# Please Help..My Canon 6D Problem



## Kennysyl2e (Jun 27, 2014)

Please help me..regarding on my canon 6D problem.
Anybody can tell me what is the problem on my camera?
My setting is Manual, ISO 500, s. speed 500, F 1.4 . I have try another setting of colour white balance, but all come out also like that..!!


----------



## Max ☢ (Jun 27, 2014)

Hi,
If this scene was illuminated by fluorescent or other discharge lamps, then you don't have to worry as what you see here is a stroboscopic effect between the light output cycle from the light sources (both intensity and color of the light change in a cycle whose frequency depends on how the lamp is driven) and the image recording from your camera. This can be solved by changing to a longer shutter time.


----------



## ajfotofilmagem (Jun 27, 2014)

The ambient lighting was fluorescent lamp, right? This type of lamp produces light pulses in cycles of 60 hertz. When shooting with a shutter speed much faster, you will see in the photo a small part of the cycle, where the color of the light is different, compared to the color of light in the complete cycle. In conclusion, this is a normal effect when shooting at speeds 1/100 or faster, with fluorescent lamps.


----------



## Max ☢ (Jun 27, 2014)

This peculiar lamp-camera interaction occurs also with other light sources than fluorescent tubes. Below is the aspect of a high-pressure mercury lamp which I shot a long time ago. The red band is the decaying fluorescence output from the yttrium vanadate coating at the moment when the mercury discharge is extinguished at the zero current crossing.


----------



## Kennysyl2e (Jun 27, 2014)

Thanks Max & ajfotofilmagem for your solution..
Yes, im shoot on fluorescent lamp. I change the speed to 1/200, then the problem can be solve.

Huh.. im worry is my camera problem..


----------



## Max ☢ (Jun 27, 2014)

you're welcome - don't worry about the 6D, although its not a perfect camera, it is not that bad. When problems such as this one arise, its often a problem of settings incompatible with the lighting properties of the surrounding environment.


----------



## Mt Spokane Photography (Jun 27, 2014)

Kennysyl2e said:


> Thanks Max & ajfotofilmagem for your solution..
> Yes, im shoot on fluorescent lamp. I change the speed to 1/200, then the problem can be solve.
> 
> Huh.. im worry is my camera problem..


 
Changing speed to 1/200 is not the answer. The light flickers with the 60 hz powerline, so slow down the shutter. 1/60 or slower is best


----------



## Kennysyl2e (Jun 29, 2014)

Changing speed to 1/200 is not the answer. The light flickers with the 60 hz powerline, so slow down the shutter. 1/60 or slower is best
[/quote]

Thanks Mt Spokane , I will learn it.


----------



## Max ☢ (Jun 29, 2014)

Mt Spokane Photography said:


> Changing speed to 1/200 is not the answer. The light flickers with the 60 hz powerline, so slow down the shutter. 1/60 or slower is best



When discharge lamps are driven at mains frequency (not always the case, newer systems work at higher frequency) the flicker occurs at 120 Hz, not 60Hz, because as opposed to current, light does not have a polarity. So, in principle a shutter time of 1/120s or less is safe. In practice, however, the flickering effect is still minimal even with a shutter time spanning 1/2 to 3/4 of the light flickering cycle because the lamp is in the off state only a fraction of the total cycle (typically a ms of less out of the 8.3 ms flicker period), and this is during and close to this off-state that the lamp color changes the most. So, in practice 1/200s or less should be fine.


----------



## McSpike (Jun 29, 2014)

Just a query...
Obviously, many of us are from the US, where we use 60 hz A/C current.
In many other parts of the world, the standard is 50 hz. How much would that change the answer to the original problem? He fairly obviously is a English-not-first-language person, so may need the clarity?

With the math from Max, I gotta think he'd still be fine with around 1/200, but just wondering.


----------



## Max ☢ (Jun 29, 2014)

Yes, at 50 Hz the light flicker cycle would be reduced to 100 Hz, but the light duty cycle (ON/OFF phases) remains relatively unchanged, so a shutter time of 1/200s covers half of a light flicker cycle and this should be borderline-OK from a photographic point of view.

Below is an oscilloscope recording from a capacitive probe connected to a fluorescent lamp driven at 50 Hz via a magnetic ballast. The first and strongest potential spike in the waveform from from the bottom trace corresponds to the phase when the discharge extinguishes and re-ignites when the lamp current changes polarity (the top trace is a zoomed-in view of this phase). Neglecting the potential oscillations caused by electrons oscillations in the electrode region (this occurs at re-ignition while a specific current flows at the electrode interface with the mercury plasma), this phase lasts around 1 ms which is 1/10th of one current half-cycle, or 1/10 of one light flicker cycle. So a shutter time covering five times this ratio should be OK.


----------



## Mt Spokane Photography (Jul 6, 2014)

Max ☢ said:


> Yes, at 50 Hz the light flicker cycle would be reduced to 100 Hz, but the light duty cycle (ON/OFF phases) remains relatively unchanged, so a shutter time of 1/200s covers half of a light flicker cycle and this should be borderline-OK from a photographic point of view.
> 
> Below is an oscilloscope recording from a capacitive probe connected to a fluorescent lamp driven at 50 Hz via a magnetic ballast. The first and strongest potential spike in the waveform from from the bottom trace corresponds to the phase when the discharge extinguishes and re-ignites when the lamp current changes polarity (the top trace is a zoomed-in view of this phase). Neglecting the potential oscillations caused by electrons oscillations in the electrode region (this occurs at re-ignition while a specific current flows at the electrode interface with the mercury plasma), this phase lasts around 1 ms which is 1/10th of one current half-cycle, or 1/10 of one light flicker cycle. So a shutter time covering five times this ratio should be OK.


 
Unfortunately, the color changes as the light dims, as well as the flickering, so you want to average out the color fluctuations too. You might get 80% keepers at 1/200 and 95% at 1/100, but close to 100% at 1/50.

If you have only one chance to get the shot, be conservative. If you are going to take several shots, just scratch any with bad lighting.

Lighting with electronic ballasts is the way to go, but sometimes we don't have a choice.

Even without flicker, the color of a old technology fluorescent light can be difficult to correct, and when its mixed with incandescent light, its frustrating.


----------



## privatebydesign (Jul 6, 2014)

Good illustrations here.

http://www.guyrhodes.com/photo/wb_experiment_large.jpg

http://www.guyrhodes.com/photo/flicker_lapse.gif

http://www.sportsshooter.com/message_display.html?tid=20873


----------

