Flash Falloff

[Alfry]

I have just built a bracket to hold my flash at the right sort of angle to my sigma 150mm Macro to cut out the problems associated with shadows caused by the lens, which works very well. but having very little experience of using flash I am now getting images in which the flash is causing the background to blacken out. This is a nice effect but not suitable for all the images that I wish to take. I am using the Nikon system with iTTL. Any suggestions anyone?

[matt_xyz]

if you're using flash as your primary light source then you will get dark backgrounds, that is the price you pay. The alternative is to use a mixture of ambient light and flash and to try to get the balance right. This does require there to be a certain amount of ambient light in the first place. If you're peering into the back of a dark bush to get a moth then you may have little option but to light your image entirely by flash (and hence to have a dark background).

Where there is some ambient light try to meter so that you're 2/3 or 1 stop underexposed and then use flash to make-up the difference. You may also need to apply some flash exposure compensation is the flash is still too bright (or not bright enough).

Matt

[nightshade]

I use an SB600 with a stofen diffuser to enhance natural light,I tried fill in but
do not have a suitable second unit

[peterjclarke]

Alfry, What subjects are you photographing?

[Alfry]

Hi thanks for the advice so far I have been out today but the light was pretty poor so i didn't get much chance to try out balancing the ambient light with flash.
I am trying to set myself up to photograph insects specifically Dragonflies and Damselflies and am using my time at the moment to try to get the equipment and skills to use them together before the next season.
So far I have only used natural light but I have read several books on the subject and they all recommend that some flash is used but they fall far short of telling you how exactly to achieve the effects ie lifting the shadows without causing unsightly highlights or just giving your images that little bit of sparkle to lift it overall.
Ralf

[mh68]

Originally Posted by Alfry

... but they fall far short of telling you how exactly to achieve the effects ie lifting the shadows without causing unsightly highlights or just giving your images that little bit of sparkle to lift it overall.
Ralf

Thats where a bounce card or diffuser comes in - both allow the subject to be evenly lit without blown highlights or harsh shadows. The shot below is my old setup - the bounce card directing all light onto the subject, no direct light from the flash head at all.If you check out my macro Gallery link on my signature you`ll see the lighting effects achieved with this simple setup.
A diffuser over the flash head softens the light too, but bear in mind both setups may require the flash output to be increased slightly as some light is obviously lost with these methods.



Mark H

[Alfry]

Thanks for that I notice that the bounce card has been mentioned on a previous thread do you prefer this or the difuser
I believe Matt said that he uses a Stofen diffuser I have just looked this up and it seems like a tidy unobtrusive piece of kit. I did think about using old plastic milk bottles but somehow I just don't think that it looks very good I just can't seem to work out how to cut it and anyway the diffuser is only about £15 so I think that is probably the route I will take
BTW you guys have some incredible macro shots on your sites it certainly gives me something to aspire too.
Ralf

[mh68]

The only drawbacks to the bounce card is that it can catch the wind, and sometimes spooks skittish subjects while youre getting into position. Most of the time I had no problems with it though.
Near the end of last summer I did a little experimenting with simply diffusing the flash which worked out quite well.Nothing fancy, just a dried out floor wipe (for its strength) placed over the flash head and secured with a band.I didnt try this extensively but the results I managed were similar to the bounce card.Something with a bit of texture helps to soften the light - even several layers of toilet paper has a positive effect on the light from the flash.There`s no end to the experimenting you can do, i`ve made diffusers out of milk cartons for the onboard flash of the camera in the pic above,and i`ve seen such things as pringles tubes made into effective diffusers/flash bounces.
I`ve recently seen some very nice fabric folding diffusers on Ebay which are very cheap, but look as though they`ll do the job - they just secure onto the flashhead with elastic.The list is endless.

Mark H