where do you put your filters?

[stefan_marquardt]

hi, still trying to find a good solution as to where to put filters on

wide-angle-lenses (which are the lenses I use 90% of the time).

 

has anybody ever tried to cut lee-filters into an disk-shape and put

them between the centerfilter and the lens (so to avoid putting them

in front of the lens, which is not always practical on a 47xl or

72xl-lens)? this way you still have a multicoated front glass and you

dont need any special filter holder. also the filters would be nicely

protectec.

any thoughts?

stefan

[mark_sampson]

There's a bracket called a "Xenophon" sold by Calumet. It holds gels behind the lens. I use one mounted on the back of a Schneider 121mm Super-Angulon, and it works well.

[neil_poulsen1]

I put mine on the reverse of the lens, and I use Kodak Wratten Gels. I like this, because gels are the best and introduce the least amount of interference. I purchased a Xenophone (Calumet) 4" behind the lens gel filter holder and mounted it onto the rear of a reducing lensboard adaptor. So, I don't need a separate Xenophone for each lensboard. This was an excellent $50 solution to all my filter holder needs. Plus, the gel's are less expensive, although more perishible, filters. I see in another post that you have an Arca. Is it a Classic F, which is what I have? There's plenty of room in this camera for the 4" filter, with movement. The Arca Classic F cameras have an oversized bellows, which I like a lot.

 

With this said, the one problem that rear-mounting of filters can introduce is a bit of spherical abberation for very wide-angle lenses. e.g. a 47. I see also where you use this lens. The reason for this is that, the more oblique the angle, the more filter through which the light needs to pass. This could introduce a slight focus shift towards the outer edges of your photo. But, gels are very thin. We always deal with some degree of abberations with any lens setup. The question becomes, how serious is the problem? Try, and then decide.

 

Some people will warn that rear-mounting filters will offset the plane of focus by about 30% of the thickness of width of the filter. With gels, this is negligible. But, under any circumstances, focusing with the filter mounted takes care of the problem.

 

One nice thing, there is less potential for flare by rear-mounting fitlers. Compared to front-mounting, there's not as much light passing through the filter, and this reduces scattered light. You also don't have the problem (like with front-mounting) for light to reflect off the front of the lens, and then back off the rear of the filter and into the camera. In some situations, if one's not careful, this can create a hot-spot.

 

With an Arca, another possibility is to get a compendium lenshood and mount filters behind this hood. Norman McGrath does this, and it seems to work fine. But, this means that you need to mount the silly hood for every shot in which you need filtration.

[scott_walton2]

Sometimes in the front and sometimes in the back. I too have a Xenophone

and like it. With the wides your talking about, I highly recommend the rear

mount. Got to Calumet to find the Xenophone holder system.

[john_luke]

If we are talking soley Wratten Gelatin filters, it is fine to tape one behind the lens. If you need to use 2, putting a sandwich on the rear may cause a ghosting near strong high-key areas. Try one on the front, the other on the rear if you need the compensation of 2 filters.

 

For grads, polarizers, or anything of real thickness, the front is the way to go. Even if you place them on the rear, and re-focus to compensate for rear placement focus shift, the filter can disrupt the wave of the light in a more damaging manner than if on the front.

 

I't ok to put filters on the front. I know the stories about covering up the lenses multi-coating, but the pros put filters on the front all the time. How else do people use medium format? You need to pay heed to any raw light that may be hitting the lens. Pay special attention to ceiling track or can lights. With wide angle lenses, these can do horrors, as it is usually a light that is right above the camera that you aren't paying attention to. I always use several grip stands with black cards surrounding the lens to keep extraneous light off the filters and lens.

[stefan_marquardt]

thanks for all your very helpfull answers - I am going to investigate this calumet-filterholder.

I have tried the filters in front of the lens (usually an 47 or 72XL)but had some real problems from those lights just above the camera (as mentioned).

Sometime when I use the 6x9 back on the arca (discovery) I feel the rear end of the 47XL lens is just about touching the gg. I wonder if the filter an the rear of the lens might be in the way (I haven´t seen this calumet-device yet).

 

Would putting the lee-filters between the lens and the centerfilter cause any optical problems?

[john_luke]

The dedicated CF is designed to be placed where it should. If you place it further away to accommodate a resin filter, it may not perform as designed. I regularily affix my Lee 4x6 resins or square polarizer on the outside of my #3C CF on my 47mmXL. I have some tiny tiny plastic black clamps I bought at Ace Hardware. They are usually sold on a card with other mini clamps near all the other impulse purchase gizmos in the hardware store. . When I affix my glass polarizer in this fashion, I make a "safety harness" with a length of gaff tape tethered to the camera standard.

[stefan_marquardt]

I was thinking of putting the (cut round) lee-filter just on the back of the CF and then screwing the CF in it´s normal place ( the lee-filter tightly sandwiched between the lens glass and the CF). This way it would be held in place by the CF and no need for a filterholder, or any construction in front of the lens. would this not work?

[andreas_schmidt2]

"I have tried the filters in front of the lens (usually an 47 or 72XL) but had some real problems from those lights just above the camera (as mentioned)"

 

Stefan,

 

in this case, use a compendium bellows lens shade. In most cases they are big enough to go over the lens and filter. The good thing about a LF camera is that you can perfectly adjust the shade by controlling on the ground glass.

 

Andreas