Flash Metering patterns


Until the release of the Dynax/Maxxum 9 all Minolta AF cameras had a center-weighted TTL-OTF flash meter. There was a single metering cell, and it metered the entire frame while giving higher emphasis to the center than the periphery. The problem of such a metering pattern is that small foreground objects are often “overlooked”, and flash exposure is dominated by the larger background. This way these foreground objects often end up overexposed.

4 Segments, Spot

With the Dynax/Maxxum 9 Minolta introduced a TTL-OTF flash meter with 4 segments[1]. The camera can now meter smaller sections of the frame separately. It can then put varying emphasis on the four segments depending on AF and other factors. The Dynax/Maxxum 9 can also be forced to use only a single segment of the four.

Using a multi-segment flash meter is a big step forward. With these cameras the overexposed foreground objects are much less of a problem.

14/40 Segments

When the camera uses pre-flash metering, it uses its ambient light meter. In all later Minolta and Konica Minolta AF cameras this meter is divided into 14 segments. Sony DSLRs are equipped with a 40 segment metering system.

[1]: Multi-segment TTL-OTF flash metering was actually already implemented in the Minolta Vectis S-1, but within the Dynax/Maxxum line the 9 was the first.

The current Minolta AF/Sony Alpha flash system has grown quite complex, and it is not very well covered in the manuals. That's because this would involve to cover some very basic concepts, and there are many combinations of cameras and flash units with different capabilities that would have to be documented. What I try here is to explain how the Minolta flash system works in detail. This compendium assumes that you have some basic knowledge of photography, ie. you know that an aperture is and you know how a shutter works. Sony has taken over further development of the Minolta A mount (now Sony Alpha mount) and has also kept the Minolta AF flash system with their new DSLRs. When this compedium says "Minolta", the same is true for "Sony Alpha", too, except when noted otherwise.