Limitations of conveying power of beam photos

Through experimentation, I found that digital camera is nowhere close to showing the difference in brightness the same way our eyes see it perhaps due to limited dynamic range.

With a light dimmer, lamp and a camera with manual controls, light up something at max brightness and manually set the shutter speed & aperture, so the EV reads +2.

Keeping the camera setting the same, dim the light down until you can barely see the lit surface in camera's screen.

Compare the difference between the perceived brightness difference between two pictures and the perceived brightness difference between the two dimming levels of the actual photographed surface with your own eyes.

You'll immediately notice that the difference is far more dramatic in photo.

That's only a problem if you expect to establish some kind of "standard" of beam shot, but that's not possible.
The purpose of beam shots is only to compare one light to another light in the exact same setting and with the exact same camera settings. That means that the only standard you can determine is between the lights you shoot during one session.

If you adjust the camera best to make the brightest light in your test session to look as "normal" as possible (to what you see with your eyes), and then take all the remaining shots without touching the camera, you will arrive at a good relative comparison of lights, but only between the lights you used in that session.

Handlobraesing said:

Through experimentation, I found that digital camera is nowhere close to showing the difference in brightness the same way our eyes see it perhaps due to limited dynamic range.

With a light dimmer, lamp and a camera with manual controls, light up something at max brightness and manually set the shutter speed & aperture, so the EV reads +2.

Keeping the camera setting the same, dim the light down until you can barely see the lit surface in camera's screen.

Compare the difference between the perceived brightness difference between two pictures and the perceived brightness difference between the two dimming levels of the actual photographed surface with your own eyes.

You'll immediately notice that the difference is far more dramatic in photo.

Click to expand...

Perhaps someone should try taking HDR beamshots... all it takes is at least 3 different exposures per shot (they're static, so no worries there), and a little work with the computer. Photoshop CS3 will do HDR automatically... and there are a number of free open-source plugins for Gimp that will do it automatically as well.

Bracketing the image and superimposing them onto each other with each section highlighted in a pie graph type illustration would be a pretty good method, time consuming but effective.

When there are more than one light compared on the same frame gives the best overall impression of the lights in relation to one another.

Yes, the human eye perceives far more levels of brightness than any digital can. Film is a bit better, but nowhere close to the human eye.

in video they call that "contrast ratio" some opinions vary, but the contrast ratio of the average cameras is about 3 or 4 to 1, Film can have more like a 30-1 contrast ratio, and eyes can have more like 100-1 contrast ratio, and eyes are also totally Auto besides.

and that is why lighting for film was so different than just seeing in person, then the video or digital light collection made that many times worse, making lighting for video/digital even harder than film.

Contrast ratio is one reason why i have such troubles taking beamshots of anything, drag out the film camera, take it to be processed (and hopefully not adjusted by the processor) , then scan that in, and you get a bit more "reality", more contrast ratio to work with originally. Such a Pain.

with film you can easily see both spill and spot for example, in one picture, without either a lost spill or a burning spot in the center.
or you just go to a local CPF meeting :thumbsup: where you can compare hundreds of lights and mods and crasy stuff .