Metz 58 AF-2
Metz makes mainly two series of flash units: one with interchangeable adapters that fit a range of cameras capable of TTL flash, and a second series with built-in dedicated TTL circuits for one specific camera type. Models in the second series are known as system flash units, and the Metz 58 AF-2 is currently the top model in this series.
The Metz 58 AF-s is available in dedicated TTL versions for Canon, Nikon, Pentax, Sony and Micro 4/3 cameras (including both Olympus and Panasonic, although only "for Oly" is written at the rear of the hot shoe in this model). This page is based on the Micro 4/3 version. I have no experience with Metz 58 AF-2 for other camera types, or with other Metz models.
The above Metz 58 AF-2 is currently the most powerful system model from Metz and has a specified GN of 58/m at ISO 100 and a 105 mm lens, which is not terribly exciting but is still respectable, and useful for general photography (although of course not large studio sets, large groups of people or public events).
The Metz 58 AF-2 replaced the earlier 58 AF-1 model. The only difference seems to be the metal flash foot in the AF-2 (plastic in the AF-1). This flash unit is relatively large (bigger than the Nikon SB 800, and comparable to the Nikon SB 900/910). It looks especially large on a Micro 4/3 camera. One of its characteristics is that it has a small, fixed flash window on the main body, in addition to the large, swiveling and tilting head. The small flash tube inside the fixed window is useful to produce highlights in a (human) subject's eyes and to lighten the shadows in the eye sockets and other recessed areas that may result from indirect illumination by light reflected by the ceiling when the flash head is tilted all the way up. The power of the smaller flash tube can be reduced in steps or switched off in the options. Both flash tubes are quite far from the lens axis even when the flash is directly mounted on the camera, and unlikely to produce "red eyes". The front of the main body has also a rather strong red LED illuminator to aid the camera's autofocus in low light and a light sensor used when working in the traditional, non-TTL automatic mode.
All my portable flash units have an adhesive Velcro strip fastened around the head, useful to attach small light modifiers. The Metz 58 AF-2 does not come equipped with a Velcro strip, but one is easily added.
Manual power regulation
Manual power regulation is available in steps from 1/1 (full power) to 1/256. This is equivalent to a range of 8 stops, which is a broad range and useful in macrophotography and photomacrography, where the flash is close to the subject and the required power is modest.
Doors, controls and connectors
The battery compartment door on the right side of the main body slides open to admit four AA batteries. The door remains attached to the main body when open, so there is no danger of dropping or losing it while changing batteries. Sanyo Eneloop rechargeable batteries work fine in this unit. I currently use only Sanyo Eneloop AA and AAA batteries in my equipment because ordinary rechargeable batteries (especially cheap ones) lose much of their charge in a few days to a couple of weeks, and I got tired of taking out my equipment for a quick session, only to discover that batteries are dead. Sanyo Eneloops keep much of their charge for at least one year.
The Metz 58 AF-2 can also use a Metz external power supply, too expensive for me to consider its purchase, that plugs into a socket on the left side of the main body. A nearby standard USB socket is used to update the flash firmware. A small, flush red window on the left side covers the TTL receiver sensor. This model does not have flash trigger connectors, other than the hot shoe.
The rear of the main body carries an LCD control panel, a sliding power switch and four pushbuttons, used to access all options. After some getting used to, the menus become quite easy to navigate, with each button largely retaining the same, or similar, functions among different menus. Quite a number of options and operating modes are available. A not-so-intuitive feature is that it takes one button press (of any button) to turn on the illumination of the LCD panel and tell the flash that you want to do something with its settings, and a second press to do whatever the button is supposed to do. Another not-so-intuitive feature is that forgetting to press the "Enter" button after changing a setting usually leaves the unit unable to flash until you remember to press the expected button. Two of the buttons are black and two translucent-white. The function of each button in each menu and sub-menu is indicated on a line along the bottom of the LCD display.
The small flash tube on the front of the main body can be set to full power, 1/2 or 1/4 power, or off. This is useful to control the amount of highlight and shadow-filling. This secondary flash does not have a zoom mechanism.
When the flash is in wireless TTL slave mode, one of its front red LEDs flashes about once a second to show that the unit is ready to operate. A beep function is also available to tell whether the last flash was sufficiently powerful to expose properly.
In addition to the LCD panel, the rightmost button lights up green when the flash is ready to fire. The next button ait its left lights up red/orange while the flash is recycling.
Head tilt and swing
The flash head can be tilted or swung while pressing the round gray button on the right side of the head. The button is only used to unlock the head from its normal, forward-facing position. At other inclinations, the head is kept in place by click-stops. This is the standard design for flash units of this power class. The right gray button has a scarcely visible "PRESS" label. An identical gray button, without a label, is located on the left side, but it cannot be pressed and has no function.
There are no click-stops between the positions for horizontal and 45 degrees upward inclination. The next stops are at 60, 75 and 90 degrees. The head can tilt downwards from the horizontal orientation, but only by a minimal angle. No click-stop is available at this very slight downward inclination.
Built-in light modifiers
A diffuser and a white reflecting card can be manually slid out from a slot above the main flash window, as customary for this type of flash unit. Neither a separate diffusing "box" that mounts onto the front of the flash head nor gelatin filters are supplied with this model. The diffuser covers only a part of the flash window and looks a bit inadequate and out-of place there. However, it does completely cover the light-emitting portion of the front window once the flash zooms to wideangle (which it does automatically when the diffuser is swung out).
A usable plastic stand and a lightly padded pouch accompany the unit. The pouch has no internal compartments and is just big enough to house the flash alone (the stand does not fit in the pouch). While the pouch is good enough for storage and to prevent it scraping against other equipment inside a camera bag during a walk, it is neither durable enough nor padded enough for carrying on a belt or hanging outside a camera pack.
Build and design quality
The build quality of this model does feels lower than Nikon, Canon and Olympus units (but its price is also significantly lower). This is noticeable, for instance, when tilting and turning the head, or operating the (soft plastic, not rubber, and rather mushy) rear buttons. For instance, the head turns by a full 180 degrees only toward the left (not the right), so you may have to try twice if you want to point the head backwards for reflected illumination from a wall at your back. A few forum posts and web sites also warn against placing external reflectors or diffusers close to the flash window, lest they cause the latter to overheat.
The click-stops of the head inclination feel a bit too weak to be completely reassuring. These click-stops may be insufficient to keep the head in the desired inclination with an external light modifier mounted on the head.
The quality of the electronics seems reliable, and most of the time this flash unit does what it is expected to do.
When the unit is in slave mode, the leftmost button, which normally is used to change mode, has no function and it is not immediately evident how to switch from slave mode to another (e.g., TTL) mode (hint: try the second button from the left, and don't forget that the first press of a button to start a configuration change is always "dead", even when the flash is not sleeping). Other items in the configuration menus are also somewhat obscure. A minimalistic help functionality in firmware would be a welcome alternative to carrying along a printout of the user manual or an online version on a smartphone.
This model in not weather sealed, and should be kept away from rain and high humidity. In addition, the inside of the head is not fully lined by a reflector when the flash is zoomed to high focal lengths, which causes a substantial fraction of the emitted light to be absorbed by black plastic surfaces. This, in turn, rapidly increases the temperature of the head casing. The manual cautions against quick sequences of flashes at full power, but in my unit the head starts to produce a faint smell of heated thermoplastics after only two-three quick flashes at full manual power with the head fully zoomed in. Hopefully this is a normal behavior, or a temporary characteristic of factory-new units.
A small motor does the zooming, which only moves internal parts and is automatically activated by the camera body when using CPU lenses. Manual zooming with non-CPU lenses and manual overriding of the zoom settings with CPU lenses are possible with the configuration buttons.
As a whole, this flash unit seems to be somewhat larger and heavier than necessary, given its not very high power (especially compared with the small Micro 4/3 cameras it is designed to work with). Hopefully, this means that the designers have incorporated reasonable safety margins into the power electronics. My limited use so far seems to indicate a good battery life.
A couple of unusual features are included:
Lens focal lengths for the zoom settings are not displayed as the actual focal length on the flash panel. Instead, they are specified as equivalent to 135 film or full-frame sensors (i.e., twice the actual value of the focal length of Micro 4/3 lenses), and range from 24 mm to 105 mm (plus an additional setting of 12 mm with the diffuser panel placed against the flash window). The same is true for the manually overridden zoom settings. This implies that the user is forced to make mental calculations and adjustments: a 25mm Micro 4/3 lens, for instance, is equivalent to a 50 mm on a full-frame body (=135 film). If you don't take this into consideration when manually setting lens focal length on the flash, and instead set the actual focal length, you will be wasting three-quarters of the flash power on an unnecessarily large subject area. Since this flash model is sold in a specific version for Micro 4/3, and all Micro 4/3 lenses display their actual focal length (not the 135 film equivalent), this design choice by Metz does not make much sense, and seems to indicate a lack of attention to detail. The logical solution for the Micro 4/3 flash version would be to display the right focal length for Micro 4/3 cameras. This could simply be done with a firmware upgrade, since the firmware is Micro 4/3-specific in any case.
In spite of being available in separate versions for different camera types, the user manual does not explain in detail the range of available TTL functions. Instead, it gives a teutonically brief dismissal: "It is impossible to describe all camera types and their individual dedicated flash functions within the scope of these instructions." and refers readers to each camera’s operating instructions. Apparently it is not Metz's problem if some of this information is not available in camera manuals, and is instead provided in the dedicated Olympus or Panasonic flash manuals - which you are not likely to have because you decided to buy a Metz flash. Hopefully, Metz is supporting the full range of Micro 4/3 flash functions even if it will not tell us what these functions are.
Another missing information item in the manual is a clear indication of the guide number (GN) at different zoom settings. This cannot be reliably computed from the only GN provided (at 105 mm equivalent, i.e. actual 52 mm lens focal length for Micro 4/3), because the efficiency of the reflector and zoom lens are likely to vary throughout the zoom range and among different flash head designs. The Pentaxforums site does report the following data, which do not completely agree with the Metz specifications and may instead come from actual measurements:
Occasional German and French words somehow found their way into the English portion of the Metz manual, and if you are not a polyglot this may leave you puzzling about what is really meant at certain points.
The Metz user manuals for all models can be downloaded here.
The Metz 58 AF-2 in Micro 4/3 version is a relatively cheap, dependable unit that does what it is supposed to do (once you learn how to coax it), and worth its price in spite of a few quirks. On the other hand, if you want the best quality in all senses and are willing to pay substantially more, you might decide that the top-of-the-line Olympus or Panasonic units suit you better.