Calibrating your light meter to your UM4.6k

Does anybody have any video tutorials that talk about calibrating your light meter with your camera, in my case the UM4.6K.

I found some videos on the net but they're mostly about still cameras. Also, since I don't have much experience with this, I don't know if what they're saying is correct.

For example, this one is good BUT you cannot do this on a video cam:

Can someone point me to a resource with instructions for getting my cam and my Sekonic in sync.

Thank you.

It shouldn't really matter what camera you are using. There's a cine option on most light meters to show shutter angle instead of shutter speed.

Hey Johnny,

Do you currently have a light meter? If not, I suggest the "Sekonic LiteMaster Pro L-478D-U", which is about $339 (on B&H). It's by far the easiest meter and it has a touch screen.

There are other light meters out there that have a cine option, but really you will need to set the meter to your shutter speed (1/48th at 24fps) and the ISO you have set for the camera. You can then put the meter with the dome up in front of your model's face and see what he meter tells you the f or t stop should be (they are synonymous).

That's a basic use of the light meter. You may also want to up the aperture on the camera a little bit—but that's where you decide how you like to expose.

Then you get into lighting ratios (which the light meter will do too). So you hear a 2:1 or 4:1 a lot, which relates to the fill and key on a face. How many stops under is the fill? Without a light meter, it would be near impossible to eyeball this. Though now the new trend is to use false color on a monitor to "color" in your lights since each color in the spectrum is set to a certain range in brightness.

Hey Johnny,

Do you currently have a light meter? If not, I suggest the "Sekonic LiteMaster Pro L-478D-U", which is about $339 (on B&H). It's by far the easiest meter and it has a touch screen.

There are other light meters out there that have a cine option, but really you will need to set the meter to your shutter speed (1/48th at 24fps) and the ISO you have set for the camera. You can then put the meter with the dome up in front of your model's face and see what he meter tells you the f or t stop should be (they are synonymous).

That's a basic use of the light meter. You may also want to up the aperture on the camera a little bit—but that's where you decide how you like to expose.

Then you get into lighting ratios (which the light meter will do too). So you hear a 2:1 or 4:1 a lot, which relates to the fill and key on a face. How many stops under is the fill? Without a light meter, it would be near impossible to eyeball this. Though now the new trend is to use false color on a monitor to "color" in your lights since each color in the spectrum is set to a certain range in brightness.

Hi David,

Thanks for trying to help out. I probably did not explain myself clearly enough.

I know how to use a light meter and happen to have the same exact model you suggested

Problem is that light meter results will differentiate from camera to camera. That's why you have to build a camera profile. So an f5.6 at 400 iso on a Ursa M will look different than an f5.6 at 400 iso on a Red. The meter will just tell you the same, but each camera responds differently. You have to calibrate the meter to the camera.

Even lenses can affect the result (if you want to go that deep).

So what a meter gives you is the same whether you have a BM, a Red or Alexa. Of course, results will not be the same exposure wise on all 3 cameras. To have accurate representations you need to calibrate the meter to your specific cam.

Hope I'm more clear now

It shouldn't really matter what camera you are using. There's a cine option on most light meters to show shutter angle instead of shutter speed.

Hi Aaron,

See my reply to David above as it explains more.

As far as I understand (and know from experience) a light meter gives you a reading for proper exposure but that will not result in accurate similar exposure across all brands of cameras. To do that you have to calibrate the meter to the cam as I understand it.

Ah ok, I was thinking it might be a general question about light meters.

Yes, that meter can be calibrated for most cameras, but unless Sekonic has added any of the BM cameras (or Red for that matter), then it's more of a manual process. Unless anyone on here has a trick? They do have that app to control settings and profiles on the meter.

I was kind of under the impression that other shot color charts with Blackmagic Film Log and corrected in the base grade.

Someone asked Roger Deakins that same question about calibrating. I know he's used to Alexa and film, so maybe he doesn't experience much of a shift.

https://www.rogerdeakins.com/set-stuff/light-meter/

I have Seconic lite Master pro L 478D-U and an Ursa mini pro as well as the mini 4.6k. Heres what you do. If you haven't updated your Seconic app yet, uninstall your current version from your computer first. Then go to the Seconic website and download the latest version 5 ( See the link below ). UPDATE your Seconic light meter to the latest version if you haven't already done so. Get a color chart (I have an Xrite color checker classic) Put your chart in front of your cam. Set the T stop or F stop on your lens and the ISO you use the most when shooting on your Ursa mini camera 4.6k. ( I keep my ISO at 800 ) Use your light meter and measure the light hitting your chart. Measure the incident light values as well because you have to input that into the Seconic app. Bring your footage into DaVinci resolve and grab 3 still Frames of your chart. Create a folder and Export the 3 stills inside the folder. Open the Seconic app click create new profile. Click the first menu that pops up (It says quick mode) use this first mode to get your feet wet. When you get comfortable you can go to advanced mode after. When that opens, select the chart that you used, there's 4 charts to choose from. Click next at the bottom. Next set the Cine mode to the left of your screen to "On". Then set your ISO and fill out all the other boxes..eg frame rate, shutter, and aperture. There's a box at the bottom that says 1/10. Look at your lite meter readings.. there's a small number next to your F stop reading you got from measuring your chart. For example you may have a reading of 2.8 with a small number to the right, under the 8. Select that number in the drop down menu box labeled 1/10. Click next and you will get the option to select the folder with your still images. Click Open after you select the folder. You will see your 3 still frames. Click on the small white square box on the top right corner of your stills. A menu will pop up, enter your ISO, Frame rate, Shutter etc.. Do this for all three stills. Click next, a bigger picture of your still frame will pop up with 4 green markers on it. Move the markers to the 4 corners of your chart in the frame. Do this for all 3 frames. On the left side of the menu you will see Light output/ correction value (EV) Enter your EV values from your meter for all 3 still images. (The brightness of preview slider is used if your image is under exposed and you need to brighten it to place the green markers on the 4 sides of your chart so you really don't need to mess with it). Click next.. it will say measuring ..you may get a message saying The set level does not exist in the image. Click OK. Your profile will be created . Save your profile. Connect your lite meter L 478 D-U via USB to your computer ..it will pop up in the Seconic app. You will see the profile you saved. Click on it, then Select transfer to light meter. Now you have your profile for your Ursa 4.6k. Boom! There it is

Here's the link to download the latest DTS version of the app.
https://www.sekonic.com/united-states/s ... ndows.aspx

Someone asked Roger Deakins that same question about calibrating. I know he's used to Alexa and film, so maybe he doesn't experience much of a shift.

https://www.rogerdeakins.com/set-stuff/light-meter/

Maybe. Deakins is a special case being that he came up in the ranks in a different world and has so much experience....

For me, a mere mortal, I'll take any help I can get

I have Seconic lite Master pro L 478D-U and an Ursa mini pro as well as the mini 4.6k. Heres what you do. If you haven't updated your Seconic app yet, uninstall your current version from your computer first. Then go to the Seconic website and download the latest version 5 ( See the link below ). UPDATE your Seconic light meter to the latest version if you haven't already done so. Get a color chart (I have an Xrite color checker classic) Put your chart in front of your cam. Set the T stop or F stop on your lens and the ISO you use the most when shooting on your Ursa mini camera 4.6k. ( I keep my ISO at 800 ) Use your light meter and measure the light hitting your chart. Measure the incident light values as well because you have to input that into the Seconic app. Bring your footage into DaVinci resolve and grab 3 still Frames of your chart. Create a folder and Export the 3 stills inside the folder. Open the Seconic app click create new profile. Click the first menu that pops up (It says quick mode) use this first mode to get your feet wet. When you get comfortable you can go to advanced mode after. When that opens, select the chart that you used, there's 4 charts to choose from. Click next at the bottom. Next set the Cine mode to the left of your screen to "On". Then set your ISO and fill out all the other boxes..eg frame rate, shutter, and aperture. There's a box at the bottom that says 1/10. Look at your lite meter readings.. there's a small number next to your F stop reading you got from measuring your chart. For example you may have a reading of 2.8 with a small number to the right, under the 8. Select that number in the drop down menu box labeled 1/10. Click next and you will get the option to select the folder with your still images. Click Open after you select the folder. You will see your 3 still frames. Click on the small white square box on the top right corner of your stills. A menu will pop up, enter your ISO, Frame rate, Shutter etc.. Do this for all three stills. Click next, a bigger picture of your still frame will pop up with 4 green markers on it. Move the markers to the 4 corners of your chart in the frame. Do this for all 3 frames. On the left side of the menu you will see Light output/ correction value (EV) Enter your EV values from your meter for all 3 still images. (The brightness of preview slider is used if your image is under exposed and you need to brighten it to place the green markers on the 4 sides of your chart so you really don't need to mess with it). Click next.. it will say measuring ..you may get a message saying The set level does not exist in the image. Click OK. Your profile will be created . Save your profile. Connect your lite meter L 478 D-U via USB to your computer ..it will pop up in the Seconic app. You will see the profile you saved. Click on it, then Select transfer to light meter. Now you have your profile for your Ursa 4.6k. Boom! There it is

Here's the link to download the latest DTS version of the app.
https://www.sekonic.com/united-states/s ... ndows.aspx

SUPER AWESOME... THANKS!

I'll put this in practice asap.

This is exactly what I was looking for.

Follow up question: I'm assuming the 3 stills are at different values? I mean: regular, underexposed and overexposed?

I'm asking because all profile building videos I see (especially Sekonic) do it this way. In your post I'm assuming that's what you meant by 3. Just want to make sure I'm understanding this correctly.

Thanks again

Yes my friend you can have 3 different set of values for the 3 different stills and more in advanced mode. In quick mode or any other mode for that matter you can have one set of values that you use the most for all three stills. It makes the calibration for your camera more accurate with different values for all three stills.

This new article by Steve Yedlin may be the info that OP is looking for:
http://www.yedlin.net/180321.html

Just like all of Yedlin’s other writing and videos, it’s a very interesting and informative read.

HERE ! This is (for me..) the most accurate calibration profiling.

http://indiecinemaacademy.com/create-se ... ter-video/

silvio bonomi

HERE ! This is (for me..) the most accurate calibration profiling.

http://indiecinemaacademy.com/create-se ... ter-video/

silvio bonomi

Thanks!

I will share my UMP camera profile when I have time to set it up. Or is there already a UMP profile we can download somewhere?

I built a profile in my Sekonic L-758 for my Ursa Mini 4.6K. I don't know about your model, but with the L-758, you have two options, one for normal dynamic range and one for higher dynamic range. The UM4.6 is definitely a higher DR camera. So, instead of 3 exposure values you take 5 exposure values. That is by far the trickiest part of the process. I had to use a combination of lighting, NDs, and shutter values as well as aperture to get the proper exposure range.