Dental photography

[JonB]

Never mind about sending me the pict - the image retained its exif data. This is the data for the above image:


Notice where it says "Exposure Program" and its blank? It should say "Aperture Priority". If you notice the exif data i posted above this post it says "Shutter Priority" for the image i got the exif from.

Make sure you have your camera properly set up or else nothing will work! Find out how to set the camera on "Aperture Priority" and if your cameras aren't going there for some reason - they need to be sent in to Canon or a repair facility.

The odd thing is it should say something there - Manual, Shutter, Aperture, Program - something. But there is nothing - that worries me a biit.

 

[JonB]

Here is an answer from an experienced pro shooter I know - though not real helpful...

Rebels are consumer cameras and are set up from the factory to be as user friendly as possible. We are trying to use them in more a of a "pro" environment with manual settings or non- "automatic" settings. We aren't just doing snapshots.

"Jon, I once (a couple of months ago) tried setting my 5DM2 up according to what one high-end nature photographer used and didn't see much difference until I started using some flash. I was getting results similar to what you're seeing with the Ti. The shutter speed acted as if it was in shutter priority mode no matter what I did which usually forces the shutter speeds into the "need a rock-solid tripod" areas. It took me a couple of days to figure it out and I returned most of the custom functions back to default. I think what did it for me was the "protect highlights" custom function. Don't know if some of the techs are setting up the camera incorrectly or if it's set by default, or if something else is going on. I don't have a Ti to play with either. "

So go into your custom functions menu and look around - maybe this is the setting that will make the difference.

 

[JonB]

Here is another thing to look for and I'm betting lunch this being it.

"in the custom functions menu of the camera, there is a function where you can change it to shutter between 60-200, always at 200, or auto. I'm thinking you need to investigate that one."

Set the shutter to always be on 60-200 in the custom functions and see if that makes a difference.
On my 20D custom function #3 is "Flash sync speed in AV mode" with the option of
#1 - 1/250 sec
or
#2 - Auto

I have mine set on 1/250 all the time!

***edit***
i just tested it on my 20D and this is definitely the problem! Set the custom function to 1/200 fixed and that will solve it.

 

[Alistar]

Jon, I just dug through my entire custom menu, and could not find a custom setting for shudder speed when using a flash. I think we begining to find the difference between a "pro" camera and an entry level. Looks like I might be in the market for 5D or something comprable.

I really appreciate your help in all this, Jon.

As I side note, I just met with a new prospective doc and his staff over lunch. Took the camera and a case I competed. Showed him the pics and case. He said "you've got all my bussiness", before he even took a bite of his sandwich.

Thanks to everyone for your contributions in this thread!

 

[JonB]

Man, that's the whole purpose of this thread - in my opinion. If better pics can mean new work for you - then its a full on win!

There must be a custom function for that. The advice about the 60-200, 200, auto choices I got from the POTN Rebel T2i thread. They know their cameras better than I. I'm betting its there - but unless i had a Rebel in my hands, I can't begin to tell you where. Keep looking.

 

[JonB]

FOUND IT!
Its hidden in chapter 10 of your user manual, page 192. Here are screen shots:




The modern Rebels are pretty advanced, so I'm not surprised they have this capability.

 

[Alistar]

Ha! Jon, you're awesome! I'm such a noob I passed right over the "Custom Functions". I was expecting it to be under the "flash control" menu option. There is a lot of stuff to mess with in the "custom functions" menu. Time to start experimenting.

Anyway, I got in that menu and got it set right. Set on Av mode F/22, ISO 200, and ETTL on the flash and......pics come out perfect! Even in "very" low light.

Thanks again Jon.

 

[JonB]

Cool!

Be careful with the custom functions though - even when you know what they do, it can come back and bite you. One time in Chicago during the Midwinter meeting, I was shooting some low light cityscapes one evening and had the camera on a tripod and had set the custom function for mirror lockup set.

As it sometimes happens... well always happens, i got so into what I was doing and forgot what time it was getting to be - so I had to rush over to the Vita hospitality party where I got my camera out and corralled Mark Jackson, Jason and the President of Vita for a photo and the camera seemed to fail right there. I reset it and it did the same thing. Worried, I looked at them in a panic as they looked back in utter shock and disbelief - so i tried again and it failed again.

I told them i had to take a look at the camera and try again later, so I took a seat in a dark corner to hide my red face and spent a few minutes looking at everything. It finally dawned on me to check the mirror lockup feature since it was the last thing I had done and sure enough that was it. I never got the shot of those three together the way I wanted it - but it was a lesson well learned. Always change your custom functions back after using them for special purposes!

 

[Jorge]

Some settings I learned in a course, views as for the AACD
I adapted the distances for an APS-C sensor camera so the magnification remains as intended

AV and 1/200 exposure (via Custom function) or M and manual 1/200
Manual flash at 1/4 power (eg. MR-14EX)
ISO 200
Obejtive: Canon 100mm F/2.8 macro on an APS-C size sensor camera
All landscape orientation
White balance: do not remember, but sure not AWB, at least use "flash"
No tripod needed because with F/20 and 1/200 flash light is much greater than office light
No AF, manual focusing (back and forward the camera, lens manual focused at desired distance)


Aperture:

F/6.3 for full head portrait (magnification 1:10, working distance 5 feet)

F/20 for full smile (mag. 1:2, work. dist. 31cm)

F/18 for full arch occlusal view (mag 1:2, work. dist. 31cm, not F/20 because of mirror)

F/29 for some teeth (mag. 1:1, work dist. 17cm)

With manual settings darker objects show darker.
With ETTL tend to 18% reflective, if more or less background is included exposure can change.

For lab photos you can begin testing yout gear with this settings for those magnification ratios, and then write down your preferences.

Any comments welcomed.
Regards

 

[JonB]

Thanks Jorge,
The AACD does have some specific hoops to jump through, so I'm not surprised that they recommend those settings.
I would only disagree with the ƒ 6.3 setting for head and shoulders work simply because it is rare to have a face depth that would require that much depth of field. A head and shoulders shot is a portrait - not a dental image -and therefore needs to have less depth of field not more. While there isn't a lot of difference between 5.6 and 6.3 - it does get noticeable when you go to ƒ4.0 - which is all you need for a head and shoulders shot. 2 or 2.8 would be better but we're typically shooting with a 100mm macro lens and stuck with the low compression it can give us - whereas in a studio setting, we'd use a 70-200 out towards 180 or so and get good compression at 2.8. As long as you focus on the eyes at ƒ2.8 you can't go wrong.

I would want to double check the 1:1 and 1:2 working distance ratios as well - as I know the 50mm ƒ2.5 Macro delivers pretty consistent 1:2 ratio while the older 100mm ƒ2.8 Macro is a reliable 1:1 ratio at full focus.

Auto focus is alright for most shots - but if you want 1:1 on the 100mm, you do have to go with manual focus all the way to max and rock back and forth to get it.

The original dental photography course i took a long time ago had simplified the settings issue probably because it was geared toward doctors who were just getting their feet wet with cameras for the first time. Its still a good rule of thumb since by now most of them seem to set the cameras on auto and let the assistant shoot the pics. Hence two settings - ƒ22 for intra-orals and 4.0 to 5.6 for head and shoulders is more than sufficient. They get confused with much more on their plate.

Thanks for your input - its always helpful whenever anyone has more info to share!

 

[Jorge]

The AACD requires 12 views at a predetermined magnification ratio for clinical case submissions (they sell a 18 pages booklet about that)

The exposure settings are from a one half day doctors course I managed to assist some years ago.

The F/6.3 aperture for portrait is -I think- the needed aperture at 5 feet when all the other parameters remain equal, I mean ring flash at 1/4 power, ISO 200, speed 1/200.
I think the purpose of this method is to only change distance and aperture from one type of view to another.

The working distances (not focus distances) is what I determined empirically to obtain the same photographied area the AACD requires.

What I mean is that when AACD said 1:2 it was referred to slides of size 24x36 milimeters, so the area photographied was 48x72mm (eg. full smile).

Now, with APS-C size sensor cameras, to photo that area, 48x72mm, the working distance with the Canon 2.8 USM macro (not the last IS version) is that I wrote. If you have a full frame camera (eg. Canon 5D) then you can continue to use the magnificacion scale on the lens but with camera whose sensor is 17x22mm you can not use the mag. scale if you want to photo. that area of 48x72mm.

Hope I managed to explain the idea, if not we can continue ellaborating on that.

 

[JonB]

Thanks again - like i said, the AACD has some specific hoops to jump through and it is helpful to have all that worked out for different sensor sizes. I guess the shooters who happen to be using a 1D Mark III or Mark IV would have to work out their own ratios and distances since the AACD numbers are for a 1.6 sensor and the Mark III and IV bodies are 1.3 crop factor. Not to mention the Nikon APS-C bodies are 1.5 crop factor which throws another small monkey wrench into the mix. Every slight difference requires a slightly different distance ratio.

You can understand why the AACD wants these specifics as its the only way to ensure a standard or set level playing field for all contributors. It makes judging the work or showing it, and printing it much easier if everyone follows the standard. It would be like herding cats any other way.

Do i think their standards are the end all be all for everyone? Not on your life! Not unless you will be submitting your work for their scrutiny. Its sorta like shoe horning a size 12 foot into a size 8 shoe because there are more people who have feet closer to 8s than size 12s.

My focus and interest in contributing to this thread has absolutely nothing to do with making everyone wear size 8s. I just want people to not be afraid to use their cameras, know what they are doing, be confident when they move away from the automatic settings and get in and muck around with custom functions, alternative lighting techniques, learn about depth of field, how shutter speeds affect the way the ambient light in an image looks and so on. If the AACD is important to someone - all of these things need to be understood before you try to shoot a series you are going to submit to AACD.

I hope you continue to contribute - especially if anyone has more questions on the AACD specs. We might want to start an independent thread in this forum specifically to deal with those. What do you think?

 

[JonB]

Now back to the day to day grind...

You may remember the image of the macro shoot i did for another dental company with this image -


Well I am free to post a few picts of some of the results now.




Please feel free to critique these images to the harshest level if you wish. Tell me what you think and don't worry about offending. I'm here to learn from other eyes as well!
Thanks!

 

[JonB]

All I hear are s in here - did everyone run for the hills?

 

[TheLabGuy]

What did you use for the mirrored picture Jon (beautiful btw). A black shiny tile?

 

[JonB]

Thanks Rob! It was a mirror. A 12 x 12 square that I bought at Home Depot. I'm thinking a nice metal mirror would do nicely here, as its tricky to get the lights just right so you don't reflect the surface of the glass. Now, finding some mirrored metal may be a trick. I have a dental mirror like that but its small enough to go inside the mouth - good for single teeth, but not whole models.

 

[Jorge]

Years ago I have bought a laser surface mirror at the big online auction site.

Regular mirrors reflect at the silver but also at the front glass surface, again at silver etc.

Regards

 

[Alistar]

The mirror is a cool idea, and the pics look really nice and crisp Jon.

I've done some experimental shots on CD's. I got the idea from the cover of the last Ivoclar news letter(mini magizine with clinical show-work cases). Gives the pic a little random artistic rainbow-laser flare...but it's not exactly a "professional" look.

Thanks for the advice on experimenting with settings..but it didn't come soon enough. Had a patient in the office the other week and had the same experience you had. I didn't have time to correct the settings and monkey with things, so I just went without the pic.

 

[JonB]

ISO Comparison

One of my doctors sent a card over for shade purposes and I noticed right away it was way grainy. Looked at the exif info and saw that he shot it at ƒ22, 1/200th and 1600 ISO! I'm betting he set it for something else and forgot and left it there.
Anyway - here is a good visual of what you can do to clean up an image in photoshop with high noise in it.

The image on the left is as shot, while the right is retouched in photoshop. You lose some detail cleaning it up, but then the noise makes the detail unusable anyway. It would have been much better had the ISo been set to 100 or 200.

 

[NicelyMKV]

Ok finally got my flash in. Getting a little better.
iso 100, 100mm, f2.8, 1/50.

I have a 26 unit case coming up the 9th so I am really wanting to learn what I can before then. The doctor is going to let me take all the photos I want before and after so don't want to lose a good opportunity.