at 1/300 or fast on my D300, there is terrible random discoloration

[gabriel_afana]

Has anybody ever heard of this? I was messing around with my 50mm f/1.4 and I noticed that if I take several pictures one

after the other, each photo will look slightly different. Some will have this brownish shadow/overcast on random locations

(sometimes on the right of the pictures, sometimes on the left of the picture....top corner, bottom corner...etc).

 

This happened on a D300 and a D80. I thought it was the 50mm f/1.4 lens, but it happened with a 17-50mm as well.

 

I did many tests and concluded that the determining factor was the shutter speed. Anything faster than ~1/300 it becomes

noticable. slower than that it looks perfect. I can take 10 pictures in a row and they all look the same. At 1/500 or 1/1000,

if I took 10 pictures in a row, each picture will look completely different with this crazy brown shadow/overcast.

 

Does anybody know what this is?

[Jerry_]

A guess: the light 'flickered' in your room and the slight variation of light made each of your exposures unique.

 

 

 

If you test in sunshine, chances are good you will get the same result using Manual mode....so long as you have Auto ISO off, and use one of the spot meters. If you use 'Matrix' metering, you may get some difference in exposure.

 

 

[And you are certain you do not have auto-bracketing on?]

[lex_jenkins]

Without seeing the photos and EXIF data this is just a wild guess, but...

 

Most of your photos are taken with flash in dark conditions and tricky club lighting, right? Could this be from using a faster shutter speed than the camera can sync with for flash?

 

For example, even with FP flash on my D2H and SB-800, results can get very inconsistent when pushing the combination beyond intended limits. The FP flash is only useful in very limited conditions.

[daire_quinlan]

I've actually seen this before, we puzzled over it for quite a while before working out what it was. In our case it turned out to be what Gerald W. Litynski said, flourescent lights in the room. The telling point is that it happens when you shoot faster than the sync speed, IE at no point is the entire sensor actually exposed. As the shutter curtains move down across the sensor the light is flickering at a particular frequency, so chunks of the sensor can miss out on being illuminated completely. Alternatively it could be your shutter dragging, which wouldn't be good news ...

[rainer_t]

-- "Some will have this brownish shadow/overcast on random locations (sometimes on the right of the pictures, sometimes on the left of the picture....top corner, bottom corner...etc). "

 

I guess the room was lit by fluorescent light. In that case, this is normal. Use a slower exposure time. 1/60sec will do. 1/90 might still be ok.

[gabriel_afana]

Wow, you guys sure are pretty damn smart! I can post the pics here, but you all already know what Im talking about.

 

Yes, I was taking pictures in my office (flourescent lights) with no flash...I will try shooting outdoors and see if that works (Sounds like it will be ok).

 

That is an interesting thing....so its basically the frequency of the light-wave that is not fully hitting the camera sensor that is causing that? Does anybody know what the frequency is of flourescent lights?

[rainer_t]

Technically, everything that uses AC directly (like tungsten bulbs and fluorescent lights do) will have an

oscillation frequency in their output that is double of the AC they are using (double because there is a maximum

in the power output at the positive input maximum as well as on the negative input maximum of the supplying

voltage... and because power is the product of voltage and current).

 

So, in the US, you'll have the light flicker at 120Htz and in most of the rest of the world, with 100Htz.

 

But there is something, that fluorescent light does, and tungsten light does not: Flourescent light changes its

color temperature throughout a cycle of its oscillation, and tungsten stays pretty much the same. Also, the

amplitude of the oscillation of the power output is higher with fluorescent light than it is with tungsten light.

This is why you will not notice this effect with tungsten light, but you do with fluorescent light.

 

The point is, your exposure time shall be long enough to catch about one full cycle. Only this will give you and

averaged and even colortemperature over the complete frame.

[gabriel_afana]

Rainer, thanks for your reply! Very informative