Lens correction filter

Step 1

Open an affected image and choose Filter: Distort: Lens Correction Figure 1 shows the filter’s dialogue box. Notice the grid that assists us in lining things up.

Step 2

The first job is to straighten the image. It's impossible to fix all the other angles if the image is not straight first.
Choose the straighten tool for the left side of the dialogue box as shown in Figure 2.
Click-&-drag across the image to define the new horizon, Try to follow a horizontal line in the image if there is one

Step 3

The image suffers from keystoning – it's narrower at the bottom than the top – so we'll adjusting the Vertical Perspective to make the top and bottom the same width.
Adjusting the Horizontal perspective appears to rotate the image through 3D space. What's really happening is that we're making one side narrower than the other to combat perspective problems. You can also change the Angle to counter a diagonal distortion Figure 3 shows the perspective repaired.

Step 4

Notice how the image appears to bulge. Move the Remove Distortion slider to the left to 'bulge out' and move to the right to 'pinch in'. This also works by choosing the Remove Distortion tool, which is the topmost tool icon on the left of the Lens Correction window. Once the tool is selected you can drag in the image, although I find that the sliders give you more control.
After adjusting the distortion, you may need to go back and again tweak the perspective. The Vertical Perspective has been readjusted to compensate. (see Figure 4).

Step 5

Finally, choose an edge option:
Transparency: Produces transparent pixels outside of the distorted rectangle
Background Color: Fill the empty pixels with the current background colour
Edge Extension: Stretches edge pixels to fill the background (see Figure 5).
Click OK to apply

Step 6
The before-&-after Figure 6 shows the power of the Lens Correction filter. To finish off the effect, crop the image to suit your needs. As you can see this really is a great tool for fixing distorted images

Screw heads

Step 1
Make a circular selection.
Tip: Hold down Alt/Option to draw from the center. Hold down Shift to draw a perfect circle. To move the selection while drawing, hold the spacebar.

Step 2
Select the gradient tool. black to white circular gradient. Make sure you check the reverse box on the top bar.

Step 3
draw the gradient starting from the center and you should have something like this.

Step 4
Now how about the slot?
Make a new layer. Draw a long rectangle and fill with dark gray.
To trim the slot: Ctrl/Cmd click on the layer 1 thumbnail to select it. With the top layer active hit Ctrl/Cmd+Shift+I to invert the selection. Press the delete key. Now you should have a nicely trimmed slot.

Step5
To make the slot look recessed:
Add a layer style to the slot. Hit the little "f" at the bottom of the layers pallette. Use inner shadow wih the default settings except for the size, move that up a little bit for more realism.

Step6

We are done, but how often is the slot perfectly vertical? Press Ctrl/Cmd+T for free transform. Move your mouse on a corner until it turns into a curved arrow. Drag it around until you have a nice angled slot.

Final