How to improve your image quality

Last Update:- 7th May 2023

1. Introduction.

This article discusses Image Quality and the know-how to improve it. Digital photographers are not encouraged to improve their digital photography skills, and it's nothing new to see comments like, "Who needs technical knowledge?" The trend is AI, and the expectation is AI will fix anything.

We are reviewing digital cameras and the image signal from the subject to the SD card. This includes the histogram, why the RAW format is necessary, and the Exposure Mix. Our focus is better image quality with any camera. We also review the differences between digital and analog cameras. 

Olympus EM5 MKI with 12mm f2.0 lens - ISO200, 1/500, f8.0 (Jpeg out the camera - slightly edited).

It hurts when M43 photographers recommend avoiding apertures below f4 to prevent diffraction or staying below ISO800 because M43 sensors are tiny. The latest social media trend is 16MP and 20MP cameras are not recommended for wildlife and landscape photography. These recommendations look more like a marketing reality versus experienced photographers with factually inspired advice.

For more on future trends and collective opinions, see this link.

More recent YouTube documentaries from photographers with mirrorless cameras are more inspiring than social media when considering the content, excellent video, and photography skills.

The Content:-

1. Introduction
2. Theoretical summary of exposure
3. Why should we consider using a light meter?
4. Can I trust the histogram on my Olympus camera?
5. What are the benefits of using raw versus jpeg files?
6. Improving Image Quality - summarizing everything
7. Summary of all my articles on exposure & image quality
8. Conclusion

This is one of the best videos on exposure, with simple and good examples.

2. A theoretical Summary of Exposure

Definition for exposure: The amount of light per unit area reaching the photographic medium.

It's good to have a good understanding of exposure and to broaden your experience on the various reflected light situations and what to consider when setting your exposure:-

• Understanding how to read and manage Illumination versus Luminance?
• Incident versus reflected and how the different materials reflect the light...
• The Exposure Value System (EVS), also known as exposure or EV charts...
• What is Neutral or 18% gray, and why is this critical for digital photography?
• Why the zone system, and why is this a good tool for middle gray and color?
• The Photons to Electrons graph and variables like Sensor Saturation and SNR.
• All image sensors have a noise floor, and we control the visibility of the noise floor.
• See this article: Exposure Mix and how-to manage your "SNR and ISO" Ratio.

Figure 1.

2.1 The Exposure Value System or EV charts

The Exposure Value System (EVS) was designed to have different exposure combinations for each Light Meter reading or Exposure Value (EV). For example, it's possible to use different Aperture and Shutter Speed combinations based on the camera or Light Meter exposure reading. We also use EV charts (below) to plan our Aperture and Shutter Speed combinations. 

The ISO stays fixed on analog cameras, and the photographer only works with the Aperture and Shutter Speed. The ISO function gave digital photographers the freedom to randomly change the amplification of the image signal from the sensor. This was a mistake, especially for untrained digital photographers. It is critical to master the roles of the ISO function versus the aperture and shutter.

The camera's Auto Exposure feature canceled any benefits of having the EV System. Promoters use this to promote false theories on noise and the ISO function. For example, how many photographers think the ISO changes sensor sensitivity or the size of the sensor determines image noise? The truth is sensor sensitivity is set at the factory, and each image sensor has a noise floor. The ISO function amplifies the sensor's image signal and the sensor's noise floor. These basics are critical...

The above EV chart is one of the handiest tools for analog and digital photographers. It helps to determine the correct exposure mix, plus it's possible to plan your aperture and shutter speed combinations for your creative needs. See the above video for more information.

You need the following for Light Meters and EV charts:-

• A basic understanding of how to use these EV Charts
• A proper understanding of setting a neutral (18%) gray WB
• Become comfortable working with gray scales or zone charts

Olympus EM5 with 14-150mm MKI f4-f5.6 - ISO200, f5.6, 4 Sec - Raw file edited with WorkSpace.

The SpiderCube is another exposure option for Olympus photographers. We can measure our Dynamic Range, White, Black, and 18% gray points with the Cube. Point the camera to any of the Cube's sides and take a measurement. The camera's light meter reads the Cube's black, white, and neutral gray values. They create 3 green spikes on the camera's histogram. The chrome ball is used to adjust a polarizer filter.

One could do separate articles for the Cube and Spider ColorCheckR. I added two videos to my reference list. This is not a paid promotion on DataColor products.

It's about a tested solution to determine the dynamic range, neutral gray, and white balance. The Cube's value improves with regular use for the professional and hobby photographer.

I studied different light meters and EV charts to improve my exposure know-how and ability to visualize techniques like ETTR. As you improve your skills in exposure and ISO, you will become more confident with your digital camera's Auto Exposure function.

The Zone System as developed by Ansel Adams - See Wikipedia.

The camera's exposure is 1-Stop above 18% gray with an ETTR of +1EV. The resulting image is not only brighter, the tonal data also improves. Always select an 18% gray exposure with the camera or WS if accurate colors are critical. The next step is to have the correct WB and exposure for snow. You can also use your camera spot meter with the zone system to quickly determine the dynamic range of your image. For example, Workspace and the Enhanced Raw Format are perfect for resetting ETTR adjustments (exposure comp in WS) or doing color corrections...

One would typically do the following with the Enhanced Raw File and Workspace. The first step is to adjust the exposure to 18% gray with the Exposure Slider. The Exif data from the image tells us if we used exposure compensation. Any brightness adjustments are changed with the brightness slider or the Tone Curve function in Workspace. Why are these steps or the sequence critical?

Figure 2 - The above graph explains the terminologies you should know.

2.2 The Exposure Equation

The exposure equation shows the link between the ISO, aperture, and shutter speed. We know the ISO does NOT add more light onto the sensor or change the sensor's sensitivity. 

The different uses for ISO are:-

• Analog photography. The ISO synchronizes the film's sensitivity with the light meter.
• Digital photography. The ISO amplifies the image signal from the sensor - article.

How do we set the exposure? The exposure formula is abstract because it does not explain the different variables. We can only move forward knowing the ISO amplifies the image signal and the Aperture and Shutters Speed expose the sensor. The aperture and shutter speed also determine the optical characteristics of the image. The application of this knowledge improves with practice.

Exposure Equation.

For example, many Olympus cameras will go lower than ISO200. The EM1 II and III can go down to L100 and L64. Others only have the ISO-Low option. Promoters and influencers promote the idea of not using ISO values below ISO200. Let's take a closer look at the ISO function.

The ISO equation shows the ISO is directly proportional to the Aperture and Shutter Speed. That means the ISO increases with lower Aperture and Shutter Speed values and vice versa. This explains why the ISO amplifies the image signal. The reason is the Aperture and Shutter Speed are the only 2 variables exposing (adding light) the image sensor. The native ISO of the camera is determined with a fully saturated sensor. This also explains why the camera's dynamic range decreases at high or lower ISOs. (See Figure 1) This knowledge should not be a reason not to use lower ISOs. The real benefit of using ISOs below the native ISO is less image signal and noise amplification.

Olympus EP3 with 12mm f2.0 Lens - ISO200, 1/400, f7.1 (Raw edited in PhotoLab 4 and PS).

3. Why should you consider a light meter?

One of the more critical challenges cameras have is the interpretation of exposure measurements. The reason is the sensor's luminance perspective. (Figure 2) As you know, the focal length of your lens determines the field of view (FOV) and what part of the scene luminance is seen by the camera. FOV causes the camera's exposure reading to change as you move your camera. The camera's FOV (field of view) impacts the camera's automatic "exposure" readings.

This means it's good to think when using the camera's auto-exposure function. Consider your subject, illumination, and the luminance (reflected light) linked to the camera's field of view and ambient conditions. Light meters look at the total FOV and are practical for complex exposures.

The most concerning aspect of digital photography is the general level of exposure skills. Add to the complex features of modern digital cameras, and many photographers will never master the basics of digital exposure. For example, spending time with a group of photographers half my age, I was stunned at their lack of knowledge on optimally exposing the camera's sensor.

These are good bargains secondhand.

You should know these older meters require special batteries if you like an old-style light meter like the Gossen below. If you find compatible batteries for these meters, please let me know. The other alternative is mechanical meters because they don't need batteries. I use the above light meter.

Five simple reasons to use a Light Meter:-

• They make it easy to read both incidence and reflected light.
• Cameras only measure part of the scene or lens Field of View (FOV).
• They help us to measure the reflected light that's exposing the sensor.
• Light meters also improve our engagement with the exposure process.
• We can measure the scene's dynamic range (DR) with Spot Meters.

There are more benefits to using a light meter. For example, we can use the camera spot meter with a light meter to determine and manage our exposure settings and SNR to ISO ratio.

4. Live View and the Histogram on Olympus cameras?

Olympus was the first manufacturer to introduce a working Live-View for DSLRs. I have an older E330, and it's fascinating how they implemented Live-View. The E330 was launched in 2006 and used the first 8 MP Live MOS sensor. Apart from Live View, the new Live MOS sensor demonstrated the commitment from Olympus to design excellent Four-Thirds and M43 cameras. For example, the Standard CMOS sensor's pixel control wiring impacts its Optical and Quantum Efficiency more than Live MOS or BSI sensors. This already showed in the Olympus product strategy from 2006.

Modern Olympus cameras use advanced Live-View features to read the information directly from the sensor. The only difference between the data from the sensor and Live View is the sensor is a linear device. The sensor's RAW data has to be converted with an appropriate Gamma or Display profile for us to see the data. The REC 709 is a typical display profile. Also, see this article.

The Truepic Processor overlays a Gamma or REC 709 profile over the RAW data coming from the sensor. This display profile is fixed, which means the Live View display is directly linked to your sensor data. The Olympus Gradation function adds another layer to the exposure calculation. For example, the Gradation "Auto" option changes the sensor's linear output to a flat DR profile.

Let's trace the image signal path from the sensor to the camera's display:-

1. The Reflected Light from the scene is recorded by the image sensor.
2. The raw image data is sent from the sensor to the camera Truepic CPU.
3. The Truepic CPU applies a display REC 709 profile to the image signal.
4. The camera then accesses the ART processor to add any creative settings
5. The display shows a profiled view of the Art Processor and Sensor Data.
6. You can, therefore, trust the histogram as it tracks the sensor signal 100%.
7. Experiment with the Gradation function and see how it changes the AE.

Promoters like to distract Olympus photographers when saying the Olympus histogram receives its info from a JPEG file. Why is this incorrect? The Live View data does not come from a JPEG file? There are no available JPEGs before we record the image. Why do M43 photographers argue about this? Olympus only uses the file information when we open the Enhanced Raw File in Workspace.

For more information, see this link.

It's possible to test almost any exposure information with your Olympus histogram. For example, does the data come from the image sensor or the JPEG file? We can determine this with the "Live View Boost" function. This function can be found in menu D for most Olympus OMD cameras.

Select "ON" for Live View Boost and the On1 or On2 Live View option. This will disable the Exposure and Art Processors. This means the Live View display is a fixed signal from the Image Processor. See the Users Manual for more information about the On1 and On2 options.

If you want to study a captured image histogram, go to playback, select the image, and press the INFO button until you see the histogram on the camera's display.

Olympus EM5 MKI with 75-300mm lens - ISO1000, 1/1250, f6.7 (Raw edited in PhotoLab 4, PS & Luminar 4).

It's good to trace the image signal path if you have questions. As we have seen, the histogram is connected to the CPU (Image Processor) and the CPU to the sensor. Any adjustment the photographer makes to the CPU is displayed on the histogram. It is practical to cancel all the ART adjustments when you set your exposure or when you like to optimize (ISO to SNR ratio) the image sensor.

One of the reasons the above example or way of planning/thinking is not general knowledge amongst M43 photographers is because Olympus cameras use unique and powerful features like:-

1. How the Four Thirds design improves the image signal transfer to the photocells
2. Olympus invested much R&D in optimizing sensor sensitivity (Live MOS sensors)
3. Olympus cameras have unique options like Highlights & Shadows to adjust the image.
4. Olympus developed a class-leading Live View function to support photographers.
5. It offers a win/win situation when you combine these elements with good exposure skills.

Unlike promoters raving about resolution, we know it does not relate to effectiveness. The absolute features, design, and type of display have a more critical role in their value and functionality.

Olympus E-520 with 14-54mm f2.8-3.5 - ISO200, f5.6, 1/100 (Jpeg edited w PS raw and Luminar 4 - sky replacement).

Talking about leading somebody down the garden path - why does the 20MP EM1 have less noise than the 10MP E520?

See this article for more information about Workspace and editing your images in Live View. For more on my How-To page on WorkSpace, see this article. (See technique 19)

5. Why should we use raw and jpeg files?

Image editing is more acceptable today than in the past. Digital photography introduced a completely new era of artistic freedom. Social media would be different without digital photography. We also witnessed this creative revolution amongst the younger generation because they are surrounded by digital devices, editing applications, filming, and social media. How radically different to when we had film roles as a recording medium and how we physically joined film strips into a final movie.

Unsurprisingly, 80% of all social media images started as jpegs. What percentage of those living from photography work with raw files? For example, many RAW editing features are now available to jpegs. These include adjustments like white balance, highlights, shadows, or noise reduction. Thinking about it, most raw converters like Lightroom are nothing more than regular image editors. This is probably why Workspace and the Enhanced Raw Format is an open secret...

Have you wondered why I started reviewing the digital image-taking process? Like most, I was influenced by reviews and "fact statements" like "full-frame cameras capture more light" or have less noise and better image quality. After buying the Sony A7 MKII/III, I learned the images are different but not necessarily better. How do you personally define better image quality?

The IQ differences between the A7 II and my Pen-F were so insignificant that I knew there must be a way of improving the results of any camera. It became clear the answer was to control the luminance reaching the sensor. This is how my journey started on exposure and digital cameras. In my quest for that tiny and "subjective IQ improvements," I started studying digital cameras.

As digital cameras improved, the invisible Auto and AI features became advanced. That means each new generation of digital cameras needs fewer photography skills. The older the digital camera, the more joy old-school photographers have by optimizing the image-taking process for the best possible results. This is a creative and rewarding process that no IA can copy.

We know the current range of M43 Live MOS sensors is nearly as sensitive as BSI sensors. We also know pixel area is one of many factors impacting sensor efficiency.

Studying the differences between jpeg and raw files, we see jpeg files are 8-bit, and raw files are typically 12-bit or more. A typical jpeg file has 256 shades of gray for each RGB channel, whereas a 12-bit raw file has 4096. These differences keep on adding to make raw files more interesting than jpegs. Have you asked yourself why can't the Raw Converter change the ISO?

The short answer to why photographers prefer raw and not JPEG files is simple. Raw files have more image data to work with. This brings me to another question. Photographers are prepared to sell their complete camera kit for a subjective and tiny improvement in image quality. Why would they not consider working with raw files or improving their exposure skills?

Workspace and the Enhanced Raw Format are the best reasons to use raw files. Everything changes once you master the concept of having access to your camera settings in Workspace

Olympus EM5 MKI with 12mm f2.0 lens - ISO200, 1/500, f8.0 (Jpeg out the camera only slightly edited).

6. A summary of improving your image quality

As said in the above section, my articles on exposure, the digital camera, and digital photography mainly benefit those who:-

• Needs that +1% image quality improvement without buying a new camera.
• Needs to master the digital image-taking process and new camera features
• Are challenged by Astro, night cityscapes, or other demanding photography
• Know that a different-looking image does not mean you improved your IQ

In one example, a surprised M43 forum poster replied, "But this applies to all cameras." I will never forget this reaction because only the M43 community doesn't seem to know. Everyone else is using ETTR. It's as if the M43 community is safely locked inside this "my inferior small sensor" space.

The Digital Exposure Triangle explains almost all digital camera and digital photography FAQs.

When I had my first Olympus, the E410, I loved taking nighttime images of the city. I always have my tripod with me, and it was OK to use ISO200 and select the appropriate aperture and shutter speed. I knew it was impossible to take handheld images at night. As digital cameras improved with better IBIS, it was mindblowing how fast people turned their backs on basics and started demanding super-high ISO capabilities, the largest possible sensors, and the best IBIS in the world.

Out the window went everything photographers learned over the past 50 years. Have you ever seen your local news presenter jumping left to right, back to forth, or in and out of the frame while presenting the evening news? Why on earth would YouTubers do that? Did you know my 6-year-old GH4 has AF tracking and will track the sitting or standing presenter while recording an interview? 

Olympus E-410 with 14-42mm Kit lens - ISO100, 1/160, f10 (Edited with PhotoLab 4 and PS).

Similarly, marketers present sensor size as the way to photography heaven. In fact, the physical size of the backplate holding the pixels plays absolutely no role. Also, the diameter of the photocell is only one of many variables impacting your sensor's sensitivity. 

You need to know your camera and what technique works best with what application. That said, there are so many more ways of improving image quality:-

• Using image bracketing techniques (stacking) to control noise and exposure
• See this quick and powerful PS technique on how to manage complex exposures
• Many more PS editing techniques from the same photographer. See this link
• The high-detail HDR technique I recently posted is another example
• Using good old analog photography know-how, like using a flash or a tripod
• Olympus features like Live Comp and Live ND give good image quality
• The Olympus Hi-Ress Mode (The answer is to practice for good results)
• Simply applying ETTR in poor lighting and editing (correctly) in the camera 
• An interesting technique called image averaging uses multiple images
• If you use the Gradation function, select NORM when the highlights clip

Folks, I am at the point where I take clean and detailed images at ISO3200 with most Olympus cameras. In some cases, the results at ISO6400 are even great. At the same time, I am constantly working on my PS editing skills. The only thing standing between you and great M43 images is social media misinformation and your studying and practicing too little.

Olympus E-410 with 14-42mm Kit lens - ISO400, 13 Seconds, f13 (Edited with PhotoLab 3 and PS)

7. A summary of my related articles on exposure and image quality

• All the basics you should know about digital cameras and exposure - link
• Photowalk with my Gossen exposure meter and the 2-step exposure technique - link
• Some casual photos from my EP-7 and a general discussion - link
• ETTR summary plus a real example - link
• How to use the Olympus Gradation function - link
• See this 2024 article on advanced exposure techniques and Workspace - link

8. Conclusion

My journey continues on image sensors and all the related information in my articles. I have tried several examples, and the results are without question. The M43 sensor is all we need for stunning results. It's time to move on to the next chapter.

My next focus is:-

• Improving my image editing skills (working ON1, Workspace, and PhotoLab).
• Filming, video editing skills, and interviews and storytelling or documentaries-
• My wife wants to start a storytelling series with videos creating unique characters.
• I will spend time improving my exposure skills and applying exposure techniques.
• I will spend less time writing articles but follow my emails and comments.
• I need to again bond with my Pen-F with both jpeg and raw format photography.

I wish you all a great season, lots of fun with your cameras, and bring home great photos...

Why is it not possible to change the ISO in Workspace? I assume the reason is any ISO adjustments in photo cameras happen to the analog image signal. There is no digital history of these ISO adjustments. It is possible to change the ISO in the ProRes Video Format. The camera applies digital ISO amplification in ProRes mode.

References

• Cambridge in Colour article on the raw format - Link 
• Interesting article on how the raw file is rendered - Link
• 5 Reasons to Shoot and Edit in Raw Format - Link
• A closer look at the Zone System and metering - link
• Seven times the camera's lightmeter will fail you - link
• Great article on exposure and ISO invariance - link
• Another article (same writer) on ISO invariance - link
• How to use the Zone System for digital photography - link
• How to use the zone system with your lightmeter - link
• How to use the SpiderCube with your Olympus - link
• How to use the SpiderCube and ColorCheckR - link
• Zone system from an analog photographer's point of view - link
• Use image averaging in Photoshop to control noise - link
• How to simulate long exposures using image averaging - link
• A must-see paper on sensor sensitivity - link
• A detailed study on image sensors, noise, and ETTR-link
• A good story of a Pro photographer changing to M43 - link
• Interesting reference paper (pdf) on the histogram - link
• Video from Robin Wong on Olympus and using a high ISO - link