No sin at all, in my opinion–except perhaps waiting too long to put them on, and possibly not seeing someone in the glare of the sun.
In general, a second or two of distraction is not generally going to allow an accident. Where speed is a factor, highways are usually limited access, which limits what can happen in a second. I would say that you were not seriously distracted, any more than you would be by someone speaking in the car, or a radio going with a good song or news item, or any of several other possibilities. (Such as even checking the rear view mirror to see what is happening behind you, which means you cannot simultaneously attend fully to what is in front of you, and also what is going on to either side!) Part of being a driver is knowing when total attention is demanded, and when you can monitor what is happening without absolute attention at every instant.