misuring shutter in d90.

shiny4

shiny4

Well-known member
 
Last edited:
one solution for indoor use.
this method can work if you want to use a light to calibrate your camera at the bestt iso-shutter.after you have archived your best solution use the light intensity in front of your lens every time you shoot.
for the shutter control you can use your computer monitor and use EV+/- BUTTON ON D90.
1:chose 75Hz for the computer monitor refresh rate
2:use this card on your monitor:
http://www.ledametrix.com/synctest/syncscreen.jpg
3:if you have a camera with shutter control you can archive the exact interval in the image at each shutter time and then you can use this graphics for testing shutter in d90.
look here:
http://www.ledametrix.com/synctest/index.html
 
my current idea to be able to set the shutter to 1/50 every time is to use an LM1881 sync separator to extract the 50hz from the composite out (in pal mode) and let it feed a led, which you hold in front of your camera then adjust exposure until it stops flickering. ideally it should be put in a cap so that the background doesn't disturb (even small changes will change the auto exposure), and have a dimmer (a 555 pwm?) to adjust the iso at the same time.

/matt
 
damn, that ic doesn't put out a pulse per vsync, it just goes from low to high, so it's only a 25hz signal. i guess i can combine the pwm and a frequency doubler, one pulse with variable length for every flank, in the same 555 circuit but it's been almost 20 years since i knew how to design more complex circuits. ;-)

/matt
 
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