Artificial Lighting for Tongue Diagnosis

[Guest guest]

In a message dated 3/6/2006 9:27:02 A.M. Eastern Standard Time,

tom.verhaeghe writes:

 

She recommends shooting in aperture priority mode, if possible. Use a

larger diaphragm, e.g. use 2.8 instead of 8 or 11. This way your

depth of field will increase, making the whole tongue sharp, instead

of only part of it, or only the face.

 

 

 

You have that part about aperture wrong. A smaller aperture gives a greater

depth of field (i.e. f 11 is smaller than f 2.8)

 

You made some very good points about reflected light, what ever you do keep

it the same.

 

I have rice paper over the windows (shoji) it makes for very even light all

day, consistency is the key.

 

 

 

[Guest guest]

This is a reply from my friend Kari Decock, a professional

photographer and acupuncturist, that was posted to the CHA list some

time ago, in reply to someone who had posted some pictures:

 

" here's the reply I got from my friend (my translation):

 

- she likes your pics and sees you also took some with lateral ambient

light. She does not recommend direct sunlight= too harsh. If you use

sunlight, filter it through chalk paper or a very thin curtain

- she noticed some pictures are out of focus. She thinks the main

reason is because people moved, but there are also instances where

other parts of the face are really sharp. Probably because you lost

sharpness using a bigger aperture.

She recommends shooting in aperture priority mode, if possible. Use a

larger diaphragm, e.g. use 2.8 instead of 8 or 11. This way your

depth of field will increase, making the whole tongue sharp, instead

of only part of it, or only the face.

- if you have flash synchronisation at faster shutter speeds, make use

of it. Try 1/125 and always make sure you have enough depth of field=

small diaphragm

- standardization: she noticed you used a grey card. That's great, but

you let your clients hold them, so you lose any standardization you

might get. Always use a grey card from the same distance and from the

same angle.

She further recommends to have the clients seated against a wall or

head support, so that they won't move. Use a tripod. To make maximum

use of available light, you may use a piece of white cardboard in

which you make a hole so that your camera's lens can peep through it.

The panel will reflect light and brighten shadows. BUT this can also

increase glare on the wet spots on tongue surfaces. Explore. She

thinks the glare you got on your pics is really not too bad. She

reckons it could function as a control for wetness of the tongue.

Always ask people to close their eyes, especially children, when you

flash from such a short distance. Children better cover their eyes, as

this can be dangerous.

She noticed that the colour of the garments clients wear also

influences colour balance to some degree. If you really want to

niggle, you can let the clients wear a light grey scarf, so everyone

will get the same reflex. Even the photographer's clothes can

influence the picture.

- you can soften your flash by using chalk paper or professional half

tough spun or full tough spun from LEE filters, or ROSCO (sorry don't

know what these are). Chalk paper may be the easiest, but you will

need stronger light.

- as long as you use a flash, you will get some glare. But, she thinks

it is not too bad... "

 

regards,

 

Tom.

[Guest guest]

Chinese Medicine , KarateStan wrote:

> You have that part about aperture wrong. A smaller aperture gives a

greater

> depth of field (i.e. f 11 is smaller than f 2.8)

>

> You made some very good points about reflected light, what ever you

do keep

> it the same.

>

Yes I wasn't sure anymore about that. Thank you for correcting and

kudos to Kari for her excellent advice for taking good quality tongue

pictures.

 

Tom.