Auction Web sites are increasing in popularity. That’s good news for photographers who want to sell old and outdated gear, and for photographers looking for a bargain on old and even new gear.

On all the auction sites, photography plays a key role in the sales pitch. If the photo of a product is sharp, the seller has a much better chance of making the sale than someone with the same product at the same price but with a poor-quality photo.

If you are interested in selling online, here are a few tips for taking images with effect:

Choose a plain background: You want your item to stand out in your picture. One way to do that is to choose a plain background in your home such as a carpet or table top. If you don’t have a plain background, create one by having someone hold (or place) a white sheet or piece of material behind the item. To make your item stand out even more, choose a background color that your item does not blend into.

Shoot for sharp pictures: When it comes to online photos, the sharper the better. Make sure you focus is on your item. If your camera lets you control depth-of-field, select an aperture that lets you get your entire item in focus.

Fill the frame: The larger your item is in the frame, the better it will look on the auction site. If you can’t get close enough to the item, crop it with your digital imaging program. If you are going to sell a lot of small items, you might want to consider getting a macro lens, a set of screw-on macro lenses or a camera with a macro lens all of which you can find on auction sites.

Think about lighting: Bright light usually makes items look better. If it’s too dark in your house to take a natural light picture, use a flash. Another option is to photograph your item outdoors on a sunny day.

Send small JPEG files: Auction sites post relatively small pictures, so there is no need to send a large file. Submit a 5×7 JPEG file at 100 DPI and your picture will look good on the site (if you have a good picture to start with).

A word about digital enhancements: If you have a digital-imaging program, blur the background to make your item stand out even more. However, don’t use it to make your item look better than it is.

If you are interested in selling online, check these online auction Web sites, all of which begin with the “www.” prefix: amazon.com (go to Sell Your Stuff), ebay.com, half.com, ubid.com and yahoo.com (go to Auctions).