Under exposed pic but have no clue why

Discussion in 'Nikon DX DSLR' started by Nik-onRules, Jul 31, 2007.

  1. Nik-onRules

    Nik-onRules

    27
    Jul 31, 2007
    Ottawa
    I'm new to this forum and this is my 1st post, so if this is in the wrong category please let me know.

    My partner and I shot a wedding this saturday , and for some reason a searies of pictures were under exposed which never happend to us. We both shoot with Nikon D200 and all other pictures turned out great.

    Here are 2 examples of some shots.

    Saturday conditon were rainy, lots of clouds, very humid everything outside, when raining we were under something for the pics and on the side of a river.

    1st pic.

    Wb: Flash
    ISO: 200
    Aperture priority
    1/640 f8

    Lens was a 35 - 70mm 2.8 Nikkor
    focal lenght 58 mm

    Flash SB800 set to TTL BL FP. Now I did some comparison between the cameras and flash, trying to see what went wrong and realized that her flash had a little M activated. According to nikon material this put the flash zoom head on manual. So a lot of the full lenght shots seems light the focal lengh is too far from the subject and that the flash because on manual was not set toa proper focal. That's my theory but i could be wrong.

    You will see with the pic it looks like the flash never kicked in, there is no catch light in the eyes and the faces are not even lit up.



    [​IMG]





    2nd image

    Wb: Flash
    ISO: 200
    Aperture priority
    1/640 f8

    Lens was a 35 - 70mm 2.8 Nikkor
    focal lenght 52 mm



    [​IMG]




    We think it has to do with that M on the flash. Because not all her pics turn out underexposed. She thinks that at 1 point she made a changed to the flash and it might of activated this option.

    Mine turned out great and that was the only difference between our 2 cameras was that M on the flash.

    We did a small test yesterday but unfortunetly the conditions were not the same so the test did not help. We will need to retest on another cloudy, low light and on the side of the river to see if that was the problem.

    Thanks for all your answers in advanced.
    Dan
     
  2. It probably was the batteries dying, rather than the manual zoom on the flash. These images were at 50mm+, which is roughly in the middle of the flash zooming range, so it couldn't have that dramatic an effect...

    Also, with a 1/640s shutter speed (well over the sync speed of 1/250s), the FP feature of the flash had to come into play, thus reducing your lighting range (it takes a lot more power in FP mode, with the multiple firings), further depleting the batteries. This was even further accentuated by the f8 aperture: as you know, it takes twice as much light to illuminate a scene at f/8 than it does at f/5.6, and 4 times as much light than at f/4.

    Finally, the background is pretty dark as is, and I am not sure that TTL BL was the right mode there, perhaps TTL would have done a better job, but not on dying batteries. All kinds of weird things happen when the batteries get weak. I would suggest changing them at fixed times (or number of shots), rather than waiting for them to show signs of weakening.
     
  3. Nik-onRules

    Nik-onRules

    27
    Jul 31, 2007
    Ottawa
    Hi Philippe,

    Thanks for the feedback. I was thinking about the batteries but I changed them before that. My rules on batteries are, we do the brides house if shooting outside, the groom and the church. Then no matter what, before we go to the park I put in a new set of batteries.

    But these are rechargables, so i'm wondering if maybe, they are no longer able to keep a stronger charge. I had them for 2 yrs.

    This is strange since have been shooting with the D200 for 3yrs in the same conditions and never had this problem.

    Thanks,
    Dan
     
  4. Baywing

    Baywing

    Feb 22, 2005
    CT USA
    I assume that the problem only occurred with your partner's rig. Is the flash mounted to the camera hotshoe or on a bracket? I recently had some problems with a flash sync cord when using my SB800 on a bracket, there were random shots where the flash didn't fire. I haven't had the inclination to do a thorough check, but the sync cord is my prime culprit. If your flash was directly attached to the hotshoe, search these forums as I recall there have been several issues lately (within the last month-6 weeks) where the SB800/D200 combo was having erratic flash triggering. Some seemed due to improper seating of the flash on the camera, others seemed to be D200 issues. You may need to send both units in to get checked.
    I'd suggest a test run with the gear, maybe sit it on a tripod so you can see what is going on.
     
  5. Nik-onRules

    Nik-onRules

    27
    Jul 31, 2007
    Ottawa
    The flash is sitting on a bracket and not on the D200 directly. I use the nikon cord SB-21, something like that.

    But that is a good idea, did not think of the cord that might be the culprit. I'll do some reasearch on that avenue.

    Thanks,
     
  6. Baywing

    Baywing

    Feb 22, 2005
    CT USA
    If it's the SC-29 (or earlier SC-17?,19?) there are several very small gauge wires in that cable. One little pinch or kink seems enough to break one, usually the one that matters most:biggrin:. I use a Stroboframe bracket that pivots for verticals, and the cable really likes to drape in the joint area where it would get pinched if I don't pay close attention. That seems to be the weakest link, and the cheapest fix.
     
  7. Exif mentions flash as the light source and "strobe return light detected", so it looks like the flash did fire.
    If the flash was properly directed at the subject, I'd have to go with Philippe's reasoning.
     
  8. Nik-onRules

    Nik-onRules

    27
    Jul 31, 2007
    Ottawa
    We too uses the same bracket Stroboframes. You are correct Nikon cable is way too long and it can stay stuck in the joint when you flip the camera on the side and the flash on top.

    These are all good suggestions and i need to investigate deeper.

    Thanks,
     
  9. Just an observation, but her bouquet seems to be dead center of the frame shown, now if the camera flash did not fire and the meter was set to spot metering (off the white boquet), then ...
     
  10. Nik-onRules

    Nik-onRules

    27
    Jul 31, 2007
    Ottawa
    We did not do a spot meter on the bouquet. I rarely use the spot meeter.
     
  11. At ISO 200, F8, 1/640, and SB800 set to TTL BL FP, the flash is only good out to about 8 feet max. To check that, try those settings again, and look at the distance scale on the back of the flash. Anything beyond that distance is going to be underexposed. It looks like you were a good 10- 15 yards away from your subjects. You are just asking too much from the flash. You will have to get closer, or open up a couple of stops.
     
  12. BINGO!!! We have a winner!
     
  13. Nik-onRules

    Nik-onRules

    27
    Jul 31, 2007
    Ottawa
    Yep, those are all good suggestions. I need to retest once I get another day like we had on Saturday.

    I went and look back at all the pictures last night from when I changed the baterries, which we took a lot of pictures on that set and they are nice, but once we moved down to the water and the lighting condition re-change, I think the batteries might of been starting to loose it's charge plus the combination of distance and the f stop. It was so humid, so that might of contributed to the batteries being low on charges.

    I also notice that in the camera usually 1 battery usually last the complete wedding, but by dinner time, i had to change the battery in the D200. So i'm leaning towards the batteries in the flash.

    Thanks you for all your feedback.

    dan
     
  14. francishmt

    francishmt

    152
    Jun 29, 2006
    Dan, I think I may know the answer to your question.

    If you have the stofen on, or the SB800 diffuser is pulled out (even oh so slightly), it will default the flash to 17mm manual. This means the flash won't "zoom" out for extra power.

    Just make sure the diffuser is all the way inside next time. It should solve the problem. Let us know if this fixes it.

    Francis
     
  15. Nik-onRules

    Nik-onRules

    27
    Jul 31, 2007
    Ottawa
    Hi Francis,

    what do you mean by "stofen on"? do you mean the little white plastic dome that you put on the flash to diffuse the light?

    As for the pull out diffuser I don't use it that much and we did not have it on this particular shoot.

    I tend to use the pullout card and give and angle to the flash.

    But thanks for the info i did not know that it defaults the flash to 17mm automatically. That's good to know.

    I love this site you guys are amazing....:Wink:
     
  16. francishmt

    francishmt

    152
    Jun 29, 2006
    Yeah, the "stofen on" is that white plastic dome.

    Even though you didn't intentionally pull out the diffuser, it's possible the diffuser is not tight in position, therefore putting the flash at 17mm.

    If that's not the problem, then I have no idea.

    Francis
     
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