Photography Made Easy: Inverse Square Law

There always seems to be two camps when it comes to photography: those who go by feel and those who go by technique. Neither one is necessarily a wrong approach but knowing the technical stuff definitely helps when you are faced with problems or unexpected results. In this video Mark Wallace explains the inverse square law and how it affects light falloff. I'll admit, not having gone to school for photography, it did take me a while to completely grasp this idea when I first started shooting. Once you understand this concept, you should be able to not only light your scenes better but also become more versatile when giving a single light double duty lighting both your subject and the background.

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15 Comments

Bas ter Beek's picture

Wow, nice one. I never knew the falloff was that 'heavy'. Thanks!

Very good, i was reading book about it but this video is very helpful.
Thank you

Lee Morris's picture

Wow, I really needed to see this. I knew the basic idea but I never truly understood "why". Great stuff!

Holy crap, you look like a stylized devil. Forget the retouches and under-lighting... Save this pic for Halloween, k?

Kellen Freeman's picture

I teach a photography class and this always scares the crap out of people (apparently because math=scary). This video really gives a good mode of unpacking it, though.

Also, I usually hate this dude. But he did a great job this time.

He bridged hatred to "dude" status, with a single video?

It really was a good explanation, eh? I will use it.

Doug

Joop van Roy's picture

Good explanation. It might also be helpful to show a simple graph where y= amount of light and x=distance from lightsource. like this:http://www.eoearth.org/files/115601_115700/115635/250px-Inverse_square_g...

Awesome info with this. I had read about it before but it didn't really stick. Looking forward to playing around with this on my next shoot.

If you make the marks on the floor at 1', 1.4', 2', 2.8', 4', 5.6', 8', 11', 16' and 22' you can take meter readings at each mark and you will find that there will be a one stop difference between each mark and two stops between every-other mark. Knowing this makes it easier to light group portraits, i.e. one stop drop off between 11' and 16'.

This was a great explanation (credit where credit is due: Inverse Square Law would have put us to sleep *if* it had not been demonstrated so well that we could compare results).

Distilling complexity into understandability (is that a word?) is an art. Good job, Adorama.

(p.s. fix your audio echo in the garage. Adorama owes you a studio w/ acoustic foam by now. :)

Your company name has shown up on my bank account statements quite a bit recently and... I always appreciate the value.

Keep it up... These tutorials are great and if given a little polish (additional funding), they could be spectacular. Don't change anything other than the set or audio. The teacher and topic are on-target.

Gracias.and kudos to F-Stoppers for re-posting.

I had to write an essay on this law as part of my photography degree. I did not not find it too hard to get to grips with after I read up on it from various sources.

Endy Studios's picture

This is great! Thanks for sharing!

Love going over this stuff!

-N.

Brilliant explanation - thanks!!

As a twelve year pro I can say this was a very good video especially the past about handling group photos. That was very helpful.