GF1: White Balance for Light Sticks?

[ctawn]

I tried to take some shots that included light sticks at an amusement park. Plenty of ambient colored lights in trees. So I set GF1 to shutter speed priority mode (30). Everything turned out as expected except the colored light sticks, which were almost entirely white. Playing with white balance settings didn't seem to matter. Is this some kind of limitation of florescent lighting? They looked normal in the digital view finder...

 

[f6cvalkyrie]

Hi,

without seeing an example picture, I can only take an educated guess : the fluorescent tubes are overexposed. This is very often the case when you expose dark (evening) scenes with visible light sources. They are too strong compared to the rest of the scene. You could expose for the light sources, but then the rest of the scene turns too dark. The dynamic range of the scene is just too big to be registered correctly.

One way around it : HDR with a shot for the highlights and a shot for the shadows.

I hope this helps :smile:

C U,
Rafael

 

[photoSmart42]

Were you using AWB (auto white balance), or custom WB? AWB is limited in its interpretation of what is white, so it's best for situations with complex lighting to do a custom WB using a gray card. It could also be an issue of overblown highlights caused by the intensity of the light stick if they were really bright compared to the rest of the background.

Sometimes these things happen because we're dealing with software algorithms that are a software programmer's interpretation of how the sensor should interpret the world it sees.

 

[ctawn]

exactly, the educated guess is correct -- the light sticks were over-exposed. it was on AWB but I adjusted it up and down with the dial to no effect. no idea what HDR is... and it seems like you're saying even with a grey card there's no way to get both the color of the light sticks and the background. but what puzzles me is why does the preview look just fine?

 

[photoSmart42]

exactly, the educated guess is correct -- the light sticks were over-exposed. it was on AWB but I adjusted it up and down with the dial to no effect. no idea what HDR is... and it seems like you're saying even with a grey card there's no way to get both the color of the light sticks and the background. but what puzzles me is why does the preview look just fine?

I think the software for the preview in the EVF/LCD errs on the side of brighter lights (it's also a function of how you've set up your metering), so while you saw the glow-stick more clearly in the EVF/LCD, what you probably didn't notice was the loss of detail in the shadows.

If you want to capture the glow-stick specifically, you might have to do a spot meter on it, then do an AE lock to lock in that exposure before you move your camera to compose the scene the way you want. You'll lose detail in the shadows, but that's the compromise of having a limited dynamic range.

 

[f6cvalkyrie]

no idea what HDR is...

To learn more about HDR (High Dynamic Range), this may be a good starting point :

High dynamic range imaging - Wikipedia, the free encyclopedia

C U,
Rafael

 

[ctawn]

To learn more about HDR (High Dynamic Range), this may be a good starting point :

High dynamic range imaging - Wikipedia, the free encyclopedia

C U,
Rafael

I see... thanks, I'll study that. Any specific ways to implement that on the GF1 that you can recommend?

(I see for sure I'll need to use RAW mode. Seems like a tripod would also be essential.)

 

[f6cvalkyrie]

Sorry, ctawn, I don't own a GF1 but a G1.
In general, you can do it with one or more RAW - files.

If you should just one RAW, then develop it 3 times, at - 2 stops, normal and +2 stops. Merge these 3 pics and adjust parameters of merging for your liking.

If possible (camera on tripod and no moving objects in the frame), try shooting 3 pics (minimum), at -2/0/+2, develop them normally and merge.

Be aware that on many forums, participants can react rather hostile on "overcooked" HDR images. Have not seen any such reactions here, but you never know

Have fun, the serious work is just starting.
After HDR, there is still "focus stacking" left ... and many other techniques

Rafael

 

[f6cvalkyrie]

Sorry, I forgot to add this link for interesting tutorials on HDR

HDR Tutorial | High Dynamic Range Tutorial

C U,
Rafael

 

[JoepLX3]

Be aware that on many forums, participants can react rather hostile on "overcooked" HDR images. Have not seen any such reactions here, but you never know

Personally I like it for a limitted amount of picture within a collection and only if you keep some kind of "natural" look, that is as if you could have made it in darkroom, but then inside your PC .