Geartalk: Changing My Canon 5D Mark II Focusing Screen

Ever since i’ve been bitten by the Zeiss Distagon ZE bug, i’ve hardly used any of my other lenses with any great regularity. The 28mm Distagon (read my Day 1 review) is an excellent multi-purpose lens, well suited for the type and style of photography i currently enjoy. It is however, a manual focus (MF) lens. The accuracy of focus depends on how well i can see things in the viewfinder and how accurate the depiction of “in-focus” appears in the VF. Despite the fact that a ZE mount does speak to the Canon body, and the camera gives off the familiar in-focus “beep” when it thinks focus has been achieved, finding focus with the default focusing screen is a pain — slow, inaccurate and prone to false positives.

The Canon 5D Mark II comes default with the EG-A focusing screen. Very clear, quite bright, and a well-meaning all-purpose FS. But its inadequate for MF purposes. Due to the clear finishing, it’s difficult to tell the difference between in-focus and out-of-focus (OOF); it all looks the same especially in hair-splitting scenarios, where micro focus is required or when using wide aperture lenses and DOF is very thin, such as the case with the Distagon 28mm at f2.

To solve this problem, Canon offers the EG-S, a “super precision matte focusing screen”. I looked for it high and low here in Kuala Lumpur and couldn’t find it. I was in Singapore a few weeks ago for work (visiting the impressive Google campus), so i popped over to the famous Cathay photography super-store at Peninsula Plaza and was not surprised at all that they did have it in stock; it seems they have EVERYTHING in stock, the store is so large and well equipped. The helpful staff there showed me how to install it (very easy, 10 second job, no risk at all to your camera as long as you do it in a relatively lint/dust-free space), and i was away.

Two beautiful girls

Taken with the EG-S focusing screen, overall light was low, indoors. No issues focusing.

The difference was immediately noticeable. What the screen does is darken out the edges of the viewfinder considerably, akin to in-camera vignetting and brighten the middle of the screen dramatically. The additional contrast makes it easier to see the subject to determine focus. If the subject is even slightly OOF, it’ll be obvious, thus allowing for adjustments. If the EG-A was giving me 4/10 performance in terms of ensuring focus with a MF lens, the EG-S was giving me 8/10 performance with the misses my own fault rather than the screen’s. It really is quite good and works normally with regular AF lenses with no issues whatsoever. The only downside is that in low-light and with lenses that have a greater aperture than f2.8, the screen is slightly dark, and this may cause composition issues. But it’s not as big a deal as it sounds, and not a real hindrance in real-world use.

But i was still unsatisfied, i wanted the “real” (i use the world liberally) MF experience. Being brought up, my first camera was an old Nikon, about 30 odd years ago. It had a split-prism focusing screen, something that looks like this.

praktica super tl 3  split screen viewfinder

The great advantage of the split-prism is that focus is easily achieved by aligning the image in the focusing circle; there is very little guesswork involved. Get the image aligned, and focus is guaranteed, all other things being equal. The bad news is that Canon doesn’t offer split-prism screens for the 5D Mark II. It does offer them for the Canon 1Ds and some enterprising techs sell modified Canon EC-Bs for the 5D Mark II. I found one such vendor on Ebay who had a good rep, and since the price was cheap, i gave it try.

Customized EC-B Focusing Screen

The customized focusing screen from Ebay

The focusing screen arrived a week later, swapping it in was easy. There are tabs on the focusing screen and in the camera that make it easy to align and lock the focusing screen into place. Pop out, pop in, 10 seconds flat.

The customized screen delivers on it’s promise — it’s a split-prism and is extremely bright in the middle and very, very dark around the edges, much more so than the EG-S. I would say, in low-light conditions, too dark to the point of being unusable if composition along the edges is a concern. But, focusing has never been easier for MF. If the EG-S is 8/10 as far as focusing ease and accuracy is concerned, i would rate this customized screen as 9/10; it’s really hard to miss focus. I switched over to a couple of other AF lenses, and they all performed normally; the focusing screen doesn’t influence how the camera finds AF.

Here are a couple of shots taken with the customized focusing screen, heavily cropped into the subject to demonstrate focusing accuracy. Also worth noting that since finding focus is so easy, focusing times are very short as well.

Rayyan Harris, chillin' and posin'

Rayyan Harris, chillin' and posin'

It would seem that i’ve solved my problem with MF lenses on the 5D Mark II. Both the EG-S and the customized EC-B do the job admirably. Since the swapping of the focusing screens is painless, it really does depend on mood and circumstance which focusing screen will be used, though i feel the EG-S will generally see more use as a balance between needing to nail MF and having a bright enough viewfinder for most conditions.