I am going to be driving to remote Wyoming to capture this solar eclipse. I have a Canon T3i, and a LG G6. My goal is to record diamond ring to diamond ring, and click a few pictures in between, while taking a few 360 photos from my LG G6.
Would recording the eclipse from diamond ring to diamond ring damage the T3i? I can use my polarize lens filter if I need to.
To photograph the diamond ring without risking damage to your camera (and your eyes as well if you look through the viewfinder) you need a proper solar filter. (A number 14 or darker welder's glass is an acceptable solar filter because welder's glass must also filter UV and IR as well as visible light).
Without one you will likely not be able to get a usable image, even if it does not damage your camera. At your camera's lowest exposure value of ISO 100, 1/4000 second and f/22 or f/32 (depending on your lens) the 'diamond' will still be far too bright for your camera to record it without blowing it out in a huge blob of white glare.
If you are using a very wide angle of view, it probably won't hurt the camera, but you'll still just get a blob of white light several times the actual size of the sun.
Since under no circumstances should you look directly at the sun through your camera's viewfinder without a proper solar filter in place, you're caught between a rock and a hard place.
If you use Live View you can see what you are shooting, but the sensor is constantly being exposed to the sun's UV and IR radiation as well as the visible light.
On the other hand, if you shoot 'blind' by aiming the camera using LV and then shooting from viewfinder mode (without looking through the viewfinder!!!) there will be a significant amount of the sun's energy reflected up through your camera's viewscreen, pentamirror, and eyepiece. The heat could affect things such as the adhesives that hold the five pieces of your pentamirror together. That's not the worst of it, though. Some of it will go through the 60/40 primary mirror, bounce off the secondary mirror, and be directed through microlenses into your camera's Phase Detection Autofocus Array. Even if you have AF turned off, the light will still be reflected into the PDAF sensor by the secondary mirror. So if you use viewfinder mode to prevent damaging your image sensor, you may just melt the microlenses or fry the AF sensor instead!
You will definitely not ruin your camera during totality even if you don't use a filter.
The diamond ring is more dangerous specially if you start too early before the first diamond ring and end too late after the second one. You might want to check this question. Your lens is also an important factor. Of course a strong telescope is more dangerous than a simple zoom lens.
I've taken Diamond-ring (and Baily's beads) images using a SkyWatcher Maksutov-Cassegrain 102/1300 telescope without any problems (not Canon T3i but Pentax cameras). Of course I was using fast shutter speed (but why would you use a slow speed?).
Actually once I was stupid enough to take a direct photo of the Sun using the same telescope without my filter and the camera is still working correctly. Do NOT do that.
