Photoclubalpha

Hi all,

Sorry for having been absent quite a long time from the forum... been quite busy professionally! So hardly any time left to shoot, apart from the usual christmas stuff.
Hoping for better times and better weather...

I recently purchased two HVL-F58AM flash guns (for my father and my brother, who both went ALPHA). I tried them out in my improvised studio and noticed a few things:
- The flash guns are extremely sensitive to the WL-signals from the onboard-flash... Much more so than the Minolta 5600 HS, which I used so far... So no failures because of flashes that don't fire.
- The flashes have "passed out" a few times, giving me a "Overheated" warning.
Anybody experienced that too? Since I had to flashes and both did it at least 3 times, I suppose it has to do with my handling... I was shooting full power most of the time, and maybe I worked too fast.... The extremely short recycling time makes it possible, unlike working with the 5600HS, but is it possible that the flashes are not built for that kind of work?

Thanks for your opinions,

cheers Jonathan

Read the instruction manual and there is a part about overheating - they do have a thermal cutout. Not many battery power flash units do. There is very little indication of why it happens, just a panel on Page 17 of the manual. It does mention room temperature, and suggests a 10 minute wait for the unit to cool down. Maybe try a cooler room setting?

David

Does that mean you can have problems with it when using as fill flash under the sun?

Yes, if you let it heat to 50 C it will cut out. 50 C is quite possible if you leave a product in full sunshine in summer. That could render it useless.

Now, let's have a version for tropical use with a silver padded jacket all round it.

David

It is quite normal for a smallish on-camera flash unit (as opposed to a studio flash head) to overheat when firing four or five flashes per minute at full power for several consecutive minutes.

-- Olaf

the studio lights i've seen were fan cooled as well as the control unit. I would think it would take a considerable amout of external heat input to make them shut down.

Thanks all for your opinions.

It seems like a good idea to make the flash shut down before it blows into your face... I have never noticed any problems with th 5600HS, but maybe I actually oversaw the problem and put the machine at risk...
I actually shot 350 pictures in less than 2 hours, most of them full power.

Well, I will keep the 5600 in case on of the others shut down.... I can always replace it and use it for a few minutes, so the others can cool down...

Cheers
Jonathan

Sounds to me like the F58 is a bit "overclocked." I've never had this problem with my F56 (though certainly the recycling time of the F56 must be nice). This is marginally unrelated, but why can't Sony introduce a flash that uses the same infolithium battery that the camera uses? In addition to simplifying one's camera bag (and bolstering unit sales), would there likely be any recycling time advantages?

KevinBarrett wrote:Sounds to me like the F58 is a bit "overclocked." I've never had this problem with my F56 (though certainly the recycling time of the F56 must be nice). This is marginally unrelated, but why can't Sony introduce a flash that uses the same infolithium battery that the camera uses? In addition to simplifying one's camera bag (and bolstering unit sales), would there likely be any recycling time advantages?

Probably not. The NP FM500H (for one obvious example) is a lithium ion battery. Lithium Ion batteries all have relatively high internal resistance, which limits the maximum current they can deliver (which is most of what matters for flash recycle time).

To give some concrete numbers, even in perfect condition, Lithium Ion batteries have an effective resistance of about 320 milliohms per cell vs., (for one example) about 100 milliohms (or less) per cell for nickel-cadmium's. The NiCd's have much lower total capacity, so they'll discharge relatively quickly, but while they last, they'll recharge the flash about three times as fast as Lithium Ion batteries would.

Nickel Metal Hydride batteries are somewhere between the two in both respects: slower cycling and longer battery life than NiCd, but faster cycling and shorter life compared to Lithium Ion.

For flashes, Lithium Polymer would probably be the best choice. These can combine high total capacity with high maximum current -- though the maximum current rating varies widely among different lithium polymer batteries (often as much as 10:1 difference in maximum current for batteries with the same total capacity). Unfortunately, that would lose the simplicity advantage, unless they also used Lithium Polymer to power the camera. Offhand, I don't see a lot of reason they couldn't do that, but I don't see much obvious advantage from it either.

When I was selling cell-phones for AT&T, I seem to recall Sony Ericsson's being among the first phones we sold that used lithium polymer batteries...what if Sony started exploiting that technology? We'd have cameras (and possibly flashes) with a greater range of operating temperatures, for sure...but then we'd have another battery change, ugh.