Multiple exposure on camera - 5DIII

[SabrinaMarthend]

Hi!

I have a question, hope somoene can help me!
(Also, I speak from Brazil, please forgive my english)

I want to make double exposures with my camera (5DMArkIII) using pictures that I already took last month. 
I put the pictures on my card, they all appear in my camera. So far so good.

But when I try to make the double exposures, I can only work with like half of them. The others are seen as "no compatible".

Why?

And how do I make them work?

PS: All of them are in RAW.

Somoene?

[Waddizzle]

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@SabrinaMarthend wrote:

Hi!

I have a question, hope somoene can help me!
(Also, I speak from Brazil, please forgive my english)

I want to make double exposures with my camera (5DMArkIII) using pictures that I already took last month. 
I put the pictures on my card, they all appear in my camera. So far so good.

But when I try to make the double exposures, I can only work with like half of them. The others are seen as "no compatible".

Why?

And how do I make them work?

PS: All of them are in RAW.

Somoene?

---

The files may need to be JPG format.  

It would be easier to do using a computer.  You will have better control over the process, too.

[kvbarkley]

Waddizle:

Actually they need to be in RAW, which surprised me, too.

Sabrina:

Read the manual, there are a *lot* of caveats: