Q - How can I light close-ups of coins and jewelry when I want to shoot straight down on them to avoid distortion?
Q - This is a very real problem because for best effect you need both a sidelight to highlight the relief and detail and a reflecting surface to lighten up the shiny metal face of the coin.
The solution is a piece of clean glass at an angle of 45 degrees between the lens and the coin and light off to the side 50 that it highlights the detail and part of the light bounces off the glass onto the metal.
You will have to adjust the angle of the light and the tilt of the glass for best effect. You can judge the ratio of highlight to reflected light by looking through the camera.
Q - What lens and filter and what angle of view and time of day is best for photographing spider and web?
A - You will need a close-up lens, a bellows extension, or a close-up filter. The best bet is a macro lens that is automatic so that you can simply focus close-up through the lens and the change in exposure is made in the lens. A good focal length for macro work of this kind is from 55 mm to 105 mm. The longer focal length has the advantage of taking in the same size image with the camera farther back from your subject.
The best time of day to photograph the web is early in the morning when there are drops of dew on the net-work of the web.
In order to highlight the gossamer filaments, you have to find an angle of view from where the sunlight shines through and strikes the almost transparent web, or you won't be able to see it.
Besides catching the right angle of light on the web, you need a dark background for contrast. This can be had by moving your camera position so that a shadow area is in back or simply placing a black piece of card-board or cloth in the background.