Martina or ravioli?
Added 2021-03-12 08:31:00 +0000 UTCDon't ask me why the old style spotlight used with Martina gave less banding/flickering issues compared to the LED unit used with Cristiana, but it clearly did, particularly on videos!
So I suspect it is not simple matter of frequency of alternate current used for powering the units, but more of an issue with LED light in itself.
Anyway, I was experimenting again with the LED spotlight to make some professional pictures of ravioli for a new client, and at 1/13 of a second it seems to give great results, even better than flashlight.
So LED light powered with alternate current might still prove very useful, but not for the shortest exposures I need for my nude project.
No, I'm not going to show you the ravioli's pictures, I'm pretty sure you prefer Martina's bottom.
Comments
Well, thanks, now I understand the difference and why the older incandescent light gave no problem! I guess I will have to keep using that... or buy a battery powered LED unit. Thanks. π
Bramley Apple
2021-03-12 16:43:23 +0000 UTCAlternating current comes in waves of 50 Hz, that means that the voltage and current are zero 100 times a second (two passes each waves, 50 waves a second - that equals 20 milliseconds for a wave that goes up from zero, then down to zero, then down below zero and up back to zero.). That means that the light would be off during those passes through zero volts. But: basically all old lights before LED work by getting a material to glow, for example a gas or a spiral of tungsten. That glowing does not stop within the few milliseconds that the current stops flowing between the sine waves of the electricity since it doesn't cool off in that short amount of time, so it's still bright even though there is no current for a millisecond. LEDs however can turn on and off in that short amount of time, it's not heat that makes them shine. Our eyes and brain together are way too slow to notice it and just see it as a constant light. Your camera is of course faster with those shutter speeds that are 1/50 or fractions of that. Most LED drivers are produced so cheap that the rectifier makes the alternating current into more of a pulsing direct current. LEDs themselves always need a direct current since they are directional, so it's not the alternating current itself that is bad, it's the driver that cannot transform it properly. I hope my rambling wasn't too confusing, I felt like trying to explain. :D
Suckerpuns
2021-03-12 15:50:42 +0000 UTC
