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  #1  
Old January 22nd, 2009, 11:21 AM
John Prendergast John Prendergast is offline
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Default Profiling a Sekonic 758 DR

Has anyone had any success in doing this?

I have made several attempts and as far as I am concerned I have carried out the procedure correctly and even when doing it with ambient light, when I eventually get a curve that is joined up, when I install that profile into the camera, the resulting exposures obtained from the reading given using the newly made profile are way out (like a stop or more under)

Has anyone had better success?, If so, lets discuss.

I am managing for now, just by adjusting it manually to give readings that give correctly exposed shots for my camera (D2X).

For the unsuccessful profiling, I have been shooting raw, then processing the RAW files into full res, high quality jpgs in CaptureOne Pro the using those jpgs for the test.

All other steps for the procedure have been carried out as the instructions state. I have been using the Mk1 target, the one with the fewer patches on and that you need eleven separate exposures for the test.

Any ideas? Or does it just not work?
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  #2  
Old January 22nd, 2009, 01:39 PM
Bill Miller Bill Miller is offline
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Instead of using a profile from the meter to the camera. The easy method is to calibrate the meter to your camera. The 758 will allow saving 3 different cameras.

Calibration is easy and less then a 5 minute job.
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  #3  
Old January 23rd, 2009, 12:30 AM
Kathy Rappaport Kathy Rappaport is offline
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Default Difficult to sue

That meter is not so easy to use. I bought one and can't figure it out myself. The 358 is so much easier!
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  #4  
Old January 23rd, 2009, 12:45 AM
Ken Tanaka Ken Tanaka is offline
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John: I must agree with Kathy. That new L758DR is one nutty meter. I tried one last year and returned it, deciding to stick with my older L758 for studio-style work and a L308 for occasional outdoor work with meterless cameras.

The concept of the L758DR sounds promising but, in fact, even when you get it working it really offers negligible practical value-added over its predecessor. But as you've discovered, the design and language of Sekonic's documentation (translated from Japanese) is absolutely bewildering and an exercise in blood pressure management.

Today's digital cameras' reflected meter systems, when used properly, are more precise than a 3rd party meter. That aside, just having the ability to make unlimited free test exposures can make the value of a handheld meter marginal. But in no case is it worth the struggle that that L758DR imposes.
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  #5  
Old January 25th, 2009, 03:34 AM
Frank Doorhof Frank Doorhof is offline
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I don't know what the problem is with your meter but I do know what I experienced and it's similair and I have a FEELING I know what's going "wrong".

In photography 18% gray will render a spike in the histogram dead center.
When you calibrate your meter it would best be with photographing a 18% graycard with a very large lightsource so there is even light on the card.

When you look at the histogram in your RAW convertor (with everything flat) the spike of the card should be dead center, if it's underexposing set the meter to the value it's underexposing, measure again, adjust the light, measure again and take the shot, now it should be ok.

With the new 758 software you HAVE to use their card, which is a big FLAW in my opinion, with the last software you did not have to do this and you could manually take the shots and add the offset in software.

The first problem I have with the card is that I can't use all my lenses, it's simply with the MF system not possible to take the whole range of exposures (most lenses have a range of 4.5-32)
But I do have one 2.8-32 so I did it with that lens.

When you do EXACTLY as the manual states my meter underexposed app 1/3 off a stop.
It really puzzled me why this happened and to be honest it drove me nuts.
I tested it with both the Leaf system on the RZ67ProII and the 645AFD/III and finally I did the same with the Canon 5D, all three were CONSISTANT in their underexposure.

What I did was give an offset of -1/3 stop in the first option (what did you measure) and after that the calibration process was flawless and the meter did exactly what it supposed to do.

I know that a lot of camera makers are not working with 18% gray anymore but with 12% gray, this is mostly used as far as I understood to make sure the exposure of the reflective metering IN THE CAMERA is protected against blowing out highlights.
This would explain why the meter is underexposing I guess.

HOWEVER for a METER this is incorrect in my opinion.
A calibrated meter should render the subject you measure ACCURATE.
And the "laws" still say that 18% gray should render a spike in the dead center of the histogram, not 1/3rd stop down.

I have talked about this with Sekonic but got no response, which I think is weird.
The funny thing is that you see alot of people on the net praising the calibration of the 758DR and that's it's the best thing arround while they clearly are using a meter that underexposes........
The problem is that they probarbly trust the calibration process and don't check it, and still use photoshop to change the exposure slider.

I have calibrated the 758 the way I described and I have perfect exposures with the meter (never have to use the exposure slider with the 645AFD/III and 5DMKII) so the meter is VERY RELIABLE and good, but the new software in my opinion is faulty.

But I COULD BE WRONG.
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  #6  
Old January 25th, 2009, 04:38 AM
Doug Kerr Doug Kerr is offline
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Hi, Frank,

Quote:
Originally Posted by Frank Doorhof View Post
I don't know what the problem is with your meter but I do know what I experienced and it's similair and I have a FEELING I know what's going "wrong".

In photography 18% gray will render a spike in the histogram dead center.
I'm not sure what you mean by that.

If we meter on a gray card and set the camera accordingly, the location of the histogram spike for the card will not depend on the reflectance of the card. That is the basic nature of reflected light exposure determination.

And that location will depend on the "exposure strategy" adopted by the camera manufacturer . (In cameras that follow all the applicable ISO standards, that will be the result corresponding to a photometric exposure of 12.8% of "saturation". But many real cameras expose somewhat "hotter" than this, about 20% not being uncommon for some Canon dSLRs)

And "dead center" isn't really a well-defined exposure result indication owing to the use of different histogram scale schemes for the exposure result axis on histograms in different cameras.
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Old January 25th, 2009, 04:53 AM
Frank Doorhof Frank Doorhof is offline
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I think you misunderstand me.

When I photograph a 18% graycard with a calibrated meter it SHOULD render a spike in the center of the histogram.
Simply because 18% gray is middle gray, it's a simple fact as far as I know.

When we use a meter we want the meter to render the object we photograph correctly.
If we measure the light hitting (reflective) or falling on (incident) a 18% graycard it should in my opinion render a spike in the center of the histogram.

I test this with an leaf aptus connected to leaf capture with everything flattened.
When I use the meter as I calibrated it now everything I measure and shoot is 100% accurate, skintones are correct etc.
When I use the calibration method from Sekonic everything is underexposed, INCLUDING my test shot with the 18% graycard.

I always use a 18% graycard with a piece of white, with the calibration process done as sekonic says, the white is underexposed and the 18% gray card is underexposed.
Adding the offset manually the white is where it should be and the 18% gray spike is dead center.

It's not that difficult I think ?
Hope this clearifies what I meant.
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Old January 25th, 2009, 05:41 AM
Doug Kerr Doug Kerr is offline
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Hi, Frank,

Quote:
Originally Posted by Frank Doorhof View Post
I think you misunderstand me.

When I photograph a 18% graycard with a calibrated meter it SHOULD render a spike in the center of the histogram.
Simply because 18% gray is middle gray, it's a simple fact as far as I know.
Try it with a card having a different reflectance (such as a WhiBal card), or a piece of white paper. Assuming that you meter only on the card (paper), you will have the same spike on the histogram from the card (paper).

This is the nature of the reflective exposure metering process.

Now, insofar as metering for a "good" assignment of the luminance of different scene objects to photometric exposures (and thus to exposure results), that is another matter altogether. If we meter on a gray card we are in effect making an incident light measurement, with the "calibration" of our ad hoc incident light metering system dependent on the reflectance of the card. If the target card has a reflectance of 18%, then the photometric exposure for the card will be 18/100 of the photometric exposure of an object of 100% reflectance.

With the meter calibration and exposure strategy of the typical dSLR, this will place the photometric exposure for a 100% reflectance object near saturation . (For a camera to ISO standards, it would be 1/2 stop below saturation.) That is a reasonable way to "map" the reflectance of scene objects to the "tonal scale" of the camera (following in effect a Zone System philosophy).

Quote:
If we measure the light hitting (reflective) or falling on (incident) a 18% graycard it should in my opinion render a spike in the center of the histogram.
And if so, so will such an exercise with a card of a different reflectance. Again, I suggest a simple test with a target of a different reflectance. If you meter (only) on the target, the location of the histogram spike (we assume the spike is from the target) will be unchanged.

Keep in mind that if all the exposure meter sees is the luminance of the card, it has not way to "know" what reflectance, combined with what incident illuminance, led to that object luminance.

So the light from an 18% reflectance target illuminated with an illuminance of 100 cd/m^3 will look exactly to the meter, and to the camera imaging system, like the light from a 36% reflectance target illuminated with an illuminance of 50 cd/m^3. Assuming that in each case, metering is on the card only, how will the camera "know" to give the image of the card in the first case an exposure result of 18% of saturation but the card in the second case an exposure result of 36% of saturation? It can't. It will give both the same exposure result (and thus the same histogram indication for the part of the image that comes from the card).

Quote:
Hope this clearifies what I meant.
It does. Thanks.

Best regards,

Doug
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  #9  
Old January 25th, 2009, 05:53 AM
Frank Doorhof Frank Doorhof is offline
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Hi,
I think I know where you are going but please read this :

The cards used are the target from Sekonic and a QPcard (both recommended for calibrating the meter and both 18% gray, and both have the EXACT same problem).
I tried with a white piece of paper and got similair results but slightly hotter than the white pieces on the sekonic and Qpcard which would be correct because white paper often uses whiteners.
When I SPOT meter the white piece of paper and the white part of the Sekonic or QPcard, the Sekonic and QPcard are the same, the piece of white paper is different (again logical).

When I measure incident I measure the light hitting an object, in my case a model.
When I take the shot I want the skin of the model to be EXACTLY what she/he is in real life.
In other words my meter has to be reliable.

When I measure the 18% graycard with incident the meter should give me an exposure where when I photograph the 18% graycard it should render a spike in the center of the histogram, or in other words the item I record is rendered correctly.

With the REFLECTIVE metering it works indeed different, here the angle of the light and the camera angle is VERY important as is the reflective quality of the material.

BUT ....
In most case we are calibrating the incident reading for normal modelphotography.
I use reflective only for my backgrounds and when shooting outside and I want to make sure something is not blowing out or dissapearing in shadow.

The cards I use are the QPCARDS and the SEKONIC testchart, both are designed for calibration purposes.

I think it's wrong when you market a 18% graycard with a calibration software package that after calibration the 18% graypatch is rendered as a 12% graypatch.

I understand why cameras will do this with their reflective metering, but in reality when you measure incident it should render the card as 18% gray.

In practice my story is correct as far as I know.
When I use the Sekonic method ALL my shots are underexposed (exactly as expected), in other words my models skintone is too dark.
When I use my own method described in my first post all the shots I take are accurate and I don't have to use the exposure control.

I really don't care about what Sekonic thinks to be honest I want a meter that does exactly what it's supposed to do and not a meter that does it but I have to remember to open up 1/3 stop
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Old January 25th, 2009, 07:39 AM
Doug Kerr Doug Kerr is offline
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Hi, Frank,

Quote:
Originally Posted by Frank Doorhof View Post
Hi,

When I take the shot I want the skin of the model to be EXACTLY what she/he is in real life.
I suspect that by that you mean something like one of these:

If a certain area of the model's skin has a reflectance of 21%, then in the delivered digital image the "exposure result" for that area of skin is:

A. The exposure result that would come from a photometric exposure of 21% of saturation. [Please excuse me for stating this in a more "finicky" way than people often do, but no other way of saying it is really indicative of the situation I want to define.]

or perhaps

B. The exposure result that would come from a photometric exposure of 21% of 1/2 stop less than saturation (which would be the exposure result that would come from a photometric exposure of 14.8% of saturation).

(You may not have thought of it in such terms, but some such description is needed if your statement is to have an specific objective meaning.)

Now, if you base you exposure settings on the indications of an actual incident light exposure meter, whose calibration factor falls at the middle of the range permitted by the ISO standard for such meters, then:

1. If your digital camera defines its ISO sensitivity in accordance with the ISO standard for sensitivity (speed), then you will in fact attain result B, above.

2. If your digital camera defines its ISO sensitivity 1/2 stop down from accordance with the ISO standard for sensitivity (typical for certain lines of Canon EOS cameras), then you will in fact attain result A, above.

Note that none of this involves the number 18% or a reflectance of 18% for anything.

Now, if instead of using an actual incident light exposure meter, we use a reflected light meter, and meter off a gray card, then, if the meter's calibration factor falls in the middle of the range permitted by the ISO standard for such meters, and the gray card we use has a reflectance of 18%, then:

3. If your digital camera defines its ISO sensitivity in accordance with the ISO standard for sensitivity (speed), then you will in fact attain result B, above.

4. If your digital camera defines its ISO sensitivity 1/2 stop down from the ISO standard for sensitivity, then you will in fact attain result A, above.

So when you say you want your meter to be "reliable", perhaps you mean, "you would like its calibration factor to be at the middle of the range allowed by the ISO specification", or, if the result I describe above as predicated on that is not what you want, you may mean, "I would like the calibration factor of my meter to depart from the middle of the range allowed by the ISO specification by a certain amount, which takes into account:

a. Your preferences as to the actual rendering of the model's skin, and

b. The approach used by the manufacturer of your camera in assigning an ISO sensitivity to its imaging system.

Confession: I have stretched some of the numbers to make this come out "tidily". If we use the actual centers of the ranges of the ISO standard for the calibration of the two types of exposure meters, then the second part of the story would require the presumption of a gray card with a reflection of 16%.

Best regards,

Doug
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  #11  
Old January 25th, 2009, 08:32 AM
Frank Doorhof Frank Doorhof is offline
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What I want is simple
When I photograph my model or 18% graycard I want a print that is correct.
With the original calibration this is not the case eveything is too dark
When I offstet the meter so that the spike of 18% is dead center everything is perfect.

I appriciate your posts and understand me you are right in you story however in my opion a meter shoul give me an aperture and when I use THAT setting the tones should be accurate on my monitor AND print.
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Old January 25th, 2009, 10:32 AM
Ken Tanaka Ken Tanaka is offline
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You guys have run off the rails and are not helping John with his 758 DR. Start a new thread to rant about gray cards and exposure purism.
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Old January 25th, 2009, 10:55 AM
Frank Doorhof Frank Doorhof is offline
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I think it's perfectly ontopic.
It's the problem with the software.
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Old January 25th, 2009, 11:33 AM
John Prendergast John Prendergast is offline
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Hello Frank, Many, many thanks for your input into this problem.

I think that I am going to take your very sound advice and abandon the Sekonic software and procedure. Its rubbish.

I'm going to now do it the way that you suggest and if it is OK I will keep you informed of my progress, privately of course.

Incidentally, in CaptureOne Pro, you can crop into an area and the histogram then only reads for that chosen area.

If I do this with the WhiBal Grey card, the sekonic grey card and the Lastolite eezybalance grey target, they all give different readings when shot under identicle lighting.

Are any of them accurate?.

Anyway Frank, you lighting technique and exposures seem that perfect to me, I will take what you say as gospel and follow that creed.

Many thanks again

Thank you to all other contributers, I have what I need, ref this question so I wont waste any more of your bandwidth.
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Old January 25th, 2009, 07:05 PM
Doug Kerr Doug Kerr is offline
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Hi, Ken,

Quote:
Originally Posted by Ken Tanaka View Post
You guys have run off the rails and are not helping John with his 758 DR.
My apologies to all. I got carried away.

I'll try and confine discussions of my technical outlooks to appropriately-placed dialogs.

Quote:
Start a new thread to rant about gray cards and exposure purism.
No thanks. Rant is not my milieu.

Best regards,

Doug
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Old January 25th, 2009, 07:16 PM
Doug Kerr Doug Kerr is offline
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Hi, John,

Quote:
Originally Posted by John Prendergast View Post

Incidentally, in CaptureOne Pro, you can crop into an area and the histogram then only reads for that chosen area.

If I do this with the WhiBal Grey card, the sekonic grey card and the Lastolite eezybalance grey target, they all give different readings when shot under identical lighting.
Well, if you mean when exposure is done with an incident light meter (or with identical exposure, regardless of how chosen), it's not surprising - I believe that they all have different reflectances.

If you mean when exposure is done by using a reflected light meter off the card, then that result is surprising.

Quote:
Are any of them accurate?
In what regard? Do you mean do they have their advertised reflectance? Do we know what those "advertised" reflectances are?

Do you mean, "does making an exposure by using a reflected light meter off them give the same result as using a properly calibrated incident light meter", then for I don't know. I don't know if any of them have reflectance chosen for that use.

Best regards,

Doug
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Old January 26th, 2009, 12:21 AM
Frank Doorhof Frank Doorhof is offline
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I know that some material will only work for whitebalancing.
Often they are a bit lighter or alot lighter than 18% gray simply because 18% is rather dark and for whitebalancing a lighter area is preferable because there is less chance on noise appearing in the balancing area.

For calibration of the meter use the Sekonic card or the QPcards.
From those I know they both measure the same.
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Old January 26th, 2009, 03:44 AM
John Prendergast John Prendergast is offline
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Quote:
Originally Posted by Doug_Kerr View Post
Hi, John,



Well, if you mean when exposure is done with an incident light meter (or with identical exposure, regardless of how chosen), it's not surprising - I believe that they all have different reflectances.

If you mean when exposure is done by using a reflected light meter off the card, then that result is surprising.



In what regard? Do you mean do they have their advertised reflectance? Do we know what those "advertised" reflectances are?

Do you mean, "does making an exposure by using a reflected light meter off them give the same result as using a properly calibrated incident light meter", then for I don't know. I don't know if any of them have reflectance chosen for that use.

Best regards,

Doug

Erm...yes, at least we know what they are alleged to be,

Lastolight Ezybalance = 18% Grey, see below
http://www.lastolite.com/ezybalance.php

Sekonic Profiling Target = 18% Grey (Because they say it is)

WhiBal Grey Card = I now know through checking that this cards purpose is to correct white balance and not necessarily as a reflective reference for accurate exposure. Their specs say that this card has a reflec tive index of around 70 instead of 118 so that makes sense. Frank Doorhof was right on the button here as the card is this way so as to better calibrate white balance rather than accurate exposure.

Its as simple as this, I want to take a reading where the incident reading matches a spot reading from an accurate Grey card exactly and that reading, when entered into the camera, gives me a bang on exposure whether is is an ambient reading, a flash reading or indeed, and more often the case in my situation, a combination of both.

I need this as, the same as Frank seems to do, I want to take an incident reading and then be able to plot the rest of the scene by spot metering it whilst keeping all areas inside the dynamic range of that particular camera (or atleast, inside its clipping points). I want this so I can plot the lighting to get the very best range of contrast and brightness range, that the camera can handle without trying to drag it back or lift it up in PP.

Seems a straightforward enough desire to me.

Interestingly enough, I have recently listened to an audio clip by Sekonic USA, where one of their "experts" discusses this meter and he distinctly states that the histogram spike of the grey card should end up to the right of centre once the meter is correctly set-up. Very, very strange. If that is the case, it definately wont be reading 118, which is what the first version of the software stated to aim for.

I'll try to find the clip.

It may be asked, why havent I asked Sekonic about this, I have, at least I asked the people at the number given for UK support but they just turned out to be the distributer of Sekonic (Johnsons Photopia) in the UK, and didnt have any idea and didnt want to know once they realised I didnt buy it off them.
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Old January 26th, 2009, 03:55 AM
Frank Doorhof Frank Doorhof is offline
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that's the VERY frustating part in this, you don't seem to able to get a correct or whatever answer.

When I calibrate with whatever camera the spike is on the LEFT side of the center, not the right
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Old January 26th, 2009, 05:08 AM
John Prendergast John Prendergast is offline
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Yes Frank, I know what you mean. I have been trying to get to the bottom of this for ages with zero success. This conversation with you is the most progress I have made so far.

Here's a podcast that can be downloaded at the link below featuring the Product manager of Sekonic, Phil Braden. I'm not sure if this ithe one which says about the histogram spike being to the right but the interesting part is from 45mins 30 secs into it where it discusses the 758 Data Transfer Software.

http://www.studiolighting.net/e077-s...raphy-podcast/

I have now also discovered that Sekonic is saying that if the Target being used does not have the registration crosses on, they should be contacted to have it changed.

My target is the Mk1 version and has no registration crosses, even though, the Mk1 version that Sekonic now show, does. I will contact them and see what they have to say.

P.S. These bits of cardboard (Profile Targets) are 100 to buy, thats right, one hundred whole english pounds.
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Old January 26th, 2009, 08:05 AM
Andrew Rodney Andrew Rodney is offline
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Quote:
Originally Posted by Frank Doorhof View Post
When I photograph a 18% graycard with a calibrated meter it SHOULD render a spike in the center of the histogram.
I'm not so sure. Which histogram? If you're shooting Raw, there's a world of difference in the actual level that tone would hit versus a rendered image and the encoding color space would play a role too.

As to the meter question, got one when it first came out, tried the calibration process with software and supplied target. Not sure it worked (the instructions at the time where vague and again, asked us to hit a value based on an output encoding space without defining that space). IOW, it was a kludge. I heard Sekonic updated the process, updated the software etc but I haven't gone there yet.

The concept is great. The hardware is great. The calibration process is a kind of goofy. I guess I should revisit it again. It would be cool to calibrate the meter to the actual ISO sensitivity of the camera, at various ISO settings based on ETTR.
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Old January 26th, 2009, 08:12 AM
Frank Doorhof Frank Doorhof is offline
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You can do it with varies ISO settings.

I do the calibration process in my own workflow, meaning RAW flattened ProphotoRGB.
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Old January 26th, 2009, 08:15 AM
Andrew Rodney Andrew Rodney is offline
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Quote:
Originally Posted by Frank Doorhof View Post

I do the calibration process in my own workflow, meaning RAW flattened ProphotoRGB.
What is a Raw flattened ProPhoto RGB?
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Old January 26th, 2009, 08:42 AM
John Prendergast John Prendergast is offline
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Quote:
Originally Posted by Andrew Rodney View Post
I'm not so sure. Which histogram? If you're shooting Raw, there's a world of difference in the actual level that tone would hit versus a rendered image and the encoding color space would play a role too.

As to the meter question, got one when it first came out, tried the calibration process with software and supplied target. Not sure it worked (the instructions at the time where vague and again, asked us to hit a value based on an output encoding space without defining that space). IOW, it was a kludge. I heard Sekonic updated the process, updated the software etc but I haven't gone there yet.

The concept is great. The hardware is great. The calibration process is a kind of goofy. I guess I should revisit it again. It would be cool to calibrate the meter to the actual ISO sensitivity of the camera, at various ISO settings based on ETTR.
Your right there, Andrew. The histogram we are referring to would be the one where the frame has been filled with the Sekonic Grey card.

You are also right that when shooting Raw, the chosen output space will also have a noticeable effect on the output itself.

Hence, it is suggested that the tests are carried out using your normal working procedure including RAW conversion and profiling procedure.

I spoke to Sekonic USA tech department and they told me that the registration marks arent critical and to just line the crosses up with the corners of the card.

They also told me not to bother with all of the (mind boggling)compensation factors asked for in the manual when trying to calibrate for flash, just shoot f2.8 to f22 and for the other required images just repeat the highest and lowest exposures because the software wont work without 11 images even though it wont take any notice of the ones completely blown out or blocked up (this is for the Mk1 target).

They also told me that they have an updated PDF of insructions for the procedure that can be obtained by emailing them at info@sekonic.com.

Might be getting somewhere, now.

Andrew, The Sekonic software will allegedly build a profile for every ISO you enter into it. It will do this for both flash and ambient and store details of three different cameras. Or.... you could use this for storing the different results of three different output profiles.

Idid read somewhere that someone who had gone to the trouble of profiling different ISO's had also noticed that not only where the profiles for different ISO's not the same, but interestingly, for what ever camera he was profiling, ISO'200 produced the widest dynamic range (like, even wider than ISO 100). So it seems these DSLR's may have a sweet spot for dynamic range that might not necessarily be the slowest film speed.
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  #25  
Old January 26th, 2009, 08:52 AM
Andrew Rodney Andrew Rodney is offline
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Quote:
Originally Posted by John Prendergast View Post
Hence, it is suggested that the tests are carried out using your normal working procedure including RAW conversion and profiling procedure.

Sekonic needs to further explain all this. What "normal" working procedure? For example, I want the meter to properly apply exposure, based on ETTR and the white clipping of the Raw data, not what the default rendering in a Raw converter might be. I can build a "normalize" preset in say Lightroom for import whereby not using it and viewing the image would produce a blown out appearance. But the data would be in the highlights (and provide the cleanest shadows) once I applied the correct preset for that exposure. IOW, I don't want good looking exposure with a Histogram in some arbitrary spot just when viewing the Raw with some default rendering setting. I want the most data I can fit based on proper exposure for Raw, linear data.

The big issue as I see it isn't the debate if proper exposure of so called middle gray is 12% or 18% or whatever after rendering. What I want is the best exposure not based on film, but the linear encoded Raw data. I don't want to blow out highlights but I want as much data in that portion of the tone curve as possible without clipping data I want to retain, without regard to a rendering setting in a Raw converter. That will provide the most data in the shadows, reducing noise.
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Old January 26th, 2009, 09:00 AM
John Prendergast John Prendergast is offline
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Well, my "normal procedure" is, to shoot RAW in a D2X, camera space set to Adobe RGB, process those RAW files in CaptureOne Pro with an camera space of generic D2X and an output space of Adobe RGB (or if it is going to the web, a frontier etc, sRGB). The images used for the test will be the jpgs generated by CaptureOne using these parameters without any editing at any stage.

I assume they mean that you should use the same parameters for the test (for my tests, with my camera, of course)
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Old January 26th, 2009, 09:45 AM
Andrew Rodney Andrew Rodney is offline
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I want to meter for scene referred, not output referred data.
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Old January 26th, 2009, 09:55 AM
John Prendergast John Prendergast is offline
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I want to meter for light, how my camera sees it and how much of a brightness range of it, my camera's chip can handle.
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Old January 26th, 2009, 10:00 AM
Andrew Rodney Andrew Rodney is offline
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I want to meter for light, and how much of a brightness range of it, my camera's chip can handle.
Thats scene referred. That's happening before a lot of Raw rendering. The rendering is, or should in an ideal condition, be based on the scene referred data.

Whether you're viewing something on the back of the camera LCD or in some Raw converter, you're not necessarily and nearly never dealing with scene referred data.
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Old January 26th, 2009, 10:09 AM
John Prendergast John Prendergast is offline
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Originally Posted by Andrew Rodney View Post
Thats scene referred. That's happening before a lot of Raw rendering. The rendering is, or should in an ideal condition, be based on the scene referred data.

Whether you're viewing something on the back of the camera LCD or in some Raw converter, you're not necessarily and nearly never dealing with scene referred data.
Well as long as I get a perfectly exposed shot (print) from the exposure information given to me by the meter without any post production exposure editing, I am not remotely interested in the geekspeak.
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