We need mirrorless cameras where ISO does not affect the EVF brightness (or focus) while still showing usable raw histograms.
April 10, 2023
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Yes. If the camera computes the histogram before the EVF stream, it could also be a raw histogram.
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Duplicate?
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thats not base iso but extended. so its digital gain not analog.
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Likely both.
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Lets all agree to change the name to "exposure circle" 😁
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That article almost makes sense to me. I didn't understand this bit:
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I think it's just that the same camera could achieve -5EV+f/2 and -6EV+f/1.4, since each change represents a halving+doubling, so a camera which requires f/1.2 at -6EV is a bit worse in the comparison.
Sherm -
EV isn't directly related to the light in the scene.
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Sounds like he is willing to accept dark review/OOC images, a little bit at all ISOs (-1 EC) and even darker when the resulting ISO exposure index falls above 3200. This would get him an extra stop of headroom safety at all resulting ISO settings, and even more when the setting would have gone above 1600 if it weren't limited.
I don't know if his camera has something like Canon's HTP, but HTP gives that -1EC under the hood without a stop of darkening for the default output, so you wouldn't see darker images until the ISO exposure index goes past a max ISO setting.
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Perhaps it would be helpful to mentally separate empirical facts from people's recommended or favorite exposure/ISO setting strategies. If you fully understand the empirical facts without any "editorial" about application first, then you can listen to such editorial and recognize it for what it is - people's preferred strategies for managing risks, with different people having different priorities, but hopefully, on an accurate assessment of the empirical realities of the ISO settings.
The brightness triangle "works" to get brightness on-target with camera/software defaults (if EC is set for the key of the scene), just as a tricycle is guaranteed to stand up. The question is, do you need that, or need it all the time? The answer is no; it is not necessary to balance OOC image brightness to do photography, so breaking the lightness triangle open at the "ISO/exposure" vertex is possible, and possibly advantageous if you want more room for highlights or if you want less read noise, etc., than what you would get by prioritizing default brightness.
Many of the posters here probably dream of a mode of operation with cameras where you just choose your exposure time and f-number (or pupil size), and the camera just counts photons with no practical upper limit, and perhaps has an AI that analyzes the image and does a sought of auto-brightness for the EVF and OOC images, and assigns an assumed ISO exposure index in the metadata, but we don't have such cameras yet, so we do the best we can to emulate such a camera, which would serve many people well for most of their photography. Different people use different strategies, based on personal headroom vs shadow noise risk priorities.
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It only 'works' for one scene luminance (aka Lv). To actually work it needs another dimension for Lv. It becomes a lightness Toblerone (and like all triangular nomographs, it's only triangular if you arbitrarily limit the dimensions of the parameters to make it triangular).
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Somebody referred to the function of the ISO control.
That should be "Functions", not "Function".Don Cox
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Most cameras already have an auto-brightness mode for EVF. The setting typically involves turning "exposure simulation" off. I wish all cameras would allow assigning "auto-brightness" to a function button.
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It helps to preserve night vision, too ;)
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The problem is that it has conflated 'EV' and 'EV₁₀₀'. Most photographers seem to use them interchangeably. The authors don't have as analytical a mind as you do, didn't spot the contradiction, and just waded into making nonsensical statements. EV is a measure of the light transmission of the lens/shutter system (aka 'exposure settings'), and as they say is a combination of exposure time and f-number. EV₁₀₀ is a measure of scene luminance (the SI unit would be lux). The problem is that manufacturers have just written 'EV' and put the other important parameter - using 100 ISO film - in a footnote or small print, where it gets ignored. So, when you're talking about a light level of 'EV -2' what you're saying is that is the light level is such the 100 ISO film would have 'correct exposure' with an EV of -2.
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That would not improve photon noise relative to exposure one iota. If there was always the same response, say always 2e for 1p, the photon noise would be exactly the same. If the response was inconsistent, like 2e 70% of the time and 1e 30% of the time (1.7e for 1p), then photon noise relative to exposure would actually increase. If there is readout noise in the system, then it will decrease read noise relative to exposure, which would be the main value of such a system. There are photosites like this; they are called photo-avalanche diodes. I believe that Canon just announced a consumer video-oriented camera that uses such technology recently, and as one might expect, the pixel density is relatively low to accommodate the spatial needs of such a diode. Of course, this isn't the only way to get to infinitesimal/irrelevant read noise; the projects that Dr. Eric Fossum has been working on create infinitesimal read noise with very small photosites.
