Waterproof vs. Weatherproof
All the nylon fabrics we use on our products have a .50 or .75 oz. waterproof ureathane coating on the back side. The problem with any sewn product is that the needle holes from the sewing machine instantly cause the waterproof fabric to become vunerable to moisture. Because of this, we don't really decalare our products as waterproof, rather weatherproof. In a light snowfall or drissle or quick down-pour our cases w/o an additional raincover are fine, but for extended time in such weather we recommend extra protection. In the apparel industry, mountaineering parkas or sailing foul-weather gear is usually seam taped which renders the clothing waterproof or in the case with GoreTex® products they are “waterproof / breathable.” The practice of seam taping is not commonly used in the making of packs or bags. There are too many seams and webbing intrusions to make seam taping practical. We do not offer a “camera rain cover” for this very reason. Many on the market are not seam taped and are therefore not waterproof.

Why we do NOT make long lens rain covers…
We have had requests for shooting raincovers -- for use with a camera and lens, especially long telephoto lenses (300/2.8 and larger). At this point we don't offer any models. I have studied this topic and my current opinion is that to make an effective raincover it has to: One, have no seams (which is nearly impossible to design) or use factory seam taping and two, utilize a heavy “above average” urethane waterproof coating. The seam taping is a rather specialized process which with our small volume we can't justify. The heavy urethane coating would also make the product very stiff. TV cameras, such as those used in an outdoor stadium, use a heavy vinyl fabric instead of lighter, more supple nylon. It is waterproof, but is not very portable which is something still shooters need. Visit this link (link coming) for a listing of manufacturers that make long lens case rain covers.