Flash questions.

Discussion in 'General flash photography, lighting, and technique' started by bmiller, Sep 15, 2008.

  1. I'm slowly getting a handle on using the sb-600 flash.The folks on this website have been quite helpfull and i appreciate it. I just have a couple of questions to help clarify a few things.
    When indoors, with the camera on manual i have been metering for the room on center weighted, and setting shutter speed to underexpose for 1 stop.Is this done with the flash on or off ? Does the camera care? In the limited cases i've tried it doesn't seem to matter.
    I haven't read anything about direction of the flash head. Indoors i've been trying a Demb with the head pointed up at 45 degrees.
    When using flash outdoors on a bright sunny day i have my D300 set to 1/320(FP) flash sync speed. At 1/320 shutter speed, ISO at 200 flash on TTL-BL do i adjust aperture to expose properly. Secondly what metering do i use outdoors?
    Things a slowly coming in focus.
    Thanks again for your help.
     
  2. If you want to underexpose/overexpose the ambient light only (not flash), you do that with the camera on manual and you do it with the shutter speed or aperture , but make sure the subject is in range with the aperture being chosen . You can use the EV compensation on the camera when using P ,A, S mode , but this will effect the flash and ambient light both . If you want to adjust flash exposure , you do that with the exposure compensation on the flash (it will have no effect on aperture/shutter speed , but will effect the output of the flash). Outdoors I will use matrix metering with flash set for ttl-bl . I usually use shutter priority and set shutter to 1/250 , but if I want a larger aperture to blur background , than I will set camera to sync. at higher speed using FP.
    Here is an example using high speed sync. 1/4000 @f2.8 / SB-800 / 85mm
    102512756.jpg
     
    Last edited by a moderator: Sep 16, 2008
  3. Thanks Bill. I get the shutter speed ambient relationship, and also adjusting flash output for subject exposure. The Tutiki tutorial states to meter ambient and adjust to -1 using shutter speed dial. So far this is working ok. I just wasn't sure if the flash should be on or off at this point. Thanks for the clarification.
    I'll try matrix metering outdoors. Question about flash sync speed. That's a great picture. I have my flash sync speed at 1/320(FP). I sure didn't think you could go that high a shutter speed and still get a properly exposed picture. I thought the flash speed itself was only 1/1000 of a sec. so 1/4000 of a sec. exposure would be too fast for proper exposure. What do i know? I guess this is what high speed sync means.
    I assume outdoors you don't need to use manual. Shutter priority at max sync speed, adjust aperture for proper exposure and fire away, using of course TTL-BL. Adjust aperture if desired for DOF. Well it was worth getting up this morning. I learned something new.Thanks
    Brad

    P.S. Without starting another thread, i have an sb-600 and am thinking of getting the new sb-900. For those who have one, are there any big advantages over the sb-800.I could pick up a used sb-800 as there are lots for sale since the sb-900 came out. I looks like a much stronger flash, but bigger also.
     
    Last edited by a moderator: Sep 15, 2008
  4. With the D-300 and SB-800 combo using the FP mode , you can sync. at any shutter speed . I would assume that is the same on the SB-600 , but I'm not sure. Just remember that your flash range is greatly reduced and it consumes more energy when shooting above 1/250 , so you may want to be selective in using it only when you need the wider aperture or faster shutter speed. Normally outdoors when using flash I use shutter priority set to 1/250 , matrix metering , ttl-bl . (the reason for 1/250 is so it will choose a larger aperture so to get more range out of the flash)
    If I need a larger aperture to blur the background , than I will use FP and use aperture priority and choose an aperture needed , but of course you can do the same with manual or shutter priority , it all depends of what you are after . here is a site that explains high speed sync . , and how it works : http://www.naturescapes.net/082006/rp0806.htm
     
  5. Thanks Bill for the link. Your explanation clarifies high speed sync somewhat. This creates a whole new learning curve, but worth it in the end. I'll read the link a few times in the next couple of days and try out the high speed flash when the sun comes out.
    Thanks again
    Brad
     
  6. Subscribing for the good info here... :smile:
     
  7. The D300 has flash sync settings of 1/250, 1/250 (FP) , 1/320 (FP) among others. What is the significance of having 2 high speed sync settings? The help description at either one is basically the same. I can set it at 1/250 or 1/320 as max flash sync speed, and yet still set shutter speed much higher with either one. Not sure why there are 2 choices.
    The Dallas/ Philly game in HD is a beauty so far.
    Brad
     
  8. That is a good question , and I have no idea . I'm going to do a google search and try and find out. Were only talking about a 1/3 stop difference, so why would they offer a choice in the first place .
     
  9. The D300 manual is a bit confusing. It states on pg. 288 that high speed sync is activated in P OR A mode if the shutter speed is greater than 1/320 or greater than 1/250 sec. Pg 289 indicates via a chart that the built in flash will work at 1/250 (FP) -1/320 (FP) if camera is set to 1/320(FP) but will not work if set at 1/250 (FP). If anyone with a D300 that can figure this out, it would be appreciated.
    The P or A mode is something to remember.
    Just when i thought i was figuring this out.
     
  10. The manual is confusing to say the least. Beings they are offering a choice to choose , I would assume there is a reason for choosing one over the other. The manual don't explain that. No luck so far with google search. It seems everybody else is just as confused :biggrin:
     
  11. garyosborne

    garyosborne Guest

    If you follow Thom Hogan's advice:

    -for repeatable results shoot in TTL (not TTL-BL). TTL-BL tries to balance ambient light with the exposure, meaning it can do unexpected things

    -Shoot manual, set the exposure based on the BG light (underexpose -1 ev if you want) THEN turn the flash on, take test shots. DON'T shoot in P mode, you can't shoot at F2.8 in P mode so if you have fast lens it will be wasted.

    - set flash mode to rear curtain (this allows to shoot really slow shutter speeds, in the other modes this is restricted)

    -if the flash is not the main source of light e.g fill you will need to dial down the FEC anything upto 2 EV, again test shots are your friend
     
  12. Gary, is this Tom's guide for indoor flash, or is this the setup for indoor and outdoor ? Interesting about not using TTL-BL and rear curtain sync.
     

  13. Nice info. Thanks! :smile:
     
  14. garyosborne

    garyosborne Guest

    The info was from Thom's guide for the D300. I'd imagine his actual flash guide would go into much more detail. TTL-BL works well the thing is he was suggesting the results are not always repeatable. I have learnt to shoot in manual mode for flash work, using the cameras meter. I don't have the guide to hand but my post above was mainly for outdoor flash where the flash is not the main light source. Indoors (depending on the situation) the flash becomes the main source. i try to avoid black backgrounds which is common with indoor flash photos, therefore i would push iso up to say 400 and open the aperture up to get some detail in the background. I chimp until i get it right
     
  15. This is the second reference i've read about using TTL outdoors and not using TTL-BL. The D300 guide indicates the high speed sync only works in P and A. This is something o keep in mind, although in most cases setting the flash sync speed to 1/320(FP) would be a fast enough.
    In a case of bright sunlight and a heavily shaded area will a faster shutter speed be needed to cut down on blown highlights?. In a case like this do you meter the brighter area and then recompose on the subject in the shaded area? Matrix or center weighted? Point he head of the flash up 45 degrees towards subject and test from there.
    Gary i believe you said you use matrix outdoors.The Tutuki guide says to use center weighted indoors, which i have been using, and it works ok. Maybe i'll get Tom's flash guide, although the web has lots of conflicting info.
    So many questions.
    Thanks
    Brad