You could interleave the illumination of the subject with each photo taken 1. Illuminate 2. Take photo 3. Show photo Repeat. If step 2 is really short, you c

You could interleave the illumination of the subject with each photo taken 1. Illuminate 2. Take photo 3. Show photo Repeat. If step 2 is really short, you could have the illumination phase be much shorter than the show photo phase and the user of the phone would see it as 4 short flashes over their own photo.