Could you use two polarizing filters as a variable ND filter?

[Ralph Javins]

Good morning, BetterSense;

Sorry about the fact that the polarizing filters do attenuate the light even without consideration to their orientation. I have used mine as a neutral density filter with fast color film.

Three different 50 mm lenses. OK. You might buy one ND filter to fit the largest filter ring size, and buy a step-up adapter ring for each of the two other lens filter ring sizes. For example, if the largest filter ring size is 58 mm, buy the filter to fit it. If the two other lens filter ring sizes are 52 mm and 55 mm, buy a filter step-up ring to go from 52 mm to 58 mm, and another one to go from 55 mm to 58 mm. You can leave the step-up rings attached to the two smaller lens filter rings. Then just transfer the filter as necessary. One other point is that you might need to buy two more lens hoods or lens shades to fit the 58 mm filter step-up rings on the two smaller lenses.

You do have access to the internet. One source for filters is B & H in New York City. They carry several brands; Tiffen, Hoya, B&W, and others, along with the Cokin, Hutech, and Lee filter systems. All of these have Neutral Density filters in varying strengths. They do ship internationally if required. Look under www.bhphotovideo.com. I have purchased some unusual filters through them that I could not find in any of the photo shops out here in Latte Land.

I do admire your courage in taking on the photographic world with one camera and one film. That, sir, is a challenge. You have my respect in your venture.

 

[Vanishing Point Ent.]

Singh-Ray Variable Neutral Density Filter.

I think Spiratone actually used to sell a "variable ND filter" that was just two polarizers, one stationary and one rotating, mounted to be used in this way.

Cameras that use beamsplitters for metering, like Canons from about the mid-1970s need circular polarizers.

The thing is, if you're going to carry a second filter anyway, and it's really no big deal to carry two or three filters, you might as well make it an ND and do it properly than to try to use two polarizers, because a continuously variable ND filter is rarely necessary.

If you find yourself in this situation often, then just don't shoot 800 speed film as your standard film.

Singh-Ray sells a Variable Neutral Density Filter, but
it's very expensive.

 

[Poisson Du Jour]

If the camera has a semi-silvered reflex mirror so that the meter cell is actually reading through the mirror then you'll need to use a circular polarizer. The Leicaflexes, Miranda Sensorex, and Nikon F3, to name three different cameras I know of, have this requirement.

Nikon F3??
Dunno.
It also holds true for most cameras employing evaluative and/or matrix metering systems, including all my Canons (noted also as far back as the Canon T90).