He didn't. I can't read it unless I pay and if I pay I can read it but can not post for you to read in order to prove any thing. That is why the ISO standard is a secret.
There is hope.
OK, now I understand the issue raised. Not a typical daylight scene, and the 'proper exposure' is very much determined by what the photographer wishes to capture and portray to the viewer...no 'standard' for that subjective portrayal.
This is one of the reasons I've gone to a digital camera for meter determinations.
For difficult to meter shots like this, I find using a digital camera and adjusting the settings so it looks right in the viewfinder gets the exposure in the ballpark for your film camera.
This is great. Thank you.https://en.wikipedia.org/wiki/Light_meter
- ISO 2720:1974. General Purpose Photographic Exposure Meters (Photoelectric Type) — Guide to Product Specification. International Organization for Standardization.
- ISO 2721:2013. Photography — Film-based cameras — Automatic controls of exposure. International Organization for Standardization.
https://en.wikipedia.org/wiki/Film_speed
"Digital camera ISO speed and exposure index
In digital camera systems, an arbitrary relationship between exposure and sensor data values can be achieved by setting the signal gain of the sensor. The relationship between the sensor data values and the lightness of the finished image is also arbitrary, depending on the parameters chosen for the interpretation of the sensor data into an image color space such as sRGB.
For digital photo cameras ("digital still cameras"), an exposure index (EI) rating—commonly called ISO setting—is specified by the manufacturer such that the sRGB image files produced by the camera will have a lightness similar to what would be obtained with film of the same EI rating at the same exposure. The usual design is that the camera's parameters for interpreting the sensor data values into sRGB values are fixed, and a number of different EI choices are accommodated by varying the sensor's signal gain in the analog realm, prior to conversion to digital. Some camera designs provide at least some EI choices by adjusting the sensor's signal gain in the digital realm ("expanded ISO"). A few camera designs also provide EI adjustment through a choice of lightness parameters for the interpretation of sensor data values into sRGB; this variation allows different tradeoffs between the range of highlights that can be captured and the amount of noise introduced into the shadow areas of the photo.
Digital cameras have far surpassed film in terms of sensitivity to light, with ISO equivalent speeds of up to 4,560,000, a number that is unfathomable in the realm of conventional film photography. Faster processors, as well as advances in software noise reduction techniques allow this type of processing to be executed the moment the photo is captured, allowing photographers to store images that have a higher level of refinement and would have been prohibitively time-consuming to process with earlier generations of digital camera hardware.
The ISO (International Organization of Standards) 12232:2019 standard
The ISO standard ISO 12232:2006[66] gave digital still camera manufacturers a choice of five different techniques for determining the exposure index rating at each sensitivity setting provided by a particular camera model. Three of the techniques in ISO 12232:2006 were carried over from the 1998 version of the standard, while two new techniques allowing for measurement of JPEG output files were introduced from CIPA DC-004.[67] Depending on the technique selected, the exposure index rating could depend on the sensor sensitivity, the sensor noise, and the appearance of the resulting image. The standard specified the measurement of light sensitivity of the entire digital camera system and not of individual components such as digital sensors, although Kodak has reported[68] using a variation to characterize the sensitivity of two of their sensors in 2001.
The Recommended Exposure Index (REI) technique, new in the 2006 version of the standard, allows the manufacturer to specify a camera model's EI choices arbitrarily. The choices are based solely on the manufacturer's opinion of what EI values produce well-exposed sRGB images at the various sensor sensitivity settings. This is the only technique available under the standard for output formats that are not in the sRGB color space. This is also the only technique available under the standard when multi-zone metering (also called pattern metering) is used.
The Standard Output Sensitivity (SOS) technique, also new in the 2006 version of the standard, effectively specifies that the average level in the sRGB image must be 18% gray plus or minus 1/3 stop when the exposure is controlled by an automatic exposure control system calibrated per ISO 2721 and set to the EI with no exposure compensation. Because the output level is measured in the sRGB output from the camera, it is only applicable to sRGB images—typically JPEG—and not to output files in raw image format. It is not applicable when multi-zone metering is used.
The CIPA DC-004 standard requires that Japanese manufacturers of digital still cameras use either the REI or SOS techniques, and DC-008[69] updates the Exif specification to differentiate between these values. Consequently, the three EI techniques carried over from ISO 12232:1998 are not widely used in recent camera models (approximately 2007 and later). As those earlier techniques did not allow for measurement from images produced with lossy compression, they cannot be used at all on cameras that produce images only in JPEG format.
The saturation-based (SAT or Ssat) technique is closely related to the SOS technique, with the sRGB output level being measured at 100% white rather than 18% gray. The SOS value is effectively 0.704 times the saturation-based value.[70] Because the output level is measured in the sRGB output from the camera, it is only applicable to sRGB images—typically TIFF—and not to output files in raw image format.[citation needed] It is not applicable when multi-zone metering is used.
The two noise-based techniques have rarely been used for consumer digital still cameras.[citation needed] These techniques specify the highest EI that can be used while still providing either an "excellent" picture or a "usable" picture depending on the technique chosen.[citation needed]
An update to this standard has been published as ISO 12232:2019, defining a wider range of ISO speeds.[36][37]
For the same reason, and more, I’ve been just using light meters to determine a possible exposure.
But I understand the potential value of a preliminary “digital proof”… like we once did with Polaroid.
Yet even an incident meter will give a variety of readings, not always a single reading that is consistent...the technique is important, just as technique of holding a grey card.
I still have my Polaroid back for my Mamiya rb67. Unfortunately there's no instant film available for it anymore.For the same reason, and more, I’ve been just using light meters to determine a possible exposure.
That's why I'm using it. Add to that you can frame the shot before setting up the film camera and tripod, see what the scene looks like in grayscale, snap a picture or take a video the reference later when you get home, record the settings on the video as you setting up the camera for reference when you get home, and determine which lens to set up on your film camera by using zoom on the digital to make that determination.Several reasons:
And all of the above happens in real time in a EVF on modern mirrorless. If I were shooting transparencies slowly (tripod landscapes) I would definitely be measuring with my Fuji XT3.
- They can do evaluative / smart metering way better than any old school meter because they're using the full digital sensor + supercomputer (by the 80s standards) to evaluate the scene. They're not limited to a finite set of "zones" anymore.
- They give you an instant review, effectively performing a function of a meter + Polaroid back.
- Some models can highlight the areas that are likely to be clipped, when the contrast is excessive so you can make more intelligent trade-offs.
The shot shown above was a night shot. How do you use an incident meter at night?
Why do you feel this way: ".. If you don't trust reflected readings, from a gray card or otherwise, then using a digital camera ain't right for you."
Yes, thanks for reminding me of that. I also use the clipping indicators as well as the histogram on my Olympus E-PL1. What I then do is snap a picture that I use to transfer the exposure setting to my 4x5. That acts like storing the settings in the memory of a hand help meter. Later, when the film is developed, I can look at the digital picture to analyze if the film came out exposed improperly. Better than keeping notes.
You may be focused on the wrong part of that post. Read all other sentences again. And be advised, a 10% variance on shutter speed is fantastic; some shutter specs allow up to about 1/3 stop… and many real shutters will exhibit that or more.
Sorry, but I don't know how that answers my question.
What it suggests is that you stop fretting, walk away from the keyboard, and take some pictures metering in whatever way works for you.
Since I shoot landscapes, an incident meter, or reading a gray card often doesn't help when I shoot distant views where the lighting is different.
Maybe that's why I was getting different readings from my incident readings. The gray card I was using might have been twenty years old. How long does it take before they're not good anymore?
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