ND Filter Stepping Down

[NorBro]

Some people buy a large variable ND filter and step down to their different lenses to save money on different filters.

Does this affect the quality of your image in anyway as opposed to getting the correct sized filter for your lens?

 

[Chris Johnston]

That's exactly what I did. Lots of step down filters.
The only other reason I can see NOT to (other than $) is the possability of viginette shooting wide?

 

[AtticusLake]

Does this affect the quality of your image in anyway as opposed to getting the correct sized filter for your lens?

Can't see how it would. The step-down ring is just a disc with a big hole where it attaches to the lens; it doesn't add anything whatsoever to the light path. And it (should) make a completely light-tight seal between filter and lens. Certainly way better than using something like the Cokin filter system, which lets light in the side (I briefly experimented with that).

It should actually be less prone to vignetting, if anything, because the step-down widens out straight off the lens thread, unlike a filter which would extend forward at the same diameter for some distance.

(Actually, thinking about it, with a very wide lens there could be issues, as the filter ends up farther forwards... but my wide lens, the 11-16, is already a 77mm thread, so I don't use rings with it.)

 

[alaskacameradude]

(Actually, thinking about it, with a very wide lens there could be issues, as the filter ends up farther forwards... but my wide lens, the 11-16, is already a 77mm thread, so I don't use rings with it.)

^ This is exactly right. It does push the variable ND out further ahead, which 'can' cause vignetting if you have a very wide lens. However,
you need to check filter sizes. For example, my Heliopan is a 77mm filter. The kit lens is 67. So I need a step ring. With just a step
ring, I get no vignetting, even at the wide 18mm end of the lens. However, the Heliopan has no front threads, so I bought this rubber
sunshade which has threads on both sides. I put my 67 to 77 step ring on, then the rubber sunshade, then the Heliopan in the front
threads of the sunshade. This sunshade has 3 setting, which allow it to be 'folded' back all the way flush with the Heliopan at
wide angles so the shot won't vignette from the sunshade. Yet it was still vignetting! I finally figured out, it was because it was
putting the Heliopan filter out from the lens that extra little bit. So on something wider than 18mm, it theoretically 'may' cause
vignetting. However, the 11-16 lens is 77mm, which means you need no step ring, just put the Heliopan filter directly on the
lens. So, in conclusion, I think you end up having most bases covered if you get the 77mm size, you use step rings with lenses
18mm and higher, and if you want the extra wide of the 11-16, you just screw directly into the lens. Of course there may be other
lenses, even wider that it wouldn't work with, so do your homework and look at how wide the lens is. The 67-77 step ring is 'this'
close to affecting things at 18mm so any lens wider than that, which also needs a step ring, may not work. In that case, what might
work is to get a 82mm variable ND which would be a little wider and may solve the vignetting. Lots of options here.