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Dental Photography in practice Part 22 - Flash

Posted on 16 April 2012

 

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

 

Ringflash

Wired…… Canon, Dine, Marumi and Sigma.

Wireless…Metz.

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.

18 Comments
15/04/2012

Mike, you have grouped the sigma and canon ringlash into one category. Is there any particular reason for this? Are they both pretty much identical in terms of performance and features?

Many thanks for your article

16/04/2012

Yes thats right...they both produce similar results and have similar settings.

16/04/2012

Is the difference in price between the two just marketing then? I'm looking to buy a new ringflash, and was all set on the mr-14, but then saw the sigma em-140.
Are there any differences at all between the two?

16/04/2012

Setting these flashes on manual is essential for consistent results....the main difference is the the manual setting on the Canon once set is stored whereas the Sigma needs to be reset if you change back to ETTL for any reason.

20/04/2012

Y can see a great diference between circular and modular lights. (SB-R200 from Nikon).
The rest, I can see only more and less light.
Happy to find a web site dedicated to clinical photography. Congratulations!
Dr. Jorge Garat.
www.odontoclinica.cl

20/04/2012

This is a nice review of available intraoral flash attachments-

Kevan

31/12/2012

Mike, have you had any experience with the Opteka RL-600?
I saw it at the BDA conference this weekend and was v.impressed. I think its the poor mans canons MT-24EX and for £80, quite a bargain.

29/04/2012

Hi

No experience...I will have a look at it...generally you get what you pay for...but I will check it out and report back to this post.

29/04/2012

Great - thanks!

09/05/2012

I have now got an Opteka...which looks good...I have a course on Monday when I will put it through its paces and see what I think...if it does what it says then it is a good cheaper alternative to the mainstream flashes.
Hopefully have some feedback for you later next week.

17/06/2012

How did the Opteka handle the course then Mike? Any pro's/con's over mainstream flashes?

31/12/2012

Opteka seems to be handling fine, manual option and option to turn one side of flash off makes taking full face views easier.
Not as robust as mainstream flashes and you have to switch to manual each time after switching off...otherwise all seems Ok at present....and for £75 well worth a try.

Mike

31/12/2012

Hi Mike
Love reading the articles.
I have a tamron di II 18-200 mm 1:3.5 - 6.3

I have also a cheap Chinese ring flash (About £20) from ebay.

I have an old nikon d 70 which I love

Which is the most important to change - the lens or the flash ?? I used to use my boss' camera, but have to now quickly get my old hobby camera upgraded for dental work.

Alistair

03/09/2012

Hi Alistair
Definitely change the lens to something like the Tamron 90mm Macro.
Then see how the flash performs...you may need to change that to...but if its working OK you can wait and see.

Hope this helps

Mike

24/09/2012

Hi mike

I just brought a sigma ring flash I'm not sure what setting I should be using, can you help

Thanks

25/09/2012

Hi Harpreet

I would suggest you change the mode to 'M' (Manual) and set power of both flashes to 1/4...try that with camera 1/200, f22, 100 ISO.

Hope this helps

Mike

03/02/2013

Hi Mike.. Regarding the dine ring and point flash.. how much are these? Where can i buy this from? Thanks.. Yusra

29/01/2016

Useful review since I'm looking to replace my flash

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