I got my Sony A700 focus screen changed to the Type M Focusing Screen at a Sony Service Center. They charged RM70 for it. (Yes that’s the same price as the Nikon and Canon counterparts.)
The screen has to be changed there itself because they need to update the camera firmware as the focusing screen darkens considerably with darker lenses, compared to the standard focusing screen. The metering unit is above the viewfinder and if you ordered it online and did it yourself, your camera would overexpose, depending on aperture.
I got my original focusing screen as well, with the box which it came in.
The Type M is a plain screen and looks no different from the standard A700 screen. It does not have a split-prism rangefinder in the middle like manual focus SLRs. I’d have loved that, though!
Its texture is finer, and you can see smaller ‘diamonds’ compared to the standard focusing screen when you point at distant lights and go out of focus.
Manual focusing with the Minolta 50mm F1.4 is a joy – you can literally see the creaminess of the F1.4 as you go in and out of focus. It allows much greater precision. If you press down the DOF Preview button while changing the aperture, you can see that it starts to darken and the DOF increases at F2.0 onwards. On a standard screen it darkens and the DOF increases about F3.2 * onwards. I’m not sure of the exact aperture as different people get different results at different times.
Thus, the Type M screen would in theory feel 1.33 stops darker when a F5.6 lens is fitted.
Does a Type M screen feel brighter with a F1.4 lens? Unfortunately, no… but the only way to test it is to stick a digital camera on the viewfinder and measure how much light gets transmitted to the viewfinder.
You can see the 50mm F1.4’s superb, punchy color better. For once it feels that what you see is what you get. Sometimes, you can misfocus in manual focus when you think the viewfinder is sharp but it isn’t, and is only kinda close.
When I first put on my F4 beercan, I was like “whoa, that’s dark, did I put a polarizer on it or something?”
I compared it with KJ‘s standard A700 with a Minolta 50mm F1.4, and XJ and I found that my screen seemed less contrasty and sharp. This is probably because mine is showing a F2.0-like view (the Minolta is less contrasty and slightly gauzy wide open) while his shows the lens at F3.2, pretty contrasty already.
Would I recommend it? If you shoot a lot at F2.8 or brighter, this is for you (I suppose you’ll leave a F5.6 lens to AF). If your lenses are mostly darker than F2.8 then I do not recommend it.
– Greater focusing accuracy, you’ll be sure that whatever you focused on is spot on
– Shows focus to F2.0 or so
– Really shows the creaminess and color of your bright lenses
– Lenses darker than F2.8 get noticeably darker
– Macro with dark apertures gets even darker than a normal screen when you press the DOF Preview button
– Does not affect your image quality, it only helps with focusing
Note that the Sony A700 is the only Sony Alpha body that offers serviceable focusing screens; for the A100, A200, A300 and A350 a third-party option is required. There is also a Type L SI which comes with grid lines for architecture, which replaces a different screen (and so, the Type M and Type L SI can coexist. Thanks Pete Ganzel for the info!)
* David Kilpatrick claims that a normal viewfinder is only accurate to around F4.5. Your results may vary.