Question about TTL
- Thread starter glay78
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Generally yes.
Non-D or non-CPU lens do not communicate the distance information for the metering though. But TTL will still work without the distance information... I think.
Non-D or non-CPU lens do not communicate the distance information for the metering though. But TTL will still work without the distance information... I think.
TTL = through the lens.
it means measuring the quantity of light that comes into the camera through the lens. doesnt depend on the lens. i mount a m42 screw mount lens on my slr, it still meter the scence. i mount a 1st party or third party af lens, it also show me same reading.
it means measuring the quantity of light that comes into the camera through the lens. doesnt depend on the lens. i mount a m42 screw mount lens on my slr, it still meter the scence. i mount a 1st party or third party af lens, it also show me same reading.
TTL is metering thru the lens. both ambient and flash. during film days, flash fire once cos flim is neutral grey in colour and the reflected light from the film falls on e sensors at the bottom ( remove the lens and you can see the sensors). thus, the mode you choose, spot, matrix etc affects the prosessing/choice of sensors used.
now, in digital, since there is no film and the CCD captures light right on the spot, the light is not reflected back to the sensor. thus the flash ( like sb-800 has a preflash, this pre flash is the one that is bounced off the shutter curtain to be measured by the sensor and the the the 2nd flash is when the curtain opens.
since the amount of flash is determined by amount of light bounce off, compensation is needed for extreme white of black object. e.g if you shoot a black cat, more flash power will emit cos the black doent reflect much light, thus to get a true black cat like it really looks, you may need to close down 1/2 a stop or more. experience w it.
TTL will work with any nikon lens. cos the metering comes from the camera not the lens. just that AFD(distance) lens will feedback focusing distance and help camera determine exposure. personally don find AFD or AF have much difference
hope this helps
now, in digital, since there is no film and the CCD captures light right on the spot, the light is not reflected back to the sensor. thus the flash ( like sb-800 has a preflash, this pre flash is the one that is bounced off the shutter curtain to be measured by the sensor and the the the 2nd flash is when the curtain opens.
since the amount of flash is determined by amount of light bounce off, compensation is needed for extreme white of black object. e.g if you shoot a black cat, more flash power will emit cos the black doent reflect much light, thus to get a true black cat like it really looks, you may need to close down 1/2 a stop or more. experience w it.
TTL will work with any nikon lens. cos the metering comes from the camera not the lens. just that AFD(distance) lens will feedback focusing distance and help camera determine exposure. personally don find AFD or AF have much difference
hope this helps
IMHO, AFD or AF will not affect flash's TTL (or iTTL). Since any distance (or no distance) will not count into correct illumination calculation.
Flash will do pre-flash, sensor receive feedback of pre-flash through lens, and determine what illumination power will sufficient for the scene, mirror up, aperture set, and "flash..." the amount of necessary power. Photo taken.
Regards,
Arto.
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