OMD severe flash exposure problem

Started Apr 11, 2013 | Discussions thread
Paulmorgan
Senior MemberPosts: 1,689
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Re: Flash behaviour for all to see.
In reply to New Daddy, 9 months ago

New Daddy wrote:

New Daddy wrote:

Guy Parsons wrote:

Just now playing with E-PL5+FL-300R while having a coffee break.

Here's the thumbnails from FastStone Viewer. Deliberate fast speed to eliminate ambient light adding in, because it's just the flash behaviour I am interested in.

All f/5.5, 1/200, ISO 400, my normal +1.3 flash comp, TTL flash, metering as shown below.

2903 Matrix

2904 Matrix (lowered camera to include paper on table)

2905 Centre weighted

2906 Centre weighted (lowered camera to include paper on table)

2907 Spot (on timber wall)

2908 Spot (on timber wall) (lowered camera to include paper on table)

I know my conclusion, what's yours?

There's no need at all to bother any more with this thread.

Regards.... Guy

This is an outdated thread, but I'm bumping it up rather than starting another.

I use Panasonic m4/3 and its TTL has been a big mystery.

1. I have also felt that Panasonic TTL metering tends to underexpose, which is confirmed by your findings. I guess permanent +1.7 FV compensation for me too. No big deal.

2. In earlier post, you showed that the ambient metering (be it matrix, center-weighted and spot) has no effect on the TTL metering for Olympus m4/3. John King demonstrated that with DSLR 4/3, TTL metering was affected by the ambient metering method. I think both results are not contradictory, because they are different systems, and even within the same system, different bodies behave differently. (Nikon is a notorious example.) From my limited testing, I think Panasonic's TTL metering is also unaffected by the ambient metering method.

3. What's really disconcerting, however, is the way the TTL meter is thrown off by the white object in the frame. It is not inevitable, because the latest Nikon TT-BL doesn't get fooled that much.

4. I was wondering if you took the "active focus point" as a factor in any of your tests. From my limited testing, I think Panasonic's TTL metering biases for the active focus point. (Nikon's TTL-BL utilizes the focus points, and it's one of the reasons that made nice balanced flash possible. I think the underexposure with white object in the scene can be avoided if m4/3's TTL metering concentrates on the active focus point and disregards other objects in the scene.)

Since my new GX7 is on the way, I'll try some test shots when it arrives to see how it behaves in Situations 2, 3 & 4. It's a pity that the manufacturers do not share the TTL metering mechanism with their customers and leave it to the customers to figure out on their own. I read this post on Nikon (http://desmonddowns-ttlblflash.blogspot.com/2009/06/nikons-new-ttlbl-flash-and-cls-wireless.html), and I'll also have to run similar tests to figure out m4/3's TTL.

I think making flash TTL do what we want (or is it us humans understanding TTL better?) is really important, because the ambient:flash balance is not something that we can fix easily in PP. (So, I think we really have to nail a balanced ambient/flash shot in camera, as opposed to trying to rescue in PP.)

Never mind about #4. It looks like the OP already conducted tests and concluded that the active focus point doesn't have weight in TTL metering (http://www.dpreview.com/forums/post/51287894). My experience with Panasonic is a little different, but I'll do more test with GX7.

This hole thread has been a bit of a lame argument, TTL will always differ between different brands and different bodies, nothing is perfect.

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