Solar Filter Buying Guide
In 2017, interest in solar photography reached a fever pitch when the Great American Solar Eclipse made its way across the United States.
As epic an event that was, solar eclipses are actually fairly common. In fact, the next total solar eclipse in the U.S. is just a few years away in 2024.
But you don't have to wait for an eclipse to photograph the sun...
In fact, the sun is a fantastic subject for photography, provided that you have the right kind of solar filter to protect your delicate camera gear.
Here are a few critical questions to ask when buying a solar filter for your camera.
What Material is Best for Solar Filters?
There are two common types of materials used to make solar filters - glass and polymer.
Of the two, glass filters offer better quality because the clarity of glass is significantly better.
This is an important point because when viewing a glass filter and a polymer filter with your eyes, you will only be able to tell a slight difference between the two.
As an example, the Helios Solar Glass® Threaded Camera Filter shown above boasts high-resolution, reflective coated Helios Solar Glass® with a filter rating of ND5.
That means that the filter blocks 99.999 percent of the sun's rays, making it safe for you to take photos of the sun.
When shopping for a good solar filter, a glass filter (the thinner the glass, the better) that's ND 4.8 or higher should be your top choice.
Should I Buy a Threaded or Slip-On Solar Filter?
The manner in which the solar filter mounts to your lens is really a matter of personal preference.
For some photographers, a threaded mount is preferred if for no other reason than the friction required to mount the filter ensures a tight fit.
However, slip-on solar filters are easier to remove, and though some photographers worry that they don't offer as much protection against light leaks, this is simply not the case.
Light travels in a straight line - just like sound - so it can't turn the corner around the filter, and then again turn the corner into the lens.
As a result, the type of solar filter you choose - threaded or slip-on - comes down to personal preference as either type can get you awesome results like the image above.
How Can I Tell if a Solar Filter is of Poor Quality?
Investing in a solar filter means looking for a filter that's built to high-quality standards.
Often, finding that kind of filter also means understanding what constitutes a poorly build filter.
In this case, the primary indication of a poor solar filter isn't necessarily the housing in which it's mounted, but is instead the filtering substrate.
That is, if the material used to create the filter is subpar it will be easily scratched, experience flaking, or have pinholes in it, all of which can allow too much light into your camera, thus potentially damaging it.
If you look at a filter and see any of these aberrations on its surface, you know that it isn't worth the expense or the potential damage to your eyes!
Instead, filters like the Helios Solar Glass® Threaded Camera Filter I mentioned earlier provide the type of high-quality construction you should demand.
These filters are built using a process that ensures good adhesion of the thin metal film coating to the filter glass, which protects against excessive scratching.
What's more, though pinholes can occur in the manufacturing process, Seymour Solar filters have a strict quality control. You might have one or two, but not usually. The acceptable threshold for pinholes is 20 per aperture inch, which produces no ill-effects for your solar photography. Pinholes are even easy to cover up - just use a permanent marker!
Using a quality filter like this ensures that you get the best possible images of the sun.
Are Solar Filters Durable?
The short answer is no, not all solar filters are durable.
That's because cheap solar filters are poorly made, so with time, they will deteriorate and you'll find yourself having to buy a new filter.
However, well-built filters can last a lifetime, provided that you take care of them.
Proper cleaning is a must, so regardless of the type or brand of filter you buy, be sure to consult the cleaning directions provided with your filter to ensure a long life.
Proper storage of your solar filter is also a must - remove it from your lens and keep it in its carrying case when not in use to protect against scratches and other damage.
By sticking to these solar filter buying guidelines, you'll be able to find the right solar filter for you.
