Pro shooters - what's the consensus on the SB-900 overheating issue?

[nigel fraustbyte]

<p>Have you ever thought of talking to a Nikon Tech about this.</p>

[Ed_Ingold]

<p>How do you know if your flash is overheating? The little thermometer symbol in the SB-900 continues to register, even if you have the thermostat turned off. In other flashes, you would probably notice changes in its operation, or maybe an acrid smell or something. It's never happened to me so I can't say for sure, but bad things happen when the smoke gets out.</p>

[ShunCheung]

<p>I hope people realize that having a theromstat automatically cut off a flash when the thermostat thinks it is "overheating" is the equivalent of your camera can potentially shut down at some unpredictable time at its own choosing. Would that be acceptable to you?</p>

<p>If you are strictly an amateur photographer and your primary objective is to protect your equipment, and you don't mind that your equipment can all of a sudden stop working, auto cut off is not a big deal and may in fact be a welcome feature. If you are a pro working inside a studio, and your flash suddenly stops working, it may be a bit embarrassing in front of your customer, but you have plenty of time to change flashes and reshoot, it is also not that big a deal.</p>

<p>However, if you are a professional wedding photographer, news photographer, or sports photographer ... and are paid to deliver images at critical moments, you cannot afford to use equipment that can quit on you all of a sudden at times you have no control of.</p>

<p>When a flash overheats, it can shorten the life of the flash tube. I don't think anybody here is dumb enough to keep pushing a flash until smoke starts coming out. Therefore, if you need to use your flash for a little longer than when the thermostat would have cut you off so that you can find a convenient time to swap flashes, it shouldn't be that big a problem. When you are a pro paid to deliver images at critical moments, the fact that you may need to replace/repair your flashes more often is simply part of your business cost. While there are certainly reasons that Nikon puts a thermostat on the SB-900 as well as the SB-700, there are also reasons that Nikon lets you switch that feature off.</p>

<P>

By no means I am suggesting that one should simply switch off the thermostat and keep using the flash. If you are a heavy flash user, use some common sense and rotate among 2, 3 flashes to give them time to cool off.</P>

[ilkka_nissila]

<p><em>I hope people realize that having a theromstat automatically cut off a flash when the thermostat thinks it is "overheating" is the equivalent of your camera can potentially shut down at some unpredictable time at its own choosing. Would that be acceptable to you?</em></p>

<p>When I've asked about it, all of the people who've described the situation report having used a low ISO and mid to small apertures.</p>

<p><em>I am going to assume that is was ISO 100 somewhere around 5.6 or 8 as it was a backlit sunny scene. Probably shooting 20-30 fill shots over that course of 15 mins.</em></p>

<p>That kind of settings will cause the flash to give a near full power flash on every shot. While the flash will let you do that for a while it's not intended usage for a prolonged time; the manuals typically have warnings about the number of full power flashes and the recommended limits are - not surprisingly - similar to or smaller than the number of flashes in the interval quoted by people who have experienced thermal cutoff. If you need more light than an SB-900 gives at 1/8 or 1/4 power, IMHO you should increase the number of flashes that are firing at the same time, or use bigger flash units<em>, </em>rather than increase the flash power to 1/2 or 1/1, which should be saved as desperate measures. At 1/1 power the flash will give quite random amount of light anyway, it's not reproducible. You don't drive your car at maximum speed for prolonged periods either (and outside of Germany, not at all, I hope) and expect a long life for it. It should not come to anyone as a surprise if you use a regular car for drag racing, if the bolts holding the motor to the body of the car come loose or something like that happens. The max specs are not meant for regular use.</p>

<p>At weddings, when using speedlights as fill light for the wedding portrait (background lit by direct sun, such as in the OP's case), I put two flashes behind one umbrella and it works fine. If I want to reduce the ambient light level in the flash then I'd need to carry a portable 400Ws unit with battery. This gives more freedom over the lighting ratio and is more comfortable with big pops of light than a speedlight. The studio I sometimes rent also has a set of this kind of lights that can be used on location. One speedlight is fine when the subject is in the shade or on an overcast day, or e.g. in a forest but not in open, direct sunlight.</p>

<p>I'm pretty sure Nikon only put the thermal safety features in because they were getting piles of flashes to be repaired, and felt that having to repair flashes under warranty having been driven too hard is just too expensive. With digital, people shoot a lot more pictures in a given event. And yet some shoot using settings they'd use with film, at ISO 100-200. They also want faster recycle times etc. These requirements are not physically compatible without without making the flash substantially bigger (and more expensive), due to the requirement of a cooling system. Larger powered flashes have fans etc.</p>

<p>Many studio flashes have heat sensors too and they too will not fire when overheated. This can happen very easily, and all you can do then is wait. Though because they are much bigger and many have active cooling, they return to normal temperatures more quickly than a small flash within a closed housing. I've shot with a 1600 Ws Hensel unit near minimimum power (4-5 stops below max power) in a normal room temperature studio and sometimes the flash would make me wait for a while before I can continue. The apertures were (two flash units, the big flash that made me wait was used as fill) f/11 (ISO 200), so there was more light used than could be used with just two speedlights. To reproduce that scenario with SB-900's I'd use 4-6 of them (I don't have so many). But it's easier with lights that are designed for heavier repeated use. Whenever I use speedlights in the studio at base ISO, I run into recycling issues and have to use something like ISO 400, f/5.6 to keep the recycling time to a tolerable level (without external battery packs). If I want more depth of field, I cannot create a fluid working situation where I can trust the flashes to fire the same amount of light every time, if I just base it on speedlights behind umbrellas and panels. So I'd argue that they're not the right tool for situations where broad depth of field and rapid shooting in the studio are required, such as group shots, dancing etc.</p>

<p>As to how to solve the potentially rapid situations where the equipment must function reliably and without interruption e.g. during the ceremony; I don't use any flash during the ceremony, so I don't have flash related problems. I do use flash during reception and for outdoor portraits. During reception I up the ISO to 800-1600 and combine the flash with existing light at wide apertures. The flash pops at near minimum power here. The biggest difficulty here is balancing the colour of the flash with existing light. I do not use flash only as lighting the whole room with flash only, without any existing light used, as using multiple flashes here creates a tripping hazard (I have had to jump in to prevent flashes from hitting the floor when people bump into them in the reception), and lighting the whole room with just one light creates a quality of light which I do not like. Also, if you use so much flash that the ambient light is not visibly present in the image, the flash pops will likely be distracting and unpleasant to the subjects. With just faint pops of fill light, the subjects are more comfortable and pay less attention to the photographer.</p>

<p>For outdoor portraits in sunlight, as I mentioned things work out better if you use more than one flash unit and put them on stands (two behind one umbrella works for me). No recycle time problem, and no overheating issues. If you need to move more quickly and use an on-camera flash for fill, then I suppose the quantum is the right flash. I prefer softer fill so I use an umbrella and that means I will have stands anyway, to mount multiple flashes is not a problem.</p>

<p>(I too am not a professional photographer.)</p>

[zack_zoll]

<p>The problem isn't that there is a thermostat; the problem is that it is set too low for <em>professional </em>use. Let me give you an anology:</p>

<p>A car manufacturer creates a transmission that revs up to 8,000 RPM in a given gear, but can damage the system if run that high. This is pretty common for most vehicles. So to help avoid that, the transmission will automatically shift at 6,500 RPM, or sometimes just not rev any higher. This is called a rev limiter. It's not standard, but it's not uncommon either. Your average driver won't even know that the system is there. But a professional driver, to whom each second counts, will want to get the engine up to 7,500 RPM before shifting, as it makes the car run slightly faster, and still comes in at the 'safe zone.' A professional driver should know where and when he should shift his gearbox for maximum performance, and without damaging his car. As a professional, that is his job. However, production cars aren't designed for professionals; they are designed for people that might not know better and just want to floor it, so they often include a rev limiter.</p>

<p>The thermostat is your rev limiter. It's there to protect Joe (or Jane) Camera from blasting away at full power during the kids' nighttime football game and killing the flash. It's not there to assist professionals. Disable it, and it will work better for a professional. And as a professional, it is your job to know enough about your equipment that you don't blow it up.</p>

<p>Also, using external battery packs that are not made by Nikon will throw off the thermostat. Quick-recycling packs are higher voltage than the flash normally uses (the Nikon pack for the SB-800 was 6 batteries, for instance), which will produce more heat than normal voltage. I've hurt my hand taking batteries out of a quick-recycle pack, but never from taking them out of the flash itself.</p>

<p>And since we're chiming in, I wouldn't call myself a professional photographer either, but I was for several years, and now I teach professionally. I still get talked into professional gigs by friends and business associates now and again. I view the thermostat on the SB-900 the same way as the menu scheme on the D40/3000/5100/etc. I hate it, but it helps Nikon to sell their product to a much broader audience. If this is the kind of stuff they need to do to get the money to pay for developing a new 24 1.4 and 85 1.4G, then I'm more than happy to deal with it.</p>

[Jerry_]

<p>Perhaps a camera accessory manufacturer can create (...invent?) a mini-air conditioning pack that will take care of the heat issue in the SB-900 speedlight? The folks at NASA have the inside track on keeping hot things cooler...and they need something to keep 'em busy when the Space Shuttle Program is no more.</p>

<p>A few copper tubes, some freon, and a mini-fan - compressor unit would do it.</p>

<p> </p>

[ilkka_nissila]

<p>Cooling is not difficult to implement when designing a device but to keep it compact, it has to start from the inside. The flash tube should be contained in a thermally conductive material such as a copper piece that surrounds it from most sides except the front window. The gaps are filled with a thermally conductive paste. Then put a Peltier element with one side on the copper and the other on a heat sink. Add a fan on top of the heat sink and put everything inside the flash housing. Holes for the part of the housing next to the fan, so that air can circulate and the fan can do its job without the user's fingers being able to obstruct the fan or touch the heat sink. This kind of thing cannot be added to an existing flash design - it has to be built from the ground up with cooling in mind. There's no way to keep it as compact as it is now. As for an aftermarket product, in that case the whole flash unit would have to be cooled and the setup would be very large and heavy. I doubt the flash shoe interface could handle the additional weight.</p>

<p>Shoe mount flashes are compact because they have some limitations regarding power and shooting rate. For high power rapid rate shooting there are many products available.</p>

[rodeo_joe1]

<p>I'm kind of with Ilkka on this, although the Peltier-effect cooler is probably going a step too far.</p>

<p>"The problem is that Nikon totally messed up the thermostat on the SB-900." - I disagree Shun, the real problem is that EVERY current flash manufacturer has messed up their design philosophy.</p>

<p>I'm attaching a picture to show the difference in size between how proper professional flashguns used to be made, and the pathetic little tubes that are being fitted to today's so-called "pro" equipment. The tubes used in modern hotshoe mounted units are barely any bigger than the tube in the camera's built-in popup flash - so of course the stupid little things are going to overheat!</p>

<p>The picture shows a 25 year old Metz 402 compared to two different so-called pro quality flashguns of more recent manufacture. The old 402 is still working well and pumping out roughly the same amount of light at standard coverage as both those modern guns can manage at their maximum zoom setting. And really is there anything those modern guns can do that the old manual guns couldn't - given a little help from slave triggers? It's just a source of light for goodness sake! It doesn't need computer control, and it shouldn't need an overheat detector if built right in the first place.</p>

[rodeo_joe1]

<p>Ooops! Here's the illustration, and apologies for the dreadful lighting! On camera flash is really nasty isn't it?</p><div></div>

[andrew_holman1]

<blockquote>

<p>On camera flash is really nasty isn't it?</p>

</blockquote>

<p>+1</p>

[ShunCheung]

<p>If I were to design the thermostat shut off system, I would put say a 2-minute count down warning message that can be displayed inside the viewfinder and on the back LCD under live view so that the photographer has plenty of warning to change flashes. Or there can just be a warning without auto switch off. Any sudden auto shutdown is simply not acceptable for professional usage in general.</p>

<p>As the way it is, the SB-900 is already huge. Any additional cooling system is not realisitc; it'll add more mechanical moving parts and power consumption. Any serious photographers who use a lot of flash should have at least 2 and preferably more flashes on hand so that they can rotate them.</p>

<p>I should point out that I bought my SB-900 very early, back in August 2008, almost as soon as it was available. (The SB-900 was announced on July 1, 2008, along with the D700 body.) Of course I am not a professional wedding photographer. So far, I have not even run into the overheat situation once myself.</p>

[Jerry_]

<p>"I doubt the flash shoe interface could handle the additional weight."</p>

<p>Most *wedding photographers* use a flash-bracket, so the weight problem should not affect the use of a modified SB-900 <if a mini-air conditioner could be developed> speedlight.</p>

<p> </p>

[ronald_smith6]

<p>From what I can gather, the SB-900 works perfectly with AA alkaline cells and was designed specifically for those batteries. The trouble comes when you use NiMH batteries and try the fast recycling feature - far more heat is generated by the rechargeables than alkalines, this is simply a by-product of the design of the unit for those who want/need quick recycling and the grief comes from the heat build-up.<br>

If you use Nikon's own external battery packs (SD-8A or SD-9), the problems disappear. To me, it seems that Nikon is almost forcing you to use one of these pricey devices to max out your SB-900 if you want fast recycling - NiMH cells won't cut it.</p>

[dan_brown4]

<blockquote>

<p>On camera flash is really nasty isn't it?</p>

</blockquote>

<p>IMHO, always use on-camera as fill, and it works very nice, thank you. This is pretty easy once you have a good high ISO body.</p>

<p>But, if you're stinging for breaking news, let her rip and take what you can get.</p>

[rodeo_joe1]

<p>Well, if the SB900 was about half of it's asking price you could almost forgive the lack of performance, but this is supposed to be Nikon's top-of-the-range <em>professional</em> gun. To say you need to use alkaline batteries is just madness, as is expecting someone to carry 3 so there's one that actually works at any one time. Let's take a moment to think about what the tag "professional" should actually mean.</p>

<p>Nikon really need to cut down on the high-tech needless crap they put into their flashes and concentrate on power, recycling time and, above all, reliability. It's really a joke when I can fit a Canon 540EZ to my D700 and have it work perfectly in manual mode, but if I put a film era Nikon-dedicated gun onto it the camera refuses to fire!</p>

[zack_zoll]

 

<blockquote>

<p ><a name="00YlVw"></a><a href="../photodb/user?user_id=2403817">Rodeo Joe</a> <a href="../member-status-icons"><img title="Frequent poster" src="../v3graphics/member-status-icons/1roll.gif" alt="" /></a>, May 21, 2011; 12:35 p.m.</p>

</blockquote>

 

<blockquote>

<p>Nikon really need to cut down on the high-tech needless crap they put into their flashes and concentrate on power, recycling time and, above all, reliability. It's really a joke when I can fit a Canon 540EZ to my D700 and have it work perfectly in manual mode, but if I put a film era Nikon-dedicated gun onto it the camera refuses to fire!</p>

</blockquote>

<p>It's funny that you say that, because I just shot some photos today with an SB-24 mounted to an Olympus XZ-1. It even had flash sync to 1/2000th. Sorry I can't post them - they were for work. But I have about a million photos from my G10 and my SB-800, and a 60D and an SB-800. The 800 has fired in manual mode for me on literally every camera I've ever tried it on, as has the 24. I'm not sure if maybe there's something wrong with your flashes? I know that the 70s flashes pretty much work on nothing new, unless you trigger them remotey.</p>

<p>As for size ... it's overrated ;) I have a giant Pentax and an equally giant Sunpack handlemount flash ... I forget the number, but they both take 6 AAs in the handle. Both of them are about the same output as the SB-900 (more light at wider zoom ranges, less light over 85 or so), but recycle more slowly. I suspect the fact that they cannot fire as quickly has a lot to do with why they are harder to burn out.</p>

<p>And lastly, the internal cooling system ... really guys? I'm not saying it can't work, but have you ever stuck your hand around the back of your fridge? It is HOT back there! The reason AC systems work is (partially) by sending hot air outward, away from the direction being cooled. I don't know enough about thermodynamics to explain it without being wrong, but I do know that in addition to weight, such a system would require so much venting that it wouldn't be even remotely weatherproof, and you'd need to wait for it to cool down before you handled it. Plus it would be constantly dripping condensation out the back end. This isn't a problem for NASA, because there is no rain in space, and not having air means no rust.</p>

<p>I'm not saying that these products are flawless. I'm just saying that maybe the good old days weren't all peaches and cream, and that progress really does exist. Personally, my only beef with the new flashes is that you can't use the CLS system on older cameras. What the hell?! If the SB-800 can meter with an old camera, and it can also tell other flashes what to do, why can't it tell them to fire based off of the meter readings it already took?! Grumble grumble.</p>

 

 

[ilkka_nissila]

<p><em> if I put a film era Nikon-dedicated gun onto it the camera refuses to fire!</em></p>

<p>It will fire if it's in manual mode. Film TTL doesn't work on digital cameras.</p>

<p><em>it wouldn't be even remotely weatherproof</em></p>

<p>That is certainly true. But if you want more power and shorter recycle times for extended time you have to cool the flash.</p>

<p><em>Plus it would be constantly dripping condensation</em></p>

<p>No, it would not. Since we're talking about cooling a small flash tube, not a large object like a refregirator, and the cooling is only to keep the flash from overheating, not to pull it down to +4C, the cooling system doesn't have to be that powerful.</p>

<p>Anyway, you may have hit a key point: if the flash has to be weatherproof, then it is always going to be prone to heating since not all the energy can be converted into light.</p>

[rodeo_joe1]

<p>"It will fire if it's in manual mode." - No, it won't Ilkka. Putting a film TTL Nikon-dedicated gun onto a D700 simply locks the camera up. And setting both the gun and camera into manual mode makes no difference. I have mainly SCA dedicated Metz and other makes of flash from my film shooting days. All of these have been rendered near useless by Nikon's lack of backward compatibility. I've had to go back to using non-dedicated hotshoe adapters or the PC synch socket.</p>

<p>The most useful old guns I have now are Sunpak AZ3600s, which work perfectly in auto-sensing mode on a D700 by using Canon dedicated TTL hotshoe modules on them. Sunpak also sold an external shoulder battery pack for these guns which brings the full power recycling time down to under 4 seconds, and gives practically instant recycling at any lower power. The guns can be fired as fast as the shoulder pack allows at full power until the charge runs down and they never overheat. And BTW, I've re-celled the shoulder pack with modern high capacity NiMH cells, which gives me around 200 shots per charge.</p>

<p>Measuring the light output from old Metzes, Sunpaks and others with a flashmeter reveals that hardly any gun, ancient or modern, will exceed a true GN of 32 in metres @100 ISO. Most modern hotshoe mounted guns struggle to reach this figure at the 105mm zoom setting while the old hammerhead guns produce this figure at their fixed reflector setting.</p>

<p>I also completely refute the assertion that having a larger tube and reflector housing does nothing to alleviate overheating problems. Of course it does! There's an immutable relationship between thermal mass, surface area and local heating for a given energy input. Put simply, small things get hotter quicker than big things - and are more likely to melt as a result.</p>

[ilkka_nissila]

<p><em>"It will fire if it's in manual mode." - No, it won't Ilkka. Putting a film TTL Nikon-dedicated gun onto a D700 simply locks the camera up. And setting both the gun and camera into manual mode makes no difference.</em></p>

<p>According to the Nikon D700 manual, the following Nikon non-CLS flashes will work (with the flash) in manual mode: SB-80DX, SB-28DX, SB-28, SB-26, SB-25, SB-24; SB50DX, Sb-30,SB-27, SB-22S, SB-20, SB-16B, SB-15, SB-23, SB-29, SB-21B, SB-29S. I think this includes most Nikon flashes that have come out since Nikon adopted the current hot shoe. Too bad your third party flash doesn't work. Good reason to avoid them.</p>

[ShunCheung]

<p>I still have an SB-24 left over from around 1990. I bought it back then for my F4 and N8008 bodies. I just tried it, and it works fine with my D700 with the flash in the A mode, as described in the Nikon manual.</p>

[zack_zoll]

 

<blockquote>

<p ><a name="00Ylh3"></a><a href="../photodb/user?user_id=19054">Ilkka Nissila</a> <a href="../member-status-icons"><img title="Subscriber" src="../v3graphics/member-status-icons/sub10plus.gif" alt="" /><img title="Frequent poster" src="../v3graphics/member-status-icons/1roll.gif" alt="" /></a>, May 22, 2011; 04:42 a.m.</p>

</blockquote>

 

<blockquote>

<p>No, it would not. Since we're talking about cooling a small flash tube, not a large object like a refregirator, and the cooling is only to keep the flash from overheating, not to pull it down to +4C, the cooling system doesn't have to be that powerful.</p>

</blockquote>

<p>My window-mount AC unit doesn't go anywhere near 4C, and that drips water out the back all the time. Actually it collects the water in a reservoir in the 'outside' part of the unit, which is supposed to evaporate. But if I move the AC unit, the reservoir leaks all over the floor. I'm operating under the impression that the act of creating two different temperate zones right next to each other creates condensation, but like I said ... I'm not a thermodynamics whiz. Or even a student.</p>

<p>Also, my SB-24 also works with the D700. Third-party flashes (even high-quality Metz units) do not use Nikon (or Canon, or whatever) metering chips. As a result, there is always the potential that those units won't meter properly with new cameras that use different metering systems. Usually that results in the flash always firing at full power, but sometimes the flash just plain won't work. But I'm 99% sure that it'll work perfectly if you trigger it with a PC cord.</p>

<p>As far as tube size goes ... I'm not saying that a larger tube doesn't dissipate heat better. All I'm saying is that there have been 30 years of technological advancements since the first 'modern' professional flash, and I'm pretty sure that engineers have learned a few tricks since then. So to give you one of my famous car analogies: a Subaru WRX, with its turbcharger, intercooler, and variable-valve timing produces almost the same horsepower as a stock 1970s Mustang, using half the engine cylinders and about 70% of the fuel. Plus that power is driving 4 wheels, and not 2 - imagine how much more powerful it would be if the WRX only had to drive the two rear wheels - it would smoke the Mustang!</p>

<p>Cars are not cameras. But I don't doubt that there's a camera equivalent of a turbocharger and an intercooler, perhaps in the form of better capacitors and heat sinks.</p>

 

 

[ilkka_nissila]

<p>Zach, your window-mount AC is 1000 times more powerful than what would be needed to cool a flash tube. For condensation to occur, you need the cooled object to be significantly colder than the air surrounding it, enough so that the object cools the (warmer) air to dew point. This is not the goal here, we just want to transfer enough heat away from the tube so that it doesn't break (and possibly also the optical elements in front of the tube, apparently they can melt). The relative humidity of the air is not 100% thus there can be a small temperature gradient without creating condensation on the tube.</p>

<p>Anyway, this cannot work in a hand-held flash because of the requirement that the casing is watertight (to some degree) and its surface cannot allow to be heated so that it's too hot to handle. Also, cooling obviously would deplete batteries quickly. Studio flashes are often too hot to touch but then they're mounted on stands.</p>

[ilkka_nissila]

<p>Also, I forgot to mention that it is one of the purposes of an AC to dehumidify the air that it blows inside your room. It has a component that is below dew point, with the intent of collecting the water. That would not be the case with a thermoelectric cooler with a very modest cooling target (i.e. cool enough that the flash tube doesn't break and the optics doesn't melt).</p>

[zack_zoll]

<p>Ilkka, fair enough. Like I said ... I don't know much about that stuff.</p>

[fred_fedak]

<p>Recently, I shot my first event using Nikon's diffuser on my SB900. After only about 25 shots or so, within a 10-15 minute period, it overheated. I used the diffuser because the ceiling was way too high to bounce off of. I never encountered this problem when using my Gary Fong diffuser.</p>