Jay... The website for the LCD states that it can be pulse-modulated to mimic infinitely variable ND... a very cool thing providing the device has negligible impact on image quality.
Jay... The website for the LCD states that it can be pulse-modulated to mimic infinitely variable ND... a very cool thing providing the device has negligible impact on image quality.
$400 would price me out (I'm so poor I can't even pay attention) but a few thoughts.
1) would it sync with flash? at what speed?
2) could you also use it as an aperture? If so how small? What shape?
3) could you use it as an ND filter?
Do you have a link to the LCD website?
Science is what we understand well enough to explain to a computer. Art is everything else we do.
--A=B by Petkovšek et. al.
Only five pages to this thread and folks won't read them... ?
Yes! I would be very interested in such a shutter, and would certainly pay $400 for it assuming that it had X sync and did not significantly degrade the image. Having a variable ND filter would be fun, but not a necessity for me.
One thing I have seen with a few large LCD windows is that they tend to have a color-cast. My recollection is that they are slightly blue. This could be an issue.
The statement only speaks to variation between the two endpoints. It does not imply high density.Originally Posted by Old-N-Feeble
Also, the variability attainable with PWM is not infinite, since the pulse width changes in discreet steps.
- Leigh
If you believe you can, or you believe you can't... you're right.
It's close to enough to "infinite" for photographic purposes... and the limited density was already addressed.The statement only speaks to variation between the two endpoints. It does not imply high density.
Also, the variability attainable with PWM is not infinite, since the pulse width changes in discreet steps.
Actually I don't think it is, the PWM seems to be more geared to eyes.
One man's Mede is another man's Persian.
Is 'extinction factor' in stops, or transmission?
A factor of 300 is not terribly large. If your shutter speed is 1/500th of a second, that means you only have a second or so that you can have the lens cap off.
I still think this is a very cool idea and would still like to see the datasheet. I happen to believe that vibration is a bigger deal than people think it is, and a variable ND could have tons of applications.
Science is what we understand well enough to explain to a computer. Art is everything else we do.
--A=B by Petkovšek et. al.
That would make the dark state darker, but would add to all the other problems, unless you could persuade a manufacturer to make a monolithic unit with two stacked light valves one on top of the other.
I suspect that would be much more expensive, certainly more expensive than learning to keep the lens cap on until ready to shoot. For most shooting you would have time to manually remove a cap, wait a few seconds for vibrations to die down, take the shot, and then put the cap back on. Bright lights at night, particularly ones that move are more likely to be a problem than taking a regular daylight shot.
Sure. There may be finesse involved in matching the drive circuit to large areas, but for a simple on-off-variable ND arrangement you only need a single big electrode front and back. Using a pattered LCD to make variable apertures, or to filter colour, would require the equivalent of a flat panel screen with an addressable array of electrodes or drive transistors, which is not impossible, but will cost. I don't even know if existing applications include such spatially varying panels - the ones I've seen are used as shutters for things like stereo projection of alternating left and right eye images.
I think this exactly the sort of use the OP envisaged. I have a Sinar shutter which goes up to 1/60s (nominal) but it throttles some of the lenses I have, which seems against the spirit of having all that lovely glass. My understanding is that pi-cells have response speeds of a few milliseconds or so, which means 1/100 should be achievable, 1/1000 much less likely. Flash sync should not be any problem. Limiting the transmissivity of the 'open' cell should also be easy, and as you say, for fast lenses in bright daylight it could be useful to be able to use the shutter as a programmable ND filter.
Posting Permissions
Reply With Quote
Bookmarks