4X5 Filter Installation/Mounting

[AJB]

To start out with, I am a total newbe to the 4X5 format and as such have a total newbe question. How and where are filters mounted on 4X5 view cameras? I am borrowing a friends Cambo Legend while he is gone for the holidays this weekend and have rented a Powerphase FX scanback to check it out and see how it functions, etc.

Anyway, the Powerphase comes with two color correction filters (AR1 & TG1) which I am assuming are mounted somewhere behind the lens. The problem is, I cannot figure out for the life of me where the filter should be mounted? Do filters require some type of mounting bracket or plate?

Any help would be greatly appreciated...

[Ralph Barker]

I'm not familiar with the Powerphase back, but if the filters are square gels, they would mount in front of the lens in a holder. The back probably requires multiple exposures, each through different filters to compile an RGB image. If you don't have a proper filter holder with the camera, you can simply hold the filter in front of the lens.

[Ted Harris]

A quick additional note. There are also systems that are designed for mounting square filters behind the lens. Horseman, for one has such a filter holder/adapter for use with their rail cameras.

[Yves Gauvreau]

I have a bunch of 75mm Wratten filter and I've used an Nikon AF-1 holder a front mounting designed for these filters but the lens end is only 52mm. There is also the AF-2 with a 62mm filter treads (I think) but the cheapest thing I've came up with is that I buy a large 77mm Cokin adapter and a downsize filter ring for each of my lens filter size. The Cokin adapter provide a relatively large face so it's easy to glue a piece of heavy cardboard on it. Make a hole the proper size on 2 such piece, use a black masking tape on the bottom to make an hinge, and put your filter in between and use either a small piece of tape to keep it close or whatever you can think of "et voil&agrave"

[Henry Ambrose]

The filters are for different light sources. I think the TG1 is for tungsten (is it blue?) and the other is an IR filter for flourescents. I'm not sure you will need either one if you use good old daylight or strobes.

If you don't see anything for mounting, take off the lensboard to see if your friend has a mount for the filters to go behind the lens.

[Kelly Flanigan]

The Phase One TG1 filter is for tungsten light. It cuts off the Infrared response of the scan back. Without the TG1 filter; the response is visible light and IR; and the images take on an IR look to them. Here I use a hood from Caprock; a model 115S; that holds the gel filter; and is a hood too. It is really too heavy; and is made for large lenses. With the PhaseOne I have; one does a prescan; and exposure is checked. Also the grey balance can be forced; using the eyedropper in software; If the scene has a grey object.