Tuesday, March 29, 2011

More on the GamiLight review...


Shortly after posting the GamiLight review yesterday I received several comments, one from Larry "From the photos, it appears to be pretty hot in the center" and another from Anonymous, "Looks very interesting, but I'd like it to be bit bigger. With that size, you can just do headshots...".

Let me address both of those comments (with info I probably should have mentioned as part of the post yesterday). I setup the light for a certain look... I wanted the image to be very bright starting in the upper left corner of the image then for it to fall of dramatically (with marked shadows) as the light (and your eyes) moved to the lower right corner.

Had I positioned the light differently, like pulling it further away and towards the front of my subject the light would have been softer, more evenly spread, and it also would have wrapped more.

Using a reflector (or two) would have helped by pushing the light into even more places.

The camera was set @ f11 and iso 200, a lower fstop and higher iso also would have helped in brightening up my subject as well.

Above is a setup shot from yesterday, in it you can see the GamiLight softbox in the upper left corner (and my daughter goofing around) the Nikon SB900 was fired manually with a pocket wizard and was set @ 1/16th power.

I hope this additional info will help folks realize that the GamiLight is a pretty darn versatile softbox.

4 comments:

Larry Wyatt said...

Hi Scott:

Thanks for the reply. Rapid fall-off certainly happened. :-)

I have a comment about your comment, "Had I positioned the light differently, like pulling it further away...the light would have been softer..."

I'd have to respectfully disagree. Bringing the light closer would have enlarged it's effective size and made it softer. Moving it farther away makes it harsher, no?

Have a great day. I read all of your blog posts and think you do a wonderful service for us photographers.

Larry

Scott said...

Hey Larry,

The closer the light is to my subject (using the Gamilight as an example) the less of the person will be lit and the harsher/bright/stronger the light will be.

With the box really close it will light only the top half of my daughter, but as I pull back the more of her will be lit, the inverse square law comes into play (the light falling off as distance increase and it covers more area).

There is a great image (and explanation) at this link that demonstrates this nicely:
http://en.wikipedia.org/wiki/Inverse-square_law#Light_and_other_electromagnetic_radiation

Also, the further I move back from my daughter the more the light will wrap around the outer aspects of her arms.

Do I have to take more pictures?

;)


Thanks for taking the time to comment here…

Scott

Larry Wyatt said...

Hi Scott:

Excellent dialogue.

You say, "The closer the light is to my subject (using the Gamilight as an example) the less of the person will be lit..." I agree completely.

You continue, "and the harsher/bright/stronger the light will be." Brighter and stronger, yes.(I'm a radiologist and have been teaching the inverse square law for 25 years.) "Harsher," I think not. Harsh(hard) light comes when the 'apparent' size of a light source gets smaller. Smaller apparent light sources create harsher(harder) shadows. Larger apparent light sources(move it closer to the subjject) create 'softer' shadows. Of course, angle of the light has a lot to do with shadows as well.

So, when you move the light closer, you have to diminish it's intensity by the square root of the distance change. In other words, if you move twice as close with the light, you have to decrease it's intensity by a factor of four to maintain the same light intensity on the subject. This can be done with aperture or by decreasing flash power.

So if you want to light your daughter's entire body, you have to move back farther, increase flash power, but the shadows will be harsher(harder....more defined).

Great discussion from David Hobby here: http://strobist.blogspot.com/2007/07/lighting-102-unit-21-apparent-light.html

Perhaps we're saying the same thing?

Enjoying the discussion.

Off to lunch with my lovely bride.

Larry

Scott said...

David Hobby?... what the heck does he know?

Only everything!

;)

I will defer to Mr. Hobby every time...

And lucky you to have a lunch date, enjoy the company...


Scott