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What happens when you have two lenses and they are two
different filter sizes?
There are two choices:
First, you can buy individual filters for each lens.
This is fine although it can run into a lot of money duplicating filters for each lens. It’s also more to carry around in your
bag.
Second, and perhaps more practical, is to use a “stepping
ring”. In this way, if you have two lenses that are 37mm and 27mm, you can buy all your filters in 37mm and use them on the 27mm
lens. How? A 27-37mm “Step Up” ring will solve the problem.
Please take note of the following comments of the use of
stepping rings -
Many people confuse the terms “Step
Up” and “Step Down”. It is critical to remember that you are always “stepping” from lens to filter size. Consequently,
a 46-58mm “Step Up” ring allows you to use a 58mm filter on a 46mm lens size while a 58-46mm “Step Down” ring means
using a 46mm filter on a 58mm lens size (generally not advisable).
Note:-
When using “Step Down” rings it is crucial that you remember that a smaller filter on
a larger lens diameter means that the filter might encroach on the image and cause “vignetting”, a cutting off of the edges of
the photo that shows up as “black: corners”. Sometimes you can get away with it, particularly if a telephoto lens is
involved. However, the practice is risky. Always test by looking through the lens and noticing the edges of the image.
The closer the size of the size down ring is to the lens, the less the effects will be. In some cases there may
be no effects due to the camera's objective lens size verses the filter size it uses. The effect will also vary on zoom lenses with
the zoom ratio.
Try viewing against a very light background. Think of
holding a 5p coin against a 10p coin. The 5p coin is clearly visible inside the larger denomination. Conversely, if you held the
10p coin against the 5p coin, the larger coin completely covers the 5p coin.
Stepping rings are a convenient and inexpensive way to
avoid having to buy extra lenses or filters. Besides, one stepping ring weighs much less than duplicate lenses or filters.
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