Filters, Matte Boxes, etc.

[ben_gervais]

I'm slowly putting together my LF 'plan' for 8x10...

 

A question: From what I read, many lenses exceed the 4" width of most

popular filters / holders. What do people here use as an alternative?

 

I work in the film industry, frequently as a camera assistant, and we

use 'matte boxes' to hold large filters which either use metal rods to

hold the matte box, or smaller matte boxes that clip onto the outside

of the lens.

 

Since I can also rent any filters I purchase back to productions I use

them on, I am tempted to build a 6.6" x 6.6" filter set with a matte

box (like the ARRI LMB-4). It would seem to me that this would work

well for 8x10, but I'd just like to know if there are any obvious

pitfalls to this venture that I'm overlooking.

 

Cheers,

-ben gervais

[tim_atherton9]

Ben,

 

If i recall correctly matte boxes are basically pretty similar to what are just called Compendium Shades in LF photogorpahy.

 

The shades are usually small extendable bellows which can be adjusted to suit the focal length.

 

Some but not all have a slot for square filters

 

Different manufacturers make/made compendium shades which usually attach in some to the front camera standard and sit over the lens.

 

Lee, Sailwaund and Lindhal etc also make ones, some of which attache to the front of the lens itself (usally using the filter thread)

 

I'm not sure of the variety of filter sizes the different brands will take.

 

Also, depending on your camera it may not have a shade set-up especially for it and so you may need to righ up an attachement.

 

Brand new they are sometimes pretty expensive (though nothing to compare to Arri prices...)

 

But they can often be found used on ebay for a decent price. Espcially older models which are perfect for handyman specials

 

EG -

 

http://www.bhphotovideo.com/bnh/controller/home?ci=1&sb=ps&pn=1&sq=desc&InitialSearch=yes&O=SearchBar&A=search&Q=*&shs=toyo+compendium

 

http://www.bhphotovideo.com/bnh/controller/home?ci=1&sb=ps&pn=1&sq=desc&InitialSearch=yes&O=SearchBar&A=search&Q=*&shs=arca+compendium

 

http://www.bhphotovideo.com/bnh/controller/home?O=NavBar&A=FetchChildren&Q=&ci=3829

[george_stewart1]

I had http://www.skgrimes.com manufacture four custom wide-angle filter holders with 135mm threads. I purchased 6" gelatin filters and trimmed them to mount in the holders. Now I have four filters for my 210XL. I also had them make a step-up ring so that I could use the filters with my 95mm thread lens. See here http://www.skgrimes.com/thisweek/index58.htm

(they indicate 90mm but it was actually 95).

[jim_simmons]

At the risk of catching holy hell about this, I'm including a photo of my solution to putting 4"x4" filters on my 90mm SA XL, with its 95mm filter threads. I just blew off the whole filter thread idea and mount my filters directly to the lens board. I've drilled and tapped all my lens boards to accept hex head bolts spaced in a 4x4 pattern. (These are the large Arca-Swiss boards, so I've got to the room to do this.) Then I super-glued 1/4" diameter rare earth magnets (very strong) to the corners of my filters. The filters just "snap" onto the bolt heads and stay in place very well. One set of filters works on all my lensboards. The depth of the bolts is set to hold the filter just a bit away from the front of the lens.

 

I'm still considering how to make a lens hood with its own magnets that snaps onto the top of this setup, but for now, I just flag the lens with a dark slide clipped into a $12 Bogen multi-clip. What can I say, after buying the Arca-Swiss and the 90mm SA XL, I'm a little short on cash?

 

And yeah, I haven't figured out my polarizer scheme just yet. I'll probably go with a threaded polarizer for that, and then screw the bolts out just a bit to allow for the polarizer. I left the bolts a little long; I've got lock nuts on the backside, and I've painted all that matte black.<div></div>

[eric_leppanen]

4" (100mm) wide filters are normally adequate for most 8x10 lenses as long as they are matched to suitable filter holders. Normal and long lenses (300mm and up, in 8x10 format) typically will not vignette even if the filter screw-thread diameter slightly exceeds the width of the filter (Lee makes 105 and 112mm filter holder adapter rings specifically for this purpose). Wide-angle lenses in the 150mm focal length typically work with 4" filters provided a press-on filter holder (fits over the barrel of the lens) is used. The great exception is the 210mm focal length, where the lenses with ample coverage (Super Angulon, Super Symmar XL, etc.) are so huge that a larger filter solution is required. However, if you can skip 210mm or accept a smaller lens with less coverage, then 4" filters should work across the board.

 

I too researched the matte box approach when I first comtemplated moving to 8x10. The main drawbacks seemed only to be bulk and expense, although the folks I spoke to were thinking off the tops of their heads, since they had never heard of it being used with LF still cameras.

[john_cremati]

The main drawback to the 4 inch filters such as Cokin is that they they typically are not coated .. My system uses two filter sizes of 67 mm and 105mm and I actually could have just did the 105mm... I have step up rings for all of my lenses ..49 to 67, 52 to 67 , 55 to 67, 58 to 67, and 67 to 105.. The whole group of step adapters did not cost more than $50... I try to only buy B&W , Heliopan high end filters...One basic set of 67 mm and one set of 105.. I would like to make a spring or clamp adapter to handle my barrel lenses to 105 mm.........jc

[ben_gervais]

Thanks everyone...

 

I'm unfortunately (or fortunately, depending on how you look at it) restricted to the use of either 4"x5.65" or 6.6" x 6.6" filters, as these are the two standard sizes for movie use. (also the only way I'll be able to make my money back by renting them back to productions)

 

My main concern, as I will be shooting colour transparencies, is filter movement for placing ND grads... it seems to me that with 4x4 filters, you would not get any movement unless on a fairly tight lens. Are ND grads just not used alot in LF?

 

Cheers,

-ben

[eric_leppanen]

ND grad filters are rectangular in shape (in the 4" filter world they measure 4x6"). For example, check out www.leefiltersusa.com/PDFs/Camera/LEECameraSysUK19_20pdf. To aid in placement of the ND grad horizon, I stick a Post-It note stickie on the front of the filter right where the filter transitions to its densest point, look through the groundglass and slide the filter to its optimal location, then remove the stickie and shoot. The filter holder must allow the filter to slide, otherwise ND grad's will not work well.