Better Image Quality with Image Stacking

Last update:- 20th May 2024

Introduction.

We are reviewing image quality and different stacking options. Image quality is the sum of sensor sensitivity, lens quality, and the image processor. It's possible to optimize the sensor's saturation and SNR, and better image processors give us more computational options. For example, should the camera set the exposure, or does the histogram assist us in finding a more efficient exposure? Stacking or image bracketing gives us more options to manage our image quality, while some like us to think the size of the sensor and camera determine everything...

I also did an article with 4 TIPS to improve your photography. link

We are reviewing the Olympus Pen and OM-D series' high-dynamic-range (HDR) options and how they improve our image quality. The camera's HDR function takes 3 to 5 bracketed exposures and converts them into one HDR image. Image bracketing (stacking) improves Shadow Details, Tonal Data, Dynamic Range, and visible Image Noise. These computational options are available with the Olympus EM5 II/III, Pen F, EM1 I/II/III, OM-1, and the OM-System OM-1 II.

Olympus EM5 II with 12-50mm f3.5-6.3 EZ lens - ISO1600, f6.3, 1/80 - 40MP high-Res image edited in Photoshop.

Stacking applications include the following:

• Traditional bracketing (exposure, focus, white balance, ISO, and ART)
• Computational functions like focus stacking and high-resolution images
• Editing software like Photoshop with various HDR options and functions
• Various camera and image editing techniques for more creative images
• The unique Olympus computational functions, Live Time & Live Comp 

One way of improving your IQ is the Photoshop Merge to HDR Pro function. It combines 2 or more bracketed exposures into one high-detail 32-bit image. This method works for product and landscape photography. The benefits are similar to HDR or the Olympus Hi-Res mode.

The Photoshop Merge to HDR Pro function also creates traditional HDR images. Follow the image descriptions for examples of stacking 3 or more bracketed images into one HDR photo.

The High-Detail 32-bit function in Photoshop

I selected 3 bracketed exposures from my photo collection to test the 32-bit HDR Pro function. I used Adobe Bridge to open the 3 images in HDR Pro. The high-detail 32-bit Pro option is one of several HDR possibilities. It's now possible to create natural-looking HDR photos. The surreal HDR look is something of the past with the High Detail 32-bit HDR Pro function.

I used 3 bracketed images from my Canon 350D and processed them with the Photoshop High Detail 32-bit HDR Pro function.

Study these 3 Canon 350D histograms. Nobody talked about sensor performance or optimizing the image sensor when I took these 3 bracketed images in 2004. I knew nothing about sensor saturation or SNR. I simply followed forum and magazine advice when taking the 3 exposures.

The histograms show the default exposure was good. The 350D did a great job selecting the best exposure for the initial image. It shifted the shadow and midrange tonal data to the right and protected the highlights. It helps to use your camera frequently and create opportunities and projects to practice these and other Olympus computational features.

Three Bracketed Exposures

                    Under Exposed                       Default Exposure                     Over Exposed

High Dynamic Range (HDR) images

What is the best default exposure for High-Detail and HDR sequences? The principle of merging stacked images into one photo allows the HDR software to select the best tonal data from each image and combine them into one HDR photo. One typically uses +/-1EV steps to create HDR photos. The initial or default exposure should maximize the tonal data for every bracketed exposure. 

Another interesting method is Exposure Blending. See this function in Photoshop. It puts 3 bracketed images into separate layers with a mask highlighting the best data for each layer. This lets us see which parts of the bracketed images should go to the final HDR photo. The photographer can tweak these separate masks to focus on specific data areas, noise, and shadow details.

Experiment and practice with your camera's exposure settings and histogram until you find the best exposure technique to complement your photography style. For example, the presenter in the above video used 2 bracketed images to explain the Photoshop "Merge to HDR Pro" function.

Olympus EM5 II with 12-50mm f3.5-6.3 EZ lens - ISO1600, f4, 1/80, -0.3EV - Enhanced Raw file converted in Workspace and edited in PS.

What about the HDR1 and HDR2 functions in Olympus cameras?

The Olympus HDR function is one of the most underrated Olympus features. It is available for most Olympus cameras and can be configured in Shooting Menu 2. The secret is to use the Olympus HDR function in Manual Exposure mode. It's also possible to use Auto or Semi-Auto (A or S) mode...

Olympus EM5 II with 12-45mm f4 Pro lens - ISO200, f4, 1/80 - this is a handheld HDR1 image - the OOC jpeg was prepped in WS and PS.

Use the camera's HDR1 or HDR2 function and set the default exposure for optimum image data. The histogram lets us determine each capture's tonal data range. The camera will automatically select ISO200. That means you need a tripod in low light. The base or starting exposure determines whether your focus is shadow, midrange, or highlight data. For example, use ETTR for the initial (default) exposure to increase your shadow data or reduce the exposure to protect the highlights.

Olympus placed HDR1 and HDR2 in the AP menu of newer cameras like the E-P7. Turn the mode dial to AP, select HDR, and press the down arrow. It is not possible to configure HDR1 or HDR2.

Olympus EM5 II with 12-50mm f3.5-6.3 EZ lens - ISO1600, f8.0, 1/250, -0.7EC - 40MP high-Res image edited in WS & Photoshop.

Conclusion

I discussed different ways to record an image. We understand the basic principles of sensor saturation and SNR and reviewed examples of various computational and exposure techniques. Knowledge is crucial because it lets us do more with the camera and image-editing software. A good example is WS and the Enhanced Raw Format. Is Workspace always better than Lightroom or PhotoLab?

Why does the camera's HDR function need bracketing? Because the shutter and aperture project a uniform exposure (image) onto the sensor. Study my previous articles for more information...

Olympus E-M5 II with 12-45mm f4 Pro lens - 40MP high res image.

Why should one ignore those who criticize the High-resolution function? Experienced photographers plan for movements caused by people or wind when using stacked images to create photos. Typical examples are focus bracketing, exposure bracketing (HDR), and high-resolution imaging. For example, full-frame cameras have a smaller DOF than M43 cameras. You will, therefore, find that many full-frame and medium-format photographers use focus bracketing for landscape photography...

Olympus EM5 II with 12-45mm f4 Pro lens - 3 bracketed exposures processed in "Merge to HDR Pro" and edited in PS.

Which exposure technique is best? Knowledge is an enabler and necessary. It's good to know more about sensors and how we optimize their performance because digital cameras can do more and are more complex than analog cameras. That's also why I spent so much time on the image sensor and managing its saturation and SNR. This article illustrated different computational and image results. Each scene is unique and benefits from an experienced photographer showcasing its beauty. The type of scene and final image determine which exposure technique is better...

The Olympus E-M5 II is a surprisingly capable camera in 2024 and can be bought "like new" for less than $250. It has almost all the computational and video features of the E-M1 II. Used Olympus cameras like the E-M10 II, E-M5 II, E-M1 I/II/III, and the E-PL8/9 are selling at bargain prices...

Best

Siegfried