C300 waveform monitor: what luminence % values do the horizontal lines represent?

[Nicholas Natteau]

Sorry to ask this but I couldn't find it in the C300 manual.

Looking at the C300 waveform display, I see the usual horizontal line graph, but what luminance percentages do those horizontal lines represent?

20% 40% 60% 80% 100%. Trying to figure out if the top horizontal line is the 90% or 80% luminance value.

 

[Matt Turner]

I've been trying to find this too... well, a definitive listing, since I'm a waveform newbie (please be gentle with me! lol).

It would appear that the middle line is the 50% mark, then increments of 10% up and down, therefore the very top (edge) line is 110% and the bottom (edge) line is -10%. This is based on where the waveform lies when the lens caps is on (2nd line from bottom) and when 100% Zebra is turned on (waveform exceeds 2nd line from top). So it gives a 0%-100% range with an extra 10% either way. I'm assuming there are no markers because this could be IRE for NTSC or volts for PAL, but there's no indication of what it actually is, or if it should just be purely treated as a %.

An added bonus question: I have read elsewhere in these forums that Canon Log with a 18% grey card should be around 40 IRE for interiors and 32 IRE for exteriors, does that then match with around the "40%" and "30%" lines on the waveform respectively (and same for any other quoted IRE values such as skin)?

Sorry for the % references, I've used that purely to indicate vertical space on the waveform. Would love some clarification.

 

[mhood]

Your description sounds like what I'm looking at on my C100...are their waveforms the same?

 

[Matt Turner]

I have a C100 too... so I'm assuming they are the same as the C300.

 

[mtnski]

You can probably make a reasonable test by setting the zebras to a given percentage value, adjusting exposure so that the zebras just come on then look at where the corresponding value is on the WFM. Will try it out on my C100 later.

 

[Mike Fizer]

I think might help:

http://learn.usa.canon.com/galleries/galleries/tutorials/eos_c300_tutorials_gallery.shtml

 

[mhood]

That did help a lot. Thank you Mike.

 

[Mike Fizer]

You're quite welcome mhood. I stumbled into a C300 loaner over the holidays and am scrambling to bone up for a shoot tomorrow. I'm stunned at the quality, coming from the mk2.

I've been running some test using some custom profiles I downloaded from xdcam user for 3200/6400, I'm gobsmacked.