Internal Flash

I do not understand d70 internal flash.

For example when I set flash to ttl mode, pop up the flash, read the exposure of the subject, it read (for example) 1/30 sec aperture 1,8, the picture gives me an about good exposure.

When I set the flash mode to manual full power, the same subject I set the camera to 1/500 sec and aperture of 13 it gives me the right exposure.
Why in ttl mode the flash never seemes to use it's full power?

Because the less you have to use flash, the better the photo as a rule.

Now the camera knows that if it can get away with 1/30 second at f1.8, and you told it it was allowed to go down to 1/30 second, then it won't need so much flash. But in the same situation if you go to 1/500 second (maximum for flash) and f13 (this is a silly aperture - your photos will start to lose sharpness) then of course it needs more flash. But your photo will probably suck. Internal flash and hardly any natural light is not normally a good combination.

The camera knows when there is too much contrast in the image, not just insufficient light. Both situations are reasons to use flash.

JAndries said:

I do not understand d70 internal flash.
For example when I set flash to ttl mode, pop up the flash, read
the exposure of the subject, it read (for example) 1/30 sec
aperture 1,8, the picture gives me an about good exposure.
When I set the flash mode to manual full power, the same subject I
set the camera to 1/500 sec and aperture of 13 it gives me the
right exposure.
Why in ttl mode the flash never seemes to use it's full power?

Click to expand...

In TTL mode, the flash will only use as much power as it needs to give you a right exposure. That is what it is designed to do. In TTL mode, you can get proper exposures with a range of apertures - the flash will be adjusted for you. In manual full power, the aperture needs to be set carefully to get the right exposure. It will depend on how close the subject is to the camera, and on the ISO you have selected.

--
Regards,

Rafael
http://www.pbase.com/aviles
-----------------------------------------

“The real voyage of discovery consists not in seeking new landscapes but in having new eyes.” M. Proust

Maybe my question was not clear enough, I mean when I set the shutterspeed to 500 the metering gives me underexposed, a correc metering acording to the camera is at 30. So any other settings do not gives me the correct exposure acording to the camera, I can take the picture with ttl mode at 500 shutterspeed but acording to the camera it is underexposed. So I the in camera metering seems not to take acount of the flash when it is poped up. What am i doing wrong or is this normal

JAndries said:

... So I the in camera metering seems
not to take acount of the flash when it is poped up. What am i
doing wrong or is this normal

Click to expand...

This is normal, it is the way it works. The camera's meter measures ambient light as the lens sees it. If you were to take the picture without using the flashm it would be underexposed. The camera's meter cannot predict how much light the flash will put out.

--
Regards,

Rafael
http://www.pbase.com/aviles
-----------------------------------------

“The real voyage of discovery consists not in seeking new landscapes but in having new eyes.” M. Proust

THANKS FOR THE INFORMATION it was highly appriciated

With the D70, unless the metering mode is set to Spot or the exposure mode is set to Manual, you are actually using TTL-BL, as opposed to Standard TTL. TTL-BL is only for fill flash, and will not try to act as the main light source. Select spot metering and you'll get Standard TTL.

JAndries said:

THANKS FOR THE INFORMATION it was highly appriciated

Click to expand...