I think...

if someone have ipod touch(3,5" lcd) can use it as light and dimmer.you can copy on you ipod white jpeg images with different IRE value.
from white 100 ire to 90-80-70 or 60.then using it to lock the exposure.
you can play also the video that is suggested to this post(http://www.dvxuser.com/V6/showthread.php?t=147373&highlight=d-exposure) to calibrated the shutter speed.
i'm waiting for nikon d90 and ipod touch.if someone want ,can do same test.
 
how does one go about creating such images...
i mean i have a Adobe Fireworks where i can change color numbers, say from #FFFFFF
format for pure white...

or RGB values, but not sure how to create necessary IRE there
 
Ire really means nothing in this context, it refers to ntsc video levels. Although the typical conversion function between rgb and ntsc yuv is known, to create a true reference scale you need to know the gamma of the phone/ipod display as well as the contrast range, which you don't so just make a few of different brightness from 0 to 255.
 
shiny4 said:
yes,
if you want you can use rgb value in 8 bit scale from 0 to 255.
look here to grey scale in macbeth colorcecker card:
http://www.mambo.net/cgi-bin/TempProcessor/view/113.
Click to expand...

attached is this colorchecker card recreated for iphone.
there are png images for iphone/ipod touch resolution 320x480 pixels 300dpi

lets assume:
- use full brightness, auto-brightness OFF on your devices
- put it right in front of your lens/mattebox so no other light other than iphone screen gets in

now with these... hopefully someone competent cant record approx. iso/shutter values so we have at least some kind of reference table to be the base platform.

(two files due to the site file upload limit)
 
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you can probably test shutter, but how can you really test the ISO? just comparing pictures? the camera won't tell you what ISO you're recording video at, so you're just gonna have to guess.

on another note, a co-worker has a Oscilloscope and I'm post the videos of each +/- value matched with stop and a sample clip of an evenly lit space so you can see ISO...gonna be at least a days worth of work.
 
Car3o said:
you can probably test shutter, but how can you really test the ISO? just comparing pictures? the camera won't tell you what ISO you're recording video at, so you're just gonna have to guess.
Click to expand...

yep, pure guess on the ISO part.
However, when one goes for a brightly lit object trick, I think the D90 brings the ISO down to 100 1st, before increasing shutter speed. Canon operates that way too (showing those values). so i think in this case, we're always stuck at ISO 100.
just a theory...

even if it is incorrect, there's certainly a top & bottom limit where D90 kicks in the shutter / iso adjustment and pattern for which to adjust 1st. it is not random as the camera just follows the code in its firmware to autoadjust that certain way.... cannon has these shutter limits too at which it does its predictable behavior. With the oscilloscope and solid lit object like iphone screen and universally agreed images that pattern can be traced.
 
only difference will be i won't have the iphone. so tests won't coincide with the iphone at all. but it'll help those who have the closet light.
 
if everything that applied to stills applied to d-movie we wouldn't be having this discussion. no, the compensation only changes the target exposure value, the camera gets there the same way as always, i.e. whichever way it wants no matter what you tell it. ;-)

/matt
 
instead of dimming the light, i got the 3x3 cavision filter to put in my matte box and used pieces of paper to dim the light. works pretty well.
 
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