Rear Curtain on SB-600

[pemongillo]

<p>I must be missing something here. I have my SB-600 flash on my D7100. I have it set on manual at .5 seconds, ISO 500 and f3.5. I have also tried this on Shutter priority. Why is my flash firing twice. I don't want it to fire when I depress the shutter, I just want it to fire at the end of the exposure. How do I get the first flash to stop? Pictures look over exposed as well.</p>

<p>Thanks</p>

[didereaux]

<p>I suspect what you are seeing is the TTL exposure flash (the first one). Set your flash to manual mode. Also double check that you actually have set your 2d curtain flash on the camera (not part of your problem, just a reminder to double check everything).</p>

[Palouse]

<p>Do you have red eye flash on?</p>

[pemongillo]

<p>It is ttl exposure flash and no I don't have red eye on. Id rather fix red eye in PS than have the extra flash of light. I have excepted that the flash is going to fire twice. I don't like it, but shooting on manual isn't going to work in this situation. Thanks all. Just wanted to make sure there was nothing wrong with the flash.</p>

[Palouse]

<p>Here is a short piece on how RCF works, perhaps it has something we can learn from.<br>

http://www.scantips.com/lights/flashbasics5.html</p>

 

[rodeo_joe1]

<p>Paul, you say that you have the camera set to manual, right? Then TTL flash exposure is pretty pointless, because the camera's meter can only control the flash exposure and not the exposure for ambient light. So the camera pre-flashes to determine the correct flash exposure, and gives the correct amount of flash power <em>based on the subject being lit by flash alone</em>. Then, in addition, your manually set exposure gets put on top of the flash exposure - with the result of overexposure.</p>

<p>You need to adjust the flash exposure compensation, or do manual flash exposures based on Guide Numbers, and/or reduce the ambient exposure to balance the flash. Or alternatively leave the camera to control the ambient exposure as well with a balance of Shutter priority mode and a minus exposure compensation, and possibly flash exposure compensation as well. Any way you look at it, this technique needs some experimentation to get right.</p>

<p>But the only way you'll get rid of iTTL pre-flashes is to put the flash into manual control. If you look at the example picture given on page 47 of the SB-600 PDF manual, you'll see that manual flash control was used. Presumably with manual camera exposure mode as well.</p>

[pemongillo]

<p>THANKS Joe. Well its too late to worry about. I was trying to get my wife squared away for a month in Mexico including Day of the Dead. She just left. Your explanation explains some things I saw in trying to set up her camera and flash. I shoot with rear curtain at night a few times a year and have gone back and looked at the pictures I like. They are all over the map as far as settings, BUT they have never been overexposed enough for me to not be able to adjust them in RAW. Thanks for taking the time to respond....all of you. I am not much of a flash buff, so its always a challenge.</p>

[tom_boston1]

<p>Why is your wife using rear curtain flash? It is not needed for night time flash photography.<br>

<br />And with respect to Rodeo Joe's comment above, there is absolutely nothing wrong with using TTL flash together with manual ambient exposure. Set the camera exposure to get the desired ambient/background lighting and the Nikon system is very good at giving accurate flash exposure of the main foreground subject, especially if used in direct flash mode (i.e. not bouncing)<br /><br /></p>

 

[5711]

<p>you can use manual mode with flashes alright and still use exposure dials<br>

especially at night this comes in handy</p>

<p>dont you just must love nikon? :)</p>

<p>well, here is why<br>

use the +-EV button on your camera to controll the overall exposure compensation<br>

use the flash compentsation on the flash<br>

if you dial in -1 EV on your camera and +1 EV on your flash, those two cancel each other out.<br>

test it with different settings when it is dark.<br>

take a friend with youand go to some busy street (background, lightballs, bokeh, balbla)</p>

<p>set the camera to 0 EV, take a shot of ambiant light<br>

dnt like it? switch to manual and get the exposure of the background right<br>

pop on your flash and light your subjekt<br>

probably not going to look really flattering right now, so maybe move the flash in close and dial it down.<br>

now use the camera compensation to controll overall exposure till you like it.<br>

controll the flash so the light looks as you want it.</p>

<p>do try to overexpose on purpose..tell your subject to close his or her eyes for this, please do not forget that!</p>

<p>with new cameras like the 610 oder d4 you can disconnect the flash and overall exposure</p>

<p>it is a little bit confusing<br>

try to get it working, you will end up loving it.</p>

<p>by the way: during the day, this all changes a bit as the background is now lit by the sun and you will have to adjust for that</p>

<p>hope that helped.</p>

 

[5711]

<p>one more important thing:</p>

<p>if you need more light in the background but cannot get it with the exposure or fstops</p>

<p>use iso</p>

<p>i often end up using iso 1000 for ambiant light.<br>

why the heck not.</p>

<p> </p>

[pemongillo]

<p>Thanks again for the great flash lesson. Tom Boston my wife as well as everyone else uses rear curtain lash for creating an image that shows movement with a point of sharpness. I have found this produces very interesting results at night...... not complete darkness of courses; streetlights, illuminated puppets, the list is endless. Try it you like it if your looking for something potentially more artistic. The method is full of surprises and of course crap. But it is a tool. Like most tools many can find other uses for it than what it was originally designed for.</p>

[5711]

<p>you're welcome<br>

i took the shot that made it as the photo of the week, october 14th, 2014, just like i told you:<br>

http://www.photo.net/photo/17856551</p>

<p>it is no secret, just takes a bit of practicing and for that i recomment:<br>

annoy those around you the most, that are most likley to not run away this instant :D</p>

<p> </p>

[tom_boston1]

<p>Paul, yes, if someone is trying to show movement (of the main subject) then the rear curtain is necessary <em>where the direction of the movement is important.</em> </p>

<p>Not "everyone" uses it that way. Every once in a while someone thinks they <em>have</em> to use rear curtain flash to do those shots where the background is nicely illuminated by ambient light and the main subject is illuminated by the on-camera flash. (For example, a night time shot of someone in Paris with the Eiffel Tower in the background.)</p>

<p>In any event, Norbert's system gets you into the ballpark. Manually set the camera to get the desired exposure for the background via ambient light. Then set the the flash exposure to get the main foreground subject lit as desired. Whether or not rear curtain gets used is relevant only to showing motion in a particular direction.<br>

<br>

Manual flash exposure is recommended for consistent results. If the moving subject shifts a lot, the scene that the pre-flash evaluates could be quite a bit different. There's a lot of vaguely explained calculations that the iTTL/CLS system uses to decide how much flash exposure to use. Focus distance, selected AF sensor, and the position of objects in your scene can all affect the flash exposure, especially if your main subject does not fill out a large portion of the scene.<br>

<br />By the way, for this rear curtain and slow shutter stuff, the ambient light should usually be underexposed. If the camera is set to expose for ambient light, the main subject gets lit properly by ambient light (resulting in a blur) and the addition of the flash light results in overexposure of the subject.<br /><br /><br>

</p>

[tom_boston1]

<p>Paul, the short answer to your specific question is: <br /><br />Yes, the first flash you see is the pre-flash used by the iTTL system to calculate exposure and the 2nd flash is the actual exposure itself. Without rear curtain, these will happen almost simultaneously.<br /><br />Why the image looks overexposed depends. You'd really have to show the image. 0.5 secs, f/3.5 at ISO 500 sounds like it might be too long for a nighttime city shot. And iTTL isn't real consistent and isn't always perfect at reading your mind about what you want it to expose for. <br /><br /><br /></p>

[tom_boston1]

<p>Norbert, cool shot. How is the camera mounted? Was the train car actually moving? What were the exposure settings?</p>

<p>This is a good example of a motion shot where rear curtain shutter isn't necessary.</p>

<p>Thanks!</p>

[pemongillo]

<p>Great image Norbert. Looks like you could have been vaporized in the next split second, but you obviously survived.</p>

[5711]

<p>first off: thank you, guys<br>

glad you like it!</p>

<p>explaination:<br /> actually it is fired exactly in the middle of the exposure (manually)<br /> rear curtain would have been needed otherwise.<br /> i chose to trigger it manually as the road is rather pumpy and i hit that button towards the end of the exposure <br /> when the track would allow it.</p>

<p>you might argue flash freezes the motionblur, yes but flash does not control the image artisticly.<br /> in order to have them sit "rather calm" you have to release the falsh after some time of steady movement.<br /> otherwise there would be unwanted ghosting of the people and bend lightining streaks.</p>

<p>rear curtain should be used when you want to freeze something at the end of an exposure and have them pop out.</p>

<p>if you use front curtain, light will "overwrite" your image.</p>

<p>Model: NIKON D3;<br />ExposureTime: 3/1 s;<br />FNumber: f/10;<br />ISOSpeedRatings: 200;<br />ExposureProgram: Manual;<br /> flash set to -3<br /> camera exposure set to -1</p>

<p>this is a cable car, two waggons connected to each other, im in the first one holding the camera out the window on the right and releasing the flash with my pocketwizard-thingy in the left.</p>

<p>_______________________________________________________________________<br /> here is anotjher example of rear-curtain usage:<br /> https://500px.com/photo/78904337/front-flip-by-norbert-wabnig?from=user</p>

<p>_______________________________________________________________________</p>

<p>on topic:</p>

<p>if you check the shot i just posted linking to 500px<br /> the preflash fired too as i did this in ttl but i set the exposure for the background down, do not remember to what extend but i am quite sure for about -2 stops</p>

<p>iso was 1600 oder 2000</p>

<p>the preflash does not matter, rly<br /> if it is too strong, the camera sees black only.<br /> just underexpose and it will have less and less power till it is not to be worried about</p>

<p> </p>

[tom_boston1]

<p>I'm not arguing so much about what rear curtain does (or with the results of your fantastic train photo) as to some fine details about when it's actually necessary.</p>

<p>In that diving photo, rear curtain versus front curtain would be a drastic change. Clearly needed to get the desired effect.</p>

<p>In the train shot, you mention something I had never thought of before. For a very slow shutter, if the flash goes off on the front curtain, the humans in the photo might think the shot is finished and they'll move at the beginning of the exposure and be blurred by the ambient light.</p>

<p>Just to be sure, it looks like the flash is sitting on the floor in front of them and the only thing the flash is illuminating is the humans. Is this correct?</p>

<p>I marvel that you were able to get a steady shot for three seconds between two connected cars while hanging the camera out a window with one hand.</p>

<p>But the usual thoughts about when rear curtain is necessary are modified in this train scenario because the subject and the camera are fixed relative to each other. The background is moving instead. Normally, the camera and the background are still while the subject moves.</p>

<p>In this special case, there will be no background light streaking over the subjects faces because the faces are always on the same spot of the sensor. The background streaks never touch that part of the sensor because the background streaks do not shine through the heads. (The light streaks will _not_ overwrite the image.)</p>

<p>If you did the thought experiment of using the 3 second exposure and rear curtain flash, you'd end up with exactly the same result as using the 3 second exposure and and front curtain flash and moving the train backwards. In neither case, would you get light streaks over the faces because the faces and the camera are moving together.</p>

<p>I feel like there should be a shorter way of saying all of this. Sorry.</p>

<p>How many tries with the handheld camera did it take to get this sharp image?</p>

<p> </p>

[5711]

<p>that's right.<br>

rear curtain flash freezes stuff at the end of an exposure.<br>

here the ppl would have been more blurred, and there would be light streaks through that blur, depending on the location the train goes through at the moment, this could be a pain..so it is rear curtain.</p>

<p>i took about 50-60 shots. they were all sharp<br>

i had one over exposure as light situtaions change alot when you do such a thing and it kinda blew out all the light as we went </p>

<p>flash photography really is alot of fun but comes with some stuff yo uhave to figure out.<br>

if it was too easy, it would be boring, wouldn't it :)</p>

<p> </p>