Reading Camera Data

I would like to use the arduino with a sd reader to read out a sd card that is still in a digital camera

Any body who tried that?

Does the camera act as a USB mass storage device when connected to a USB host? If so a USB Host shield might allow the Arduino to read the camera contents without taking the SD card out of the camera.

What are you trying to accomplish?

I have a arduino with a ethernet shield and the thing im trying to do is taking a photo with the camera (by powering the shutter button with the arduino) and then stream the photo that got stored on the sd card trough a web server like the example on the internet

I would like to use the arduino with a sd reader to read out a sd card that is still in a digital camera

If you said something about the camera in question, perhaps more meaningful answers could be provided.

At first glance, though, I'd say that it was very unlikely that the camera provides an easy to use way to read the SD card while it is still in the camera.

Its not about the camera I want to read the sdcard simultaneously by 2 devices

So the camera has an sd card and then I will wire the sd card to the arduino so 1 sd card 2 devices is is possible? (Like splitting the sd)

So the camera has an sd card and then I will wire the sd card to the arduino so 1 sd card 2 devices is is possible? (Like splitting the sd)

How do you propose to physically do this? Are you planning to solder wires to the SD card? After doing this, will it still fit in the camera?

I know you have a Sd to Microsd converter and you get a ribonwire so you can solder
http://www.dealextreme.com/p/sd-to-microsd-transflash-card-converter-module-27001

So it will fit but I dont know if it will work

Allowing any device, in this case an SD card, to be read by two machines requires that both machines know about it and make hardware provisions for it. That is allow the interface lines to enter a tri-state. In your case this is not possible because you have no way of modifying the cameras's circuitry.
If you want to hack into that module you can isolate the SD card with tri-state buffers from the camera and attach the arduino to it with tri-state buffers. But this is a tricky soldering job and would require a custom PCB.

And no way off syncing 2 sd cards or something like that?

I haven't a clue as to what that means.

Is there a way to sync 2 sd cards

Is there a way to sync 2 sd cards

Start writing some software to read both cards. Decide which file on each card is more up to date, and write that file to the other card.

Synchronising is not some low level function, it involves reading files and the meta data and deleting some files and copying files over. You still need independent access to both SD cards. So I don't understand why you think it is an option.