During a routine test (yes testing has become a routine activity these days ;) ) for AF-C subject tracking using my D600, I encountered a weird output on some of the images. It was an inconsistent yellow band appearing randomly across the image. I first thought this has to do with my WB settings and forced it to fluorescent white balance and still saw the same phenomenon occur on some of the images.
Test Case Steps on my D600 with 24-120 F4 combo:
1. Shoot in JPEG or RAW.
2. Manual setting at 1/200 sec, f4, ISO 6400, 44mm
3. Continuous drive mode (This is the key to replicating this ...details will follow later)
Yellow band from middle to lower part of frame:
Yellow Band from Top to middle part of frame:
OK..my immediate reaction? along with a bunch of other disgruntled D600/D800 users, return the camera to Nikon and claim warranty. However, before taking any drastic measures, I wanted to double check if this had been observed by other Nikon D600 users and searched through various photography forums.
Guess what? This does not only happen with D600, but D800, D700...yes D700! and the discontinued D90 too..So what is causing this and do we have to live with these jaundiced images when shot under such lighting conditions? Good News! No ..Courtesy: few other photogs with a little more physics and electrical background, the reason is out there along with the fix for it..
Reason for Yellow Banding:
When shooting in continuous drive mode (a.k.a high speed shutter shooting, normally 4-5 frames per second) under fluorescent lights in the US, since the refresh rate for fluorescent lamp is 60 Hz, there is apparently some synchronization issue between the camera frame refresh and the light source refresh rates, in other words, if the shutter speed on your camera is not in the multiple of 1/60 (for example, 1/200 sec like the test case above), you will see yellow banding across the frame in a random fashion!
If not shot with the correct shutter speed, there is no way to fix this, even if you shoot RAW!
WB adjustment in RAW Post processing workflow will not fix this!!
FIX:
When shooting under fluorescent lights, ensure your shutter speed is in synch with your light refresh rate. In the US, it is 60Hz, so shutter speeds like 1/60, 1/125, 1/180 should take care of this banding.
For countries like India/EU: I believe it is 50Hz (so shutter speeds in multiples of 1/50 should work fine)..similarly the more recent twisted fluorescent bulbs have 80Hz refresh rates..so multiples of 1/80 may be required
Below is a test case to avoid the yellow banding
1. Shot in JPEG setting
2. Manual setting at 1/60 sec, f4, ISO 6400, 44mm
3. Continuous drive mode (This is the key to replicating this ...details will follow later)
Image without yellow banding
So when next time when you see yellow bands under fluorescent lights, check your Shutter Speed settings..it will save you from heart stopping moments and also some time in not dealing with the camera vendors with return hassles.
I am not sure if this is observed by my Canon buddies, if it is due the light science phenomenon explained above..It is bound to happen on any camera ..unless the camera is smart enough to sense the source and auto adjust the shutter speed ..am I expecting too much from Nikon? I will first let them fix some of the bigger issues in the next firmware update :)
Hope you find this information useful..
Until next time.....
