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Dental Photography in Practice Part 20 - Flash

Posted on 20 October 2011

To read Mike Sharland's other articles on dental photography, access his expert column by clicking here

 

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

Conventional Ringflash

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.

Twin flash

Canon ring 2.jpgAn 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.

 

DSC_4082-Edit.jpgRing 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 mike@thedigitaldentist.co.uk.

 

 

16 Comments
20/10/2011

Hi Mike,

Just wanted to clarify:

Both the marumi drf14 and the canon mr-14ex have a guide number of 14metres at iso 100, so surely they are both as powerful as each other?

Granted the marumi doesn't have any manual features, but one can always use flash compensation?

21/10/2011

Hi yes on paper they appear the same, but I have found the Marumi gives a softer light.

Mike

21/10/2011

Just to mention the Olympus ringflash, which is a true ringflash. Whether this is of true benefit in dental photography I am not entirely sure: it appears that the centrals can be slightly more exposed but I haven't compared that to other ring(but actually twin-in-a-ring)flashes.

Mike, do you have any experience in that respect?

24/10/2011

Hi

No not had any experience of the Olympus...would be useful to have some examples for my next article where I intend to compare as many ringflashes etc as I can. I am hoping the comparioson I do will highlight pros and cons...each light source will be different though especially in terms of the light ouput and specifically 'specular reflection'.

30/11/2011

Hi Mark,

If I keep my camera on Manual & keep the aperture, shutter speed and iso constant for all my photographs, will a ring flash on ETTL discharge the same light output each time?

30/11/2011

Hi

No if a flash is set to ETTL it will discharge the amount of light it feels the image needs, which means in some images you will either get too much or not enough light.....so thats the reason for having the flash set to Manual too...so that we have exactly the same light output every time.

Hope this helps

MIKE

30/11/2011

Mike, any news on when the reviews of different ringflashes is due?

Many thanks

01/12/2011

Due in early January I think...but if I can get it done sooner I will.

Mike

01/12/2011

Thanks Mike

23/01/2012

When I take images with my Canon SLR, I get two images, one which is the larger raw image. How do you save these images? Save the raws separate for legal purposes and use the others to send/save etc?

23/01/2012

Hi

Yes thats correct 2 images...one will be a .jpg the other a RAW file...which for Canons will be CR2.
RAW files just stored on a removable hard disc and the jpgs used as you would normally.

23/01/2012

Thanks Mike. Sorry I wrote my earlier question before reading your articles!
Im on article 6 so far, good help thanks

23/01/2012

Hi Mike,
Do you have any more news when the review of different ringflashes is due?

Many thanks

23/01/2012

Hi
Yes review has been submitted so should be out soon.

Mike

23/01/2012

Thats great!
Will it form part 21 of your articles on dentinal tubules?

24/01/2012

Yes it will.

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