HDR PQ HEIF: Breaking Through the Limits of JPEG
As Canon’s latest flagship professional DSLR camera, the EOS-1D X Mark III boasts amazing continuous shooting speeds and support for 5.5K RAW movie recording, but let’s not ignore its various improved still shooting features. In this article, we take a closer look at its support for the HDR PQ HEIF format, which takes still image shooting to a whole new frontier.
EOS-1D X Mark III: Speed and image quality are just the beginning
The EOS-1D series of cameras is Canon’s top-of-the-line full-frame DSLR camera. Throughout history, it has been highly relied upon by professional photographers in a variety of genres including sports, news, wildlife, portraiture, fashion, and landscapes photography. It is therefore not surprising that the EOS-1D X Mark III, the latest model in the series, boasts various new and enhanced features geared at further improving image quality. These include:
- - A CMOS sensor with improved high ISO speed noise reduction capabilities
- - The new High Detail Low-Pass filter, which prevents moire and false colours for pictures that are clearer, sharper and more faithful
- - The new DIGIC X image processor, which enables high-resolution sharpness processing as well as improved noise reduction
You can read more about these in the following: Introducing the EOS-1D X Mark III (1): Still Shooting Performance It’s evident that the images shot with the EOS-1D X Mark III will be clearer and sharper than before. But what if we said that these alone are not enough to reflect the camera’s true capabilities?
Photography is not just about what you can capture. It's also about what you can see.
When we talk about still shooting features on a camera, one thing that we sometimes tend to forget is that photos are not just about what you manage to record as data. What you can see when you display the shot on a monitor matters too. If the data on the colours and tones of an image that is captured by your image sensor is not within the range of what your display device can show, then you won’t be able to see the image accurately. JPEG is one of the most widely used formats for digital images especially photographs, but it was first created in 1992. Being popular has its downsides—display devices keep improving, but the JPEG format has not quite evolved to keep up. HDR (High Dynamic Range) monitors have become more widespread in recent years. These monitors use a colour technology that enables them to display a wider range of colours and contrasts than conventional SDR (Standard Dynamic Range) monitors, which also means that they can show the details in light and dark areas more faithfully. For this reason, images shown on a HDR monitor look more realistic, as though you were seeing the scene with your own eyes.
Digital images are mostly stored in JPEG format because it can be displayed on just about any display device, including older ones. But the colour space and dynamic range of 8-bit JPEG doesn’t take advantage of what the new HDR monitors can offer.
The difference between RAW, JPEG and HEIF
Colour space, bit depth and what it means for you
Colour space: The range of colours that can be represented or displayed Bit depth: The number of unique shades of colours that can be represented or displayed Conventional TV and computer monitors generally all share a uniform colour space and bit depth. Even if your image contained more colour information than this colour space and bit depth, it would not make any difference to what you see on the screen because your monitor would not be able to display them.
How much colour information can RAW, JPEG and HEIF capture?
The CMOS image sensor on your EOS camera captures and outputs contains a much larger colour space and bit depth than a JPEG file—14-bit colour information, to be precise. This information is what is recorded in a RAW file, and but you would have to post-process it to be able to recover and see the details.
If you are recording in JPEG, the 14-bit information is compressed into an 8-bit format. This means that colour information gets lost, and the colour space becomes much narrower, i.e., sRGB.
Learn more about how JPEG and RAW are different n:
In comparison, recording in HEIF on the EOS-1D X Mark III gives you 10-bit colour depth within the same file size as a JPEG file. Because of the way this information is rendered, unlike RAW, you can see its effects without having to post-process them first. In other words, you can enjoy the visual impact of this wider dynamic range straight out of the camera.
The beauty of HDR PQ HEIF: Supporting new HDR standards
Say goodbye to that overprocessed look
Let’s go back to the last time you tried to create an HDR still image. Regardless of whether you did it manually in post-processing or using the HDR mode on your camera, it probably involved taking a few exposures of the same shot using different exposures, and then merging them together. This helps you to extend the dynamic range represented in the shot and retain more details in highlights and shadows. It certainly is a way to make images look more dramatic. However, regardless of how you achieved your conventional HDR shots, the colour information is ultimately recorded in the narrow SDR range of colours, which causes the tones and contrasts to appear less smooth. This is what makes it so easy to end up with a shot that looks overprocessed. How, then, do movies and videos manage to achieve that ultra-realistic, cinematic look with just one exposure? That’s because they record images with a large colour space and high bit depth, which has not quite been possible on traditional digital cameras until now.
These two images were converted from exactly the same RAW file. The conventional 8-bit JPEG file looks brighter but flatter, whereas in the HEIF*, you can see more details in the light and shadow areas, and there appears to be more dimension. This is because the HDR PQ HEIF format is able to handle the image information captured in the RAW file better.
*Know this: HDR PQ-like JPEG
To enable web display, the "HEIF" examples in this article are HEIF files converted to HDR PQ-like JPEG. This is a special JPEG format that renders images to resemble what they would look like when viewed on an HDR display, but they are still 8-bit files and subject to the limits of our SDR-based monitors. So, if you are amazed by the difference now, expect even better with actual HEIF on an HDR monitor!
The different HDR standards: What is HDR PQ?
There are currently two main HDR standards:
- Hybrid Log-Gamma (HLG) is highly interchangeable with SDR monitors
- Perceptual Quantizer (PQ) is optimised for HDR monitors
The EOS-1D X Mark III uses the HDR PQ standard, which is also used in video HDR formats such as HDR10, HDR10+ and Dolby Vision. As this standard records contrast in absolute values, the image quality is more stable across different display screens. It is increasingly widely adopted for video production, but can also be used in still photography.
HDR PQ combines the PQ gamma, which enables images to display a wide dynamic range close to that of what the human eyes see, with the ultra-high resolution that your EOS camera capable of. (Fun fact: “4K” works out to approximately 8 megapixels, and the average new camera has much more than that!) The result is a very realistic look, with contrasts that are presented appearing close to what we see in real life.
The EOS-1D X Mark III still image workflow
How do you work with a HEIF file?
The table below shows the differences between the still image recording formats on the EOS-1D X Mark III. Although they contain a lot of information, HEIF (HDR PQ) files are the same size as JPEG files. You can also record to two different file formats at the same time, i.e.:
- C-RAW+ JPEG
The amount of data a HEIF file contains means that you can also convert it into a file format that holds less information. So:
- RAW/C-RAW can be converted to HEIF (HDR PQ) or JPEG
- HEIF (HDR PQ) can be converted to JPEG
Still image recording formats on the EOS-1D X Mark III
* Size when HDR PQ is off.
**12-bit during electronic shutter shooting.
Displaying HEIF images
If you don’t have an HDR monitor
Currently, most computers are SDR monitors that can’t display HEIF images in their full quality. This is also true for the rear LCD screen of the EOS-1D X Mark III. But even if you don’t have an HDR display device, you still can get a very close representation of what your HEIF image will look like on an HDR screen…
- On your camera: When you playback images on the rear LCD screen using the “View Assist” function
- In Digital Photo Professional: When post-processing the image or converting from RAW image shot with HDR PQ set to “On”
You can also convert HEIF files to an HDR PQ-like JPEG file, which will result in an image that resembles that in the HEIF file.
If you do have an HDR monitor
If you are using your computer:
- Make sure your computer has a graphics card that supports HDR PQ, too
- Open up the HEIF file in Digital Photo Professional If you are connecting directly from camera to monitor:
- Use an HDMI cable to connect the camera to the monitor - You will be able to playback the HDR PQ HEIF files and RAW image files shot with “HDR PQ: On” stored on your camera memory card.
Summing up: The file format to keep an eye on
HEIF images are not just about the wider dynamic range, but their amazing dimensionality, which makes them seem so real, they could almost be 3D images. Our SDR-based monitors aren't doing them justice, but just imagine the examples in this article, with even better realism, tones and contrasts. These will perfectly complement HDR display devices, which are increasingly becoming mainstream.
It also has other advantages:
- No need to post-process (unless you want to): It provides an amazingly wide tonal range (10-bit colour!) straight out of the camera, saving post-processing time. Yet, the file size is similar to that of a JPEG. It's great for photographers who need to take many high-quality shots and deliver them as fast as possible
- Holds more detail than conventional JPEG: If you like pushing your RAW images to the limit in post-processing, exporting your edited images to HEIF will ensure that more of the tone and contrast details in your edits are preserved. In fact, as long as you have the RAW file, you can output your images to HDR PQ HEIF anytime—such as when you finally get that HDR-ready monitor.
With HEIF, a whole new world of image quality awaits. Take a step into it, and you would also be stepping into the future.