O-MD E-M5 - The RawDigger Base ISO Challenge (Continued)

Started Apr 19, 2012 | Discussions thread
OP Anders W Forum Pro • Posts: 21,466
Re: Normalization of EM5/GH2 RAW EV Scaling Levels when comparing

Detail Man wrote:

Anders W wrote:

You tried to determine the extent to which the E-M5 "underexposed" relative to other cameras already in the post I link to below, and, in so doing, made unwarranted use of the shutter speed values.

http://forums.dpreview.com/forums/read.asp?forum=1041&message=40963062

As you have (once again) not provided the specific text that you are citing (which I find to be rather cryptic and seemingly strangely circuitous when communicating), I read through the entire post again as a result. There is only one statement that could be construed to comport with your latest assertion of debate that I was at that point in the thread relating the data to "exposure":

Open each RAW file in RawDigger, and add up all of the average values in each of the RGGB channels (in the "Avg" column, which is found in the image statistics located in the upper-right area of the main program window) for each RAW file, in order to calculate a number for each individual camera that is proportional to the (averaged) exposure value of each of the RAW images .

In the post to which I linked you say, and I quote:

"Results [the number of EV that the E-M5 under-exposes by relative to other cameras]:

Relative to the GH2: 1.537 EV

Relative to the GX1: 0.817 EV

Relative to the G3: 1.285 EV

Relative to the E-PL3: 0.588 EV"

Other than presenting the resulting data-points, there is nothing stated in the post regarding the any of the cameras "underexposing" relative to each other . My use of the term "exposure" in general (as it related to "Exposure Value", which is a function of ISO Gain in addition to scene illuminance, T-Number, and Shutter Speed) related to the ratio of the maximum possible RAW-levels divided by the average numnber of RAW-levels indicated by RawDigger . So what ???

See quotation above.

It rather puzzles me that you often seem to engage yourself with what seems to me to be rather unecessary argumentative pedantry that seems to arise out of realms of interaction essentially removed from getting to the facts, and more in the realms of some imagined heights from which you may imagine yourself to reign intellectually, always "outflanking" your interlocutors - yet failing at the same time to communicate in a straightforward manner (preferring insted to make vague references to the writings of others, as well as of yourself). What gives on that ? You could (often, I imagine) easily find and quote a specific passage(s) in the time that you (instead) spend authoring such seemingly circuitous epsistles. There seems to be some personal pleasure that you derive from this modus operandi that I find to often be somewhat divorced from making progress.

Although I have hitherto tried my best to temper myself, I must admit that my patience has gradually worn increasingly thin. If you actually mean what you say above and below, this post is the last communication between us.

Detail Man wrote:

I still do not get your ignoring the ratio of the DPR Shutter Speeds, and preferring to set that ratio to unity. Only you know why that is your approach (but call it whatever number you may like).

See above. Why would I want to use the shutter speed if all I want to determine is the degree to which the sensor is saturated?

I don't know, and I no longer care. All that really matters is that in sutuations where you cite a numerical value (such as "0.85 EV"), you cannot expect others to telepathically intuit what you are talking about. Why not just clearly spell-out your derivation of such a number (no matter how "goofy" it may strike me) ? It is not my intention to dictate your methods - I do need to be able to precisely understand your "language", and efficiently translate them to an understandable form.

Instead, one has to eventually discover that you have your own personal "system" devised that you imagine that others will patiently struggle and strain to discover and understand (as if that were their solemn duty). In the time that we have spent going around about your "personal language and approaches", you could easily have simply "spelled it out" in the first place in a straightforward manner. I'd then know how to translate your "language", and we could go from there. In the time that we spend circuitously decoding your crypt, mountains could be moved ...

The shutter speed used by DPR tells me absolutely nothing about the extent to which the sensor is saturated in these two shots. If you think it does, please explain how?

I have lost interest. Just wanted the "Anders/DM conversion coefficients". Got it now. Thanks.

Now if I wanted to determine something else, for example the total amount of light that each sensor had been given, I wouldn't use it either inasmuch as it would tell us something about that only to the extent that the lighting of the scene was identical across cameras/sensors. But as we know, based on Andy's reports, we have no reason to think that it was identical.

Classifications are of course always debatable. I'd prefer in this case to discuss them as two separate things although they are in some ways related.

I think that it is a good thing that we do not work together daily in such "pedantic ivory towers".

That sounds like a good approach that you could take (now that you have RawDigger installed).

I have no immediate plans to start "projects" of my own in this domain. I am merely trying to help out in the capacity of consultant/critic.

I see. Will restrict my further reports as "mere technician" to "executive summaries" kept brief for the "highly-paid consultant". Really, I think that your "calling" leans closer to "professional critic" ...

My feeling is that chances are that we have explored what we can regarding these subjects "in this domain". You have a substantive intellect. Have mostly enjoyed our communications. Regards.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +28 more
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