Occasionally the subject you are focused on isn’t all “in focus!”
A very expensive "Tilt/Shift" lens allows you to correct perspective and keep the entire image in focus. The focus problem is a common issue with macro and closeup photography, whether you are shooting plates of food for a restaurant menu or items for sale. Info about Tilt-Shift Lenses from wiki
It’s best to use a tripod to capture the images you'll need. Take care to focus (use Focus magnification if your camera supports the function) and take as many images carefully focusing each shot. In this example I shot 4 photos. You might need more... don't move the camera, use flexible or moveable spot focus.
Import the images into Lightroom --- The procedure is:
In Photoshop you can toggle the Layers Panel on and off by pressing the (F7) key. With Layers panel "on" select all the layers
Make sure all the layers are highlighted (light grey), hold down the shift key or the Command key (Mac) or Control key (PC) and contiguously select each layer.
2. Now Choose the Photoshop Menu:
Edit > Auto-Align Layers
Photoshop will align each layer so all the images are aligned.
3. With layers still selected choose
Photoshop Menu: Edit > Auto Blend Layers…
You get the Auto-Blend Layers Dialogue box...
4. Choose ◉ “Stack Images” and experiment with choosing
5. √ Seamless Tones and Colors
6. √ Content aware fill transparent areas
Click okay and you'll see the new "all in focus image" at the top of the "layer stack", remember Photoshop only displays the "top" layer!
To send the finished image back to Lightroom Use the Photoshop Menu: > File > Save
Back in Lightroom you'll see your new image...