Issue 1: Ease of use and portability
Square Filter
Can be quite cumbersome to use.
Large kits take up a lot of storage including filter holders for various lenses.
Circular screw on filter
Simply screw on to a lens.
Stored easily in a round case.
Issue 2: Adaptability
Square Filter
Once you have a kit, step up and step down rings can be used to fit various lenses.
Different lenses have different adapters that can attach to the filter holder.
Circular screw on filter
Generally inflexible.
Can be stepped down to a smaller sized lens but cannot be stepped up if the lens diameter is larger than the filter.
Some wide-angle lenses do not have a filter thread to attach a circular filter.
Issue 3: Creativity
Square Filter
Filter holder kits holding square and rectangular filters allow stacking of 2-3 filters allowing for many different combinations and hence creative variations.
The filter setup can also be rotated allowing for easy change of orientation of GND’s in particular.
Circular screw on filter
Generally inflexible.
I would avoid using circular GNDs due to its fixed position of graduation and difficulty with rotation.
Issue 4: Durability
Square Filter
Filters are prone to scratches both when in use and if not stored properly.
Circular screw on filter
Much more durable than square counterparts.
Issue 5: Light leak
Square Filter
Can be problematic if not properly inserted.
Circular screw on filter
No issues with light leak.
Issue 6: Vignetting
Square Filter
Rare except with certain ultra-wide lenses.
Circular screw on filter
Can be an issue, particularly when attempting to stack filters.
by Dylan Toh
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