How to read the DxOMark Image Quality database

Last updated:- 19st April 2024

DxOMark has been in the image quality business since 2003. They empower photographers with good information and knowledge, helping them make informed and autonomous decisions. They translated this goal into a unique Image Quality Database, which many photographers use to learn more about their cameras. The test data also enable photographers to use their cameras more efficiently. 

Did you know DxOMark does not support the "size and capture" theory? It's exciting to discover how they use a theoretical model to test, evaluate, and present their test data on camera sensors.

Please visit DxOMark.com and demonstrate your support by liking my EM1 II conversation with DxO. Add comments and ask DxO for updates on the EM1 III, EM1X, EP-7, EM10 IV, and OM-1.

Note:- The Olympus EP-3, EM5 II, and G11 images were done for this article...

Do all 16MP and 20MP Olympus cameras have Good Image Quality?

                                                                                                                        Source:- DxOMARK

The challenge with finding a new camera is repetitive expert opinions and commercial bias. Accurate information became a rare marketing quality in 2023/2024. For example, many photographers see no or little IQ benefits when they "upgrade" to a new camera or format? It is, therefore, comforting to know that DxOMark uses its own scientists and camera test engineers.

With a small camera portfolio, DxOMark became one of only a few companies using a theoretical test procedure for Camera Sensors and IQ. With almost 400 tested cameras since 2012, they created one of the most reliable test results (databases) for camera sensors, lenses, and image quality.

Olympus EP-7 with 17mm f1.8 lens, ISO200, f7.1, 1/800 - Raw file converted and edited in Workspace.

We are focussing on the DxOMark Image Quality database. While relevant, the DxO database does not include data on computational features, size/weight comparisons, auto-focussing, or the practical aspects of using the camera or lens. For example, I always enjoyed my Olympus EM1 II, but the EM1 MKIII supercharged my passion for Olympus and computational photography.

I tested the impact Pixel Area has on 15 cameras in this article...

Olympus EP-3 with Lumix 20mm f1.7 lens, ISO200, f5, 1/500 - Raw converted and edited in WS. This is the EP3 "OOC" jpeg look.

This article reviews the test results DxOMark published over the past 11 years. These test results can be found in the sensor (image quality) database at DxOMark. I also included a short example of using these test results and how they benefit M43 photographers. Finally, I added an example of preparing any camera for "acceptable image quality" and what that looks like in real life.

See this DxO article discussing the challenges of designing mirrorless camera sensors...

Olympus EM1 II

How should we interpret the above DxO Scorecard? DxO publishes a scorecard on its website for each tested camera. The scorecard includes an Overall Test Score, Color Depth in Portrait mode, Dynamic Range in landscape mode, and Low Light ISO performance in Sport mode. The summary markers (below) apply to the overall score plus the 3 applications DxOMark reviews. 

Also, study the summary notes from DxO in blue:-

Overall Score

• The DxO tests are done at the camera's base ISO and using a logarithmic scale.
• They measure sensor sensitivity, color depth, and the sensor's noise floor.
• The difference in sensor sensitivity is 0.3EV for every 5 points.

Portrait

• The higher the color sensitivity, the more color nuances can be distinguished.
• A 22 Color Depth means the sensor or camera is an excellent performer.
• Anything less than 1 point between 2 cameras is insignificant.

Landscape

• DxO regards a dynamic range of 12EV as sufficient (excellent).
• There is no significant DR variance between the EM1 II and 13.3EV.
• A 0.5EV difference between cameras can be regarded as insignificant.

Sports

• DxO measures the sensor's Saturation and SNR (logarithmic) at the camera's base ISO.
• The Low Light ISO rating is set at an SNR of 30db, a DR of 9EV, and an 18-color depth.
• With a linear progression on M43 sensors, an estimated OM-1 Low-Light ISO is +2000 *.
• Considering the GH5 & GH5 II, how much did the EM1 III and EM1X improve (+1600)?
• A Low Light ISO difference of 25% is the same as 0.3EV and only slightly visible.

* Why did I up my estimated OM-1 low-light ISO rating from 1867 (calc.) to +2000? The BSI sensor is more sensitive than Live MOS sensors, plus several TruePic X efficiency improvements. See this link for a more detailed description of the above DxO test procedures.

Photographed with the 40MP Fuji XT-5. Did you know the XT-5's pixel area is less than the EM1 III?

The DxOMark sensor database has several benefits for photographers. For example, the theoretical principles discussed in my articles reflect the theoretical model DxO uses to test camera sensors. A theoretical model says each sensor has a unique Noise Floor while highlighting the importance of Sensor Sensitivity, Saturation, and SNR as indicators to monitor sensor performance... 

The illustration below explains image sensors, saturation, and SNR (noise).

Figure 1.

What do we learn from the DxOMark database? Image sensors are better in 2023, and no 2 sensors are technically similar. The DxOMark database shows that the practical differences between sensors are tiny, and each image sensor is unique from a design or technical aspect. The DxOMark test results also showcase the improvements sensor manufacturers achieved in the past 20 years. 

Study this link.

How to use DxOMark to Compare two cameras. The following example teaches us how to interpret the DxO test database or how we create a visual reference for Acceptable Image Quality. I used the Olympus EM1 II and Canon R because they represent Pro cameras from 2016 to 2018.

The Canon R and the Olympus EM1 II.

DxOMark uses two "Image Quality" benchmarks for digital cameras. The first is what they define as Good Image Quality, and the second is Acceptable Image Quality. Good image quality means a color depth of 22, a dynamic range of 12EV, and a saturated sensor (+30db SNR) at base ISO. Each of the three variables has to be within the specified range for a camera to have good image quality.

What do we learn from the Sports Low-Light ISO? Many "experts" mistakenly suggest this category determines the camera's ability to use high ISOs. This category only specifies Acceptable Image Quality. That means the ISO (amplification) and specific exposure at the sensor to saturate the sensor with an SNR of 30dB, a Color Depth of 18, and a DR of 9EV. Study Figure 1 and this article.

Acceptable image quality is helpful because it shows us more about the sensor's exposure behavior. Do the following test to get a feel for what acceptable image quality looks like with an EM1 II:-

• Find a similar scene to the above EP-3 photo and take an image in A-Mode at ISO400.
• Increase the ISO to 1250 (1312) and take another photo. Inspect your Raw File in WS.

Olympus EP-3 with Lumix 20mm f1.7 lens - ISO200, f5, 1/800. Raw file converted and edited in Workspace. EP-3 "OOC" jpeg look.

Acceptable IQ does not imply we shouldn't use higher ISOs. This DxOMark rating says that any ISO value above 1312 (EM1 II) will underexpose the sensor, which reduces the color depth, DR, and SNR. We discussed sensor Saturation and SNR in these articles. Those studying my articles should be able to optimize any camera at higher ISOs. For example, we can increase (ETTR) the EM1 II/III exposure by up to 1EV. We can also explain why, plus manage visible image noise (Sony A7R4).

Sony A7R4 with FE 24-70mm f2.8 lens. (ISO3200, f7.1, 1/800) The A7R4 had Acceptable Image Quality and visible shadow noise at ISO3200.

What's the main advantage of using a Canon R? Let's say we like to capture a Grey Heron bird in flight (4th image above). That means upping the ISO by 3EV to ISO1600 for an increased shutter speed of 1/4000. The Canon R is within its sport (low light) range at ISO1600 with more than acceptable image quality. The EM1 II will deliver acceptable image quality with an ETTR of +1/2EV. One could also get the +0.5EV by increasing the aperture and ISO800 (similar DOF). Another parameter not included in the DxOMark scorecard is the AI noise reduction from Workspace. The mistake many make is the practical aspects of applying and using M43 versus full-frame cameras. 

Olympus EM5 II (one of the best) with the 12-35mm f2.8 Lumix Lens. ISO200, f5, 1/500 - Raw file converted in Workspace.

Is the visible noise the same for different cameras? An SNR of 30db does not mean the structure of the noise floor is identical for any two sensors. The visible part of the sensor's noise floor is different for the Olympus EM1 II and the Canon R. The reason is the sensor's noise floor is a function of sensor design and not sensor size. Take a few minutes to study the illustration in Fig 1.

Olympus EP-3 with Lumix 20mm f1.7 Lens - ISO200, f5, 1/640. Raw file converted and edited in WS. This is the EP-3 "OOC" jpeg look.

How does one apply the Overall DxO Rating? One of the most critical IQ variables in sensor design is Sensor Sensitivity. The sensor's sensitivity depends on its Optical and Quantum efficiencies plus its Pixel Area. For example, Live MOS, BSI, and low pixel count sensors are Optically more efficient than higher MP or Standard CMOS sensors. See my articles for more info on sensor sensitivity.

Why is it incorrect to say the ISO adjusts sensor sensitivity? The native sensitivity of the sensor is measured and adjusted at the factory. This means the sensor is calibrated for digital cameras as it leaves the factory. Size and capture advocates like to provoke meaningless discussions about the ISO offsets in the DxOMark database. The ISO standard states that the image brightness should double or half at every full-stop ISO adjustment (amplification). Nothing more or less...

EP-3 with Lumix 20mm f1.7 - ISO200, f5, 1/640. Raw file edited in WS. (>Acceptable IQ, Color Depth 20,8, DR 10.1EV, Low light 536)

Conclusion.

One of the most fascinating DxOMark test results is good Image Quality. This implies a color Depth of 22, a DR of 12EV, and an SNR of +30db (saturated sensor) at ISO200. DxOMark data shows that all the 16MP and 20MP cameras from Olympus have Good Image Quality, and the Olympus 10MP and 12MP cameras have more than acceptable Image Quality. Olympus cameras are some of the most exciting and cost-effective photography solutions for family, nature, and street photography.

The tiny IQ differences between M43 and APC sensors are also fascinating. For example, study the Olympus E-M5 versus the Canon 700D or the EM5 II versus the Canon 760D. Research the different sensor types in digital cameras, ie. BSI versus Live MOS or Standard CMOS. Most APC and Canon cameras have Standard CMOS sensors. The DxOMark database also highlights the theoretical inconsistencies in the "size and capture" theory. Finally, it's difficult to speculate why DxOMark failed to test the Panasonic GH5S, G9, and GH6 or the Olympus EM1X, EM1 III, or OM-1.

I trust you know why one can't say cameras have a Noise Floor, Saturation capacity, and Signal-to-Noise ratio (SNR) and simultaneously promote the idea that large sensors have less noise because they "capture" more light (commercial size and capture theory). This explains the animosity towards DxO and the ongoing critique of any DxOMark test results.

Canon G11 IS (10MP CCD), Raw file in PS, ISO80, f4.5, 1/250. (>Acceptable IQ, Color Depth 20,4, DR 11.1EV)

One of the biggest mistakes the "experts" make about M43 cameras is claiming two or more 16MP and 20MP cameras have the same Image Quality. The IQ characteristics of all cameras change with each sensor and Image Processor variation. For example, the various Live MOS sensors and TruePic VII, VIII, IX, and X combos offer meaningful IQ and performance variances.

What are the 5 additional reports DxOMark could add to its database:-

• Basic sensor info - readout speed, AST, and DR.
• Info about the sensor's noise floor, like size and types.
• Create a test criteria to test & evaluate Image Processors.
• Test & present the main benefits of using different sensor types.
• The safety margin (ETTR gap) manufacturers apply at "100%" exposure.

See this article from DxOMark on sensor size and mobile phones - link.

All the best and God's Bless...

Siegfried

This is how I convert my Enhanced Raw Files?

Last updated:- 22nd January 2023

Many photographers convert and edit their raw files with the same software. PhotoLab and Lightroom are examples of converting and editing raw files with the same applications. While safe for accurate White Balance and evenly exposed raw files, converting your Olympus raw files in Workspace and editing the 16-bit Tiff in Photoshop is often a more rewarding editing strategy.

We are studying an example of converting and editing the same raw file with different applications. You should know I used the same White Balance for the various raw converters in this article. My default Color Space is typically RGB for my raw files and SRGB for the web.

Olympus EP-7 with 12-45mm f4.0 lens - Out of the camera jpeg (ISO200, f5.0, 1/100).

The above scene had more shadow detail in real life. It's easy to assume there was no reflected light from the shadows when viewing the JPEG. No reflected light means no image, no matter how hard we push the ISO. The example below is an edited version of the above JPEG. Did the camera capture or process too few color details, or will the Enhanced Raw File reveal more color information?

This is the OOC Jpeg. I increased the shadow brightness with PS.

The Enhanced Raw Format plus Workspace lets us extract more image information from the captured raw data. The key to success is the Exposure Mix we applied with the camera, the Truepic Processor, and its similarities to the Image Processor in Workspace. The Olympus Enhanced Raw Format is unique and helps us to evaluate and adjust most of our camera raw settings in Workspace.

For example, we can fine-tune the camera's exposure compensation in Workspace. That means we can verify our White Balance (18% Gray) and "Gradation" (Gamma) settings in Workspace. See the ETTR technique in the next paragraph. See this article on how to use the Gradation function.

The Gradation "High" option automatically selects the best ETTR values for your image. Think of the Olympus Gradation function as another variable in your exposure mix. You should always ask, how can I improve my image sensor's output signal, and how do I finalize my neutral gray values in Workspace? How do we reset the camera's Gradation values in Workspace? Simply select the default "Normal" option in Workspace. This will reset your image and the final tonal values to neutral gray.

Why would one use the gradation function with techniques like ETTR? We learned the image sensor does better when it is saturated. It's sometimes better to prioritize the sensor's saturation and SNR values over an accurate Neutral Gray in the camera. Think of low-light or high-contrast scenes.

It's good to prioritize Tonal Data with the camera. This is something we will review in more detail in the future. For example, how many of you worked with the Gamma function in Olympus Viewer 3? Those reading my articles can explain the Gamma function and the benefits of using ETTR. 

Also, study my article explaining the Gradation function and this article by Adobe.

It's also good to always keep a Polarizing Filter (PF) in your camera bag. Use it on your camera with the Gradation "High" option to control or cancel any reflections from water or bright surfaces. For example, why does the Spider Cube have a little chrome ball on the top of the cube?

The images below are illustrations only.

Olympus E-P7 with 12-45mm f4.0 lens - Enhanced raw file converted in Workspace (ISO200, f5.0, 1/100).

The real benefits of the Enhanced Raw Format are Step 2

The converted 16-bit Tiff files are edited in the 2nd step. It's normal for more advanced image editing techniques with more image data. Workspace (image processor) and Sensor Sensitivity (captured details) enable us to extract more image data from our Enhanced Raw Files. We know the Olympus Live MOS sensor is more sensitive than Standard CMOS sensors, and BSI sensors further improve the Optical Efficiency of the sensor. BSI sensors are more sensitive than Live MOS or Standard CMOS sensors. High-sensitivity sensors are known for their ability to capture more shadow detail.

More image data and 16-bit Tiff files enable us to apply more advanced image editing techniques, like editing parts of the image separately. The image below is an example of using different editing techniques for the shadows and the brighter parts of the photo. I upped my shadow brightness in Photoshop. The ability to divide and mask the image improves with new editing software.

It's also good to treat sensor sensitivity and image noise separately. For example, all image sensors come with a noise floor. The sensor's saturation level (exposure) and SNR are responsible for any visible image noise. Olympus gave us several options to control and manage image noise. See this excellent video. Unfortunately, the presenter did not add the Exposure Mix to his list.

Olympus E-P7 with 12-45mm f4.0 lens - Raw file converted with Photoshop 2023 - (ISO200, f5.0, 1/100).

I never use Lightroom because my preferred Adobe application is Photoshop. I like Photoshop for my raw, jpeg, and 16-bit Tiff files. Photoshop 2023 seems better than previous versions, especially with Olympus raw files. The 2023 version of the Adobe Raw Converter also improved a lot. 

Adobe said my perfectly working iMac (2014) is too old for Photoshop 2023. I decided to upgrade to a "new" Intel iMac. See the article here...

Olympus E-P7 with 12-45mm f4.0 lens - Raw file converted in PhotoLab 5 - (See the color cast on the house ).

Olympus E-P7 with 12-45mm f4.0 lens - I converted this raw file in PhotoLab 6.1 and edited the Tiff file in Photoshop.

The ClearView Plus setting is a powerful option for PhotoLab and the main difference between the above 2 images. The default value for Clearview is more aggressive, whereas mine is softer. This is also a "point-and-shoot" image and not a textbook example of optimizing the exposure mix. 

See this article for more on IQ and Exposure Mix.

Fuji X-T4 jpeg file in a similar scene. I upped the brightness in PS.

What do we learn about the Olympus EP-7?

The sensor received two different exposure levels in this example. The sensor was less saturated in the shadows with a lower SNR, less tonal data, and more visible shadow noise. The brighter areas saturated the image sensor, with less noise, more tonal data, and a higher SNR. What happens if I increase my exposure mix (shutter and aperture) with 1EV?

The available detail in the raw file means the sensor's sensitivity is good, and the low level of visible noise tells us the sensor's noise floor is relatively small. For example, I only used the "standard" noise reduction option in Workspace, the Prime setting for PL 5, and only a little noise reduction for PS.

This is the best-ever photography and lens combo from Olympus. Each Olympus enthusiast should own at least one like this!!!

The question is, why did I select casual exposure settings with no ETTR? We do not always need 102% image quality. This is important to those "creative" photographers who prefer specific results from selecting different or "creative" exposure settings (Working with different tonal levels). 

The E-P7 is an excellent street photography camera for those working with color, monochrome, and creative techniques. What are the top 5 reasons why this is the best-ever Olympus combo? How was it possible for a forum reject* like the 17mm f2.8 to reach this status? What do you think?

The original images I used for this article (I needed something for WS).

Conclusion

The images below remind us of the EM1 III's excellent image quality with something like the 17mm f1.2 pro lens. Take a moment and consider the 4 cameras in this article. Each camera offers superior image quality with specific strengths and weaknesses. The decision of which is best for you and your needs is no longer a process of evaluating image quality. The Fuji X-H2 and X-H2S are excellent examples. They use unique image sensors to offer specific strengths and benefits...

The process of converting raw files and separately editing the converted 16-bit Tiff files is the same for "normal" images. I convert my raw files in Workspace and edit them with PS or ON-1. I also started to select the jpeg option more often for my EM1 III, the E-P7, and the Fuji X-T5. I edit those jpegs in one session with ON-1. See this link.

This short article summarizes the main conclusions of my journey on image sensors. I don't wish this on anyone. Study my articles to see the effort it takes to break away from the programming effects of the "size and capture" marketing program. Why is this important? You will only master your camera if you step away from anyone promoting the size and capture theory.

Take care and God's Bless

Siegfried

* Undisclosed or paid forum promoters habitat in the negative and are not paid to be positive. - link

Walking the Dog Instagram Pictures

Fuji X-T4 with 35mm f1.4 lens - ISO3200, f3.6, 1/18, -1EV Exp comp (Provia film simulation & handheld) - Raw file converted in PL-6.

Instagram Images

This version of the image was prepped in Photoshop.

Olympus EM1 III with 17mm f1.2 lens - ISO1000, f1.2, 1/30 handheld - The amazing benefits of M43.

Olympus EM1 III with 17mm f1.2 lens - ISO1250, f1.2, 1/13 handheld - Amazing detail and M43 benefits.

Fuji X-T5 with the 23mm f1.4 lens - ISO3200, f3.6, 1/7th, -1EV comp - Jpeg OOC and handheld.

Photowalk and Advanced Exposure Techniques

Last Update:- 27th May 2024

My wife and I were driving past the old town of Rapperswil at the far end of Lake Zürich. Returning from our appointment, we decided to stop at Rapperswil and spend an hour or two in this lovely old town. My wife with her EM10 III and myself with my Pen F and 12-50mm f3.5-6.3 EZ lens.

I also wanted to try my Gossen light meter. The idea was to try the Gossen with more demanding exposure techniques like ETTR for street/city photography. (Walimex is a Gossen)

Olympus EM1 II w 30mm Macro, 2x FL600, mini studio, RC Mode.

Regular visitors to my blog know I've been on a journey studying the camera's image sensor, types of image sensors, the size and capture theory, and different exposure and focusing techniques.

While searching for information for my new Gossen, one thing led to another, and I came across the Sekonic YouTube presenter, Joe Brady. In his videos, Joe demonstrated the benefits of using external light meters with modern cameras. Joe convinced me to add the Gossen to my exposure toolbox. The Gossen was tucked away in my photography "to-do" list until I saw Joe's videos.

It's now 3 years since I started studying image sensors. In that time, I read different articles on DPReview and participated in heated forum discussions. I always compared the information I received to theoretical and technical articles published by engineering schools, image sensor manufacturers, the European Machine and Vision Association, and other enthusiast websites. 

As in most situations, finding that one thing that matters needs unpacking much fluff and talking. Without getting too much into the sensor size debate, those who did change from one format to another know it's way more than the size of the sensor or pixel area. The 3 factors we should consider are buying/selling costs, the size and weight of camera equipment, and the available lens offer.

Focussing on one thing, I discovered the key to optimum image quality is having the image sensor at its optimum SNR and saturation level. (Figure 1) It became clear that the digital camera is not a digital paintbrush. The ideal SNR is specific and available in a small operating window. This motivated me to shift the creative part of my digital photography to the post-processing phase.

The image recording phase is simply a data-collecting phase and nothing more. The goal is to select the "best" exposure mix to push the sensor to its ideal performance window. This "ideal" performance window happens when the sensor reaches optimum SNR or Saturation levels. (See Figure 1) The sensor records more tonal data with the lowest visible noise at full saturation.

Figure 1.

It took my wife and me 2 hours to complete our photo walk in Rapperswil. I selected an ISO of 200. The cloudy conditions would benefit from the higher DR at ISO200. I started with an aperture of f5.6 and aperture mode. That meant I had to carefully select my focus point and monitor the histogram when using ETTR or upping the exposure. This process of monitoring and adjusting the exposure is quick and takes seconds. The photographer's experience in advanced exposure technique guides the decision to use an ND or Polarizer filter, stacking or bracketing, or the camera's HDR function.

Olympus Pen F with 12-50mm ISO200, f5, 1/500 - Raw file converted in Photoshop (only basic settings).

I adjusted the exposure of the above scene with the Gossen. Study the histogram. The Gossen's exposure reading was the equivalent of the camera exposure at +0,3EV. The dynamic range of the scene was influenced by the clouds. For example, one has more or less clouds in the exposure frame when pointing the camera up or down. With the camera's exposure reading pointed toward the clouds, the street-level exposure and SNR decrease, and the visible shadow noise increases. 

Not that shadows generate image noise. Less reflected light on the sensor means a smaller SNR, less tonal data, and more visible noise. Interestingly, the Gossen exposure meter is less affected by clouds because its FOV is 180 degrees. The camera's FOV is linked to the focal length of the lens...

This is the same image edited in Luminar 4 - One can see how the camera handled the DR well.

The above image is an edited version of the RAW file. While editing the RAW file in Photoshop, I knew the RAW file had enough tonal data, which enabled me to push the RAW file a little more. 

I upped the camera's exposure with the aperture "gain" option (image below). The histogram shifted to the right, and the street-level image brightness improved with the higher exposure level. My final exposure benefitted from an ETTR gain of +1EV. Moving the histogram to the right means the darker street level benefits from more tonal data and less noise. An increase in tonal data benefits the complete tonal range. Exposure techniques like HDR increase the tonal data even more. I also used the camera's over and underexpose indicators to monitor highlight and shadow clipping. The Olympus histogram is flexible enough to help us find the best possible exposure mix with ETTR. 

I rarely go for clipping-free exposures. The brighter clouds did clip a little in the above example. I was OK with that because most people wouldn't recognize any clipping. I apply the same rule for darker shadow areas. I learned it's better to clip (turn black) some darker areas and prevent non-critical areas from showing noise. This is similar to what Panasonic does for filming. For example, Panasonic allows us to work with a smaller tonal range of 15 to 256. Study the OOC jpeg below. 

This is what the camera's jpeg looks like when one applies an ETTR of +1EV.

The image below is the edited Raw conversion of the above jpeg. I pushed the sensor to its optimum saturation and SNR with my exposure mix. This allowed me to "push" the conversion of my raw file a little more. Study my articles about Workspace and the Enhanced Raw Format for more.

Those preferring out-of-camera "ready" JPEGS should read the following. The secret is to treat your Raw and JPEG files differently. The RAW file can be pushed to have more tonal data with less visible noise and can be re-adjusted to mimic the scene in post-editing. Jpegs are different and benefit from more accurate exposures. For example, we can tweak the gamma curve of Olympus cameras. This is done with exposure compensation and the Gradation and highlights/shadows functions.

The following settings allow us to create JPEG profiles in the cameras. For example, use the mid-tone slider to correct ETTR adjustments and the i-Enhance Picture Mode to activate the Olympus image quality features. The gradation function improves shadow details and limits clipping, and the highlight and shadow sliders are used to add contrast or manage the shadows and highlights.

Olympus Pen F with 12-50mm lens - ISO200, f5.7, 1/250 (+1EV ETTR) - Raw file converted and edited in PS and Luminar 4.

Final thoughts on saturating the image sensor and ETTR

Study this article to learn more about ETTR or what it means to "flood" the sensor. Study this article for more on how to read the DxOMark image quality database, and read this article discussing the 4 things that will improve your image quality. The image creation process for the above image starts by reviewing any depth-of-field (DOF) or movement requirements linked to the aperture and shutter mix. The next step is to optimize the sensor. I used the following camera setting for the above image:

• ISO200 (Manual setting - see intro text))
• Shutter speed of 1/400 (Aperture-Mode - shutter speed was selected by the camera)
• An aperture of f5,6 (The photographer's choice in Aperture Mode - f5,6 creates a large DOF)
• I used my Gossen exposure meter reading with an ETTR of +0,5EV to up the SNR.
• The histogram confirmed that I could shift the histogram to the right with +0,5EV.
• I used the histogram's under/overexposure warnings to find the final exposure mix.

The final step focuses on the reflected light reaching the image sensor. The aim is to expose the sensor optimally with techniques like ETTR or stacking. Which of the above exposure settings would you change if you had to increase the shutter speed? I manually selected ISO200. We also know that the ISO does not control the reflected light to the sensor like the aperture/shutter mix. 

Something we haven't discussed much is to 

think of the aperture as gain.

The target is exposure and not DOF when using the aperture gain effect. That means doubling the reflected light to the sensor for every 1EV aperture increase. This exposes (floods) the sensor with information. The question is, how does this affect the DOF? Something that should be talked about more is the 2-stop DOF (Depth-of-field) advantage of M43 cameras.

The "starting" depth of field was set for the city scene. It's, therefore, safe 

to slightly increase the aperture (gain) to control the image sensor. 

This M43 (DOF) advantage varies from application to application, like macro, landscapes, or city scenes. Always experiment and use your photography experience to select the best exposure mix. Photographers migrating to M43 cameras tend to prefer higher apertures. For example, they will use f8 to f11 for landscapes, whereas f5.6 to f7.1 is enough for landscapes on M43 cameras.

Pen F with 12-50mm, ISO200, f5.1, 1/200 and +0.3EV (ETTR)

Full-frame cameras have more background blur but a smaller DOF. Full-frame photographers disagree on forums, while it's nothing new to find serious full-frame photographers using techniques like focus stacking in more critical DOF applications like cityscapes or landscape photography.

One needs to break free from the commercial "background blur" hype to learn why the M43 aperture is one of the M43 segment's most exciting features. The key to unlocking this strength is re-thinking how we apply the aperture with crop sensor cameras. A depth of field aperture of f5,6 is good for city and landscape photography. The key is having the correct focus point. See this article.

It was safe to add +0.5EV reflected light to the sensor for the first image of Rapperswil. The brighter street level and 50% more reflected light onto the sensor didn't affect the original DOF much.

Consider how marketers distract M43 photographers by shifting the focus to equivalence and background blur. They effectively confuse and prevent crop-sensor Photographers from benefiting from the DOF or the unique sensor saturation or "gain" advantage of M43 cameras. Instead, M43 photographers focused on diffraction, noise, and keeping the ISO below 500.

If you want to experience the full benefit of aperture gain and how it impacts sensor performance, apply this technique to older M43 or smaller sensor cameras like the Olympus X-Z2.

The takeaway is the aperture changes the reflected light (gain) or DOF. Exposing to the right (ETTR) means more aperture gain, especially in poor light conditions with slower shutter speeds and higher ISOs. One needs as little as +0.5EV to improve the sensor's saturation. A full stop will seriously flood the sensor. More reflected light means a better SNR, more tonal data, and less Visible Noise.

It helps to practice with older 12 and 16MP mirrorless or compact cameras. The benefits are more visible with older image sensors, and it also helps to master the DOF versus gain principle. 

Does later 16MP and 20MP sensors also benefit from this technique? Absolutely, but the differences are less visible for newer versus older sensors. The camera's auto-exposure algorithm saturates the sensor more with newer Olympus cameras. See this article about Olympus' safety headroom.

Olympus Pen F with 12-50mm f3.5-6.3 EZ lens, ISO200, f5.0, 1/350, +0.3EV (ETTR) - Raw file converted in Photoshop.

ETTR summary plus a real example

Last Update:- 24th May 2024.

Much has been written and said about ETTR. Enough for most photographers to see the value in having this technique. Unfortunately, this is not the case because YouTube and forum experts continue to make wild claims about sensor size. This resulted in a powerful exposure technique being lost in a cloud of "size and capture" confusion. This article gives a brief overview of marketing.

This article discusses the 7 points photographers should know about digital cameras.

Olympus EM1 II with Leica 25mm f1.4 lens - ISO6400 f7.1 1/13Sec with ETTR - Enhanced Raw file converted in WorkSpace and edited in Photoshop.

What is ETTR or Exposing to the Right?

ETTR means the best possible aperture, shutter speed, luminance, and ISO mix. The goal is a higher SNR and a saturated image sensor. The ISO function does not control the reflected light exposing the sensor, whereas the shutter and aperture physically control the reflected light. Enough reflected light means a saturated sensor, higher SNR, more tonal data, and better image quality. This article discusses luminance, illumination, reflected light, and the direction and types of light.

What is the role of the ISO function?

We manage 4 of the variables in the exposure formula. These are the aperture, shutter speed, ISO, and luminance. The ISO does not change sensor sensitivity. It amplifies the image signal and the noise coming from the sensor. See my other articles for more about the sensor's noise floor.

I use a fixed ISO to match the ambient light in buildings while adjusting my aperture, shutter speed, and luminance (flash) mix to find an optimum exposure to saturate the sensor. Study this article for more about the ISO, aperture, shutter speed, and illumination. This article reviews the ISO as an image signal amplifier or brightness adjustment. One can also use the ISO strategically...

The most critical variable impacting image quality is understanding the ISO. 
Avoid Auto ISO settings and learn how to manually set the ISO.

What are the benefits of ETTR?

The many senseless "discussions" about photons, bigger pixels, and sensor size mean nothing if it doesn't improve your existing camera. The only variable we manage is sensor saturation. The average consumer camera records more tonal data (image quality) with a saturated sensor. Digital cameras typically double the tonal data for every 1EV of ETTR. That means the histogram moves to the right, the sensor's Saturation and SNR improve, and the camera processes more tonal data.

The under-exposed version has approximately 75% less total data.

How does one apply ETTR?

I only use ETTR for challenging situations. A fixed Exposure Shift of up to 1EV is often enough. I also prefer Aperture or Shutter Mode with a fixed ISO. For example, an ISO of 64 or 100 is perfectly OK in most daylight conditions. I also use my ISO function strategically because we know it adjusts image brightness and is part of the exposure formula. A fixed ISO lets us use exposure compensation for ETTR while monitoring the sensor's saturation and SNR levels with the histogram...

A copy of the Olympus EM1 II display when the camera selected the exposure.

Olympus cameras use a built-in safety Headroom to prevent the sensor from clipping. For example, the camera's exposure meter shows a correct exposure while the sensor is not saturated. It's possible to manage this safety headroom with ETTR. For example, one can increase the exposure by up to 2EV with the blue sky as the background. Another scene might limit the possible ETTR compensation to 0.5EV steps. The camera's exposure meter will show an overexposure reading with ETTR. We correct this in Workspace with the exposure compensation (ISO) function.

Study the image below. I used an ETTR of 1EV. There was enough available dynamic range to increase the exposure with another 1EV. This is how much the camera meter undersaturated the sensor. The processed tonal data in the shadows suffer most in these conditions...

A copy of the Olympus EM1 II display with an ETTR of 1EV.

General comments

Photographers are told that ETTR only works at the camera's base ISO. I disagree because digital cameras are designed to capture more tonal data with the histogram to the right, irrespective of the ISO value. Social media "experts" argue the dynamic range is too little at higher ISOs. The dynamic range does reduce at higher ISOs. Does this mean we shouldn't use ETTR, or should we simply manage the situation? A workable solution is to ignore these paid experts (promoters) and improve your know-how while having more experience from photographing regularly...

Tip:- The ISO effectively adjusts image brightness and not the exposure.

In terms of exposure, the following basics are critical:-

• The aperture and shutter are the only variables controlling the light to the sensor
• The ISO function only amplifies the image signal coming from the image sensor

Do this quick ETTR experiment:-

• Find a scene with deep shadows and not overly bright areas.
• Set the camera to A, S, or P Mode with Auto ISO and take an image.
• Use the above camera settings (fixed ISO) for a 2nd image in Manual Mode.
• Use your aperture or shutter speed to increase the exposure in 0.5EV steps.
• The histogram shows what's happening on the sensor with a fixed ISO.
• Download the images to your PC and study the shadow areas for noise.

Conclusion

The camera's histogram tells us when the image sensor is desaturated at base ISO or when the camera uses its DR safety area. This "safety headroom" is one of the main reasons for M43 cameras having visible shadow noise. Knowledge and experience taught me it's safe to overexpose Olympus cameras with up to 1EV (ETTR) and correct it in Workspace. The secret is a fixed ISO and watching the histogram for highlight clipping while applying ETTR (adjusting the aperture/shutter).

The most important aspect I learned from my M43 journey studying sensors, testing Olympus cameras, and writing articles is image noise has become an effective counter-marketing strategy to discredit the M43 photographers. I recently tested the impact pixel area has on 15 different cameras. The shadow image quality differences were surprisingly small. You will find the article here.

Do I often use ETTR? I have many Olympus cameras in my collection. I photograph almost every day with one of them. I regularly try something new and use these cameras while preparing my articles. I am confident the Olympus engineers selected excellent 16MP and 20MP sensors. This means these sensors perform well in a wide range of applications. I occasionally apply ETTR but found that my understanding of Olympus cameras is more valuable than focusing on noise and ETTR...

Sony A7 III with 50mm, f1.8 lens - ISO25600, f7.1, 1/30sec, and ETTR - The Raw file was edited in PhotoLab 3 plus PhotoLab 3 noise reduction.