Ok so I'm new to shooting sports. I am having trouble with WB indoors when shooting basketball. This is the situation.

I was shooting inside a gym with my 5Dmk2 + 70-200 2.8IS

Settings:
Manual
1/500
f2.8
ISO4000
custom WB by setting it at about 5000K

I was shooting with AI servo and burst a bunch. Even with my settings remaining the same the WB and exposure would differ from shot to shot when the subject was in the same position in both frames. My friend was shooting with his D700 and it yielded the same result.

So my question is by chance would this be caused by the type of flood light they used? If so how can this problem be resolved?

I wish I could post an example right now but I don't have access to the files.

TIA

RL15 wrote:
If so how can this problem be resolved?


It can't

P Alesse wrote:
RL15 wrote:
If so how can this problem be resolved?


It can't


So its not just me? What is the cause?

What you're catching is the lights going through their cycling. The only way to get around that is to use either a very slow shutter speed (1/60th or slower) or strobing to overpower the ambient lighting.

If you can't do either, then you can't solve the problem and have to deal with it.

John

Light cycling.

Most gyms have a WB of around 4000 - give or take, depending on age of the bulbs - and can vary at different parts of the gym. Maybe they have newer, updated bulbs to get you around 5000? If you want get a custom WB, make sure you expose at 1/60th of a sec.

The reason for your varying lighting is due to the lights cycling with the AC line. You'll possibly notice different lighting at different parts of the gym - even in the same frame. But the bulk of what you are experiencing is due to your shutter speed being able to capture the lights during their cycle.
What we see as normal light - is actually a fluxuation in sync with the current - going from bright white (with an almost green tinge) down to a deep red hue every 1/120th of a second (1/60th to complete a full cycle - hence getting custom WB when you have the full spectrum available) When you shoot from 1/120th to about 1/640th, you'll capture a portion of the cycle. No way to determine which part of the cycle you'll get.
The best you can do is set a WB to match the lights 'designated' color, and deal with the cycling - expect it. The only real way around it is to shoot less than 1/60th of sec - so you always get a full cycle of light. Otherwise, if you shoot 1/800th or faster, you'll minimize the gradient in your photos - but you'll still be at the mercy of where the lights where at the time of exposure.
Older Nikons and the Canon 1D were capable of this all the time because the exposure was controlled by the CCD - not by the shutter as is the case in all film cameras and newer (CMOS and LBCAST) sensors.

Here is what the lights cycling look like to a fast shutter:
http://public.fotki.com/Hammy/gym_lights/

You'll get the same result shooting under similar lights in outdoor fields at night.

Thanks guys!

I figured it had something to do with the lights but never knew this!

Thanks all!

Depending on the type of lights being used and how they are wired, you will see the lights cycle in color and intensity.

Strobing will be the best bet or you will need to do a custom WB for each shot in post processing.

Even if you plan on shooting RAW, the lights don't cycle in sync. Quite often, you'll see half your photo in green and the other half in red. My opinion... I have never and I mean NEVER had a parent or editor refuse a great shot because the light cycle wasn't right. Just deal with it.

Strobes rock for gyms.

timgangloff wrote:
Strobing will be the best bet or you will need to do a custom WB for each shot in post processing.

Custom WB doesn't work for the fact that the shutter blades and dynamically cycling cause a gradient:

Also new energy efficient lighting is dependent on activity levels in gym, probably rise in temperature. Our new lights are dimmer at begining of events, much brighter an hour or two later if there's enough activity. Indoor track has to be in the gym an hour before events to drive up the lights. It's crazy but saves about $15K on the electric bill. The electric companies subsidize the new lights, we've seen it in several gyms locally. Most have some type of windows providing light during the day. So in addition to cycling, brightness constantly readjusts due to activity.

I found I can generally do 2 white balances, one where gym floor is dominent, the 2nd where gym wall's are dominent.

another problem that i personally have experienced is that some gyms are now using different style lights which messes stuff up as well. it appears as you are dealing with cycling but keep a heads up for gyms with multiple temp lights on different sides causing problems as well.

Rl15, try strobing, indirectly, with good monolights for better results and do a custom balance to keep colors consistent. Ambient lights no longer become a problem.