice, so I'll have to wait a little bit to carry out some more test using my wife's black dress, white dress, and my gray suit. Let's see what will happen.

Regards,
Alan

[scottbergerphoto]

Alan I use the 10D. The literature says the Exposure system of the 10D and 300DRebel are the same. It sounds from your manual that that may not be true. If I gave the wrong info, I apologize. You might want to post that question at www.robgalbraith.com in the appropriate forum. Chuck Westphall of Canon will usually respond.
Scott

[CanonUser]

Scott,
I read all of Chuck's responses on that forum. He basically said the same thing you did. I think if you hold a focus point, then the surrounding area of this focus point gets emphasized during the preflash evaluation.
If you press the FEL button without activating any focus point, then center weighted evaluation takes place. The instruction in the DR manual confuses the heck out of me! I'll post a question on the other forum to see if Chuck responses. BTW, what does the 10D manual has to say about how to use FEL?

Thanks for your thoughts, Scott.

Regards,
Alan

[scottbergerphoto]

canonuser wrote:
Scott,
I read all of Chuck's responses on that forum. He basically said the same thing you did. I think if you hold a focus point, then the surrounding area of this focus point gets emphasized during the preflash evaluation.
If you press the FEL button without activating any focus point, then center weighted evaluation takes place. The instruction in the DR manual confuses the heck out of me! I'll post a question on the other forum to see if Chuck responses. BTW, what does the 10D manual has to say about how to use FEL?

Thanks for your thoughts, Scott.

Regards,
Alan
The "Short Course" manual says, " Press the shutter button halfway down and focus on the subject that you want to lock flash exposure on, and press the AE-FE Lock button on the back of the camera below the LCD panel (*) A preflash fires, FEL is displayed briefly in the viewfinder, and the AE-FE Lock icon is displayed in the viewfinder to indicate flash exposure is locked."................"Recompose the scene and take the picture. To cancel FE Lock, release the shutter button and wait for the * to disappear. To keep it locked, continue to hold the shutter button half way down."
So, for this to work, you have to focus first, then lock exposure. It makes sense that you need to focus first so that you are sure you are getting a pre flash reading back off of what you want to expose with the flash.
Scott

[CanonUser]

This is Chuck Westfall reply to my question:

"The flashmetering portion of the FEL reading is based exclusively on the part of the picture area that is covered [during the preflash] by the partial metering pattern, which is illustrated on page 84 of the Digital Rebel instruction manual.

It is unnecessary to hold the AE lock button in after registering the FEL preflash, as long as the picture is taken within 16 seconds. The FEL data can be memorized longer than 16 seconds by keeping the AE lock button pressed before taking the shot.

You can retain the FEL data for subsequent shots by keeping your finger pressed halfway on the shutter button after the first picture is taken. You can confirm that the FEL data is still in memory by observing the asterisk symbol in the viewfinder data display."

So it's partial metering verytime FEL is used. So, the next question is which metering area provides better wedding pictures, the neutral tones or the hi-lites? Stay tune.

Regards,
Alan

[scottbergerphoto]

Alan, you are absoloutely right. I just read that thread and posted a question for Chuck Westphall myself about FEL and the 10D. So, The answer is that for the 10D, and the 300D as you stated, is that only the Partial Metering Area of the viewfinder is important for FEL. I guess Dennis Curtin got it wrong, and so did I.
Scott