D700 Underexposure Puzzle

[ant_nio_gomes]

<p>Hi Rob,<br>

Never eared of something as "reciprocity failure of the sensor" and the concept applied to film was at the opposite side - long exposures.<br>

As you started from F:16 to maximum aperture and you did use lenses with automatic diaphragm there was no reason to have maximum effect with the lens wide open - as at this set it would need to move the blades.<br>

It doesn't seem to be a metering problem as you measure a correct exposure at F:16 and adjust the other ones manually.<br>

On the speed side it would only make sense if the camera was fastening the speeds too much and when you cut from 1/10000 to 1/8000 you still get the effect - and 1/8000 is the maximum speed your camera can get.<br>

Considering all this, the situation is rather strange and we can make only guesses but I thing only service can give you an answer. Maybe a processing or circuits problem, related to a component or charges control, but who knows?<br>

Regards,</p>

 

[Rob F.]

<p>Well, thanks for all the time and trouble you all have put into your responses. The vast majority were not only helpful, but polite and respectful. The D700 is now on its way to Nikon, and we will see what they come up with.<br>

The repair will take 6 to 8 weeks! At least I have my D300 in the meantime.<br>

Thanks again.</p>

[john_tran14]

<p>I have that problem with a lot of my cameras (film SLR and DSLR), it's shutter speed inacuracy. The fastest speed (1/8000 in your case) is mechanical speed without any delay. This speed is supposed to be calibrated well in the factory but it is not accurate now. You got underexposed because this highest speed is too fast, almost like the shutter opens and closes right away. All the other speeds is calculated after that by adding a delay. This delay time is usually accurate but because of the involvement of the wrong 1/8000, the slower speeds are also wrong. However, the slower the shutter speed, the less effect of the mechanical speed and the result is better</p>

<p>It's like you lost 1/10000 sec of exposure time for every exposure and that is nothing when ss is 1/250.It's more important when ss is 1/3200</p>

[mike_halliwell]

<p>In which case put a 4 stop ND filter on and redo the test. That will take all of the high end shutter speeds out of the equation.</p>

<p>If the 'problem' still exists, it's not the high shutter speeds. </p>

 

[Rob F.]

<p>John, that sounds like the clearest explanation yet. Not a very happy one, but clear. If 1/8000 is only a mechanical speed, not electronically timed, and all the electronically timed speeds are dependent on 1/8000, it sounds like ongoing trouble, since mechanical speeds--especially fast ones--get out of whack at the drop of a hat.</p>

<p>Mike, my D700 is now in the hands of the Nikon techs. The ball's in their court now. Not a bad idea, though.</p>

[michael_hamann]

<p>Rob, thank God for your post. I have a d700 with the exact same darn problem. I have posted on a couple of sites and spoken to Nikon, but no one can figure it out.<br>

For me, anything below 50mm e.g. 35mm requires exposure comp. The 35mm F2 requires between .3 and 1 depending on setting, while my Sigma 12-24mm at 12mm can require +3! I also used 28mm AIS and 20mm both which had the same results.<br>

Please contact me through website to see what Nikon finds!<br>

I love my D700 but have always been frusted with this issue.</p>

 

[Rob F.]

<p>So . . . the plot thickens. Could be it's a design glitch, in which case I sent my camera in for nothing. Funny I was never aware of it until recently. I shoot wide-angle all the time, every focal length from 15mm on up.</p>

<p>We will see what they say. I'll let you know. Thanks for that info!</p>

[Rob F.]

<p>Nikon returned the camera with a note saying there were no exposure issues. Then the camera store staff figured out that the problem was being caused by my having aperture control set to the aperture ring. While it was at Nikon, they changed it to the command sub-dial. The camera now exposes normally at wide apertures/high shutter speeds. The mystery is apparently solved.</p>

[tom_boston1]

<p>Rob, thanks for the update. It's great that you can get correction exposures across all f-stop and shutter speed settings now.</p>

<p>But wouldn't this mean that there is some sort of problem related to the AI meter coupling ring. My D700 is out on loan. But after I get it back I'll put some non-G lenses on it and see what results I get using the aperture ring to set f-stop.</p>

<p>Good catch by the store staff by the way.</p>

[mike_halliwell]

<p>So, nothing wrong what-so-ever with the metering, just mechanics. Excellent.</p>

<p>If setting the aperture via command sub-dial has 'corrected' all errors, as Tom says, there's still something very hinky with the mechanism. Using the A-ring to set the aperture doesn't actually move anything other than the 'position-to-stop' for the blades on stop-down when the shutter is tripped.</p>

<p>Testing! If you do a simple manually set test 1) by using the A-ring, and the same set with 2) the Command dial and 'pair' them, you might see where it's going funny.</p>

[Rob F.]

<p>Not a bad idea. I might just try that!</p>

[andylynn]

Could this be what the new firmware update is for? Or is it just that without the D lens info enabling 3d matrix metering

it's not as good at compensating for highlights and back lights?

[mike_halliwell]

<p>Looks like more testing for Rob! :-)</p>

<p>My D700 has -0.3>-0.7EV set and locked for nearly all outdoor, ie not studio, use. I'll see how it is this weekend then I'm out again.</p>

[EricM]

<p>I'm going through the same problem with a new used D700. 24mm af-d. It doesn't matter what meter modes, but I have unpredictable under exposures when wide open. Is there a solution to this, Rob?</p>

[mike_halliwell]

<p>Eric, does this result in shutter speeds over 1000th sec? I wonder if the correspondingly fast shutter speed is proving problematic to achieve? I'd expect this to over-expose, ie can't go fast enough, but the leading and following shutter blades work kinda differently.</p>

<p>How many actuations does your 'new' used D700 have?</p>

[EricM]

<p>Mike, it has 31,000 actuations. I just put on my my 24 prime and started shooting a friends kitten and dog under even lighting condition, in a living room, on a couch, all at f2.8, A priority, and most frames are releasing around 1/60th then sudden random under exposure at 1/250 and then the next at 1/640, then the next back to normal around 1/60. Then I moved on to anther part of the living room and it starts at 1/800, 1/1000, 1/800, then back to normal at 1/250. I can't replicate the problem on either matrix or CW metering. It just does it on either or metering option.</p>