Uneven field lighting

[ac12]

Based on my experience shooting on my high school field at night, I knew the lighting was uneven.
So, I decided to get some FACTS.

So, with an incident meter, I metered four positions on the field, measuring the light from the four standard directions.
Meter at ISO 2500, shutter speed 1/250 sec.
So as to not get in the way of the teams practicing, I only metered the field in four locations, which I presumed would mirror to the rest of the field.

This is the result:

In the pic, north is to the left.

There are only TWO light stand on each side of the field.
Light stand are on the north (left) side are on the 10 yard line, on the south (right) side on the 15 yard line.

Things that I noticed:
- The center reading of f/2.8 to the N. I had thought it would be even in all four directions.
- In the center axis of the field, on the 50 facing S is f/4, but on the 5 it is f/2. I need to determine where it drops to f/2.8
- In the center on the 5 yard line, the f/2.8 to the W and the f/4 to the E, bothers me. I expected the E and W reading to be identical.
- I thought there was less light near the sidelines, but I wasn't sure. Now I know the sidelines are a stop down from the center.
- In the corner, facing W, the f/2 backs up my shooting where I thought it was 2 stops down from the center of the field. But interestingly the f/2.8 reading facing N, is the SAME as the center.

The unexpected readings tell me that I need to go back and measure the ENTIRE field, as the lighting does not appear to be as balanced as I had thought it was.
And, I need to determine the contour lines for the aperture changes.

 

[480sparky]

Unless you're in Texas, high school football fields general are not evenly lit like an NFL stadium. Maybe it was addressed when the lighting was first installed, but over the years, HID lighting ages, changes color, and drops in light output. Reflectors get dirty, as well as bumped out of alignment. It might be possible to do a proper assessment and correction of the issue, but I doubt any school board is going to agree to drop the dime for it just for some photographer's sake.

 

[NS: Nikon Shooter]

… I doubt any school board is going to agree to drop the dime for it just for some photographer's sake.

Unless they got the cup?

 

[ac12]

Unless you're in Texas, high school football fields general are not evenly lit like an NFL stadium. Maybe it was addressed when the lighting was first installed, but over the years, HID lighting ages, changes color, and drops in light output. Reflectors get dirty, as well as bumped out of alignment. It might be possible to do a proper assessment and correction of the issue, but I doubt any school board is going to agree to drop the dime for it just for some photographer's sake.

Yes it does seem that the lighting level has gone down since last year.

No, I am not implying that I want the school to even out the lighting.
I am trying to determine the lighting topography to better figure out how to shoot the field.

 

[ac12]

I did the full field, but my some of results conflict with the first test.
I think the use of the incident dome is the problem.
Example, middle/south (on the right) looking south measured f/2.8, where the last time it measured f/2.
I did notice that the incident dome was being illuminated by the lights coming from the side, so the south facing measurement is being affected by the side lights. The side of the incident dome is like the sides of the players head, NOT the face.

I think I will do this again, but using the FLAT disc, by eliminating side lighting, the light measurements will be more directional.