Bounce flash photography & The Inverse Square Law
If you find the title of this article a touch intimidating, please stick around and watch the video. It is important to understand how The Inverse Square Law affects bounce flash photography, and creates a specific result where the background appears brighter when the flash is bounced properly without on-camera flash modifiers. I know that is counter-intuitive, but that is what happens when you bounce your bare flash behind you instead of using a light modifier on your flash. The accompanying video, linked to below, explains this in hopefully clear, easy to understand ways.
The photograph at the top is typical of the results. Now this might not be the way you like your wedding receptions to be lit. Perhaps you prefer cross-lighting the dance floor with multiple flashes. That’s cool too. Working with just the single on-camera bounce flash gives really good results with no cross shadows and awkward shadows. Every photo works with the light fall-off pretty even from front to deeper into the scene.
The key to this is that the light source isn’t your flash on your camera — instead it is the wall and ceiling far behind you. That is your light source now, and the light fall-off will be much more gradual. This is explained in the video. In explaining the way that the inverse square law is implicated, it is only necessary to understand that you lose two stops of light every time you double your distance from your light source. Simple. An easy enough rule to remember. From there on, everything will fall into place.
For those of you who prefer Youtube, here is the link to the video on Youtube : Bounce Flash – That one thing you need to know.
On-Camera Flash Photography – revised edition
This book is explains a cohesive and thorough approach to getting the best from your on-camera speedlight.
Particular care was taken to present it all with a logical flow that will help any photographer attain a better understanding of flash photography.
You can either purchase a copy via Amazon USA and Amazon UK, or can be ordered through Barnes & Nobles and other bookstores. The book is also available on the Apple iBook Store, as well as Amazon Kindle. Also check out the Amazon Kindle store.
Learn more about how the cover image was shot.
Another example from a different event – a Bar Mitzvah party – but the results are very similar. Notice how the hands in the front are as well lit as the boy’s face as he crowd surfs. From there on, the light fall-off is still there, but not abrupt. All the important elements in the frame are similarly well exposed. All because the flash was bounced off a wall behind me on the stage … and then the light fall-off is less rapid. All because of how The Inverse Square Law works at longer distances.
Seriously, check out the video – it is all explained in there.
Camera settings and gear used
- 1st image (at the top) : 1/100 @ f/3.2 @ 2500 ISO
- 2nd image : 1/80 @ f/4.5 @ 2500 ISO
- manual flash, on camera, bounced with the black foamie thing.
- Ambient exposure was about 3 stops under.
- Sony A9 (B&H / Amazon)
- Sony 24-70mm f/2.8 GM (B&H / Amazon)
- Profoto A1x flash for Sony (B&H / Amazon)
- Tutorial on Bouncing your flash
- The list of articles on bounce flash photography
- Black foamie thing : modifier for on-camera bounce flash
13 Comments, Add Your Own
Have you completely transitioned to the Sony A9 for client work? I noticed that in the last 3 blog posts, the camera used for the photos was the Sony A9.
1.1Neil vN says
I should do a “What’s In My Camera Bag” blog post, because it depends on what I am photographing.
My main system right now is Sony, with A Sony A1 as my main camera, along with a bunch of Sony A9 bodies.
1.1.1Quin Rickman says
I’m think of getting the Sony A1, would like to know what you think of it.
220.127.116.11Neil vN says
Quin … it is an amazing camera with two flaws:
1. You can’t do medium RAW (like you can with Nikon and Canon)
2. The Autofocus like any other mirrorless camera I have used, flounders in dark low-contrast scenarios when you have to use flash. I know my Nikon D5 is reliable then.
18.104.22.168.1Quin Rickman says
I never understood why Sony eliminated, focus assist beam from it’s flashes.
It would be nice to see a blog post about how technology evolution and the projects you’ve accepted have influenced your decision of camera equipment over the years. I still have a Nikon D500, but I’m curious what you use Nikon camera for these days.
You started with Canon, then went to Nikon, and now to Sony. You originally found Canon’s quality control lacking (you had a photo of all the service letters you received), which caused you to switch to Nikon and use that for many years happily. Then, with Sony’s mirrorless silent shutter and improved technology to reduce rolling shutter, you made the switch to Sony.
Since you have worked with three major camera systems, your workshops would be easier to teach since you know about each brand’s camera systems.
Great video. As usual, clear, simple explanation! And example of praticle uses. Thank you!
2.1Diane Stredicke says
I’d like to see this in combination with some off camera rim lighting.
3Quin Rickman says
Great video, I bounce the flash behind me, when possible, really good refresher.
4Frank aldous says
I have just bought a Godox V860iii-O. James k Boyer suggested I look you up.. and within a few moments I have learnt so much from you.
5Shelly Bobruska says
I just watched your Bounce Flash video – and it totally sunk in for me! Thank You for that! I have 2 questions…. What if the walls are not white? And how do you pick your shutter speed? When I shoot High ISO and wide open….I seem to get motion blur?
6Todd Cary says
Neil, I took a course from you in San Francisco many year ago, and you did a wonderful job of explaining bounce flash. Though I’m not a professional photographer; I do work for our museum in Bend, Oregon and bound flash has been my my approach 98% of the time. Thank you!! It does everything you say it does – even with high ceilings at events.
7Charles Church says
I am an amateur (maybe a little advanced) wanting to learn as much as possible to improve the photos I take for my personal use. I do sometimes take a few for others but not for profit or as a vocation.
Two very interesting videos/vlogs regarding bounce flash for portraits and group photos. I plan to try incorporation them into my photography. Thank you for the explanations of your procedure and the reasoning.