580EXII Is there a way to have it meter certain spot?

[bphillips330]

Lets try and explain what I mean. Lets say I am taking a picture and i want a subject to be exposed that is farther into the picture. Of course the flash is going to meter of of the brightest thing (say a persons arm or what ever that is just in front of the frame). I know that i can look at lcd and see wrong part of picture is exposed and FEC to bump up the flash.

Is there a way that i can tell the flash to meter off of a certain point, sort of like using one of the 9 focus points on my 50D and have the flash know that I want THAT to be exposed and don't care if anything in foreground is blown out. This seems quicker that keep shooting to see how much + FEC i would need.

I have done it long enought to know what to have the flash set to to begin with, just hate the guessing game with what flash will meter off of. I don't want to have to take the picture, look at screen to see what meters off of, the try and retake picture, and pray that situation is still the sme with picture.

[Curtis N]

Flash Exposure Lock will will use the spot metering circle in the center of the frame.

Aim at the spot you want to meter, press the * button to fire the pre-flash and lock the flash exposure, recompose, focus and shoot within 16 seconds.

[GH_ATL_GA]

Lets try and explain what I mean. Lets say I am taking a picture and i want a subject to be exposed that is farther into the picture. Of course the flash is going to meter of of the brightest thing (say a persons arm or what ever that is just in front of the frame). I know that i can look at lcd and see wrong part of picture is exposed and FEC to bump up the flash.

Is there a way that i can tell the flash to meter off of a certain point, sort of like using one of the 9 focus points on my 50D and have the flash know that I want THAT to be exposed and don't care if anything in foreground is blown out. This seems quicker that keep shooting to see how much + FEC i would need.

I have done it long enought to know what to have the flash set to to begin with, just hate the guessing game with what flash will meter off of. I don't want to have to take the picture, look at screen to see what meters off of, the try and retake picture, and pray that situation is still the sme with picture.

With the 1D series cameras (at least the 1DsII) you can set spot metering to be linked to the selected AF point using a custom function setting rather than having it fixed at the center spot.

I had a quick look at the 50D manual & unfortunately don't see anything comparable in the CF settings.

[bphillips330]

With the 1D series cameras (at least the 1DsII) you can set spot metering to be linked to the selected AF point using a custom function setting rather than having it fixed at the center spot.

I had a quick look at the 50D manual & unfortunately don't see anything comparable in the CF settings.

the 50D does have spot metering. I can also set certain focus points. I never knew the higher end (1d's) you can select which focus point to meter off of. I completly forgot about the FEL button (might have wrong name) to set metering. That will be just as easy to point center point over subjet, lock exposuer then recompose and snap.

[Curtis N]

With the 1D series cameras (at least the 1DsII) you can set spot metering to be linked to the selected AF point using a custom function setting rather than having it fixed at the center spot.That function only applies to the way the camera meters ambient light. E-TTL flash metering is a whole different kettle of fish.

Likewise, setting the metering mode on any Canon DSLR to spot metering affects only ambient light metering.

[GH_ATL_GA]

That function only applies to the way the camera meters ambient light. E-TTL flash metering is a whole different kettle of fish.

Likewise, setting the metering mode on any Canon DSLR to spot metering affects only ambient light metering.

In this case we are both right. If I shoot using FEL the flash exposure is locked with reference to the selected AF point. If I shoot without FEL the flash exposure is fixed to the center AF point.

I just verified this with the 1DsII shooting w/ a black speaker sitting next to a white wall. Keeping the center spot on a corner of the white wall the exposure was 'correct' whether I selected the central AF point at the wall corner or an AF point located over the black speaker grille. (I made sure I was in ETTLII, not average metering.)

Keeping the camera position constant, using FEL the exposure was 'correct' when the AF was set to center. When the AF point was set on the grille (by selecting a side AF point, not moving the camera) & using FEL the shot was quite overexposed.

I wasn't certain I was correct since I usually shoot manual mode flash, but the tests tend to verify my memory hasn't totally failed. :)

Edit: To be correct, w/o FEL the flash metering isn't locked ONLY to the center point, but rather the ETTLII pattern metering is in play. By 'not average metering' above I mean with respect to flash metering (CF14), not the camera exposure mode which was in Spot metering mode.

[canonphotog]

I also tested FEL and my 1DmkIII earlier with spot metering linked to the active focus point and noted that FEL does use the active focus point. It did this even though my metering mode was set to evaluative. I didn't try shooting without FEL to see where it metered the ETTL at, but your data looks as expected to me. When I have the time I always use FEL and a flash bracket.

[GH_ATL_GA]

I also tested FEL and my 1DmkIII earlier with spot metering linked to the active focus point and noted that FEL does use the active focus point. It did this even though my metering mode was set to evaluative. I didn't try shooting without FEL to see where it metered the ETTL at, but your data looks as expected to me. When I have the time I always use FEL and a flash bracket.

Just as you, I too noticed that the lock works when the camera is set to evaluative as well as spot. The 1DsII is not too easy to follow in its explanation of the CF13 if / then conditionals. Hopefully the III series manuals are a bit clearer! :)

[PacAce]

In this case we are both right. If I shoot using FEL the flash exposure is locked with reference to the selected AF point. If I shoot without FEL the flash exposure is fixed to the center AF point.

I just verified this with the 1DsII shooting w/ a black speaker sitting next to a white wall. Keeping the center spot on a corner of the white wall the exposure was 'correct' whether I selected the central AF point at the wall corner or an AF point located over the black speaker grille. (I made sure I was in ETTLII, not average metering.)

Keeping the camera position constant, using FEL the exposure was 'correct' when the AF was set to center. When the AF point was set on the grille (by selecting a side AF point, not moving the camera) & using FEL the shot was quite overexposed.

I wasn't certain I was correct since I usually shoot manual mode flash, but the tests tend to verify my memory hasn't totally failed. :)

Edit: To be correct, w/o FEL the flash metering isn't locked ONLY to the center point, but rather the ETTLII pattern metering is in play. By 'not average metering' above I mean with respect to flash metering (CF14), not the camera exposure mode which was in Spot metering mode.

You might want to retry the test again but this time, use a long lens, like the 70-200, so that you have enough distance between the target and the flash for ETTL to work. Also, point the flash up towards the ceiling so that the camara is not using the distance info from the lens to determine the correct exposure for the flash. I think you'll find your results will be different. From passed tests and tests I conducted tonight, the FEL seems to only use the center AF point with my 1D2 and I'm sure the 1Ds2 would be the same. Unfortunately, I don't have my 1D3 to test with at this time.

Another thing I just noticed is that when the AF point is other than the center AF point, if you look closely at the AF point, when you hit the FEL button, the center AF point lights up momentarily as the preflash goes off. This is, of course, with the AF set to OneShot mode.

[canonphotog]

The III series menus are a lot easier to access, but I still have trouble remembering where to go to access all the things I want to change in the field. That said; I'm glad I don't have to connect the mk III to the computer to change "personal functions" like I have to with the 1DsmkII and the 1DmkIIN. I keep the .pdf manuals for all my camera bodies on my desktop and laptop so I can pull them up easily and read them when I need to.

[Curtis N]

Well, I'll be darned, you guys are right.
FEL is linked to active AF point with C.Fn. I-7 enabled on my 1D Mk III.

I tested using a white card taped to the center of a black music stand. I centered the white card in the viewfinder and used center vs. perimeter AF points. Flash exposure was quite different with FEL.

This was with a Tamron lens so no distance information.

This is the sort of thing I really wish Canon would mention in an instruction manual.

[canonphotog]

You might want to retry the test again but this time, use a long lens, like the 70-200, so that you have enough distance between the target and the flash for ETTL to work correctly. Also, point the flash up towards the ceiling so that the camara is not using the distance info from the lens to determine the correct exposure for the flash. I think you'll find your results will be different. From passed tests and tests I conducted tonight, the FEL seems to only use the center AF point with my 1D2 and I'm sure the 1Ds2 would be the same. Unfortunately, I don't have my 1D3 to test with at this time.

Leo, I did my test with the flash pointed up at the ceiling. The results are more subtle doing that, but what I based my answer on was the visual indication in the viewfinder. When I press FEL on the mkIII (and spot metering is not linked to the active focus point) the center focus point flashes red. When I link spot metering to the Active focus point on the mk III, only the active focus point flashes red when I press FEL.

Since you've brought this up related to the 1DsII and the 1DII, I'll grab those bodies now and give it a whirl. My 1DII is the n version so there may be a difference there.

I'll add my findings shortly.

[PacAce]

Leo, I did my test with the flash pointed up at the ceiling. The results are more subtle doing that, but what I based my answer on was the visual indication in the viewfinder. When I press FEL on the mkIII (and spot metering is not linked to the active focus point) the center focus point flashes red. When I link spot metering to the Active focus point on the mk III, only the active focus point flashes red when I press FEL.

Since you've brought this up related to the 1DsII and the 1DII, I'll grab those bodies now and give it a whirl. My 1DII is the n version so there may be a difference there.

I'll add my findings shortly.
Hmmm, interesting point about the linking of the AF point to the spot meter. I had not given that any consideration. I'll have to check that out. You may very well be right about that.

[PacAce]

Well, looks like I won't need to test this. It's stated clearly in the manual:


With C.Fn-13-1/3, FE lock is possible with any AF point you select.


So, if spot metering is linked to the AF point via the custom function, FEL will also be linked to the AF point as well.

[Curtis N]

Just so ya'll know,

this is the first time both Leo and I were wrong in the same thread.

Just sayin'.

[canonphotog]

Well if that don't beat all, There is a note on pg 166 of the 1DIIn manual that says spot metering is only linked to the active focus point when spot metering is selected, but my testing bears out your last post. It doesn't seem to matter what metering mode is selected, pressing FEL links to the active focus point in C.fn 13-1 and 13-3. (I did check this on both the 1DsII and the 1DmkIIn)

You can bet I'll be putting this info to good use. Thanks for encouraging us to look deeper into this.

[canonphotog]

Not looking to make anyone wrong Curtis, just making sure I can get the most out of my equipment.

Both you and Leo do a great job answering questions in this sub-forum. So good that there usually isn't anything left for me to comment on. :-)

[GH_ATL_GA]

Just so ya'll know,

this is the first time both Leo and I were wrong in the same thread.

Just sayin'.

A rare occurrence indeed! :)

[PacAce]

Just so ya'll know,

this is the first time both Leo and I were wrong in the same thread.

Just sayin'.

:lol: :D

[bphillips330]

Thanks! I love when I ask such a simple questoin and get A LOT of infomratoin. I am a info freak. Now time to play!