There are many types of filters. Digital camera owners need only three types (need dictated by things that cannot be “Fixed in Photoshop”).
- Graduated Neutral Density (discussed in this Exposure Lesson post)
- Regular Neutral Density (discussed in the Shutter Speed & Light Control post)
- Circular Polarizer (for digital, it must be Circular – that does not mean that its shape is round; it means as opposed to Linear)
- Filters come in sizes which depend on your lens
- You should not buy the cheapest filter.
- Any filter, even the best, is going to introduce some image quality degradation.
- Putting a cheap filter in front of a good lens is a bad idea.
- The better the filter, the better the final image quality.
The way to save money when purchasing filters is not to buy multiple copies of the same filter – one for each different sized lens. Instead, buy just one by doing the following –
- Determine which of your lenses uses the largest filter size
- Take off the lens cap and look on the back for the filter size
- Typical values will be in the range of 52mm to 77mm (as well as smaller & larger)
- Record these values for each lens and note which is the largest
- Buy a filter to fit your largest lens (see PLAN AHEAD at the bottom of the page)
- Next you need to buy Step Up rings (much cheaper than filters) in order to use that large filter on the smaller lens
- Let’s say your largest lens (& thus your filter) was 77mm
- Further, you had two other lens – one 67 and one 52
- You would buy a 77 to 67 step up ring and a 77-52 step up ring (or you could get a 67-52 and use it together with the 77-67 for the same result).
- You now have 1 filter and two step up rings instead of three filters (and a lot more $ in your pocket)
- Of course, if you bought one 77mm Regular ND and one 77mm Circular Polarizer, you still only need one set of step up rings.
- NOTE – whatever you do
- DO NOT try buying a filter for your smallest lens and then using Step DOWN rings (yes, it is cheaper but it won’t work properly)
- If you did this, using the small filter on a larger lens will give you a picture with a large black circle around it (it’s left to the interested reader to puzzle out why this is so)
PLAN AHEAD – If your largest current lens filter size is smaller than 77mm, think twice before buying this smaller size. 77mm lens are common – most wide angle lenses are this size (and the focus lesson demonstrated the value of a wide angle lens). If your current largest is 67 or 72, what do you do when you get a lens needing a larger filter? You buy another filter, that’s what. Unless you’re certain that your current largest lens in terms of filter size won’t be larger in the future, strongly consider buying 77mm filters and the necessary step up rings. It can’t hurt and will save you $ in the future.