The Metz 54 MZ-4i, Metz 58 AF-1/AF-2, and Promaster 5750DX and 7500EDF additionally have a secondary forward-facing reflector to which some of the flash power can be directed. This can provide more forward-directed light than a bounce card in order to fill in shadows. There is a separate flash bulb, but power comes from the same source, so main flash power is reduced by about 15%.
The secondary flash on the Metz 58 AF-1/AF-2 has a guide number of 15 and covers a 35mm field of view (35mm equivalent focal length). It can be used at half or quarter power via a menu option and works with P-TTL bounce flash.
The 54 MZ-4i's flash has a guide number of 10, and can be cut in half by physically changing a filter. Unfortunately, the secondary reflector on the 54 MZ-4i does not work in P-TTL mode — non-P-TTL auto must be used instead. The 58 AF-1/AF-2 does not have this limitation.
The Promaster 7500EDF's secondary reflector is somewhat less powerful, with a guide number of about 6.4 at a much tighter angle of view of 50mm.
