Austin is right.
“50X” or any other “x” number is basically just a marketing gimmick for one camera manufacturer to say, “Our camera has more zoom than yours.” In fact, it might have less zoom, depending on how they wiggle the numbers. I was positive I had written on this topic before, but I can’t seem to find it. I did find a post about where I commented about it on the NF Google+ page, so I’ll link to it for further information: https://plus.google.com/109808589691632341353/posts/RuuctZ4yJ9k
Does anyone know how to approximately calculate the ratio between these two for comparison purposes?
To answer your question though, the answer is to compare “full-frame equivalent” mm measurements. So while your superzoom says 30X in big bold letters on it, it should also say something like “10mm-300mm equivalent”. Take those numbers and compare them with your DSLR lens, and you’ll get the info you need. Remember that if you’re working with a crop-sensor DSLR that you have to take that into account. So a 300mm lens on a crop sensor Canon camera will be 480mm “full-frame equivalent”.
Feel free to ask more questions if you’re still not sure what we’re talking about. 🙂
See here for some additional reading on crop sensor vs. full frame:
https://www.lenspiration.com/forums/topic/question-ef-vs-the-ef-s-lens-mount/
https://www.lenspiration.com/forums/topic/full-frame-lens-on-crop-sensor-camera/
https://www.lenspiration.com/forums/topic/smartphone-camera-vs-dslr/#post-16538