Strange over exposed arc artifact at fast shutter speeds in d5100?
I've had my d5100 for almost a year and a few weeks ago I noticed that on a few of my photos shot against a blue sky there was a very faint overexposed arc towards the left third of the image (landscape mode). I was able to track it down to only images taken with very fast shutter speeds (>1600) regardless of lens used (in one case, a Sigma 150-500, in the other, the Nikon 10-24mm wide angle). This artifact was in the same place in the images regardless of the location of the light source. I've put some sample images here
I sent my camera into Nikon two weeks ago (just a month shy of the warranty running out), described the problem and pointed them to the example photos. I received it back today - but the repair notice indicates 'no problem found'. Unfortunately, the weather here is such that I won't be able to take test shots for a few days, but I was wondering if anyone has seen this before, as I am worried that they didn't really investigate the issue. Could it have been something inadvertently fixed via the complimentary 'check & clean' (fyi - my sensor has been cleaned before this)?
UPDATE: Its still there. Used yet another lens (Nikon 55-300) and took a few shots on a very overcast day - sure enough, the arc was there at fast shutter speeds. Contacted Nikon and they asked me to send them some sample NEFs. This artifact can't be normal.
#1. "RE: Strange over exposed arc artifact at fast shutter speeds in d5100?" | In response to Reply # 0
This artifact can't be
No - there's something up there. The only physical thing I can think of is a fine hair but if you've looked and cleaned the sensor that seems unlikely.
The arc is opposite to the lens circle so that seems to rule out anything associated with that, but you've tried different lenses anyway.
How does an artefact like that get created either in firmware or on the sensor? A crack or fault on the sensor?
I hope you get a fix with Nikon - that's probably the path to pursue.
#2. "RE: Strange over exposed arc artifact at fast shutter speeds in d5100?" | In response to Reply # 1
Nikon cleaned the sensor as part of the servicing, and the artifact only appears at fast shutter speeds, so it unlikely to be a physical problem with the sensor itself. My uneducated guess is that it is a problem with the shutter - in fact, after much searching (this appears not to be a common problem) I was able to google a similar issue someone had with a Canon EOS 30D - a semi circular over exposed crescent in all shots at fast shutter speeds. In that case, it was suggested that this was the result of a problem with the synchronous operation of the shutter blades (http://photo.net/canon-eos-digital-camera-forum/00LS88).
Upon calling Nikon after I received my camera and found it still had the same problem, they requested I send some sample NEF files, which I did, and to their credit they did finally concur that there is an issue. I am now awaiting a prepaid shipping label to send the camera back.
What is very frustrating is that the camera was just there for two weeks for this exact problem - I wrote a detailed description of the issue and gave them both the links to my gallery showing the artifact as well as a link to the description by the Canon user. It seems that whomever serviced it during the first go around didn't actually investigate the problem by testing the camera at high shutter speeds - likely just ran the camera through some standard checks and stated 'no problem found'.
#3. "RE: Strange over exposed arc artifact at fast shutter speeds in d5100?" | In response to Reply # 2
Just an update. Nikon service returned the camera without fixing the problem a second time around, even after tech support recognized the problem. Once again, it appears Nikon service went through their standard series of diagnostic tests without bothering to actually test whether the camera body still exhibited the problem.
I am convinced that it is an early symptom of a failing shutter. Now I have uploaded new images at Nikon's request and will once again send the camera in. In my personal experience, Nikon service is pretty lame - nevertheless, I will keep sending the camera back (on their dime) until they fix or replace it - thankfully, it was originally sent in on a warranty repair.
#4. "RE: Strange over exposed arc artifact at fast shutter speeds in d5100?" | In response to Reply # 0
I suspect your shutter is the issue as it is an arc that follows part of the swing of the shutter mechanism...
Part of this video is the movement of the shutter at 1/10 of a second and makes it easy to see what is going on.
I am wondering if there is a gap of some sort allowing more light through at higher speeds, therefore overexposing that part of the image, causing your problem.
It might be there at lower speeds but more subtle. At any rate, Nikon needs to fix it. Good luck.
"Extraordinary claims require extraordinary proof " - Carl Sagan
#5. "RE: Strange over exposed arc artifact at fast shutter speeds in d5100?" | In response to Reply # 2
Just an update that hopefully may help/save someone else in the future.
Three times now I had to send the camera body to Nikon - the first and second time they sent it back indicating 'no problem found' (I am convinced they never really tested the issue at hand but just ran the camera through a set of standard tests). In both cases, Nikon support subsequently agreed that the problem still existed even after the camera was returned, and asked me to send it back in. Apparently, it is Nikon corporate policy that you need to send a camera back THREE times before they will consider a replacement (unbelievable! - it would be one thing if they tried different solutions each time, but clearly they did not). Sure enough, I sent it in a third time and they supposedly shipped me a replacement via overnight - except they don't have a tracking number to provide me with (really? Nikon doesn't track their shipments?) - and it was supposedly shipped two days ago! (We live in a quiet residential area and I work out of the home, so there is no chance it was delivered and misappropriated).
Be forewarned - Nikon support is as bad as it gets - if I wasn't so invested in lenses, I'd change brand loyalty (I still may). Oh, and I did ask at one point if I could upgrade the camera and pay the difference - nope, I had to get the same thing. I would have thought that it would be good business to sell a customer an upgraded model to keep their business. They obviously don't care.