Microsoft is offering 30GB of OneDrive space for free, as it makes a major play to snap up those storing photos in the cloud.

Pitching the limited offer directly at iPhone owners, Microsoft says on the OneDrive blog: "For those getting ready to install iOS 8, this means you won’t have to delete a bunch of photos or apps to make room for the upgrade." 

This is a limited offer, as you'll have to install the app and turn on photo auto uploads to qualify for the free space, before the end of September.

OneDrive normally offers 15GB of free storage (doubled in June 2014 from 7.5GB) and it's not just users of OneDrive for iOS who get the benefit - those using the Windows Phone app, Android app, or the plain old Windows app, will also get the storage bump. Those who enable the auto-upload feature will find that their account has a 15GB camera roll bonus added. 

We've done it, bumping our own OneDrive storage to 40GB and you can find a breakdown of your OneDrive storage online under options on the OneDrive website. 

As a quick comparison, Dropbox currently only offers 2GB of free space, Box offers 10GB. Apple's iCloud Drive offers 5GB of storage, Google Drive starts with 15GB of cloud storage. 

Microsoft's aims appear to be somewhat philanthropic, moving quickly to make the offer, saying "While it might seem strange to announce new features on a Friday evening, we've been listening to the commentary about storage on the new iPhones released today [Friday 19 September] and we wanted to get you more storage right away."