Fixed Vs Variable ND Filters
 

Just received my 7D and I have a question about ND filters (which of course are built in to my EX3 so I never have had to think about them).

I understand why and how they work. The question relates to which way to go (FYI, I only intend to shoot video with the 7D).

The Singh Ray variable seems like the smart/easy/convenient way to go but I read that it distorts color along with some other issues. True? Disagree? They work fine???

The other option is of course the fixed filters but there are so dang many to choose from I have no idea which two or three to get and the "measurement" system is all over the place (2X or .03 blah blah).

Could I get some specific advice on which two or three to get (58mm and 77MM lense sizes will cover things) to cover the majority of high light shooting situations?

Thanks in advance.

I wouldn't say the Singh-Ray distorts color at all, until you rotate the thing to the maximum setting, where the two polarizers cross their linear planes and you get a weird across-the-lens x-shaped vignette. There is some edge vignetting on the widest lenses due to the edges of the filter sticking out too far.

You might want to consider a Lightcraft Workshop Fader ND instead - they're specifically built to reduce vignetting by mating a larger sized filer to a flanged thread for your lens size. Also, they're cheaper. :) Of course, they also suffer from the polarizers' meeting at the maximum setting.

Seems like the are "out of stock" on everything. These people kosher?

Just make your own variable ND. It's simple. 1 rotating polarizer + 1 linear polarizer = 1 fader nd filter

Yes, it is simple to make your own - if you have a proper matte box with a rotating stage and the pricey large filter glass. If you stack your own on threaded filters at the end of the lens, you really are going to start suffering from vignetting at even modestly wide focal lengths. I find that I have to zoom to about 32mm on my 24-70mm when using the Singh-Ray Vari ND on the 5D Mk II. I can only imagine that I'd have to sacrifice more if actually stacking threaded polarizers myself.

Yes, I own one, and they are definitely kosher. I've heard a theory lately that they're reworking their filters, and therefore have been trying to sell out of their existing inventory. Not sure where I heard that, though... I'm waiting on the 67mm version becoming available, so I can have some adjustable ND on my macro lens!

If you make your own couldn't you make it with a bigger filter thread than your lens and use a step up ring. Wouldn't this keep the filter borders out of the lens focal view. Just a thought....I'm all about making stuff for less than I would buy it for. :-)

I use fixed filters - 77mm's at .3 -.6. 9, etc... using step down rings.

I also have tried my own variable with 2 polarizers - and yes, it does cause vignetting and it is fiddly to get right.

For fun I ordered a complete set of 4 ND's from a Chinese supplier - advertised as high quality glass - they arrived 3 weeks later for about $30 total!! I cannot tell them apart from my Hoya-B&W ND's that cost over $100 ea.

The Singh Ray variable ND is a wonderful filter. It really speeds up the workflow by allowing 1 single filter to provide just about as much ND as you will ever need to get to the depth of field you want with the simple twist of the filter.

Compare this simple twist of the variable ND to dealing with the weight and bulkiness of matte box (although they have a lot of other valuable uses as well) and a whole slew of 4X4 ND glass filters of varying strengths and the mounting and unmounting in their frames and inserting them to get where you want to be aperture wise. Or compare to carrying a bunch of screw-in ND filters of single strengths - on and off - on and off to get to the depth of field you want.

The Singh Ray makes a "thin" model that removes the front threads for other filters to help avoid vignetting, but the only time I see this effect with the normal thickness Sing Ray is with the Tokina 11-16mm at full wide open 11mm. Going to 12mm and the problem is gone.

I have read lots of good things about the Lightcraft variable ND as well other than their recent lack of any stock anywhere. And their path to market seems a little difficult to me.

Since I am just getting into this could somebody recommend, say, 3 fixed ND filters that would be a good basic kit. Don't worry about lens size I'll work that out..I am more interested in three "grades"

Thanks

0.6, 0.9 and 1.2

I understand what folks are saying, but because of the 1.6x crop factor (due to the APS size sensor) this really shouldn't be an issue on the 7D. And, on the 5D, you can simply use a larger filter.

Exactly. This is what you do and if people are complaining about vignetting they didn’t stop to apply any brainpower.

No Mike, what you do is use a matte box, unless of course you like unwanted flare and ghosting.

Strange...I have never come across the flare and ghosting but then again I have a nice deep rubber sunshade on it that I bought for $4. Matteboxes arn't nessisary.

I use hoods too, they have their place, but they are not nearly as effective or as versatile a mattebox and filters. Also, you'd need different filters and hoods for each lens with a different filter size - suddenly not so cost effective...