LCD screens on many cameras are often made of toughened glass that's difficult to scratch, but not impossible - and on some cameras the anti-reflection coating
is easily scratched.
I thought some might like to hear of my experiences with LCD protectors.
My first camera was a Canon 10D, but I never gave the LCD a second's thought, as it was indestructible - banged about my bag for years without a single mark. The 10D's replacement, an Epson R-D1, was a different kettle of fish: after only a week's ownership, the coating on the screen was scuffed from rubbing against my clothing! I quickly bought a screen protector...
I now use screen protectors as a matter of course - an LCD may be made of toughened glass with a hard, scratch-proof coating ... or it might not, and scuffed screens are at best unsightly.
A myriad screen protectors are available. Most are thin plastic films, but I've never had much luck with these - I tried several well-known brands such as Invisible Shield, and all reduced the clarity of the screen, and several started to peel off after catching on things in my bag.
When I got my Leica M8 in the summer of 2007, one of the first things I intended to do was fit a screen protector - the M8's LCD may or may not be tough, but I didn't want to discover the hard way!
I came across the Giottos Aegis - a screen protector made of multicoated Schott glass: its listed specifications made it far superior to flexible plastic films. I decided to give it a try, and ordered model SP 8250. Not cheap - I think it cost about £30. It was indeed a huge improvement on the plastic film protectors: it was crystal-clear, and has remained firmly attached for the past two years. Apart from the price, I have a few minor niggles: (1) too much unnecessary "in-your-face" white labelling; (2) the black border is slightly smaller than the LCD, obscuring about 1 mm from around the edges of the image area; (3) the corners of the protector aren't as rounded as the M8's LCD, and thus overhang the LCD by a fraction; (4) I heard that the glue is strong enough to lift out the LCD cover if care is not taken when removing the Giottos protector, and the removal instructions not followed precisely.
Good as the Giottos Aegis is, it has suffered - mainly when I went on a trip to climb volcanoes: volcanic ash is not kind to cameras, and the Giottos now has fine scratches all over it (as has the UV filter protecting the lens!): if I hadn't used the Giottos Aegis, I hate to think what the M8's screen would look like!

Recently, a corner of the Giottos Aegis has snapped off - a result of point 3 above (the corners overhanging the M8 LCD): as the LCD is slightly raised, I thought that, sooner or later, something would get under the an overhanging corner and damage the Giottos's glass, but two years isn't a bad innings.
So, it was time to replace the screen protector. I quick web search tuned up an alternative toughened glass protector to the Giottos Aegis: the GGS screen protector. It seems to garner good reviews, and compared to the Giottos Aegis, has a specification that's at least equal, and is a fifth of the price. Loads on eBay - that was the other problem with the Giottos Aegis: it was hard to get, and I had to order it from America, so shipping made an expensive product even more costly. Leica's sapphire glass cover is the perfect protection, but the £1500 that Leica wants for it is a little excessive - that's half the price of the camera!
Here's a review I found on the web:
GGS DC Professional LCD Screen Protector review.
I bought a GGS protector.
Before fitting it, though, I had to remove the Giottos Aegis, bearing in mind point 4 above. I followed the instructions for removing the Giottos protector, taking care not to lift it using much force. I also used dental floss to gently "saw" through the adhesive. The protector came off easily using this method, though it did leave a little adhesive behind, which I cleaned off with a bit of lighter fluid.
I'm pleased with the GSS protector so far: it is well made, is a more accurate fit than than the Giottos, and has much less irritating white lettering. With luck, it will protect the M8 as well as the Giottos...
