Ryan E. Walters, Cinematographer

Cinematic Excellence at 24 Frames a Second

How To Get the Most Out Of A Custom Profile (A Sekonic Update)

Back in July of 2012 Sekonic released the update to their camera profiling software (DTS) which I immediately started to use. After spending some time creating and testing numerous profiles for my 758Cine I realized something was not working correctly: the spot and incident readings were not matching up. Since that time, Sekonic has been hard at work finding and fixing the problem. With version 3.06 of their DTS software, you can finally rest assured that your meter will be calibrated correctly. If you plan on using one of my custom profiles, here is how you can get the most out of it.

A Little Background
Light values, and the standards for measuring them, differ in-between readings for Incident (light falling on a subject) and Spot metering (light reflecting off of a subject). To further complicate the matter, different companies have chosen to calibrate their sport meters to different values. Companies like Sekonic & Canon have chosen to follow the ANSI PH3.49-1971 standard and put the reflected reading at 12-13%. If you are interested in learning more about this and get links to the math behind it, then I suggest reading my post about the Urban Legend of 18%. If that sounds like it will bore you, then all you need to know is that the two different metering methods yield different results, even when metering the same 18% grey card.

Incident Reading taken with a profile created with the OLD DTS v3.05
Spot Reading taken with a profile created with the OLD DTS v3.05
As the pictures above demonstrate, additional problems can arise when the different ways of calculating incident and spot readings are compounded with a software bug. There is almost a full stop difference between these two readings which can yield disastrous results when exposing for the unforgiving nature of digital cinema. Which is why it is so important to have a calibrated meter, and to be working with a custom profile you can feel confident in.

(You might also like: How To Use A Light Meter)

How To Get the Most Out Of My Custom Profiles
To get the most out of my custom profiles, the first thing you have to do is to figure out how your meter responds to light in each measuring mode. To do this, you will need to light the 18% grey side of the Sekonic Profile Target II to the same values that I have noted in the Read Me file that accompanies each profile. After you have lit the card to within 1/10 of 1 stop edge to edge, take an incident reading at the charts position, and then a spot reading of the center of the chart. (Be sure to note these values).

Now that you have these values, you can substitute them for the values that I have noted in the Read Me file. By using the sample files that I have provided, as well as your readings, coupled with DTS v3.06 you will be able to create a profile that is custom tailored to your meter. Your meter should now deliver accurate readings regardless of whether the custom profile I created was created with the 758Cine or the 478D. Your results should look something like this:
Incident Reading taken with a profile created with DTS v3.06
Spot Reading taken with a profile created with DTS v3.06
If you are wondering if it is really necessary to go to this extra work to ensure that you have the most accurate meter profile possible, the answer is: it depends. If you are the type of person who likes to know that your meter is calibrated correctly even down to the 1/10, then yes, you need to do this extra step. If you are the type of person who is a little more relaxed about technical issues, and a variance of 1/10 to 3/10's of a stop in-between readings doesn't bother you, then you do not need to go to the extra work. Just remember that your mileage may vary.

To the more astute of you reading this, you may have noticed that in the pictures above, the spot reading and the incident reading differ by 1/10 of 1 stop. This is to be expected, and did not surprise me, as I placed the chart down on my couch and took a reading. The chart was only lit by a 23w CFL bulb overhead. While it does not represent a perfectly even light, it does represent what I would experience on set, as I never light everything with a perfectly even wash of light. Therefore the area that I spot metered and incident metered is more than likely not evenly lit, which will give me slightly different results. The good news is that 99.9% of people cannot tell the difference of 1/10 of a stop, and practically speaking you cannot set your lens to 1/10 stop increments anyway.

As with anything else in this field, I encourage you to "Test and Verify." Just because it works for me and I am happy with the results, that doesn't mean that it will fit with your style of working. But if you do like the results and the profiles I have provided, then feel free to download and use them as needed, as they have all been updated and processed through v. 3.06 of the DTS software.

What are your metering preferences? Will you be going to the extra work to calibrate your meter, or will you just use the profiles I have provided as is?

Until Next Time - Get Out There And Shoot!
Ryan E. Walters, Cinematographer

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