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wb under fluro?
leslie wand
Posted 14 years ago
i've got a shoot in a gallery that's lit with colour balanced tri-phosphor daylight 5200 tubes. it's very 'bright'!
other doing a user white balance the manual has 2 other options
a. preset fluro @ 5k or 6.2k
b. i can dial in the exact colour temp (ie. 5200)
however it says NOT to use the dial in with fluro's?
obviously 200k does give me a slight colour shift, so what would be the best option to use (NOT using user preset, which i have tried previously under fluro with mixed results)?
thanks
other doing a user white balance the manual has 2 other options
a. preset fluro @ 5k or 6.2k
b. i can dial in the exact colour temp (ie. 5200)
however it says NOT to use the dial in with fluro's?
obviously 200k does give me a slight colour shift, so what would be the best option to use (NOT using user preset, which i have tried previously under fluro with mixed results)?
thanks
leslie wand
Posted 14 years ago
ah, but it's not guessing at all - the tubes are guaranteed 5.2k - this is a no expense spared gallery.
from past experience i would probably have to wb each painting as the last time i was in such a situation there was a almost imperceptible shift towards magenta on some canvases. (that was shot on my old d90 - whereas my sony video camera was spot on every canvas with filter set to daylight 5.2k)
from past experience i would probably have to wb each painting as the last time i was in such a situation there was a almost imperceptible shift towards magenta on some canvases. (that was shot on my old d90 - whereas my sony video camera was spot on every canvas with filter set to daylight 5.2k)
I'm not a professional, but do shoot under quite a few different lighting conditions, some with a mixture of various light sources. I shoot raw, leave the WB in auto (unless I set custome WB, but I usually don't worry about it), and shoot a grey card or other 'white' source as a base shot to set WB when I process the raw files (typically done in Capture One). If the lighting changes (for example - moving from one room to another where there may be a change in lighting source, or more natural light coming in) I will shoot another base grey card shot for those pics taken under the new lighting situation.
Regards,
Bill
Regards,
Bill
wandalouzy
Posted 14 years ago
if you can, stay in auto WB and shoot a color calibration sheet in each shot (you'll crop that later); that way it'll be easy to adjust things in postpro to exact values.
if they guarantee 5200K just dial up "direct sunlight"
simples
simples
leslie wand
Posted 14 years ago
have arranged a test at the location tomorrow, will get back with the results...
leslie wand
Posted 14 years ago
ok - shot chip chart (raw + jpg) under lights - two locations, on opposite walls:
a. auto wb slightly warm - varied slightly when location changed.
b. preset wb on white ok, but changed slightly with location (bue/green'ish)
c. preset 'sun' - spot on both locations
d. ditto 'dialled in k - same as c.
think grandadwoof's direct sunlight / nikon 5.2k is on the money....
thanks
a. auto wb slightly warm - varied slightly when location changed.
b. preset wb on white ok, but changed slightly with location (bue/green'ish)
c. preset 'sun' - spot on both locations
d. ditto 'dialled in k - same as c.
think grandadwoof's direct sunlight / nikon 5.2k is on the money....
thanks
leslie wand
Posted 14 years ago
wouldn't even attempt it ;-)
if i have to shoot on location then i usually carry my own lights and do my best to control the situation.
if i have to shoot on location then i usually carry my own lights and do my best to control the situation.
rylos51
Posted 14 years ago
Remember to use a shutter speed of 1/125 or less. This keeps the power line induced color shifts evened out.
If the power supply is running at 50Hz, use 1/50th, (60Hz, use 1/60th), then you include ONE complete cycle. You could also slow the shutter to half, one-third, one-quarter etc to include 2, 3, 4 or more cycles... getting damn slow though :-)
At 1/125th, you only get 40% of one cycle... and that could be anywhere in the cycle
At 1/125th, you only get 40% of one cycle... and that could be anywhere in the cycle
PS. given the increase in LED lighting systems, it's worth considering the effects there.
LEDs are either switched On or OFF and in modern lighting systems they get switched very fast. The main advantage of switching is the power-saving possibilities.
If you're illuminating a room, say, you can make use of the way the human retina is slow to recover from light falling on it when the light disappears. You can switch on the LED for 1mS, then off for 10mS, and repeat........... and the eye cannot tell that it was ever switched off while you are only using power for 10% of the time.
The glaringly obvious problem for a photographer working under LED lighting like this is timing his shutter to coincide with the LED being ON - it's gonna be a dark image otherwise :-)
In practise, this isn't such a problem since switching tends to be in the kHz and it's quite unlikely you'd be using shutter-speeds above 1/1000th in room-lighting.
It could be different when using strobes though. A strobe pulse is pretty narrow, under 1mSec at less than full-power, so it's quite conceivable that the strobe and the LED may or may not coincide... and using pre-flashes for ttl flash metering ain't going to help :-)
LEDs are either switched On or OFF and in modern lighting systems they get switched very fast. The main advantage of switching is the power-saving possibilities.
If you're illuminating a room, say, you can make use of the way the human retina is slow to recover from light falling on it when the light disappears. You can switch on the LED for 1mS, then off for 10mS, and repeat........... and the eye cannot tell that it was ever switched off while you are only using power for 10% of the time.
The glaringly obvious problem for a photographer working under LED lighting like this is timing his shutter to coincide with the LED being ON - it's gonna be a dark image otherwise :-)
In practise, this isn't such a problem since switching tends to be in the kHz and it's quite unlikely you'd be using shutter-speeds above 1/1000th in room-lighting.
It could be different when using strobes though. A strobe pulse is pretty narrow, under 1mSec at less than full-power, so it's quite conceivable that the strobe and the LED may or may not coincide... and using pre-flashes for ttl flash metering ain't going to help :-)