Over-exposure:using G1/420EX...

[mutungi]

with upgraded firmware.......flash shots were well exposed prior to upgrading firmware to .02, but since upgrade the shots are all over-exposed! Any cure for this problem?

[mpkirby]

There is another thread on this:

http://photography-on-the.net/forum/showthread.php?t=490

1) How close are you to the subject? The closer you are, the worse the camera does trying to get the exposure right. (you need to use flash compensation).

2) If the subject is back-lit, then you need to do an exposure lock on the background, and then point at the person and take the picture. Otherwise it opens the aperture and you end up with a slightly over-exposed person (depending on the distance), and a way over-exposed background.

If you exposure lock on the background, you have a perfectly exposed background (because the flash isn't powerful enough to change the exposure of that), and a perfectly exposed foreground (because the flash fires, and fills the person.

Are you seeing a problem where the flash fires at full strength, rather then being toned down? If so, try switching to auto, rather than P mode, and see if it does anything different.

Oh yeah. What version of firmware did you come from? 1.0.0.0, or 1.0.0.1?

Mike

[AVL_]

Same problem here, especially when close to the subject. I find myself _always_ using flash compensation when shooting with a fill-in flash.

I don't know if this has anything to do with my upgraded firmware, because I bought my 420EX just after I upgraded my firmware (same day, actually :)).

[mpkirby]

I doubt it is the firmware, because I have the same problem, and I am still at 1.0.0.1 (unless 1.0.0.1 is the version causing the problems).

My personal theory is that the camera isn't doing a very good job of taking into consideration the affect of the flash on the exposure (particularly at close ranges).

Its supposed to pre-flash, and expose properly, but I'm not exactly sure how the whole system works. Does it use the G1 metering system to do this? Or is there some other magic at work (like does the flash do something itself??

If the G1 metering system is at work, spot metering should theoretically affect the power output of the flash (particularly in fill situations).

It seems to me to make it worse, not better, which leads me to believe that the flash and the G1 are not communicating very well.

Perhaps the G1 doesn't change any of its settings, assuming that when it communicates what it does to the flash, the flash will reduce power appropriately. So the G1 is forced to open the aperture wide, and then the flash gets the message to do "low" power. But the flash can only go so low. So you get over-exposure.

I really need to sit down, and reverse engineer the behavior.

Mike

[gbjune]

mpkirby wrote:
My personal theory is that the camera isn't doing a very good job of taking into consideration the affect of the flash on the exposure (particularly at close ranges).


Yeah. I'd believe that.

I took two pictures today to experiment with Fill-in flash. This was with the built in flash, so not even with 380/420/550EX...

Both pictures are so badly overexposed that even playing with levels in Photoshop makes it possible to guess what I was taking a picture of... I'd guess 95% of the pixels are white or close enough to white to not have any detail in them...

Shooting Mode
Aperture-Priority AE
Tv( Shutter Speed )
1/250
Av( Aperture Value )
2.0
Metering Mode
Center
Flash
On
Flash Type
Built-In Flash

Of course, I'm probably not helping much by using f/2.0 either, but I believe the settings should give something visible on the picture, not just white...

Like a polar bear in a snowstorm...

-Geir