Do all ND filters do this...or just cheap ones?

[Randy2468]

I have an inexpensive Vivitar Variable ND filter on my Fujifilm HS10 compact bridge super zoom.

Today was the first day I was experimenting with it in bright sunshine. Just wondering if these aberrations are normal due to not knowing how to use the filter or if they are a result of being a cheap filter (or Both)?

In the 2nd two, I was expecting a darker, but uniform photo. Instead as you can see the corners are darkened more than the rest of the photo.

The FIRST photo I deliberately did that to show the extreme effect. In the other two I'm not sure why it happened.

Thanks

 

[petrochemist]

Variable NDs are very different to fixed NDs.

Variables are made using two polarisers and are prone to dark bands such as your example shows...

 

[Alex Ethridge]

All variable ND filters suffer from something called "X Factor". The darker you go with the filter, the stronger the "X".

This has proven to be a problem for years now and I don't see why they continue to make them.

 

[Chaplain Mark]

All variable ND filters suffer from something called "X Factor". The darker you go with the filter, the stronger the "X".

This has proven to be a problem for years now and I don't see why they continue to make them.

You are expressing the Y factor regarding the X factor....

 

[Randy2468]

In all fairness, I also purchased a Zomei 58mm Variable ND2-400 filter that is multi coated and was not exactly "cheap".

There is a noticeable difference.

Only problem is on my camera when using this particular ND filter, all 4 corners of every photo have a dark rounded area where the ND filter is protruding into the photo. So basically, every photo looks like a circle.

I think I need some kind of adapter?

 

[FrancoD]

Hoya describes the "unavoidable" X factor in their version of the Variable ND filters.

Not cheap either...

http://solasndx.hoyafilterusa.com/

 

[mfinley]

The solution is spend about $350 on a SINGH-RAY variable ND. The better the filter the less distortions and the more you can get away with 'stopping down' without the dreaded X showing up.

 

[Leswick II]

You might not see these fringe benefits if you get B+W or Heliopan type. Also quite expensive. Check with folks that use this ND var. filter.

 

[Roger99]

All variable ND filters suffer from something called "X Factor". The darker you go with the filter, the stronger the "X".

This has proven to be a problem for years now and I don't see why they continue to make them.

Agreed. The filters really only work in a range that gives you a small increase beyond aperture and exposure control. I had one briefly and chucked it in in favor of a small range of different fixed filters. Swap the values around and you can get a far better range than a variable ND. You still get small problems like colour balance drift with more extreme combinations but you can usually balance this out manually with a little thought. Auto isn't always more convenient (in fact it rarely is it seems).