Photographing lights

[landyvlad]

Scenario 1. I'm changing the dash lighting in my 4wd to LED. I want to get some before and after shots which capture the actual difference in brightness.

What's the best way? Let the camera chose the settings for the 'before' and then manually program those same settings for the 'after'?

Scenario 2. Same deal but looking down the road with headlights on low and high beam, then add spotlights, then add LED light bar. Again to get a comparison of the overall lighting provided.


Advice welcomed.

I'm hoping to do the first one tonight !

[farmmax]

I'm no photographer, but scientifically, I would have thought the way to go would to use identical manual settings for both photos. Then if there is a difference it should show up. You will have to manually set everything that may be on "auto" eg ISO, colour balance.

[swifty]

Yea, manually set everything for the before shot.
But depending on how bright you expect the after to be, try and be conservative with the before setting because if the same settings result in severely blown highlights it would be difficult to ascertain the difference.
Basically you'd ideally want one set of settings to cover the entire dynamic range you expect to encounter in both the before and after shot.
But never fear, should you end up blowing the highlights in the after shot, you could retake the after shot but reduce the exposure by exactly x stops to obtain an acceptable exposure.
Then simulate the before shot in post by reducing the exposure by the same x stops.
If you don't expect the difference to be very big then the before exposure won't be so critical. But Farmax is right, just make sure the after exposure/settings are identical to the before ones.

[arthurking83]

Agreed!


My opinion on swifty's thoughts re exposure and blowing it out differs tho.


if the point is to show how much brighter the LEDs are, then you want at least one sample that with the non LED setup this is 'what I used to see'.

in the next setup with the LEDs, you want to highlight how much brighter they are.

I've taken a few images of my dash/headlights in some of my cars previously.
Settings were: (at 50mm) 1/15s, f/1.4, ISO1600. Those exposure values gave me a good indication of what I actually see with my eyes at night in a dark country environment.
At 50mm and 1/15s with no stabilisation, the dash is obviously blurry, but the lighting brightness is about spot with reality.

So if the LED lights make this much brighter and the image is blown out at some point, then you should show this to maintain a sense of comparative.

Same with the colour too. Whiter light is generally perceived to be brighter, even if the actual brightness isn't!
The contrast it produces with a grey/black road and environment changes that for us humans. It seems brighter because it's easier to distinguish differences in contrast.