Surely more than one you will come the need to make a photo slideshow with fades between them and move in After Effects, Memories on TV and such like. While this is not software that is designed exactly for this purpose (primarily by the lack of real time) and there are other software with which to do this much more easily, it is true that once accustomed to a program is very difficult to leave him to do something so simple.
More than a tutorial, this is the explanation of a technique that I can be of use when creating these slideshows easy in After Effects without creating not a single keyframe.
The technique involves creating a series of zero, each with a basic motion: zoom in, zoom out, panning left, panning right ... all with a constant speed then we will provide a basis to encourage the photos.
Null 1.Animar expressions
ENCOURAGE POSITION.
This is done with a simple expression applied to the parameter you want to animate:
t = time * 10;
x = value [0] + t;
y = 288;
[X, y]
Let us explain these variables to better understand what we are
t regulates the speed.
coordinate x is moving in the layer.
and is the coordinate in which no moves and can be located at any point, in this case is in the center of a composite PAL (576 / 2 = 288)
This expression applied to the position, would a constant movement to the right. We scale the velocity by raising the multiplier time (* 10, * 15, * 30 etc), if the value is negative, reverse the direction.
ENCOURAGE SCALE.
This same expression with few changes we can apply the scale and thus get no increases in size constantly, or what might be called zoom in, applied to a photo.
This would use the following expression for the parameter scale of zero:
t = time * 10;
x = value [0] + t;
y = value [0] + t;
[X, y]
Equating the parameters x, and we manage to scale proportionally. Subtracting the value t instead of adding it, which will be a zoom out.
In fact we will only have to configure these zero once, because this scheme will help us over and over again in our next compositions. Also you can download the sample composition of the end of this post where they are located and expressions.
Once this is completed we have a layered structure like this:
It is appropriate to rename correctly null then link them to the layers we want to animate. To be effective nulls must also be present along the entire length of the composition.
2.Añadir and link images to zero
Once done you can add pictures to our membership. We give all the same length (this is optional) and we offset each other so that it is something like this: 
Now we link the photo to a zero depending on the type of movement we want to give (zoom, pan ...). We will do this by dragging the tool to link the corresponding zero.
, sin parones ni acelerones, velocidad que también podemos variar a nuestro gusto tocando el valor multiplicador de la expresón que ya vimos antes. Once done with all the pictures, only have to adjust the position and scale we like in each case, without adding any key frame and all go at a constant speed without stoppages or accelerations, speed that we can vary our like playing expresón multiplier value that we saw earlier.
3.Añadir crossfades automatically to images
To finish our slideshow, add fades only required for each layer. Instead of manually animate opacity keyframes can opt to use one of many animation presets that offers After Effets.
I go into the Effects & Presets window / Behaviours / fade in + out frames.
When we automatically apply a fade-in and an output at the beginning and end of the layer with the length of frames that we indicate in the effect window. Moreover, by lengthening or shortening the layer, the melt will automatically adjust to the new position.
Here you can see a video of how would the composition. You can see the contours of zero (red squares) that are associated with images.
Slideshow Without After Effects keyframes from efectohd on Vimeo .
