Rudy Winston
Rudy Winston

Rudy Winston has over 14 years experience with Canon USA's Pro Products team, and has been responsible during that time for training Canon's staff on new products, creating presentations for customers and dealers, numerous writing projects, and providing technical assistance to professional and amateur photographers.

Interchangeable Focus Screens in the EOS-1D Series Cameras

April 17, 2013

EOS-1D series cameras are the only professional digital SLRs on the market, as of April 2013, that offer an option for split-image focusing in the viewfinder.
Compatible with interchangeable focus screens

For decades, the ability to change focus screens was an expected hallmark of a truly professional SLR camera. But with sophisticated new LCD viewfinder overlays, some users may assume that the EOS-1D X has lost its ability to allow for different focusing screens to be interchanged. However, Canon’s engineers anticipated this long-standing professional need and provided the camera with more options for interchangeable focus screens than any other full-frame digital SLR camera (as of April 1, 2013). This article explores the options available for tailoring the viewfinder experience to the circumstances a photographer will be using the camera in.

The standard EOS-1D X focusing screen is a plain and all-matte surface screen, but numerous others are available. Perhaps most noteworthy is that these are the same Ec-series focus screens that have been available since the original 35mm film version of the EOS-1 was introduced in 1989. So a photographer who may already be using, for instance, a split-image focus screen from an earlier EOS-1 or EOS-1D camera can use that same Ec-series focus screen in the new EOS-1D X.

Available Ec-series focus screens from Canon include:

  • Ec-C V: This is the standard focus screen, which is included with the EOS-1D X camera. It’s an all-matte surface screen with no etchings or markings on it. This version “V” (Roman numeral 5) focus screen is new for the EOS-1D X and slightly different from previous Ec-C standard screens in brightness and metering characteristics. It’s not recommend to use the EOS-1D Mark IV’s standard Ec-C IV type focus screens in the EOS-1D X, if it can be avoided, because some exposure compensation will likely be necessary if you do.
  • Ec-A: This matte screen, has a microprism focus aid in the center.
  • Ec-B: In a traditional split-image circle in center, surrounded by microprism collar, the screen is all matte from there to the outer corners. This screen will be familiar to experienced SLR users who remember film cameras from the 1970s and 1980s, before the advent of AF. As such, it’s an excellent choice for shooters who frequently use manual focus, especially with wide-angle lenses. EOS-1D series cameras are the only professional digital SLRs on the market, as of April 2013, that offer an option for split-image focusing in the viewfinder.
  • Ec-C; Ec-C II; Ec-C III: These are the previous generation all-matte standard screens from the earlier versions of the EOS-1 series. Unlike the Ec-C IV screen (from the EOS-1D Mark IV), these other Ec-C screens can be used on the EOS-1D X without need of special exposure compensation.
  • Ec-D: This matte screen has etched architectural grid lines. The EOS-1D X’s Intelligent Viewfinder Display can now superimpose its own grid lines, though these LCD lines don’t enter the overall AF array area. Users who frequently use manual focus, Tilt/Shift lenses or AF users who rely on only the center AF point may prefer the Ec-D focus screen with the etched lines that fully cover the central area of the scene.
  • Ec-H: The all-matte focus screen comes with scales and etched lines with precise measurement scales, which are ideal for macro work or shooting where a reference to subject size is required. These scale markings are not duplicated with the Intelligent Viewfinder Display in the EOS-1D X.
  • Ec-I: This matte comes with double crosshair reticle. The special purpose focus screen is for extreme high-magnification focusing, such as through a microscope or telescope.
  • Ec-L: This unique cross-split screen is an interesting option for users who like the idea of split-image focusing. The Ec-L screen bisects the central part of the image with both a traditional horizontal and vertical split-image. It’s ideal for users who like to manually focus with wide-angle lenses. This is another split-image focusing option that’s special to the Canon EOS-1D (and EOS-1Ds) series cameras, as of spring 2013.
  • Previous Ec-S, Ec-N and Ec-R screens: These are previous generation screens that will fit into the EOS-1D X. They’re a bit brighter than standard screens, such as the Ec-C or Ec-D series, with no custom function to adjust metering to compensate for the added brightness (some degree of user-applied exposure compensation will be needed if they’re installed).

The EOS-1D X viewfinder provides the widest range of available focus screens among professional digital SLRs in the world (as of early 2013) and the benefits of Intelligent Viewfinder Display technology, which is discussed in a separate article on Canon’s Digital Learning Center. All images depicting focus screens are simulated. 

Other Canon focus screens

For emphasis, the only focusing screens that can be used in the EOS-1D X camera are Canon’s screens that begin with the designation “Ec…” – screens designed for the EOS-1 and EOS-1D series of cameras. The following accessory focusing screens are designed exclusively for other EOS models as indicated and cannot be used in the EOS-1D X or any version of the EOS-1 series camera bodies:

Ed series (Ed-A, Ed-D, etc): EOS A2 and A2E 35mm film SLRs (long discontinued)

Ee series (Ee-A, Ee-D, Ee-S): Original EOS 5D only

Ef series (Ef-A, Ef-D, Ef-S): EOS 40D and 50D only

Eg series (Eg-A, Eg-D, Eg-S): EOS 5D Mark II and EOS 6D only

Removing and installing the Ec-series focusing screens

Two distinctive products greet the EOS-1D X owner, who owns one or more accessory focus screens: an empty space in the screen’s case to store the screen that’s currently in the camera and what looks like a short pair of plastic tweezers. Both come into play for removing the existing screen from the camera and installing an accessory screen.

Removing the existing screen 

Instructions are packed with accessory focus screens (read them!), but we’ll briefly review the process here.

  1. Remove the lens from the camera body, in as much of a dust-free and wind-free environment as possible. Hold the camera with the open lens mount facing straight forward.
  2. Looking inside the lens mount, you’ll see a small metal tab at the center of the top of the mirror box near the top of the lens mount. Using the supplied tool, take the tiny “hook” that projects from the center portion and place it behind this metal tab. Gently pull it forward or toward you, with the lens mount facing you).
  3. The installed focus screen and metal frame that holds it will drop down about ½ inch (approximately 12mm) and stop about halfway between the mirror and top of the mirror box.
  4. A small plastic tab projects out from the focus screen that’s in the frame. Using the same end of the tool (under the “hook”), open the tool, grasp this plastic tab on the screen and gently lift it out of the frame. Place the screen in the open space in the plastic case with the new screen.

To install the new screen

  1. Use the same tool to grasp the tab of the new screen, which should still be in its case.
  2. Holding it by the tab with the tool, place it gently into the frame within the lens mount, being sure to push it back slightly so it fully fits within the frame. The tab which projects from the new focus screen must be to the left of the center once it’s placed into the frame that holds the focus screen in the camera. If not, the screen was placed upside down.
  3. With the focus screen in place in the metal frame, release the tool from the tab.
  4. Push the metal frame upward with the top of the tool, making sure to only touch the frame. When the two reach to top of the mirror box and if the screen is properly seated in the frame, you’ll hear them engage with a slight click. At this point, you’re done!
  5. If the screen and metal frame do not seem to want to move all the way up and click into place, in all likelihood, the plastic focus screen is not sitting properly in the metal frame. Let the frame come back down, grasp the protruding tab on the focus screen with the tool and reposition it in the frame to fit securely. Then try pushing the frame gently upward again, until it clicks into place. You should never have to force it into place. If you do, something may be wrong.

Focus screens can be freely changed as often as the photographer desires. To avoid problems with dust, changing screens should ideally be done indoors or in an environment free of wind-blown particles. Focus screens are extremely delicate and susceptible to scratching, so always take your time and handle them with care.

Setting the EOS-1D X’s Custom Functions for the screen in use

Changing the focus screen in the EOS-1D X doesn’t impact autofocus (it continues to function exactly as it does with the factory installed screen, regardless of the focus screen installed), but it can and does impact the exposure metering system. The focus screens do not have any method of conveying to the camera their precise model designation, so it’s up to the user to input that information to the EOS-1D X. Canon has provided a special Custom Function for that purpose and can be accessed here: Custom Function Screen 4 > C.Fn 18 > Focusing Screen

The options you’ll see on-screen are:

0: Ec-C V (for the standard factory default focus screen)

1: Ec-A, B, D, H, I, L (for other screens as indicated)

Either way, you’re tuning the metering system to account for differences in not only brightness, but the way light is scattered by the focus screen to preserve consistent light metering. It’s up to the photographer to be certain that any time a focus screen has changed, this Custom Function is changed along with it.


Combining the superb new LCD overlay system in the EOS-1D X’s viewfinder with the ability to quickly change to a split-image focus screen or other special purpose accessory screen is an important feature for working pros and even dedicated enthusiasts.

Serious photographers are often advised to look into the options available to see how they can speed up the process of viewing, composing and focusing in certain situations or when certain lenses are used. For example, it’s easy to envision an EOS-1D X user who shoots landscapes with wide-angle lenses switching to the Ec-B or Ec-L split-image focus screens when he or she is doing that type of shooting, then reverting back to the standard Ec-C V screen for telephoto lens use.

In years past, different focus screens were an important part of a pro’s arsenal when he or she used a professional SLR camera. Today, with autofocus so prevalent, many users may feel they’re not necessary but can be an important viewing or compositional aid and provide visual confirmation that AF is working properly. For EOS-1D X owners who realize their potential, the primary takeaway from this article should be that the camera is ready to accept the SLR industry’s widest range of optional accessory focus screens.

The CDLC contributors are compensated spokespersons and actual users of the Canon products that they promote.

© 2018 Canon U.S.A., Inc. All Rights Reserved. Reproduction in whole or in part without permission is prohibited.