Speedlites

[nicolabryans]

Hi,

I am a Nikon D90 user and use a SB90, I did a Christening using this but it constantly kept over heating and cutting out has anyone else experienced this with them? I am doing a few weddings this year and going to buy another as a back up but wouldn't buy another the same so wondering if anyone could recommend another which is good for weddings but won't cut out as often?

Thanks
Nicola

 

[NorthernNikon]

This is a common "issue" with the SB-900. I say "issue" because it's not actually an issue at all. The SB-900 has a thermal cut-out which prevents the Speedlight overheating and damaging or destroying itself. No other Speedlight has one, which means that the only way you know you're cooking them is when something goes wrong.

You can switch the thermal cut-off off, but I wouldn't advise it. I experienced this when I first started using my SB-900s but now I rarely trip it, if ever.

The biggest source of heat in the SB-900 is the batteries and you've a few options open to you to avoid tripping the cut-out.

• Stop using the flash in TTL mode. Even if you only need a tiny blip of light, when you shoot in TTL mode, the flash has to charge it's capacitors up to the max just in case you need it. Doing this really taxes the battteries and thus they heat up quickly. This isn;t always a problem, but I've found that it does trip the cut-out very quickly if one of the below factors also comes in to play.
• If you're using rechargeable batteries, use lower rated ones. The higher the rating (eg 2300mAh) the more power and thus more heat. The trade off though is that recycle times are slower with lower rated batteries.
• Use low self-discharge rechargeable batteries such as Sanyo Eneloops. They don't warm up so much (and tend to have a lower capacity anyway) The advantage of these batteries is that they retain charge far longer when not in use, so they're great for spare sets to keep in your kitbag.
• If you have to shoot in iTTL mode and need really fast recharge rates, buy a separate battery pack. This takes the heat source away from the Speedlights and thus takes away the main reason for the cut-out being tripped.
• Make sure that your batteries are in good condition. I've not investigated this fully but I experienced the most trips when using a particular set of 2700mAH rated batteries. One of the four takes far longer to charge than the others leading me to suspect that its no longer fit to use and that the other three were being worked harder to pick up theslack, thus heating them up more quickly. I don't have another set of 2700mAh batteries to test out that particular theory though.
• Keep an eye on the ambient temperature. If you're in a hot room or your Speedlight is in direct sunlight or was near a radiator or other heat source before you started using it, it's going to get to the cut-out temperature more quickly. Don't be tempted to go the other way though and keep your batteries in a coolbag or the fridge until you need them, batteries don't perform well at all when cold.
• Buy an SB-910 which, IIRC, has been designed to deal with heat disperpation better thus the trip doesn't trip so often.

Now, I use 2000mAh standard rechargable batteries as my first set, with Eneloops as spares in the kitbag when I need them and I can't remember the last time I tripped the thermal cut-out.

 

[HoppyUK]

Simple answer is to reduce the power output of the gun, by raising the ISO or using a lower f/number. Switching out of TTL mode won't make any difference.

All flash guns get hot, though it's usually only a problem when you run them hard and fast and long at high power (using high speed sync/FP sync makes them particularly prone to overheating).

Some have a thermal cutout, but most don't and they can get fried. A problem with Nikon seems to be that some SB900 guns have the cutout set quite low (reported by users shooting with several guns together, one often cuts out before the others) so maybe you've got one of those.

 

[NorthernNikon]

Simple answer is to reduce the power output of the gun, by raising the ISO or using a lower f/number.

That's not the simple answer at all, because you're changing the shot, either by altering the f/stop which increases depth of field or you're reducing the shutter speed by increasing the ISO which in turn alters the effect of ambient light. It's one answer, but it's not a simple one.

Switching out of TTL mode won't make any difference.

It does make a difference. If you shoot in TTL mode the Speedlight will always charge the capacitor to max just in case it needs to fire at maximum output. If you only need 1/32 power, 31/32 of that charge is not needed.

Turning the Speedlight from TTL to 1/32 M tells the Speedlight that the maximum power it needs to emit is 1/32, therefore it only charges sufficiently to deliver that amount. Less workload on the batteries means less heat.

All flash guns get hot, though it's usually only a problem when you run them hard and fast and long at high power (using high speed sync/FP sync makes them particularly prone to overheating).

True, but the Sb-900 is capable of delivering a lot more power than most flashguns which taxes the batteries harder.

Some have a thermal cutout, but most don't and they can get fried. A problem with Nikon seems to be that some SB900 guns have the cutout set quite low (reported by users shooting with several guns together, one often cuts out before the others) so maybe you've got one of those.

I think that it is far more likely to be another reason causing one Speedlight to cut out before another than anomalies in the cut-out threshold.

One Speedlight could be working harder than the other for example while different capacities of batteries, batteries at different stages of their charge, older batteries, faulty batteries, etc will all behave differently and cause one Speedlight to cut out before an other even if they were firing to identical settings.

 

[HoppyUK]

That's not the simple answer at all, because you're changing the shot, either by altering the f/stop which increases depth of field or you're reducing the shutter speed by increasing the ISO which in turn alters the effect of ambient light. It's one answer, but it's not a simple one.


It does make a difference. If you shoot in TTL mode the Speedlight will always charge the capacitor to max just in case it needs to fire at maximum output. If you only need 1/32 power, 31/32 of that charge is not needed.

Turning the Speedlight from TTL to 1/32 M tells the Speedlight that the maximum power it needs to emit is 1/32, therefore it only charges sufficiently to deliver that amount. Less workload on the batteries means less heat.

Hot-shoe guns always fire at full power. If less power is needed, either by switching to manual or because the TTL system reduces it, the flash is cut short and the unused power recycled. The operating mode makes no difference.

True, but the Sb-900 is capable of delivering a lot more power than most flashguns which taxes the batteries harder.



I think that it is far more likely to be another reason causing one Speedlight to cut out before another than anomalies in the cut-out threshold.

One Speedlight could be working harder than the other for example while different capacities of batteries, batteries at different stages of their charge, older batteries, faulty batteries, etc will all behave differently and cause one Speedlight to cut out before an other even if they were firing to identical settings.

Well possibly, but that's a bit too obvious I think. It gets reported quite often that one particular gun consistently cuts out before the others, eg on POTN. Who knows :shrug:

 

[NorthernNikon]

Hot-shoe guns always fire at full power. If less power is needed, either by switching to manual or because the TTL system reduces it, the flash is cut short and the unused power recycled. The operating mode makes no difference.

Then I stand corrected re the capacitor charging, I'd read otherwise.

Well possibly, but that's a bit too obvious I think. It gets reported quite often that one particular gun consistently cuts out before the others, eg on POTN. Who knows :shrug:

The obvious answer is usually the one I look to first, especially when photographers are concerned.

I'm going to do some testing with my own SB-900's when I get chance and I'll see if I can replicate those findings.

 

[HoppyUK]

Then I stand corrected re the capacitor charging, I'd read otherwise.

Maybe you're thinking of studio heads. They work completely differently to IGBT hot-shoe guns. Studio heads don't do TTL of course and when you turn them down, they just put less charge in the capacitors.

The obvious answer is usually the one I look to first, especially when photographers are concerned.

I'm going to do some testing with my own SB-900's when I get chance and I'll see if I can replicate those findings.

That would be interesting, thanks. Make sure you have the cut-out enabled!

 

[NorthernNikon]

Maybe you're thinking of studio heads. They work completely differently to IGBT hot-shoe guns. Studio heads don't do TTL of course and when you turn them down, they just put less charge in the capacitors.

No, it was definitely in relation to the SB-900 cut-out as I;d just suffered from it myself on a shoot. I tried a number of things and switching the Speedlights off TTL did seem to stop the cut-outs triggering, but then I didn't do any bench testing, just on the job.

That would be interesting, thanks. Make sure you have the cut-out enabled!

Ah yes, it could be a very expensive test if not.

 

[shane1980]

Buy sb910 it's alot better on terms of overheating and have a cut off unlike the sb900

 

[Flash In The Pan]

Buy sb910 it's alot better on terms of overheating and have a cut off unlike the sb900

Sorry, that's totally incorrect, the "problem" with some SB900s was that the overheat protection sensor was too sensitive, there were never any reports of a 900 overheating.

 

[chphotos]

Shane, that's rubbish.