A Close Up is a common C-Click Reaction which generally occurs when pressing C when the character is idle. It is when the character comes up close to the screen. Close ups are used on almost every Tamagotchi since the Tamagotchi Plus. It is a more detailed resolution of the character.
A close up is an animation which consists of two frames. The animation is created by making the two frames switch between each other and repeat three or four times. For the second frame, a sound effect is heard, although this does not apply to all versions.
First the character is zoomed halfway up (consisting of two different frames which are seen twice, before and after the main animation) before coming right up to the screen, and going back to halfway before going back to normal.
Tamagotchi Plus and Connection V1, V2, and V3
Close-ups are a random animation that happen occasionally through the day, when the Tamagotchi does not need immediate care and hasn't been touched. It occurs solely with the basic adult characters, and excludes Ojitchi, Otokitchi and Oyajitchi. The animation ends if the user presses any button, or if the Tamagotchi calls for attention.
Keitai and Akai
Close-ups can happen when the character is a teen or older (but not a senior) and is one of three animations that can occur when the C button is pressed on the idle screen. From this version onward, the animation is now twice its original speed, and includes a sound effect.
Entama and Uratama
The function is similar to the Keitai, although the close up is the only animation triggered through pressing C when the character is idle, and seniors now have close-ups. Nikatchi has two new close up frames.
Connection V4 and V4.5
Close up sequences discreetly mimic those of the Entama, although they are slightly different as there will be no sound effects and when C is first pressed, the character will appear at the top of the screen briefly rather than the middle before coming halfway up close.
Famitama and Royal Famitama
Two different types of close up feature on the family pets. The first occurs when the bonding is between 200 and 299 points (20%) where the oldest character comes up close to the screen. This is similar to the Entama and Keitai, although the sound effect is heard on the first frame. The second is when the family's bonding is between 800 and 999 points (80-100%) and all characters come up close to the screen. The frames are only seen once for each character going from middle to left to right and back to middle, and only the oldest sibling is shown in full.
Connection V5 and V5C
Because they are the English counterparts to the Famitama and Royal Famitama, the V5 and V5C's close ups are the same as that of the Japanese versions.
Connection V6, V7, V8 and V9
The animations are repeated four times as opposed to three and has a different sound effect. The V6 has this as the only C Click reaction from teen stage onwards, while the V7 has it happen from baby stage onwards as the only C Click reaction. On the V8 and V9 close ups occur from baby stage onwards but are one of three (four in V9) C Click reactions.
Tamagotchi Plus Color, iD, iD L, P's
The close ups reuse the previous sound effect and can be one of three C Click reactions. They happen from baby stage onwards. On the iD L and P's the animation is different. Instead of zooming halfway up close, the character becomes enlarged while still at the bottom of the screen before going into the middle, with sparkles around it.
Tamagotchi 4U and 4U+
The close up in these versions is similar to the iD L and P's, although the animation is even faster and a different sound effect is heard, and only once. The character will also walk across the floor and then the ceiling before the actual animation happens.
Hanerutchi 1 and 2
None of the characters come up close in the Hanerutchi 1.
In the Hanerutchi 2, the halfway close up is an enlargement of the character's sprite and the actual animation features the skit character from Haneru No Tobira that the Hanerutchi character is based on. The animation may include special effects, such as speech or multiple characters.
A list of character close-ups can be found here.
Gogobuchou also has a close up animation, even though he isn't an obtainable character.