Nikon SB 600 repeat flash and high speed sync question

<p>Hi, I need some help. I am trying to get my SB600 speedlight to do repeated flash just like the built-in flash does on my Nikon D90. The D90 manual on page 235 table implies the SB600 can't do that although it also implies that it will do repeated flash function when used as a remote and commanded by my built-in D90 flash. When I have tried doing this with the SB600 on the camera hotshoe or with it attached via the SC-17 cord it doesn't seem to repeat flash. And when I set it up as a remote on the same channel as the D90 it doesn't seem to repeat flash either. If the D90 is set for command mode©, how can it send the repeat flash (RPT) command to the remote SB600 since the repeat flash setting is a different setting than the the command setting using e2 custom settings menu on the camera. Also, Can I get High Speed flash sync with the SB600 on the camera or commanded as a remote eg to freeze high speed subjects such as hummingbird wings. How is this set up? It says on pg 195 of the D90 manual that hi speed sync is not available when using the built-in flash. Thank you for your replies. Skip Wilson</p>

<p>Your reasoning and expectations are correct, and you spotted inconsistency in Nikon documanttation, or let's say poor descriptions.<br>

Many questions...let me try few..</p>

<p>To get FP from the flash, you need to set the camera shutter to speed "1/250 FP" - make sure you see there in the camera menu the magic "FP". Contrary to some opinions on photo.net, it is the in-camera electronics that controls the FP flash mode execution on an external FP compatible flash. </p>

<p>The D90 built-in flash, or any Nikon camera built-in flash, could be only capable to command remote FP flashes into the FP mode, but it has no power or capability to act alone as a FP flash.<br>

In CLS any remote flash must be set in REMOTE mode to get commander from an in/on camera commander, and participate in multiple flashes pre-flash testing, and provide acurate flash need determination that takes on account the test light from all remote flashes. </p>

<p>There are other flash remote trigger/control systems, not really compatible with CLS , that do not use REMOTE flash mode on a remote CLS flash. They do use remote CLS flash in the iTTL mode, thus being able to set their output and control them remotely. They do evaluate their light by preflash, but each remote flash works as if it was sitting in the camera hot shoe. Therefore, theoretically (?) it could be possible to program remote CLS flash to do the RPT ?, but in Nikon CLS this perhps is not possible?</p>

 

<p>According to the D90 manual, the fastest shutter speed for X-synchronisation is 1/200th and the only menu option available is Auto-FP ON or OFF. Apart from this, Frank's instructions for FP mode have omitted that in addition to setting the Auto-FP menu option, you have to manually set a shutter speed <em>faster</em> than 1/200th to force both the camera and flash into FP mode. While in FP mode the [<strong>FP</strong>] indication on the SB-600 should be showing.</p>

<p>WRT repeating (stroboscopic) flash. The shutter speed has to be long enough for whatever frequency and number of flashes have been set to play out. For example: If you set a repetition rate of 0.5 seconds and the number of flashes to 6, it will need a shutter speed of at least 3 seconds for the programmed burst to complete. Setting the shutter to 1/60th sec will only result in a single flash being output.</p>

<p>Auto FP mode: The internal flash cannot do FP flash, but it can be commander to remotes which can. This means you must disable the internal flash in commander menu by setting its MODE to be "- -". You will not be able to set a faster shutter if you don't disable the internal flash, because the internal flash cannot do this itself.</p>

<p>>Can I get High Speed flash sync with the SB600 on the camera or commanded as a remote eg to freeze high speed subjects such as hummingbird wing</p>

<p>This is the wrong idea for high speed photography. Auto FP mode is High Speed Sync, but it is NOT high speed flash. The FP mode flash becomes a continous light, and it will not stop motion any better than sunshine will (It is on all the time the shutter is open). Continuous light has no sync speed requirement, that is all this is. Auto FP is about the last thing you want for high speed photography. (FP primarily just lets you use f/2.8 in bright sun).</p>

<p>So all Auto FP offers to hummingbirds is a faster shutter speed, but no shutter is fast enough. A speed of around 1/20000 second (or more) is necessary to stop hummingbird wings, and no way the shutter can do that. The flash is called Speedlight, and the way High Speed Photography is done is with speedlights in Regular flash mode (absolutely NOT FP mode), and and a low power flash.</p>

<p>Page 88 of the SB-600 manual shows the speed of the speed light. 1/32 power duration is 1/20,000 second, and this will stop about anything. Power is low (to be fast), so it must be close to the hummingbird at 1/32 power. Page 35 says (for example) 1/32 power at 50 mm zoom has Guide Number of 21 (feet) at ISO 100. At ISO 400, this is 2x or GN 42. At f/11 (for depth), this is 42/11 = 3.8 feet will give that proper exposure at ISO 400 50mm. If in shade, this speedlight speed will be same effect as effective shutter speed of 1/20,000 regardless if your real shutter speed is 1/200 second (max sync). Except one is possible, and one is not. </p>

<p>The idea is f/11 1/200 is underexposed in shade, and remains dark in the picture (dark will not blur the bird), but f/11 gets plenty from the 1/32 power flash at 3.8 feet, and 1/20,000 second flash will stop the birds wings.</p>

<p> </p>