Sure enough, the ProX2 does not require the user to keep pictures on the cloud or use the vendor's app, you can retrieve your pictures directly from the card. Now I like the gadget.
Perhaps I'm a little pessimistic, but I've already seen targeted ads scrolling across the bottom of applications that I paid money for. Then there are the apps that suddenly won't work without access to the web, again, even after you've paid actual money for the app. Lastly, and probably first of all, there's the entire loss of privacy. While it seems that nobody is bothered by the aspect of allowing unknown individuals or government agencies to thumb through your family album, perhaps the scenario of a photographer losing rights to a creation because the fine print in the frequently ignored EULA states that all submissions become the property of the software developer is more frightening.
The X2 line of cards is probably the easiest way to limit questions about security and shooting performance. The ProX2 adds a few more features that the Mobi does not have. First take note that these cards are 2.4GHz devices, so they will not work if you have disabled 802.11G on your 802.11N router! On the plus side, the X2 will work as an N class wifi device on 2.4GHz.
Another point to consider is that the ProX2 does not use a 10 digit activation code. Also, for Mobi users, I don't think the activation code is a security risk, it's 'just' a card activation. Your wifi network will continue to use standard password lengths and that password will also need to be set inside the card during it's setup.
The ProX2 has the ability to connect to AdHoc networks, which means it can directly connect to a laptop without needing a router to act as a middle-man. This will be more useful to serious photographers. The range is up to 20 feet, so a laptop can be parked in a gearbag and does not need to remain slung on your shoulder to perform uploads.
The ProX2 has the ability to auto-delete files on card, when the card gets full. This is turned off by default. You can choose to set this anywhere between 10 & 90%
You can have more than one camera shooting in field, linking to a laptop.
On the downside, the cards have issues being reported by other blog sites. So I'm not sure about serious work using this. Besides, the ProX2 is a class 6 card and I can't go backwards from using my class 10 cards!
Good questions. The EyeFi cards are rated at class 10, but that's only rating at how fast the camera can write an image to the card while shooting. The WiFi connection will also have an upper speed limit depending on what sort of chip-set is inside the card. I see a few comments on here about using the EyeFi at conventions for news reporting. I would think that there is always occaision to photograph new products in RAW because you don't want to risk not capturing all the detail when evaluating product design. I suspect that the EyeFi is acting as an 'access point', which could mean that it's broadcasting it's WiFi ID for anyone to attempt connecting to. I think it would be nice to perform a more technical evaluation of this card.
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