What's the best way to take black and white images with a Sony Cyber-shot DSC-H70
it think the best way getting black/white images is to shot them in color (RAW if available) and make them b/w in your favorite postprocessing tool.
RAW would have the advantage, that you can gain more details from for example the sky or clouds.
It must quite surprising but the truth is that Sony skipped the B&W capture feature in many Digital cameras like DSC-H70, DSC W510, etc.
Some models with this feature are DSC-W80/W85/W90;
Even the in-camera editor won't allow you to apply B&W filter.
Obviously you are left with single but best option: Shoot in color and convert to B&W on post-production.