Dental Photography in Practice Part 20 - Flash
There has been some discussion in the forums regarding choice of light source, so I thought it was worth clarifying your choices.
The light source is a very important part of your system, and there are a number of options available. I will only cover flash light sources, as in my opinion this is your only practical choice for easy consistently lit images.
Flash types fall into 3 broad categories:
- · Ringflash (wired or wireless) (manual or automatic)
- · Twin flash (wired or wireless)
- · Ring and Point flash
Though classed as a ringflash, flashes such as the Canon MR14-EX and the Sigma EM-140 are two flashes either side of a ring, Canon come closest to a complete ring, there isn’t much advantage or disadvantage between these flashes and true ring flashes, so I am going to include any flashes that are designated ‘ring flashes’. The Sigma flash will fit Canon, Nikon, Sony, Sigma and Pentax, but you will need to make sure you specify the fit you need. The Sigma flash is priced around £320 and the Canon around £460. There are cheaper alternatives such as the Marumi flash, which I think only fits Canon..but may be wrong, at around £120, but you do get what you pay for, the Marumi flash is not as powerful as the Sigma or Canon, and will not work manually, which for consistent results is important.
Another option is the Metz wireless ringflash (£250) which will fit the Canon and Nikon and Sony, or the Sunpak Ringflash (£320)….lots of choice…all will do a good job but in my opinion the Sigma or Canon work best as ringflashes, as they can be used easily in total manual mode. Working in manual mode is ideal as you control the output of the flash so that you are getting the same amount of light each time you take a picture, on ETTL (automatic mode) light output will vary depending on the image characteristics.
A difference between the Sigma and the Canon is when set on manual mode, and you change to ETTL for some reason…then the Sigma resets its manual mode settings whereas the Canon retains these settings…is it worth the extra cost for this…probably yes.
An option that is becoming more popular is the ‘twin flash’.
Canon do a wired twin flash, Nikon a wireless twin flash, the wireless flash is more adaptable and both work well, but both are over the £500 mark, see the tests I do in the next article and see if it suits you?
The twin flash is more time consuming to use, but you do have more options in terms of light placement.
Ring and Point flash
A ring and point flash, such as the Dine Ring and Point flash, combines in one unit a ring flash and a point flash (equivalent to the ‘pop-up’ flash on a camera). The ring part is just that, a complete ring, great for getting to the back of the mouth. The point part is a point light source which will rotate to any position around the lens giving maximum flexibilty. These two light sources do not work together but are switched independently on the flash. Slightly cheaper than the Canon ringflash but more expensive than the Sigma.
That should give you at least a starter for making an informed choice of ringflash...my advice would be to get the best your budget will allow, however remember the results you get are dependant on your settings, my recommendation would for most cameras be the Dine Ring and Point flash, at just over £420 it is not the cheapest but is easily the most versatile, user friendly and compact flash on the market today. http://www.thedigitaldentist.co.uk/flash.htm
In the next article I will do a direct comparison between as many of the above options as I can, to show the light output, coverage and contrast. I will also test the number of flashes per set of batteries too…..don’t buy until you see that article…if you can’t wait contact me for more details email@example.com.