I've been using the free version of Macrium Reflect for a couple years now.  It's pretty easy to set up & use, and it's been flawless so far in creating "useable" disk or partition images that can be used to restore from if need be.
 
https://www.macrium.com/reflectfree
 
 
 

bdary
I've been using the free version of Macrium Reflect for a couple years now.  It's pretty easy to set up & use, and it's been flawless so far in creating "useable" disk or partition images that can be used to restore from if need be.
 
https://www.macrium.com/reflectfree

 
Would definitely recommend, can't beat it for free. That said it's deceptively powerful and will have a slight learning curve with understanding how to get it to do exactly what you want it to do. I had some... interesting... results the first couple times I used it to clone disk images. The automated backup service is extremely nice. 

I use EaseUS as the free version has incremental backup which I personally prefer over differential.

I prefer AOMEI Backupper Standard. it's a magic freeware which help me solve many problems concerned to backup and restore. with it, you just a few click, you can finish whatever operation you want. 
hope it works for you