Is his a problem with D700 you've seen before???

Discussion in 'Nikon' started by dmitry_kiyatkin, Feb 2, 2009.

  1. Hi, I am a little puzzled by something and I need help. I used to use D300 to photograph scale models. I use a small set of studio lights and 60mm lens. never had a any troubles. I use a D700 for my other photography. I want to sell the D300 and use the D700 for the model as well. I tried my setup today and am getting funny results. Feel like the bottom of the frame is darker than the top. This can be seen as I change the orientation on the camera. I shoot at 1/250 at f29. Camera to light is connected with a synch cord.
    Here is a pic in regular orientation:
    [​IMG]
    Here is one with camera in portrait:
    [​IMG]
    And finally upsidedown:
    [​IMG]
    Any ideas??? I use the D700 extensively for regular photography and never noticed any uneven tones in the frame.
    Thanks, Dmitry
     
  2. It looks more like sensor dust that dark spots
     
  3. No dust on sensor really. A couple of small specs, but nothing that bother me Nic. I do not know if what I mean shows up on monitor well.
     
  4. bms

    bms

    How are your lights set up? My guess it may be not the camera but uneven lightning - if it was the sensor or the lens, turning the camera upside down would reverse it, no?. Why it would not look the same with the D300, I do not know, unless you cropped differently.... Just some thoughts....
    sorry, just reread - is the arrow pointing to the dark spot? I guess then it DOES change with camera position! It is not obvious to me, but if would probably help to photograph an evenly lit surface without the model and compare....
     
  5. Hi Ben, no the arrow shows camera orientation. The dark side changes with camera orientation, so I do not think it is the light.
     
  6. bms

    bms

    yes, sorry, I corrected my post above....
     
  7. bms

    bms

    I just took the liberty of copying your pics and adjusting contrast and brightness to make it more clear to myself. In your experiment, if you only altered the variable of "camera orientation", i.e. you did not change the lighting, camera settings or model position, there is indeed a difference. Weird....
    00SK8S-108043784.jpg
     
  8. What kind of studio lights? Are they compact florescents by any chance?
     
  9. No they are small 250W strobes with soft boxes. 2 of them. No modeling light. DK
     
  10. The only way this can happen is from eneven exposure from the shutter. A vertical format sample ought to confirm it realizing the composition will be crumby.
    You really ought to evenly light a flat white board and photograph it at the same shutter speeds rather than a sweep and then send the camera back for repair. You may very well get an arguement the sweep is not smooth. The board need not be in focus. Maybe mark it with a big capital B.
     
  11. You may be picking up vignetting especially stopped down like you are. I don't know how much cropping your doing on the photos attached to your post. On the D300 this would be less evident or not evident at all because of the crop sensor. On the full frame D700 you see it. If it is vignetting it should be easily corrected in most post precessing programs.
     
  12. That is totally strange. I don't think it is vignetting (what kind of vignetting is a linear gradient?) but I wouldn't discount the possibility (yet) that the camera is functioning fine, but something about what you are doing is causing the problem, or possibly the lens. I would vary the shutter and aperture in various ways, including one at a time while varying the ISO. I would keep the lighting exactly the same if possible. What you've done so far is to show that there is in fact a gradient at one set of settings. What I'm suggesting is to leave the camera in one orientation and change the camera settings to see if the effect changes at all.
    You may want to jack up the contrast as much as possible to amplify the effect. I'd do that first to make sure it amplifies with the current settings and then see if you can get it to increase and decrease.
    Nice Tiger model by the way. I used to build them when I was a teenager, but it has been years since I've seen one as well done as this.
     
  13. Why stopped down so much? On a lot of lenses this much aperture restriction leads to diffraction. Why not experiment a little with your aperture settings just to see what results you get? With that aperture setting the camera is telling the flash to go at full power I think. Or if you really need to stop down that much then maybe slow down the shutter speed to get a little more of the ambient which might help the problem you are seeing? When I have something happen that I don't fully understand I re-create the shot as best as possible and try altering the settings to see if I can arrive at a resolution.
     
  14. What's your shutter speed, and what's the duration of these lights, and how are you triggering them?
     
  15. This is a can be a combination of 2 issues. You're shooting at a 250th and shutter sync is just a bit off. I've experienced this occasionally. Shoot at 200th or lessand you'll be good. Also, depending on flash specs, your flash sources need more than a 150th of a second to discharge. High power settings require more time to discharge. Shoot at 1 stop higher ISO.
     
  16. Hi -- Your problem is your sync speed is too high with a focal plane shutter / studio lighting setup. Try 1/200th or even slower and re-test. In a studio setting there is no benefit to high sych speed for table top work anyway -- the flash duration trumps the shutter.. Ask me how I know!
     
  17. ANSWER
    Michael H, you win the prize - at 125th this goes away completely. I think this has something to to with the synch and shutter.
    My f/u issue is this - is the camera OK or is this something that should be repaired?
    Thanks for your help, Dmitry
     
  18. Probably, like I hinted yesterday, your lights have a long duration and/or your triggering mechanism introduces some delay.
     
  19. Dmitry -- This is a very common problem when working with external (non Nikon / CLS) third party light sources. It's caused by flash latency relative to the shutter opening time. In my experience Nikon flash units (SB800 / SB900 etc) will only give even exposure at 1/250th using CLS or direct hot shoe. Triggering with a Pocket Wizard (radio) things get uneven at anything above 1/200th. The situation is the same with my studio lights (Profoto) and focal plane shutters -- leaf shutters will sync much faster without these issues. This is not a problem with the camera (Nikon's claim of 1/250th is with an all Nikon lighting system) -- just need to be aware of it and use 1/125th or 1/60th. Provided you can control the ambient light in your studio it should not be a problem at all. I generally use a slowish shutter speed even when using leaf shutters since it's the flash duration NOT the cameras shutter that counts in the studio. I know guys that actually use the focal plane shadow like an ND grad filter to mask part of the frame when mixing ambient and flash on location -- it's a interesting technique.. --Mike
     
  20. Exactly. Try 1/200 and watch your problems go away.
     
  21. Guys, This fully answers my question and solves my problem. Photo.net is awesome. Thank you everyone, Dmitry
     

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