DR readings from Sekonics software

[drdiesel1]

I used the Sekonic L-758-RD to profile my 5DMKII with the 24-105L.
I used it during the day under diffused sunlight with the new Target II.


My DR reading was 6.3 :cool: Anyone else know the DR of their cameras. Just curious what the overall numbers look like ;) Thanks.

[drdiesel1]

Nobody else using Sekonic meters and software :(

[Titus213]

I use a Sekonic meter (L-358 ) but I don't even know what a DR is (except the MD type Dr I go to on occasion).

[TMR Design]

HI drdiesel1,

I use and test the Sekonic L-758DR extensively. The Dynamic range indicated by Sekonic's DTS software is not the actual Dynamic range of your camera. Many people perform the calibration and profiling and get results of just under 5 stops and some will see as much as 7 stops. It's pretty much accepted that a 5DMkII has a greater dynamic range than 6.3 stops.

DTS is conservative in its evaluation of dynamic range and clipping points. The values it uses as Dynamic Range (-) is not really true black and the values it uses as Dynamic Range (+) is not true white. In both cases there is still detail but there is no clipping. The clipping points are also conservative and you'll find that Clipping Point (-) and Clipping Point (+) are not truly clipping. You can check the values in Photoshop or Lightroom and see this for yourself. As a matter of fact, Sekonic states that you can, and many do, adjust those points to more accurately represent the Dynamic Range and Clipping Points of your camera and this is a judgement call that you make.

It's a very common misconception that DTS is going to reveal the actual dynamic range of your camera/sensor when in fact, this is not true. Most often, if you were to expose and adjust for clipping as per the DR and clipping points in your profile you'll find some underexposure in the highlights and overexposure in the shadows.

I've been doing testing and communicating with Sekonic, Japan about the procedure and documentation for DTS and it's a very slow road. There is much to be desired and a lot of the documentation needs to be rewritten. There is talk of a comprehensive video being made to demonstrate the procedure and to make some corrections.

If you use flash to create a profile and adjust the aperture of the lens you'll find more issues and problems with the procedure.

TIP: if you're shooting the images for a flash (incident and reflected) profile then it's recommended that you adjust the output of the strobes and not the aperture of the lens. If you use a completely manual focus lens then you can adjust aperture on the lens. This is due to the fact that an AF lens will have it's aperture set at the widest position until you press the shutter, and then it will stop down to the set aperture. The fraction of a second that it takes for this to happen affects the profile and its visible when DTS creates the profile graph. This happens with either Target I and 11 images or Target II and 3 images.

[Titus213]

Oh, that DR!:o

[drdiesel1]

HI drdiesel1,

I use and test the Sekonic L-758DR extensively. The Dynamic range indicated by Sekonic's DTS software is not the actual Dynamic range of your camera. Many people perform the calibration and profiling and get results of just under 5 stops and some will see as much as 7 stops. It's pretty much accepted that a 5DMkII has a greater dynamic range than 6.3 stops.

DTS is conservative in its evaluation of dynamic range and clipping points. The values it uses as Dynamic Range (-) is not really true black and the values it uses as Dynamic Range (+) is not true white. In both cases there is still detail but there is no clipping. The clipping points are also conservative and you'll find that Clipping Point (-) and Clipping Point (+) are not truly clipping. You can check the values in Photoshop or Lightroom and see this for yourself. As a matter of fact, Sekonic states that you can, and many do, adjust those points to more accurately represent the Dynamic Range and Clipping Points of your camera and this is a judgement call that you make.

It's a very common misconception that DTS is going to reveal the actual dynamic range of your camera/sensor when in fact, this is not true. Most often, if you were to expose and adjust for clipping as per the DR and clipping points in your profile you'll find some underexposure in the highlights and overexposure in the shadows.

I've been doing testing and communicating with Sekonic, Japan about the procedure and documentation for DTS and it's a very slow road. There is much to be desired and a lot of the documentation needs to be rewritten. There is talk of a comprehensive video being made to demonstrate the procedure and to make some corrections.

If you use flash to create a profile and adjust the aperture of the lens you'll find more issues and problems with the procedure.

TIP: if you're shooting the images for a flash (incident and reflected) profile then it's recommended that you adjust the output of the strobes and not the aperture of the lens. If you use a completely manual focus lens then you can adjust aperture on the lens. This is due to the fact that an AF lens will have it's aperture set at the widest position until you press the shutter, and then it will stop down to the set aperture. The fraction of a second that it takes for this to happen affects the profile and its visible when DTS creates the profile graph. This happens with either Target I and 11 images or Target II and 3 images.


WOW. I`m not sure where to start with how correct you are. I have been hunting for days to find accurate info on how to make a profile, but everything I have found is a contradiction to the next approach.
What I did for my 5DMKII was from Sekonics website video using it outdoors. I did a custom WB at the meters 1/60 @ F4.0
I adjusted the shutter to 1/60 and came up with F/4.2. I started at 1/60 and dropped it down 3 stops to 1/8 and then up to 1/500 all at F/4.
I tried to use it indoors with flash, but it`s not working very well and I really didn`t wanna load it to my meter. How can I remove the loaded profile from my meter and return it to the default setting until I figure out how to do this with a more accurate result. Thanks.

[TMR Design]

WOW. I`m not sure where to start with how correct you are. I have been hunting for days to find accurate info on how to make a profile, but everything I have found is a contradiction to the next approach.
What I did for my 5DMKII was from Sekonics website video using it outdoors. I did a custom WB at the meters 1/60 @ F4.0
I adjusted the shutter to 1/60 and came up with F/4.2. I started at 1/60 and dropped it down 3 stops to 1/4 and then up to 1/500 all at F/4.
I tried to use it indoors with flash, but it`s not working very well and I really didn`t wanna load it to my meter. How can I remove the loaded profile from my meter and return it to the default setting until I figure out how to do this with a more accurate result. Thanks.

If you look in DTS you'll see a CAMERA_DEFAULT profile. Send that over the meter, either in the Camera position you want or all of them. That returns the meter to its defaults.

[drdiesel1]

If you look in DTS you'll see a CAMERA_DEFAULT profile. Send that over the meter, either in the Camera position you want or all of them. That returns the meter to its defaults.

Thanks. I found your tutorial, so I`ll spend some time looking at that too :cool:

I just re-profiled both the D700 and 5DMKII outside using Sekonics video info, so I`ll see how that works out. My flash attempt with the D700 had a broken curve line at the top and bottom, so I`m sure it was jacked up. As long as I have an outdoor setup to use it`s OK. I can work on the studio version anytime. Thanks for the help ;)

[TMR Design]

Thanks. I found your tutorial, so I`ll spend some time looking at that too :cool:

I just re-profiled both the D700 and 5DMKII outside using Sekonics video info, so I`ll see how that works out. My flash attempt with the D700 had a broken curve line at the top and bottom, so I`m sure it was jacked up. As long as I have an outdoor setup to use it`s OK. I can work on the studio version anytime. Thanks for the help ;)

That tutorial does work but it was prior to finding out about the issues and seeing the graph that is in DTS 2.0.

I'm still planning on writing a new tutorial but it's taking forever to get some information from Sekonic, Japan.

The broken curve is exactly what I described with respect to using an AF lens and changing aperture. If you change the output of the strobe rather than adjusting the aperture you'll get a much more accurate curve. At times I still get the break even when adjusting the output of the lights.

I've also done standard meter calibrations without the custom profile and find the L-758DR to be quite accurate even without the profile. When I use flash I have a ADJ value of +.2 and that gives me a spike that is dead center when I shoot the gray card and my exposures are spot on. Like you, I've chosen not to use a flash profile until Sekonic clears up the bugs and perfects the procedure for an accurate profile. I've been told by Sekonic that if you're getting the breaks in the curve then it's not an accurate and usable profile and you're better off just using a camera position without a profile for flash.

[drdiesel1]

That tutorial does work but it was prior to finding out about the issues and seeing the graph that is in DTS 2.0.

I'm still planning on writing a new tutorial but it's taking forever to get some information from Sekonic, Japan.

The broken curve is exactly what I described with respect to using an AF lens and changing aperture. If you change the output of the strobe rather than adjusting the aperture you'll get a much more accurate curve. At times I still get the break even when adjusting the output of the lights.

I've also done standard meter calibrations without the custom profile and find the L-758DR to be quite accurate even without the profile. When I use flash I have a ADJ value of +.2 and that gives me a spike that is dead center when I shoot the gray card and my exposures are spot on. Like you, I've chosen not to use a flash profile until Sekonic clears up the bugs and perfects the procedure for an accurate profile. I've been told by Sekonic that if you're getting the breaks in the curve then it's not an accurate and usable profile and you're better off just using a camera position without a profile for flash.

Thank you for all your help. Yeah, using amient outdoor lighting will work just fine for now and like you said. The meter is close without the profile.
How did you test the flash exposure with the WB card to find out yours was off by 2 stops ?

[TMR Design]

How did you test the flash exposure with the WB card to find out yours was off by 2 stops ?

Not 2 stops. It's 2/10 of a stop.

The standard way to calibrate a light meter without any profiling is easy.

You use the B side of your target, which is 18% gray. This is actually an 18% gray neutral (equal amounts of red, green and blue) card so it can be used to calibrate exposure as well as setting white balance.

You meter the card so you're getting even light across the card. Meter for f/8 which is considered to be the sweet spot of most lenses. Take a shot of the card so that it fills the frame. If you're shooting JPG then you'll need a calibration for easy of the picture styles you use. If you shoot on a neutral picture style shoot using that style. If you shoot RAW then picture style won't matter, as the raw editor (Photoshop or Lightroom) will disregard picture style.

Import the image to your computer and view it in your editor. There should be a single gray spike in the histogram and it should be dead center. If it's not dead center then use your exposure control in the software to adjust it so it is in the center. Let's say that you had to increase exposure by .2 stops. Take that number and set the ADJ value in the L-758DR to +.2. This is done by holding the ISO1 and ISO2 buttons down at the same time and turning the jog wheel up to give you +.2. When you release the ISO buttons you'll see the +.2 in the display. Now meter for f/8 again, shoot the image and import to your computer. The gray spike should now be centered. If it's still off then make any slight adjustment needed. Sometimes you may have to adjust another 1/10 stop to get it perfect. Once you have the spike centered then your meter is calibrated for that mode.

You can use this method to calibrate each mode separately. If you also take reflective readings then it's important to calibrate for reflective as well as incident.

[drdiesel1]

Not 2 stops. It's 2/10 of a stop.

The standard way to calibrate a light meter without any profiling is easy.

You use the B side of your target, which is 18% gray. This is actually an 18% gray neutral (equal amounts of red, green and blue) card so it can be used to calibrate exposure as well as setting white balance.

You meter the card so you're getting even light across the card. Meter for f/8 which is considered to be the sweet spot of most lenses. Take a shot of the card so that it fills the frame. If you're shooting JPG then you'll need a calibration for easy of the picture styles you use. If you shoot on a neutral picture style shoot using that style. If you shoot RAW then picture style won't matter, as the raw editor (Photoshop or Lightroom) will disregard picture style.

Import the image to your computer and view it in your editor. There should be a single gray spike in the histogram and it should be dead center. If it's not dead center then use your exposure control in the software to adjust it so it is in the center. Let's say that you had to increase exposure by .2 stops. Take that number and set the ADJ value in the L-758DR to +.2. This is done by holding the ISO1 and ISO2 buttons down at the same time and turning the jog wheel up to give you +.2. When you release the ISO buttons you'll see the +.2 in the display. Now meter for f/8 again, shoot the image and import to your computer. The gray spike should now be centered. If it's still off then make any slight adjustment needed. Sometimes you may have to adjust another 1/10 stop to get it perfect. Once you have the spike centered then your meter is calibrated for that mode.

You can use this method to calibrate each mode separately. If you also take reflective readings then it's important to calibrate for reflective as well as incident.


Great. I have one more question. I have a Whibal WB card and it meters different than the Sekonic target 18% (B Side) card. Now I`m really confused about what to use for WB. I usually shoot the Whibal in the first frame and use it to set WB on all the shots taken at that exposure. The Whibal is a "Certified" measured card, but yet it reads different on the Histogram and I can see the difference between them. Could you clear this up for me as well. I hate to keep bugging you, but the info I`m able to find talks in circles and never gets to the answer :lol: Thanks again.bw!

[TMR Design]

Great. I have one more question. I have a Whibal WB card and it meters different than the Sekonic target 18% (B Side) card. Now I`m really confused about what to use for WB. I usually shoot the Whibal in the first frame and use it to set WB on all the shots taken at that exposure. The Whibal is a "Certified" measured card, but yet it reads different on the Histogram and I can see the difference between them. Could you clear this up for me as well. I hate to keep bugging you, but the info I`m able to find talks in circles and never gets to the answer :lol: Thanks again.bw!

The WhiBal card isn't 18% gray. I believe it's more like 13%. That's why you get a different exposure, but you're not using a white balance to correlate to exposure. They are independent. The concept is to set a custom white balance and then do any calibration or profiling with the target. White balance can be set from any neutral reference as long as it is in fact neutral.

The Sekonic card is neutral but it's 18% gray and it referenced for middle gray and exposure.

[drdiesel1]

The WhiBal card isn't 18% gray. I believe it's more like 13%. That's why you get a different exposure, but you're not using a white balance to correlate to exposure. They are independent. The concept is to set a custom white balance and then do any calibration or profiling with the target. White balance can be set from any neutral reference as long as it is in fact neutral.

The Sekonic card is neutral but it's 18% gray and it referenced for middle gray and exposure.

I knew I wasn't using the Whibal for exposure, but didn`t know why it was different. Thanks.

[texshooter]

The values it uses as Dynamic Range (-) is not really true black and the values it uses as Dynamic Range (+) is not true white. In both cases there is still detail but there is no clipping. The clipping points are also conservative and you'll find that Clipping Point (-) and Clipping Point (+) are not truly clipping. You can check the values in Photoshop or Lightroom and see this for yourself. As a matter of fact, Sekonic states that you can, and many do, adjust those points to more accurately represent the Dynamic Range and Clipping Points of your camera and this is a judgement call that you make.



So you are saying the DRS is only meant to approximate the true DR of my camera, and that I need to adjust the dynamic and clipping points to suit my tastes? But how? How do I go about knowing how much to tweek the points recommended by the data transfer software? I'm tempted to forget about the data transfer method and profile by eye instead, like thus:

Clipping points: Open the target images in PS and identify which two squares become indistinguishable (both on the shadow and highlight sides). The squares closest to middle gray will be my clipping points.

Dynamic Range Points: Take several exposures of a white terry cloth towel at and near the clipping points. The frames that lose some but not all detail in the fabric will be considered my dynamic range points.

Then I dial the compensation values manually into my Sekonic meter.

Or is there a better way? Since the software doesn't finish the job for me.

[TMR Design]

You can manually adjust the clipping and DR points while creating the profile in DTS. If you save the profile and come back to it you can no longer edit.

If you took the dynamic range that the software shows literally then our camera would have horrible dynamic range, which they don't. They may be lacking but they're not as limited as you would think based on DTS.

The DR from DTS is known to be conservative and not more than an anchor point. According to Sekonic, most pros open up the DR and expand the clipping points once they know the limitations of the camera. It's easy enough to determine at what point the camera loses detail in highlights and shadows and when there is pure white or black. True black and true white will always demonstrate greater range than what the software will do on its own.

[texshooter]

. It's easy enough to determine at what point the camera loses detail in highlights and shadows and when there is pure white or black. .

How do you determine at what exposure the highlights/shadows begin to lose detail (DR points)? It's easy to determine the clipping points(pure white or black)--simply identify the two patches that are indistinguishable. But the DR points is a mystery to me. Is there some rule of thumb by looking at the profile target on how to subjectively find the DR -/+ points? Because each patch on the target is solid, they don't have any detail to judge whether they are losing any detail.

The Sekonic meter defines the DR+ point as the EV above middle gray where highlights start to "bloom." And the DR- point as the EV where the shadows start to show grain. But I've done the Sekonic target test and my shadows show no grain and my highlights show no bloom, so I'm not sure how the DT software is calculating the DR+/- points.

Also, you said that it's best to use a manual focus lens for this test because the fraction of time it takes for the aperature to close throws off the test. But doesn't the aperature close to the set f-stop BEFORE the focal plane shutter opens?

[TMR Design]

The problem with the Dynamic Range + and - points is that they are far from accurate. They don't represent the true dynamic range of your camera/sensor.

In terms of working with the points, most people use the clipping points as their reference. Once you're clipping you're clipping so there really isn't dynamic range beyond your clipping points.

[drdiesel1]

The problem with the Dynamic Range + and - points is that they are far from accurate. They don't represent the true dynamic range of your camera/sensor.

In terms of working with the points, most people use the clipping points as their reference. Once you're clipping you're clipping so there really isn't dynamic range beyond your clipping points.

How can you measure clipping and set the meter to match ?