dNorm Posted October 16, 2009 Share #1 Posted October 16, 2009 Advertisement (gone after registration) Hello folks. I am trying to figure out how to force a fill-flash with my M8.2 and SF-24D. The flash doesn't flash when the metering detects high shutter speeds. Is there a way to force the SF-24D to flash? Any input greatly appreciated. Cheers. -Norm Link to post Share on other sites More sharing options...
Advertisement Posted October 16, 2009 Posted October 16, 2009 Hi dNorm, Take a look here Need Help With Flash Please. I'm sure you'll find what you were looking for!
wattsy Posted October 16, 2009 Share #2 Posted October 16, 2009 No, I don't think so. The flash will not fire if the shutter speed is set faster than the flash sync speed of 1/180. This is for a good reason - even if you could force the flash to fire, you'd end up with images only partially exposed by the flash. Link to post Share on other sites More sharing options...
dNorm Posted October 16, 2009 Author Share #3 Posted October 16, 2009 Thanks for the response. I guess I'd have to ask how would you use fill-flash, which is often used when bright sunlight is behind the subject? Surely this is possible? This feature is even available on $200 P&S cameras. No, I don't think so. The flash will not fire if the shutter speed is set faster than the flash sync speed of 1/180. This is for a good reason - even if you could force the flash to fire, you'd end up with images only partially exposed by the flash. Link to post Share on other sites More sharing options...
wattsy Posted October 16, 2009 Share #4 Posted October 16, 2009 The short answer is that you need to stop down the aperture so that you can get the shutter speed under 1/180. The M8/M9 is no different from any other camera with a focal plane shutter in this regard (few will sync any faster than 1/250). If you want to open the aperture up wider than 1/180 will allow you'll have to consider using ND filters to reduce the exposure. Link to post Share on other sites More sharing options...
jbgeach Posted October 16, 2009 Share #5 Posted October 16, 2009 Some flashes have a high speed sync mode built in. This basically uses a series of pulses instead of one flash. It uses more battery and gives less light, but is usually fine for a little fill. However, I haven't tried it with my leica. I use my Canon 430 EX in manual mode but have not tried it. Link to post Share on other sites More sharing options...
wattsy Posted October 16, 2009 Share #6 Posted October 16, 2009 ome flashes have a high speed sync mode built in. ....However, I haven't tried it with my leica. I use my Canon 430 EX in manual mode but have not tried it. You need a camera that supports the feature. The M7 does, the M8.2 (and M9) doesn't. Link to post Share on other sites More sharing options...
Jamie Roberts Posted October 16, 2009 Share #7 Posted October 16, 2009 Advertisement (gone after registration) The longer answer here is that you need to stop down or raise the ISO to keep your shutter under 1/250th (or, as suggested, use an ND filter). Remember, you're talking fill here, not key. So start with the ambient... Let's say you have ISO 160 at f4 at 1/2000s. You need to get to 1/250. Raise the ISO to 640 and you get f4 @ 1/500 because you've gained two stops of sensitivity. Also, if you're outside in good light, don't even worry about raising the ISO, you won't increase noise perceptibly because you've got a lot of light and good exposure (you do, right? ) Ok, but you need another stop. So stop down to f5.6 and voila: 5.6 @ 1/250 s and your flash will fire. You need, as Ian already said, to stop down a little more for the M8.2's 1/180 synch speed. NOW you have another problem, which is what kind of light your flash will output at f5.6. In completely auto/ TTL mode, that's going to be determined by distance and the maximum output of the flash. In manual or A mode, I would actually recommend trying the flash set for one stop under and one stop over, just to see. That's the great thing about digital But that's how it works without High speed synch. Link to post Share on other sites More sharing options...
wparsonsgisnet Posted October 16, 2009 Share #8 Posted October 16, 2009 Take note of Ian's comment above. The M8.2 will only sync at 1/180 or slower. So, following Jamie's logic, you need the half stop between f5.6 and f8. Link to post Share on other sites More sharing options...
wattsy Posted October 16, 2009 Share #9 Posted October 16, 2009 The longer answer here is that you need to stop down or raise the ISO to keep your shutter under 1/250th (or, as suggested, use an ND filter). Maybe I'm missing something Jamie but surely you want to lower the ISO if you are trying to keep the shutter speed under the sync speed in good light? Link to post Share on other sites More sharing options...
Jamie Roberts Posted October 16, 2009 Share #10 Posted October 16, 2009 Maybe I'm missing something Jamie but surely you want to lower the ISO if you are trying to keep the shutter speed under the sync speed in good light? !! You're completely correct. I am tired today and obviously confused LOL! ND filters are what you must do if you hit the ISO wall. The problem there is will your flash have enough oomph to make a difference? In any case, you still want to aim for the highest synch speed where your aperture is not overwhelmingly closed (so aiming for f5.6 to 8), because that will also kill your flash's ability to fill, unless it's very powerful or you use more than one. Link to post Share on other sites More sharing options...
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