Last Update: 10th December 2023
Introduction
We are reviewing the "size and capture" theory, ISO Invariance, and information from my series on the Olympus extended ISO range. With everything said on forums and camera reviews, do we need a flash in 2023? This article is not a theoretical paper on ISO Invariance or the "size and capture" theory because they are part of a commercial program promoting full-frame cameras. While reading the article, ask why some manufacturers deem it necessary to use oversimplified sales arguments like the "size and capture" theory or marketing services like Astroturfing to distance themselves from these theories. Why do we see so many undisclosed promotions in this segment...
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The above video compares the Fuji GFX100S to the Sony A6000. While the GFX100S sensor is 4 times larger than the Sony, the Fuji pixel area is only 5% larger. The same Sony sensor is 1.6 times bigger than the EM1 III sensor, and the pixel area is only 15% larger. Acknowledging any optical differences between sensor sizes, we know all sensors have similar technical limitations. For example, sensors saturate when fully exposed, and each image sensor has a Noise Floor. The video is entertaining, informative, and a welcome change to the almost daily "size and capture" promotions.
Why do Marketers need Undisclosed Promotions?
Let's answer this with a question. Do you really believe the physical "size of the sensor" is the ONE variable that determines your image quality? Some photographers act like fanboys when asked, and others give clear reasons for distrusting the oversimplified "size and capture" theory. Undisclosed promotions should be your next RED flag. For example, why do manufacturers need to distance themselves from commercial programs? How does one spot undisclosed promotions? The biggest giveaway is the repetition of the same "fact statements" or simply study camera reviews...
How does the engineering community view the world?
Design engineers review each aspect of the camera, whereas reviewers deliberately focus on Sensor Size and Pixel Pitch. Engineers look at the Effective Pixel Area, the lens image circle covering the sensor, the camera's size (temperature & cooling), general energy needs, the IBIS system (size, cooling, & power needs), and the size and weight of the camera/lens combination.
What is the difference between Effective Pixel Area and Pixel Area? The pixel control wiring of Standard CMOS sensors is placed above the pixel's light-sensitive area. This reduces the Effective Pixel Area of the pixel and the sensor's efficiency when capturing reflected light. BSI and Live MOS sensors are improved versions of the Standard CMOS sensor. BSI sensors have an effective pixel area of +98%, Live MOS sensors are just below 90%, and Standard CMOS sensors are below 75%.
See this article for more on marketing and this link for more about Astroturfing (promotions).
- Olympus improved the ISO performance of the EM1 II with a 3rd stop (4%). How?
- Why do we never see discussions on the Live MOS sensor, and those who do ask are...
- Pixel pitch defines the resolution/quality of TV displays. Why apply that to sensors..?
- How does it happen that 2 cameras with similar sensor sizes & MPixels are so different?
- Sony users can reconfigure the Sony A7 series to APC mode. What happens to the IQ?
- Photographers typically see only little changes when "upgrading" to FF cameras. Why?
- Up to 98% of all camera reviews repeat the same "size and capture" phrases/keywords.
- Why did reviewers start to include ISO Invariance in more recent camera reviews?
- Have you seen any manufacturer actively promoting ISO Invariance? Why NOT?
- Which information is repeated more in reviews? Sensor size or Sensor Sensitivity?
Do undisclosed promotions add any value to photography?
Start by counting the times you find sensor-size "phrases or statements" in forums and camera reviews. You will learn that promoters link almost anything to sensor size. For example, how often do forum posters (astroturfers) review the advantages of having a fully exposed camera sensor?
Why are keywords so important? A well-known person said people accept anything if the story is BIG and repeated enough. This is why big NEWS stories are repeated on ALL the News Channels. Like the size and capture theory, people trust anything if the message is BIG and consistent.
The "size and capture" theory is literally repeated like a BIG news story:-
- The BIGGER one captures more light
- The BIGGER one has more image quality
- The BIGGER one produces less image noise
- The BIGGER one improves your dynamic range
- The BIGGER one offers better subject separation
- The BIGGER one has more... really, is there NO end..?
Undisclosed (secret) promotions offer nothing new. The biggest problem with undisclosed promotions is the level of dishonesty. We see this dishonesty in the "size and capture" theory and ISO Invariance. I am always stunned at people believing almost anything from the same basic technique...
Let's review some Technical aspects of the digital camera.
Marketing-free zones are generally found at universities teaching Newton's law of gravity or sensor manufacturers. How did Olympus invest its R&D Dollars? Olympus focussed on more efficient sensor types like Live MOS or Stacked BSI sensors, Processing Power, and Sensitivity (Quantum and Optical Efficiency). Olympus invested in Processing Power and Sensor Sensitivity. See this video.
We learn more as we review different manufacturers. The trend is BSI sensors and more megapixels. One of the more intriguing areas of R&D is the physical design of the pixel (XT-5). Another critical aspect of sensor design is firmware replacing control wiring. This reduces pixel control wiring and the sensor's noise floor. For example, sensor manufacturers place "lens elements" over each pixel to improve the optical efficiency of the sensor or firmware to reduce the image noise associated with more pixels. Olympus used firmware to boost the EM1 II's noise performance (+1/3EV).
Why did marketers introduce Pixel Pitch? Why use a term associated with TVs or LED displays? The term Pixel Pitch deliberately shifts the focus from Pixel Area to Size. For example, Pixels capture Photons, and large Pixel Areas mean the sensor is Optically more Efficient (Sensitivity).
Marketers also deliberately misinform photographers when saying Stacked CMOS Sensors. Only BSI-type sensors use stacked configurations. Marketers use incorrect information to make photographers think "old-school" Standard CMOS sensors are the same as Stacked BSI (CMOS) sensors.
Why would manufacturers use Standard CMOS sensors in 2023? Why use an OLDER technology if Live MOS and BSI sensors are more efficient? Each sensor type has advantages and disadvantages. While the trend is BSI, some manufacturers might use Standard CMOS sensors to lower costs and increase profitability. Marketers will literally say anything to distract photographers...
One clearly recognizes the main message in the above description, especially if you value accurate information. The GH5S achieved the highest-ever M43 sensitivity with 50% fewer pixels, and Dual ISO made it possible to better manage/control the visibility of the sensor's noise floor.
Always remind yourself that the size of the image sensor stayed the same while the average Pixel Count increased by as much as 400% over the past 20 years. Have you ever wondered how much your IQ degrades with 400% smaller pixel areas? How did sensor manufacturers cope with these smaller pixel areas or the increasing noise floor in the sensor resulting from more sensor wiring?
Why did marketers decide to invent ISO Invariance?
Like the "size and capture" theory, ISO invariance is a commercial program with NO theoretical or credible whitepapers. ISO Invariance is mainly found in promotions, camera reviews, and forums promoting the theory. If theoretically proven, ISO Invariance means scientists found a way to design Superconductor-like Sensors with NO noise floor or resistance to electrical current.
It's impossible to claim larger sensors capture more light, have less noise, and agree that each sensor has a noise floor. How do you explain Saturation and SNR when you like photographers to believe sensor size is the dominant variable? ISO Invariance replaced the concept that each sensor has a noise floor. In other words, ISO-invariant sensors have a smaller noise floor. Misinformation always leads to false information. This presenter tries to explain the flawed "size and capture" theory.
- Each image sensor comes with a noise floor
- The noise floor has Shot and Temporal noise
- AST is the Absolute Sensitivity Threshold
- Image sensors saturate when fully exposed
- Sensor saturation and SNR are important
Figure 3. The above illustration gives more accurate reasons why image sensors are different.
Why do reviewers and forum experts ignore the sensor's Noise Floor when they say large sensors are better? ISO Invariance became the reviewer's version of addressing the sensor's Noise Floor.
Promoters like to claim ISO Invariant sensors have more Dynamic Range. The reason for a higher dynamic range is linked to the design of the sensor or the Absolute Sensitivity Threshold (AST). See the above illustration. Marketers will alter any information to push a commercial program.
What is the Size and Capture Theory?
The "size and capture" theory says your IQ is determined by the size of the sensor. Promoters repeat large sensors capture more light, have less noise, and have more dynamic range.
A quick search shows the EM5 II and the D5500 (above illustration) were launched in 2015. The EM5 II uses a Live MOS CMOS sensor, and the D5500 has a Standard CMOS sensor. That means the EM5 II image sensor has a larger Effective Pixel Area. The D5500 uses a 24MP sensor, and the EM5 II has 16MP. The Pixel Area on the D5500 is only 8% larger than the EM5 II, and the D5500 has 50% more pixels. DxO test results show the D5500 has (13%) more dynamic range, and the D5500 has an ISO advantage in sports photography. No matter how hard you look, there is no equivalence between the EM5 II and D5500 to warrant a one-to-one comparison between these two cameras.
DPReview raved about the A7RII sensor and later said BSI sensors make no difference. The Sony A7S MK3's dynamic range improved with fewer and larger pixel areas, less pixel wiring, and a smaller noise floor (Figure 3). What captures and converts photons to electrons? Sensor size, or do Pixels capture Photons? It all depends on how one presents the information to people...
Reviewers should explain the "size and capture" theory a little better. Why would they say things like bigger sensors capture more light? Does it mean larger sensors magically attract more light? How should we explain these "size and capture" sales arguments? Didn't a theoretical model teach us that each image sensor has a unique image circle and saturates when fully exposed? I couldn't find any commercial "size and capture" arguments in the documentation of top sensor manufacturers.
At what point are pixels too small to "capture" photons, or what is the minimum pixel area to make a noticeable difference in image quality? The above DPR reviewer raved about an 8% difference. Would a 224% difference excite this same reviewer?
The above cameras were positioned with the same Luminance Perspective. Reviewing the results, it's clear that both cameras captured (received) enough "reflected light" with the same camera settings. The actual differences between these two cameras are:-
- The pixel area of each pixel in the EM1 III is 224% larger than the Pentax QS-1.
- The EM1 III has a Live MOS sensor, and the Pentax QS-1 has a BSI CMOS sensor.
- That means the Pentax sensor has a 15% sensitivity advantage over the M43 sensor.
- What if the Pentax sensor has a higher native gain and requires smaller ISO steps?
- Fewer pixels on the Pentax Q means less pixel wiring and a smaller noise floor.
Is it correct to say one captures more light while ignoring the above points? It's irresponsible to jump to conclusions like the bigger one captures more light or the size of the sensor is the main thing. Again, marketers will literally say anything to promote...
How many photographers consider the technical and optical characteristics of the sensor separately? For example, cameras with different sensor sizes are optically unique, while technical differences like sensor saturation or SNR are the same for all sensor sizes. That means M43, APC, or FF cameras are optically different but technically similar. For example, each image sensor has a unique noise floor, and all image sensors saturate when fully exposed...
Conclusion
Photography is the one area one would expect to be protected from politically trained marketers. We are experiencing the worst form of marketing or programming in the photography segment. I hope this article helps readers to reject calls for "we don't need technical information."
It looks more like a distraction when they
continue to promote "Sensor Size,"
The following items are truly critical...
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