We can use computer to transfer the photos taken by DSLR camera to our iPad. But if you need a quick way to do this, the CF and SD card readers should be more suitable for you.
these are two practical CF and SD card readers designed for original iPad and iPad 2. As we can see from the images, no matter the CF card reader or the SD card reader, in addition to the memory card slot, each card reader also comes with a USB port in order that you can directly connect your DSLR camera with iPad or iPad 2 via the card reader, you even can insert a USB flash drive holding your photos into the card reader. Once your iPad detects the photos from the external card reader, the photo app will automatically open, letting you upload files in one step. Apart from that, the portable design allows you to take it anywhere.
The CF card reader is priced at $30 USD, while the SD card reader costs $15 USD. Both readers will set you back $40 USD. If you’re interested, jump to Photojojo official site for more details.