This has been a nice discussion about the durability of glass, but I have to wonder: what's the difference between the glass used for a touch screen and the glass used for the ordinary LCD display on the back of every DSLR?
If it is the durability of the glass that's an issue, how would it be any different if a touch screen is implemented versus the traditional display?
Good point. I am also wondering about the durability of the capacitive touch capability. I had a Samsung Impact phone (admittedly not a top of the line model!)--after about 3 years, the touch screen failed. Not cracked or "damaged" mind you--it just stopped responding to touch, making the phone useless. I've since replaced it with a Samsung S4 Mini which, being a miniaturised version of their top of the line phone, ought to have equivalent durability to the S4, so we'll see how long that lasts. However, many users (most?) tend to replace phones far more quickly than I do, (some more often than they change their underwear, it seems! ) so the long term longevity of the touch screen may be less of an 'issue' in a phone.
I'm speculating wildly here, but if there is a fairly short life span for the touch sensitivity of such screens in real world scenarios, that might be why Canon is willing to put it into consumer products like the T4i/T5i or even enthusiast products such as the 70D, but shy away from it for a "Pro" type body.
Can anyone confirm or refute this hypothesis? I confess that's all it is--I have no data to either back it up or contradict it.
Both of you brought up a good point - me too: to much focusing on the glass ...
I know that two touchscreen technologies are wide spread:
- Capacitive tracking (works with fingers, small tomatoes, water filled ballons ...)
- Inductive tracking (works with specialized pencils - WACOM is a well known company)
For capacitive touch screens I have only 3 years experience and the mobile phone has survived moderately hard treatment during thes three years.
For inductive technology I am using a 10 year old IBM/Lenovo X41 tablet/convertible - the precision including the pressure sensitivity of the pencil is very very good. Last adjustment made 4 years ago.
But I see no reason that a capacitive touch screen will not survive 10 or 20 years if properly set up. My first thought was that the layers which are able to detect capacity changes by the fingers might underlie some aging. But I think these are made from the same materials like the flat screen displays and these last 10 or perhaps 10ths of years.
Another idea is now emerging: Ever tried to use your capacitive touch screen during rain? On my (Motorola DEFY) smart phone I see strange effects when it is covered with several rain drops. This is a inherent problem of capicitive touch screen technology: A matrix of electrical condensators senses changes of surrounding material. This is done by the effect that material between/near a condensator plate changes it's capacity.
Why water? Our fingers contain a lot of water but many other materials like plastics, leather, jeans, etc. do not contain water. So they designed the electronics and the capacitor matrix to be sensitive to water. That's the reason for listing the small tomato as "tool" to operate a capacitive touch screen. I tried that because I wanted to know how touch screens operate - "What special material is in our fingers?-Water. What water filled object is availabl?-Tomato."
The guys at Canon maybe thought: We have designed a DSLR for harsh environments where water might play a role. It is contradictory to have controls which operate depending on the environmental condions where these controls might be used.
I think that we all mutate to amateur profilers which try to find out how another person thinks to guess it's next steps ... funny thing!