Dental Photography in practice Part 22 - Flash
Following on from the last article, I have now done some shots to get slightly different lighting and to see if we can see different characteristics of the teeth. Sometimes just a straight ringflash image doesn’t show what we can see with the eye.
Just to recap the 3 types of flash we are going to look at are:
- Ringflash (wired or wireless) (manual or automatic)
- Twin flash (wired or wireless)
- Ring and Point flash
Wired…… Canon, Dine, Marumi and Sigma.
Weight wise the Dine and Marumi come in the lightest with the Metz a close second and the Nikon Twin flash the heaviest.
As far as size is concerned, the Dine flash wins hands down, with again the Marumi next and the Nikon Twin flash the biggest.
Why do you need manual flash? Most of the shots you take will work well on something called ETTL (Electronic Through The Lens), however this does mean that the flash is assessing every shot you take, and making flash output changes accordingly. Which means that often if you are using a ‘Contraster’ (black paddle for isolating quadrants) the flash will automatically try to get some detail in the ‘Contraster’ and consequently the teeth may be too light. This can also affect ‘before and after’ shots where there are marked differences in the subject, in particular, tooth whitening, amalgam..white fillings, rubber dam etc. etc.
Shots taken on some of the flashes using the flash functions to show the different characteristics that can be seen when modifying the output and direction of the flash.
You will hopefully be able to see the different characteristics you get by varying either the angle of the lightsource or the type of light, ring or point. A ring lightsource will give little or no shadowing whereas a ‘point’ source will give more shadowing.
A lot of the differences are due to the ‘specular reflection’ off the wet surface of the teeth, this can be minimised by drying the teeth before photography, but as you can clearly see the angle of the lightsource makes a big difference. So if your image isn’t showing the detail you need try changing the angle of view or switch to a single ‘point’ lightsource.
This is easy with the Dine flash with one switch, easy too with the Nikon twin flash…just switch one flash off. Canon and Sigma need changes on their menus to achieve a single ‘point’ lightsource, but can be done in about 30 seconds.
My personal recommendation is the Dine flash, it is small, lightweight, has a nice small ringflash for getting even lighting at the back of the mouth, and is easy to change from ‘ring’ to ‘point’ light.