Horrible flash exposure...

[Gary]

Friends -

I'm wondering why my flash exposures with the D30 and 420EX and 550EX flash units are so consistently erratic.

I've used conventional Canon SLR's with appropriate dedicated Canon strobes for years with reasonably good results. Using the same techniques with the D30 and Canon EX strobes produces extremely inconsistent exposure.

With the D30, I find myself shooting a picture, looking at the preview image, and often making a major flash compensation adjustment based on the lousy initial exposure. I'm as often overexposing as underexposing, it seems.

I get these results with two different D30 bodies, two 420EX's and a 550EX.

I'm interested in other people's experiences with this equipment.

Regards,

Gary Mortensen,
Minnesota

[jpbeale]

I'm not a pro by any means. I have a D30 and a 380EX flash. I've had very erratic results in the "P" exposure mode with both internal and external flash, but very consistent results in the "green square- dummy" exposure program. I don't know why. My flash exposures on my old Elan II were always fine in "P" mode.

I was part of a photo shoot with a pro using a D30 and studio strobes, and I noticed he would often take a test frame and then adjust the strobe power whenever he changed any angle.

[Roger_Cavanagh]

Gary,

I have a comment on my experience with the 420 and a follow-up question for you.

I confess I haven't really mastered exactly what is going on with the ETTL flash, but by trial and error I have found a method that seems to work reasonably consistently for me. Like jpbeale, I was getting satisfactory results on auto, but that's no good for CRW format. So what I do now is use manual, pick an exposure time (between 1/60 to 1/200), pick a f-stop, then check the histogram. I guess the camera works out how much light to pump out for me. Not exactly scientific, but I'll work out the proper way eventually. In the mean time, I'm not missing too many pictures. :)

Now, my question for you, since you have both the 420 and 550. I have been wondering about upgrading to the 550, would you recommend this and why?

Regards,

Roger
www.rogercavanagh.com

[JCDoss]

Roger_Cavanagh wrote:
Now, my question for you, since you have both the 420 and 550. I have been wondering about upgrading to the 550, would you recommend this and why?

I think you should upgrade for one reason: Control of off-camera flash. Keep your 420EX and use the 550EX as your primary flash and as a slave controller.

As for the flash exposure question, check out this link. It may not solve your problem, but it might help a little.

http://www.dlcphotography.net/CanonLetter.htm

JCDoss

[Roger_Cavanagh]

JCDoss wrote:
[I think you should upgrade for one reason: Control of off-camera flash. Keep your 420EX and use the 550EX as your primary flash and as a slave controller.



Good point, JC. I hadn't thought of that. More expense, oh well, you can't take it with you. :)

Cheers,

Roger

[Gary]

Friends -

The kind of photography I'm using the D30 550/420EX for is event coverage. I've done this for years with
conventional Canon SLR's and gotten usable exposures with a minimum of fuss. The event I shot with the D30 on Sunday found me making an exposure, checking the histogram, and usually making a significant flash exposure compensation adjustment before making an additional expousre. This is a lot clumsier (and slower) a procedure than I'm used to.

The FEL (flash exposure lock) system seems to help exposure accuracy considerably but I haven't used it in the past because I am really used to CF 2/1, where the AE lock button (which is used to activate the FEL) invokes AF, instead of the shutter button. As far as I can tell, setting this CF precludes using the FEL, can someone confirm this?

[JCDoss]

Gary wrote:
...As far as I can tell, setting this CF [CF2 = 1, 2, or 3] precludes using the FEL, can someone confirm this?

Sad but true. Unfortunately, the D30 must be set to CF2 = 0 in order to use FEL. One thing the D30 is sorely missing is a dedicated FEL button.

JCDoss

[chow]

I've the same experience of horrible flash exposure with the 550 EX on the D30 before. After I read throught Canon's letter to D30 user on using flash on D30, I now have 95% chance of getting correct exposure. The key is FEL. I always have the misunderstanding before that under evaluative metering, the FEL will be linked to the active focus point. But it's proved to be wrong and I realized that when using FEL in evaluative metering mode, no matter what the active focus point is, you've to use the central point to take the FEL or otherwise you will probably get under/overexposed flash. Try it and hope this help.

[JCDoss]

chow,

Actually, FEL meters the entire metering circle... more than just the center AF point.

Further, I don't think metering mode (ie, evaluative, partial, center-weighted) makes any difference for flash metering. It has to do with the focus mode, the active focus point, and whether or not you're using FEL. Ambient metering and flash metering are two different things, as I understand them (which makes it all the more unnecessarily complex).

For instance, if the lens is set to manual focus (MF), the flash will meter the entire scene and average all 35 segments. If the lens is set to auto-focus (AF), the flash will meter with emphasis on the active focus point... if you always have AF set to the center AF point (which I do, and I think most users I talk to do), then you will always meter with respect to the center AF point. The flash metering is supposed to be *like* center-weighted in this case, however many users claim that too much emphasis is placed on the AF point making it more like spot metering. I don't have a 550EX, so I can't verify that with my experience. Finally, FEL behaves very much the same as partial metering, as it meters ONLY the segments that lie within the center metering circle.

JCDoss

[chow]

Hi, Jcdoss,

>Actually, FEL meters the entire metering circle... more than just the center AF point.


What I mean is that when you set your active focus point, say at the right point, rather than the center AF point, when one lock the flash exposure by FEL, one has to use the central partial metering circle to lock the flash exposure rather than using the right focus point. After FEL using the central circle, one can then reframe his photo based on the focus of his selected focus point.


>For instance, if the lens is set to manual focus (MF), the flash will meter the entire scene and average all 35 segments. If the lens is set to auto-focus (AF), the flash will meter with emphasis on the active focus point... if you always have AF set to the center AF point (which I do, and I think most users I talk to do), then you will always meter with respect to the center AF point. The flash metering is supposed to be *like* center-weighted in this case, however many users claim that too much emphasis is placed on the AF point making it more like spot metering. I don't have a 550EX, so I can't verify that with my experience. Finally, FEL behaves very much the same as partial metering, as it meters ONLY the segments that lie within the center metering circle.

I still think that when using FEL correctly, you have much higher chance of achieving the correct flash exposure. This is due to the mechanism that E-TTL will only measure the exposure at the time you press the shutter release. If you don't use FEL, whenever you use the central focus point to focus and then reframe your photo, D30 will take the metering at the central subject during you press the shutter release, which is not necessary the subject you focus and this resulting in incorrect exposure. If FEL is being used, D30 will take the metering at the time you press FEL and thus you can freely reframe you photo while still maintain the correct exposure.


Just want to share my understanding!! :)

Regards, Chow

[JCDoss]

chow wrote:
I still think that when using FEL correctly, you have much higher chance of achieving the correct flash exposure...

chow,

Sorry if I seemed argumentative, but I was really agreeing with you! I think the lack of a dedicated FEL button on the D30 is a flaw (or perhaps reserved for a more "professional" model like the 1D). It would be nice if CF2 could be fixed to allow FEL in modes other than just CF2=0... but alas, if wishes were horses...

I completely agree with your observations... if you can manage CF2=0, you'd be best off to use FEL whenever possible.

JCDoss

[chow]

Hi, JCDoss,


Nice to know that we actually have the same understanding on the use of flash on D30 ! :)

Sorry if I also seemed argumentative (I tried not to)! :) Do share with me your valuable experience in D30 !! :) :)

[sasc]

I sent mine in for calibration and it came back underexposing twice as much as before it went in. With flash or without. Practically every photo has to have the EV adjusted separately. As far as I am concerned despite the noisefree pictures it turns out, it isnt worth all the hype about it. Besides that every lens needs a different EV adjustment. I never owned a film slr that had these problems.

[jonsimpson]

I've been having very good results.....with a 380 EX......putting the camera in AV mode....F stop about 5.6 or so.
The posted pics are at the above settings.....the first on the left boucing the clash off a cement column, the other two bouncing the flash off a white wall. All three autofocus. (I hate the look of straigh on flash)

http://jonsimpson.com/post/banner2002.jpg