why no ISO 850 on the Sekonic L478 digital light meter???

N

Nicholas Natteau

Veteran
Question for anyone who uses a Sekonic L478D light meter:

Does anyone know why there is no ISO 850 setting or 1/48 shutter speed?

I have a Canon C300 and it's native ISO is 850, but unfortunately, the Sekonic L478D only has ISO 800 and 1000, no 850 setting. Is there any way to get ISO 850 into the L478D???

Apparently you can download camera settings into it, but I'm still struggling to figure out how to do this.

Thank you in advance for any help.
 
You should be able to have it at a higher iso and then dial in a custom ND filter that will bring it down to 850. Like Liam Hall says it is pretty negligible though, it's about 1/16th of a difference.
 
Oh ok, thank you. I didn't know that. But how much of an ND filter would be equivalent to an extra 50 over 800?

Thanks again for clarifying for your feedback.
 
The difference is about 1/12 of a stop, actually. That's well within the error of measurement, interpreting the meter and setting the iris mechanically, so I'd suggest just going with ISO 800 and calling it a day. You shouldn't depend on the light meter for setting overall exposure anyway -- it is useful for setting light levels and measuring ratios, but the camera itself (with a waveform monitor) is more accurate for determining the precise iris setting.

The reason 850 doesn't appear on the meter is that there is a standard progression of ISO values in 1/3 stop increments, and the Sekonic (appropriately IMO) can only click between the standard values. Typically you'll see numbers like 100, 125, 160, 200, 250, 320, 400, 500, 640, 800, 1000 ... note that these double every three increments. A difference of even a third of a stop is just barely noticeable in the final image, and trying to read a meter with much more precision than that is probably a fool's errand. The ISO standard itself dictates that these are the values that should be used (remember, these were originally for specifying the sensitivity of photographic film).

Canon probably took a sensitivity measurement sometime that, when back-calculated to ISO, resulted in the 850 claimed -- but they really would have done everybody a favor by rounding that to 800 for publication.

I'm not familiar with the controls on the L-478D specifically (I have the simpler L-308DC), but you should be able to get the equivalent of a 1/48 shutter speed in cine mode, by setting it to 24 frames per second and a 180° shutter. Try that and post again if it doesn't work.

- Greg
 
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Nicholas Natteau said:
Oh ok, thank you. I didn't know that. But how much of an ND filter would be equivalent to an extra 50 over 800?

Thanks again for clarifying for your feedback.
Click to expand...


Thought about this for a second. I don't think there is actually a way to add in filter compensation at 1/16th of a stop. Should have realized that one! I'm pretty sure you can do 1/10th of a stop though, you'll have to play around in the filter compensation part of the meter to see what you can do.
 
Hey guys, thank you all very much for your help. Since we're talking about exposure and lighting. I was wondering if anyone here could comment on my results regarding a test I did with my Canon C300 using a single Zylight Z90.

I relied on the C300's internal waveform monitor for proper exposure, shooting in C-Log with greys exposed at 32% and whites at 62%. Please see the pics I posted here (further down the linked page) along with the video of it I posted on vimeo.

http://www.dvxuser.com/V6/showthrea...properly-exposed-when-shooting-in-C-log/page2

This was a quick test so I only used one light. I was trying to get a feel for exposing properly shooting in C-Log.
 
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