---

The Pentax AF540FGZ flash is Pentax' top flash unit, has a guide number of 54, takes four AA size batteries and is compatible with all Pentax digital SLR cameras.

The AF540FGZ has PTTL auto, PTTL front sync, PTTL rear sync, TTL auto, auto flash and manual modes, measures 76 x 142 x 107mm and weighs 380g without batteries. At the time of writing the Pentax AF540FGZ flash retails for about £350.

Extreme Macro Use

I have two Pentax AF540FGZ flashes and whilst it is the best flash that Pentax can offer, it is still not a flash that is ideal for extreme macro.

On the plus side though, at least the Pentax AF540FGZ flash has an option to switch off the auto timeout, which means that if you use it with PC-Sync the damn thing won't switch off all the time unlike the Pentax AF360FGZ.

I have two Pentax AF540FGZ flashes and whilst it is the biggest flash that Pentax can offer, it is still not a flash that is ideal for extreme macro, and the Pentax Ringflash is much better. On the plus side though, at least the Pentax AF540FGZ flash has an option to switch off the auto timeout, which means that if you use it with PC-Sync the damn thing won't switch off all the time unlike the crappy 360. On the minus side though, like the Pentax 360, the Pentax AF540FGZ flash has no concept of remembering any settings which means that you have to go through the hoops of a full menu system every time you switch it off for a few moments. This is a ludicrous oversight.

The Pentax AF540FGZ has 7 manual power settings which range from 1/1 to 1/64 which is good, but 1/128 would have been better. The real let down though of the Pentax AF540FGZ is that it cannot do a manual flash pop with rear sync and this forced me to move to a Metz 58 AF-2. This is an annoying and surprising omission for what is supposed to be Pentax' absolutely top of the range flash unit but not entirely unexpected considering how out of date the entire Pentax flash system is.

In Operation

The Pentax AF540FGZ seems to me to use better parts than the Pentax AF360FGZ and the control wheel moves considerably easier than its junior sibling

The Pentax AF540FGZ seems to me to use better parts than the Pentax AF360FGZ and the control wheel moves considerably easier than its junior sibling. Like the Pentax AF360FGZ the user interface is straightforward to grasp, clear, and has a nice illumination button that makes it easy to see when it's slightly dark or in shadow, which happens more often than you might think. If you use manual a lot you'll find yourself getting annoyed by how slow it is to change manual settings (press, rotate, press) but overall the Pentax menu system is easier to grasp than the Metz system although both are equally easy to use once you understand them.

The Pentax 540 has a swivel and tilt head and this makes it pretty straightforward to use on a flash bracket with a PTTL cord for macro. The 540 has lots of juice, seems to give a good long battery life and the output does not vary too much. Recycling time is nice and fast and the manual flashpops for extreme macro use are also fast, but not as fast as Pentax claim they are. On the flipside, the display has poor viewing angles which can be tedious. Operating the Pentax 540 flash remotely triggered by my Metz 58 AF-2 is a breeze, and in remote operation the unit works flawlessly and has never missed a shot. Thankfully it is possible to disable the timeout, so even when I'm adjusting the thing stays at the same settings. Eureka.

Recycling

given its similar price point, I have no hesitation in recommending the Metz 58 AF-2 over the Pentax AF540FGZ

The Pentax AF 540 FGZ flash recycles quickly and the ready light is fast, a boon to extreme macro photography. But, a word of caution, waiting a few seconds after this ready light comes on improves its consistency significantly, especially with exposure consistency which can be a little off if you shoot an image to quickly after the ready light comes on. I have had most consistent and reliable results waiting 20s between flash pops.

Construction

The most common problem with the Pentax 540 flash is that the flash door or foot snaps off. The flash door is quite flimsy and the notch holding it closed can snap off, and the foot seems a little weak for the weight that it has to carry when the flashgun has its batteries inside. Zoom adjustment is also very noisy which won't be ideal if you're using it for nature photography, and the diffuser flip-out apparatus easily dislodges from its hinges within the flash unit. Whilst better than the Pentax 360, this is still not a sturdy flash by any stretch of the imagination. By comparison, the Metz 58 AF-2 looks a little rougher, but seems somewhat sturdier too.

540 Has A Secret!

The Pentax 540 flash has a nice little secret that not too many people know about - a manual dial that can adjust PTTL flash output. This strength adjustment is under the "FIX" sticker hidden near the hotshoe which comes off very easily. A small jeweller's screwdriver is the best size for adjusting this dial - clockwise reduces light output, and counterclockwise will increases it. There are no hard stops on this dial so if you turn it too far you'll drop back to underexposure, and beware, a tiny adjustment goes a long way. The 360s have this as well but it is buried under the hotshoe so disassembly is required (none required with 540). On the 540 this hidden dial will get you an extra 1-2 stops; this only affects PTTL mode so if yours is constantly underexposing maybe you need to have a bit of a fiddle with this.

Conclusion

The Pentax 540 flash used to be your only option for a Pentax flash with tilt and swivel but the updated 360 now has this too. It is the best, top of the range flash unit, that Pentax does. Fact is though, the Pentax flash range is out of date and whilst perfectly ok for what it does do, is more noticeable for the features that it does not do, especially for extreme macro photography when compared to other serious photography brands. Given its similar price point, I have no hesitation in recommending the Metz 58 AF-2 over the Pentax AF540FGZ for extreme macro.

.

---