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I have owned several Sony products over the years and whilst I find that they are mainly excellent products there is one thing that I find does let them down and that is their reliance on using their own memory sticks.
The Sony memory stick pro duo's are proprietary meaning that they can only be used in conjunction with Sony products which can be irritating when you have other products which also rely on using removable storage but use the much more common SD cards.
I have a few products that use SD cards and I can swap the cards between them no matter the manufacturer and in 2011 this is exactly what I want to be able to do instead of having to carry several different types of cards around with me.
The other thing that annoys me about the memory stick pro duo cards is that I can't actually use them in my memory card reader on my laptop and instead have to rely on using an adaptor with them to transfer my files over to my laptop.
Other than the annoyance with their lack of share ability the memory stick duo pro cards do a good job with actually storing my files and they do come in different storage sizes from 512MB (which in my opinion is too small to be of any use to anyone) up to 32GB which will store literally hundreds of pictures and videos on your camera.
Obviously the larger the storage on the card the more expensive it is going to be. One of the reasons that I presume Sony still insist on using their own cards is that not only do they retain the profits from them but they can also charge what they want for them and they aren't cheap. You can buy a 16GB SD card for just over £10 whereas a Sony memory stick pro duo 16GB card will cost you in the region of £30 to £35 which is frankly ridiculous.
The Sony card I use is only 8GB as it was relatively inexpensive to purchase and it holds a surprising amount of data on it. For around £20 it will hold over a thousand 12MP photos and I have had several relatively long HD videos on it with no problems. The MK2 memory stick that I have comes with an adaptor which holds the card and turns it in to a USB stick for easy file transfer. To give Sony credit the memory stick pro duo is a high quality memory card and I have never had any problems with it.
The files transfer easily and quite quickly from the card to my laptop and I do find that it is quicker than my SD cards at transferring files on to my laptop.
The pro duo cards are tiny and designed for use with small items like cameras and camcorders and this does make them quite fiddly to use and easy to misplace.
If not for the fact that I can't use my memory stick pro duo MK2 card with anything other than my Sony camera then I would be giving the card a 5 star rating but because it is so specific to Sony products and can't be shared with my other gadgets that require flash memory then I think the card only deserves 3 stars. It's good but unless you are a complete Sony fan boy it only has a certain amount of usability to it.
I bought this 8GB Sony Memory Stick Pro Duo Mark 2 to use with a Sony Cybershot DSC-TX1. The product comes with the storage device (to fit into the current range of Cybershot cameras being produced) and also with an adapter to convert the Pro Duo into a 'Memory Stick Pro' (which was used a few years back with older Cybershot models).
The Storage Device:
The storage device clicks in to the slot in the camera like most memory cards do these days. It certainly holds a lot of data (well over 1500 10.2MP Digital Photos when the camera is at its highest setting, and over 9999 when you start decreasing the quality of the photos you are taking). It is also capable of recording 720p HD video at 9Mbps - you can capture well over 90 minutes of video with it [see below for an issue though]. Some older memory cards are not capable of recording HD video because the rate at which data is produced is not as fast as data is recorded onto the memory card. The Mark2 indicates this faster data transfer rate. [To put these data transfer rates into perspective, 9Mbps is faster than many people's broadband connections, which are often sold at 'up to 8Mbps']
There is one issue with the card, however, that I believe will affect any Memory Stick which has a size of 8GB or greater (4GB cards are not affected by this). Due to the way files are stored on the Memory Stick, the maximum file size is 4GB. Because of this, if you try and store a file larger than 4GB (which will only be a 45+ minute long video at top quality) it is likely that there will be some error with the file. The solution is to stop recording and restart again - the stick can hold 2 4GB files but not a single 8GB file. In addition, a message appears on my Cyber-shot telling me this. Perhaps it is a slight inconvenience that every time I want to take a photo or shoot a video a message will appear on screen that means I have to clear it by pressing the shutter down slightly or touching the screen. A 4GB Memory Stick will not have is problem (so it is up to you whether to buy 2x4GB or one 8GB and live with the annoying message). In either case you will not be able to have a video file larger than 4GB.
The advantages of having an 8GB stick is that I have not yet had to remove photos or video from the stick (after 8 months I've taken over 1500 photos and still have plenty of space left) - you can go on a holiday for probably a month and take photos on the camera's highest setting, without having to worry about changing memory card or moving the photos onto disk/computer (in fact, a DVD only holds ~4.7GB compared to the 8GB on the Memory Stick).
I have also found the adapter to be very useful. The adapter allows me to use the memory stick with a card reader on my Dell Laptop, as well as the card reader on my (old version of the) Playstation 3. The reader on my Dell Laptop allows me to quickly and easily copy my photos I have taken onto my hard disk, however it only accepts Memory Stick Pro cards (hence the adapter is required). Similarly, my Playstation 3 only accepts Memory Stick Pro cards so the adapter is required to convert the Pro Duo into the Pro. I can then watch the photos and videos I have taken with my camera on both devices. In addition, I can back up data on my PS3 onto the Memory Stick, as well as transfer my own video onto the Memory Stick from my laptop and play them back on my PS3 and through my Television (compared to my monitor).
It is possible to transfer photos between my laptop and camera via the cable supplied with the camera, however that does require finding the cable (often they are tailored directly for use with that camera only, so a generic USB cable may not work).
Small issue has been that some photos and videos have been corrupted, but I believe that is due to my camera rather than the Memory Stick.
Overall, this 8GB Memory Stick Pro Duo Mark 2 has an insane amount of storage and can be used for a multitude of purposes, but perhaps it is too large for its own good as its size causes an inconvenient message to appear on the screen of my camera every time I turn it on. For that reason I only give it 4 stars.