This week, I’ve taken delivery of a new Canon Speedlite 430EX flash gun and a Sto-Fen Omni-Bounce flash diffuser. The purpose of the Omni-Bounce is to provide a bare bulb effect. This means that light will be scattered in almost every direction with some reaching your subject after having been reflected off another surface. This ought to provide similar results as bouncing a bare flash, but throwing light directly onto your subject can help to distinguish it from the background as well as provide a catch-light.
Today, I set about testing different flash photo set-ups with my helpful test monkey.
Colour-wise, my test environment wasn’t ideal since the walls are coloured, but the purpose of this testing was really to get a feel for the effects of angling and diffusion of the flash, to see how subjects would be lit, and to see the effect on any shadows cast.
The flashgun was hotshoe-mounted onto my 40D (with EF 100mm f/2.8 macro lens) and all of the shots were taken in portrait format in order to fill the frame with the subject, which was about 1.5m away from the camera, and have side-shadows to better show the effect of the flash set-up.
The results of my testing were as follows:
- Direct bare flash – This gave the harshest light, shadows and the greatest chance of overexposure by the looks of things.
- Direct flash with Omni-Bounce – The diffuser helped to soften the effect of the flash light as well as soften the edges of the shadows which were still very much visible.
- 60-degree bare flash bounced – The light was a loft softer and warmer as it picked up some of the colours from the walls and ceiling. At 60-degrees, more light would be bounced than reach the subject directly, but shadows were still clearly visible albeit much lighter.
- 60-degree flash with Omni-Bounce – Similar result as without the diffuser, but the Omni-Bounce threw more direct light at the subject resulting in darker and more definite shadows.
- 75-degree bare flash bounced – Lighting is starting to look much more natural with only a faint shadow visible.
- 90-degree bare flash bounced – The light hitting the subject is now being bounced completely from the surrounding walls and ceiling resulting in few, very soft shadows. Very even lighting right across the frame.
- 90-degree flash with Omni-Bounce – Similar results as with the 75-degree bare flash shot, but the diffuser has absorbed some of the light energy resulting in a darker exposure.
- Direct flash with Omni-Bounce
- 60-degree bare flash bounce
- 60-degree bounce flash with Omni-Bounce
- 75-degree bare bounce flash
- 90-degree bare flash bounce
- 90-degree bounce flash with Omni-Bounce
- Direct bare flash
Minimal processing was carried out on these images; just straight out of Lightroom and labelled in Photoshop without any additional sharpening or colour processing.
Conclusion
Used with the flash pointing directly at the subject, the Omni-Bounce can help to soften the light and shadows to a small extent. Sto-Fen say the Omni-Bounce should be used with the flash gun at around a 45-degree angle in order to get the best from it, but if you’ve no reflective surfaces nearby then pointing your flash directly at your subject might be the next best option available.
Using the Omni-Bounce at an angle offered a nice level of light, but there were still shadows apparent due to the flash light providing a direct light source.
For the most evenly lit and shadow-less photos you really do need to bounce your flash light in order to get as big a light source as possible and you don’t need a diffuser for that.










3 Comments
Very interesting. Another thing apparently against using the diffusers is that it seems to muck up the exposure if you manually set the aperture. Camera – Canon 450d. Setting the aperture at f11 for depth of field – subject fairly close – about 2.4m or 8′. Without diffuser – nice shot. With diffuser – underexposed by about 4 stops.
Do you have any explanation for this. Is there something that I am missing?
Hi Ian,
What flashgun are you using with your 450D?
With Canon Speedlites, the flash should automatically vary the flash output so that sufficient light reaches the sensor for a correct exposure.
As long as your flash is powerful enough to offset the light-dampening effect of a diffuser then I wouldn’t expect you to see any problems with under-exposure.
It could be that you’re using a flashgun that’s incompatible with the 450D’s E-TTL II flash exposure system or perhaps it’s just not capable of outputting enough light energy to meet the required exposure setting.
What kind of environment are you shooting in at f/11? Where’s your diffuser sending the light? Are there light coloured walls and ceiling nearby to bounce indirect light towards your subject?
Thanks for th reply. Turns out that it the difficulty experienced was due to flash strength. Diffuser seems to take out about 1 stop of light under current testing circumstances, otherwise it seems o.k.