Last update: 20th August 2025
I have been following YouTube channels discussing the OM System OM-3. What sparked a discussion with ChatGPT were those justifying their choice for M43 cameras like the E-P7 or the E-M1 III. It also appears like YouTubers feel they need to explain positive feedback on cameras like the OM-3 or the new OM-5 II. Does this reflect the current market perception of the M43 segment, or is the positive feedback from those buying into smaller camera solutions a more accurate measure?
I was working with ChatGPT to analyze the Olympus E-M1 III and the Sony A7 IV in an effort to find a more reliable measure for sensor efficiency than physical size. The E-M1 III has a Live MOS sensor, and the A7 IV has a BSI sensor. The EM-1 III is the most capable pro-level camera of the E-M1 series, and what differentiates the OM-5s from the E-M5 III is the TruePic IX image processor.
My discussion with ChatGPT revealed more about the reasons why Olympus listed a 2-stop advantage for the OM System OM-1 and OM-3 cameras. We were also able to define a more accurate and acceptable way of rating sensor efficiency. The latest Truepic X processor and the 20MP stacked BSI sensor offer significant advantages, which is rare for M43 cameras over the past 5 years.
I cropped the following ChatGPT replies to improve the presentation.
A short summary of my discussion with ChatGPT.
We started with sensor sensitivity and how to measure the efficiency of complex electronic parts. A good understanding of these principles helps to improve our understanding of image sensors. This knowledge benefits all digital photographers, not only M43 photographers.
The chances of having a fully equivalent size comparison are almost impossible. Equivalence means all aspects of the products need to be similar. Simply claiming one is better than the other can lead to dissatisfied customers. See this fun example of giving the bigger one a higher rating.
The next question looked at practical differences between image sensors. I wanted a better way of rating image sensors. The aim was to quantify sensor differences with exposure stops. For example, could we say the difference is 1 to 2 stops between pro-level and budget sensors?
The next question takes a closer look at the E-M1 III and the Sony A7 IV. The goal is to find a better way of understanding the technical differences between the sensors of these two cameras.
ChatGPT noted that the EM1 III has a BSI sensor, which may have led to the use of OM-1 sensor data in the examples below. Except for the type of sensor, the results were not negatively impacted. For instance, this example highlighted the differences between Standard, Live MOS, and BSI sensors and how they influence the effective pixel area of each CMOS configuration. Please study my articles for more on effective pixel area. The effective pixel area of BSI and Live MOS sensors suggests the OM-1 might have less than a 1-stop advantage. Stacked configurations improve readout speeds.
Part 1:
Part 2:
Part 3:
I decided to add the parts below because I think they have important information for those wanting to improve their digital know-how. Much of what I discuss in my articles is reflected in this conversation. There is much more to digital photography than what is listed in the commercial information layer. The secret is to focus on those aspects making a difference for all digital photographers.
This
link discusses the commercial versus factual information layers.
The next question discussed the 2-stop depth-of-field benefit of M43 cameras. For example, how do we use this to optimize our ISO to SNR ratio? This knowledge is only critical if you need optimum results from your M43 camera. Typical applications are landscape, low light, or product photography. Please study my articles discussing the typical flow diagram of digital cameras.
The final question highlighted the 4th exposure variable in the exposure formula. Yes, it is possible to manage shadow and highlight clipping. The sensors dynamic range is only another variable.
Folks, there is no need to apologize for the M43 segment or when recognizing that there are almost no visible image quality differences between sensors. The OM-3 image quality does appear to be more refined than the E-M1 III, but what surely makes a difference is the new TruePic X processor and BSI sensor combination of the OM-3. I get great results from both my E-M1 III and the OM-3.
Best
Siegfried
