11

Yes, that cross effect is common with all variable neutral density filters, especially with very wide angle lenses (12-17mm). You'll have to do some combination of zooming out or backing off the maximum density. I did some experimenting with a mid-range filter in the blog : Marumi ND2-400 Variable ND Filter Review. The effect was almost non-existent at ...


6

I have just trialled a variable ND filter and have written a review about it Yes, it will produce similar results. It's very handy in photographing things like waterfalls, as you can dial in whatever effect you need. The drawback is that it acts like a polarising filters, so if you have large expanses of sky, the sky will not be uniform - the polarising ...


5

You can get good results with a variable filter but I have to question the necessity of having that much control. When you're stopped right down you can usually adjust the aperture by a stop without compromising DOF, likewise you can go from ISO 50 to ISO 200 without a noticeable change in noise. Here's an example scheme: 10 stop f/22 ISO50 512s 10 ...


5

As with any variable neutral density filter the numbers are only approximate. There are, in fact, 10 common ND ratings between ND2 and ND400: ND2 (1-stop), ND4 (2-stops), ND8 (3-stops), ND16 (4-stops), ND32 (5-stops), ND64 (6-stops), ND100 (6 2/3-stops), ND128 (7-stops), ND256 (8-stops), and ND400 (8 2/3-stops). But I wouldn't put any money on any of the ...


3

Variable ND filters are made up of two polarizing filters stacked on top of each other. The angle of polarization between the two is what determines the density of the system. Polarizing filters don't work so great on wide angle lenses because those filters have the most effect when the subject (sky?) is 90° to the sun. Since a wide angle lens covers much ...


3

The main advantage of the variable filter is that you can turn it so that it is at the minimum setting (letting the most light through). At that point it's about the same as having a normal polarizing filter, so should be easy to focus. Once focused, then carefully adjust the filter to darken to the desired density. In order to get long exposures in the ...


3

You can't, you are asking for the impossible. Regardless of price Vari-ND filters always show color-casts which vary in intensity across the frame. The stronger you dial it in, the more color-cast there is. A cheap one will have move oddities but even an expensive vari-ND filter still shows color casts. The color-casts are also such that they are extremely ...


2

A "color cast" can arise for a number of reasons quality control - cheaper ND filters (even the fixed ones) may be unevenly coated - I've seen reports that you can even see this if you hold the filter up to the light. I don't know that it's any particular brand, but rather some batches will be better than others. If you can buy from a shop where you can ...


2

Matt Grum is right but I can think of one difference. Variable Polarizers have a well known problem with very wide angle lens. You get strange banding in your image since the light travels so obliquely through the filters. Two polarizers could have a greater gap between them which could exacerbate this effect.


2

Functionally, there isn't much difference. The difference really comes down to very small details of each technique, or precisely how the source images for each technique were taken, environment constraints, etc. Given the following assumptions: shooting RAW; no movement in the scene (i.e., no heavy wind blowing trees around, etc.); zero color-cast of a ...


1

A great difference: graduated neutral-density filters (GND) are preset to cut brightness only in specific areas. High-dynamic-range applications (HDR) merge multiple photos of the same subject taken at different exposures. A GND is useful, for example, in a scene where the sky is very bright and there is a dark, level, horizon. HDR is more generally ...


1

This happens with all variable ND filters, good and bad. It's due to the partcular angle of the two polarizers when approaching max density. There's nothing that you can do apart from avoiding the use of that setting. Note that it will vary slightly depending on the focal length of the lens in use.


1

Many serious pros claim, @hollan says above, that cheap ND filters are a waste of money. See Strobist: http://strobist.blogspot.com/2010/06/using-nd-filters-to-kill-depth-of-field.html He recommends Singh-Ray Vari-ND, but its way too expensive for my budget. I got a B+W 6 stop ND filter and I'm very happy with it.


1

I have not used a variable ND filter that was advertised as such, but my experience with two polarizers to create a variable ND filter has been a significant colour shift toward the blue end. Perhaps filters intended to be used as variable ND filters have overcome this problem, or perhaps the polarizers I was using for this effect were defective in some way....


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