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Canon 5D Focus Screens
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Canon 5D

I bought mine here. I'd also get it here or here. enlarge.

Also see my Canon 5D review and other Canon tests.

February, 2007, March 2022

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Focus screens haven't been ground glass since the early 1970s.

Conventional ground glass screens worked great when everyone shot f/1.4 lenses and f/2.8 fixed teles and wides, but these screens go almost black with f/4 - 5.6 zooms.

Minolta pioneered, and for decades every other camera maker has used, precision laser cut plastic screens which consist of zillions of microscopic prismatic cuts.

These precision surfaces simulate ground glass and greatly increase brightness for f/2.8 and slower zoom lenses so popular today. They are designed to be bright and contrasty with these slow lenses.

Oddly, these modern screens get no brighter when you're using a lens faster than f/2.8. Try it: put on an f/1.8 or other fast fixed lens and flick the depth of field button. You'll see no change in anything until you stop down to about f/2.5!

Still think I'm making it up? Look through the front of your fast lens at the focus screen. It's black outside the area of the lens that corresponds to f/2.5!

Standard focus screens see nothing coming from the lens at annular angles faster than f/2.5.

If you're using a fast lens and want to see the real depth of field or want to focus well manually at large apertures, you need a different screen.

The standard screen with which the 5D ships is the Ee-A. The same screen with a grid is the Ee-D.

For optimum use for manual focusing or seeing depth of field with the 5D and fast lenses, use the Ee-S screen. Sadly of course this screen is great for your fast glass, but dim with slow lenses. Digital hasn't fixed this yet, sorry - you might wind up having to swap screens.

Each of these screens costs about $35.

I have no idea how to change screens; my 5D manual (page 158) says see the instructions that come with the screen. It was easy with Nikon cameras; I presume it ought to be as easy with the 5D.

Use the standard screens (Ee-A and Ee-D) with lenses of f/2.8 and slower.

Use the Ee-S screen with lenses of f/2.8 and faster.

Since they differ in brightness, the 5D's meter needs to know what screen you're using. You se this in Custom Function 00.

 

30 March 2022

Ground glass hasn’t been ground glass since 1979. As of the 1980s SLRs and DSLRs have used Bright Screens that have all been very precisely laser engraved rather than arbitrarily etched with acid or ground like the old days.

Plain matte etched or regular ground glass takes any light from any angle and scatters it in every direction. Regardless of what lens you use, you see the actual image and the actual depth of field. These screens are more accurate for focussing at large apertures, however they get very dark at smaller apertures because the light goes everywhere rather than only towards your eye. Back in the days of f/1.4 lenses these were the best, but got darker at f/2.8 and very dark at f/5.6 with a zoom lens, that as you know become very popular in the late 1970s, which is why the new laser screens were developed.

The new, modern laser-cut screens are very special and only accept light from certain angles and send it precisely to your eye. Therefore they are much brighter at smaller apertures, however they completely ignore light from other angles - and these are the angles from which light comes from the periphery of fast lenses. I kid you not: you won’t see the all the defocus with an f/1.4 lens on a modern matte screen!

Each new screen will have an optimum fastest aperture for which its designed, typically f/2.5. At apertures faster than this you simply won’t see the light from the faster parts of the lens, and thus you won’t see the full defocus effect at apertures faster than the design of the screen.

You can see this! Use your depth of field (DOF) preview with a fast lens. For most DSLRs the optimum aperture is about f/2.5. If you set an f/1.4 lens to f/2 and use the DOF preview button while looking at an out of focus image (a point of light makes this most obvious), and as you stop it down and reopen it, you won’t see any change! You can try different apertures and find the aperture larger than which you’ll see no change.

If you want to see the actual effect of f/1.4 and f/1.8 lenses, standard DSLR screens won’t show this. A screen optimized for a fast lens may be called a “high precision” screen, and warn that it won’t be as bright.

The screen you want for fast manual lenses is the darker, more precise one.

For instance, the Nikon FM (1977-1982) has a standard ground glass screen, while the newer FM2 and FM2-n (1982-2001) has always had the newer laser-cut (and interchangeable) bright screens.

For lenses with maximum apertures of f/2.8 and smaller the standard bright screens are best!

For a fast manual lens, you want the dim screen. That’s OK because while the dim screen is dim with a slow lens, it gets much brighter with a fast lens.  The “bright” screens oddly are bright with slow lenses but don’t get brighter with fast ones. That's why every camera uses a bright screen today especially with AF, while the traditional screen was better in the days of fast manual lenses.

Microprisms and split-images are optimized for slower apertures. They black-out at very small apertures, but you’ll also notice that they are about as bright as the ground glass with an f/1.4 lens but much brighter than the surrounding matte glass at f/5.6.

Mirrorless makes this all history; mirrorless camera finders are always bright regardless of how slow is the lens, and always show the actual depth-of-field if your fast lens is open.

 

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32 MArch 2022, Feb 2007