I have a situation where we have a website that is designed to be responsive (tablet, phone). Our business stakeholder discovered an issue when the site was zoomed out to 90%. His argument is that a responsive site should, by definition, respond at different zoom levels. I know this is not the case - site zooming and responsive design are not the same thing. But I do not know how to adequately explain this. Could someone help me? Thanks!
This will depend on your specific issue, but specific implementation issues are off topic here at UX.SE, so I will go with the usability part of your question.
In general, and barring some specific needs, your client is correct. Like you say:
site zooming and responsive design are not the same thing
basically because responsive design is a web design/development approach, while zoom is just a feature that might or might not be present in the massive set of tools, features, scripts and assets that a responsive approach may include.
One of the most common things to do in responsive design is to use something like this:
<meta name="viewport" content="width=device-width,initial-scale=1.0, maximum-scale=1, user-scalable=no" />
This code will disable zoom, and it's something you should avoid. You're negating locus of control to user.
However, you say that the user can zoom, so the specific problem might be very different. However, responsive design means the design has to be responsive by definition (just like your client says), so you'll need to take the proper measures to provide the solution to any issue you might have. Again, it seems to be an implementation issue, so it will depend on the issue itself
- 4 reasons not to disable zoom in your responsive design
- Should users be able to zoom in a responsive webdesign?
- Zoom for fixed and responsive sites (this one deals more with the implementation side so you might want to take a look)