Under where the three M1.7x5.5mm Phillips #000 screws were, you will notice figure eight-shaped washers.

Use a pair of tweezers to remove the washers.

Caution: Keep very careful track of where each washer was removed from. Some washers may contain a stack of two washers. Each washer is a different thickness (down to 0.01mm) and reinstalling them in the wrong spot will result in out of focus images.

You may want to use a digital caliper to measure each washer as you remove them, and record down the washer's thickness and which spot you removed it from.