Schneider Super Angulon 72mm XL - filter conundrum

[Daniel Taylor]

just ordered the 72mm XL. rented one and loved it for my aircraft hangar interio r work. the 95mm filter format presents an interesting question. how best to fil ter if needed? not sure it is a requirement, though I do love my #25 filter for cloudscapes? my thinking is to merely hold the Lee/Cokin filter in front of the lens. the Cokin holder vignettes with my 110mm XL, so I see no need to attempt t his. even the X-series most likely does the same.

suggestions?

[Michael S. Briggs]

If you decide you want to use the Schneider center filter for this lens, the filter thread becomes 110 mm. What I do is tape 100 mm square polyester filters (Lee or Calumet) to the lens.

[James Chow]

I just hold the filter in front of the lens, careful not to get it in the way when using front tilts. Tape will work, too. The problem w/ the Lee holders is that you risk vignetting w/ a wide lens.

[Ellis Vener]

Try taping the filter across the rear element. Attach one end of the tape strips the tape on the barrel of the lens. This works well with polyester, gel and res in filters Alternately: cut a polyester/gel filter to fit inbetween the c.w.f. fil ter and the front element.

[Masayoshi Hayashi]

There are some related threads discussed under Filter. Try this (http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=001 6b6) for example.

[Daniel Taylor]

the previous threads reference a wide-angle holder that isn't listed in my Lee catalogue. further investigation yields a divided opinion as to whether or not the 95mm adapter ring will work with the standard foundation kit. I was told 'no worries mate' by my Australian pro-photo buds, but I tend to believe otherwise from photo.net posts.

trying to standardize on my filter system, and need one that will support all lenses. not an easy choice apparently.

[Larry Huppert]

I doubt Lee would have gone to the trouble of making the FK-100 foundation kit for the 72XL & 90XL if a standard Lee adapter ring would have worked. Apparently the part is fairly new, and isn't in any of the catalogs. I've used a Lee WA adapter ring & foundation kit holder with the 75 SA, and could see where it started to vignette. Since the 72XL has a vastly larger image circle, I find it hard to imagine that the standard 95mm adapter ring could work effectively in all situations. If you don't use many movements, the 95mm adapter ring is probably OK (but if that's the case, why use the big & expensive 72XL?).

[Alan Gibson]

For the 72, 58 and 47 XL lenses, I constructed cardboard holders for 100mm square filters. They hold the gels against the front rim, so have no vignetting.

[Daniel Taylor]

thanks for the advice. the lens arrived and is beautiful. can't wait to find some great light. I checked the Lee dealer, and the FK100 was not listed in latest catalog. also, there wasn't a 95mm WA adapter ring available. like Alan mentioned, a homebrew solution shouldn't be too difficult to come up with. might as well put that machine shop of mine to good use, instead of just working on airplanes! in addition, after polling many 72XL owners about their solutions (some of them quite comical), if I stumble onto something cheap that worke well, I will publish the details.

[Masayoshi Hayashi]

Daniel, B&H sells FK100 for about $150. I use optiflex resin filters (0.3mm thick?, great for wide angle lenses) and recommend them.

[Larry Huppert]

Daniel, I'd be particularly interested in any solutions which work with grad filters (other than the FK-100).

[Larry Huppert]

I've done a quick visual test (no chromes or Polaroids yet) of the 72XL with the Lee FK-100 filter holder. My overall opinion is that Lee has pretty much solved most of the problem of using 4" filters on this BIG piece of glass.

My estimate is that the 72XL without any filters attached allows close to 50mm of rise with the ground glass in "portrait" position before corners start to vignette. With the FK-100 attached and setup for two filters, the worst possible case is loosing about 7 - 10 mm of rise from the outer set of filter rails coming into view. If the FK-100 is configured for only one filter, it didn't appear that you lost anything. I consider the worst possible case to be where the filter holder rails are perpendicular to the major direction of movement. In this case, with portrait format and using front rise, the worst possible case is with the filter rails are horizontal. With most filters this isn't an issue because you can just rotate the holder. It only becomes an issue with grad filters.

(an aside: Filter rail stack height is critical to minimize if your going to get the most coverage with WA lenses. Every millimeter counts. The Lee system uses a fairly non-functional cap piece whose only function is to allow the screws to sit flush. I throw out this piece, and use a hand held wood working counter sink tool on the outer rail pieces to allow the screws to sit flush without the extra piece. Alternatively, you could just get some flat head screws. My preliminary estimates above were with this modification.)

[TAN K H]

Hi Dan

You might consider using filters at the rear of the lens. I bought some old new stock Sinar 3x3 filters recently and was finding a way to mount them on my 67mm diameter lenses without causing vignetting.

I posted a request for suggestions at RPELF on USENET and some clever chap emailed me and suggested that I use Xenophon rear filter holders. If you go over to Calumet's website http://www.calumetphoto.com, and type "Xenophon" as the search string you will find them. They have both 3x3 and 4x4 gel holders (picture available at the site).

I am not sure how much rear mounting a filter would affect picture quality (I haven't personally tried it yet).

Hope this might help.

[Larry Huppert]

Does rear mounting a filter change focus?

I remember seeing the "Xenophon" at Calumet, and thought it was interesting, but quite a bit overpriced for what it was. It also didn't appear to be an easy solution if you use multiple lenses, unless you get a "Xenophon" for each lens. Changing the depth of the holder to accomodate different lenses appeared to require a screwdriver.

At one time I thought about building a rear filter holder out of a routed out piece of wood. I would also cut different length side pieces to fit each of my lenses, and attach them to the block via embedded magnets (velcro is too sloppy).

[Bob Salomon]

"Does rear mounting a filter change focus? "

It does several things - none good!

A: Any filter placed behind the lens (unless designed to be part of the lens) creates a focus shift equal to 1/3 the thickness of the filter.

B: Any fingerprint will degrade the image C: Any dust degrades the image D: Any dirt degrades the image E: Any smudges degrade the image

In short there is no positive optical reason to place a filter behind the lens.

[TAN K H]

I buy the focus shift argument A if you are using filters that make it inconvenient to focus with the filters on. But the problems with B-E applies to front mounting as well! You have to exercise care to make sure the filters are clean whether you mount them in front or behind.

[Bob Salomon]

" But the problems with B-E applies to front mounting as well! You have to exercise care to make sure the filters are clean whether you mount them in front or behind."

Not really since the image has passed through the lens and is then "disturbed" by having to go through dust, dirt, fingerprints, etc.

[Ellis Vener]

Gee Bob, have you told the guys at Sinar this? They might need to know that so t hey can recall all of the Auto Shutters and Digital Shutters thay have sold over the years. But I agree completely with you about the need for absolute clea nliness. The focusing difficulty is resolved by focusing with the filter in plac e.

[Bob Salomon]

"Gee Bob, have you told the guys at Sinar this? They might need to know that so they can recall all of the Auto Shutters and Digital Shutters thay have sold over the years. But I agree completely with you about the need for absolute cleanliness. The focusing difficulty is resolved by focusing with the filter in place. >

You may not remember but when the shutter first came out that rear mount was for gels not acrylics (which really didn't exist then.

And whether or not Sinar has a rear mount does not mean it is a g









ood place to put filter

[Ellis Vener]

Bob outside of the cleanliness issue (which is addressed by practicing good phot o hygiene) and the focus shift issue (addressed by focusing with the filter in place (or am I missing something else here?)) whta other issues would make this a bad idea? I ask this out of a case of genuine perplexedness as when I was doing my apprenticeship this was a question that came up and was told that placi ng a filter there eliminates flare and some other issues. As you already know I am a big fan of Heliopans glass filters so i am not trying to find a "cheap" sol ution".

[Bob Salomon]

Compendiums eliminate flare. And don't create focus shifts and don't degrade the image due to the condition of the filter.

[Ellis Vener]

I agree about compendiums and I agree with you about everything else in your lat est post Bob. Still I am curious as to whether or not there are other benefits. Are there?

Signed,

Perplexed in texas

[Bob Salomon]

What other benefits do you want?

Usin filters in front of the lens eliminates focus shifts and vastly reduces image degradation (except from grossly defective filter). Putting filters behind the lens creates focus shifts and does create image degardation from marred filters. In addition flare occurs on uncoated glass to air surfaces. if a non coated filter is behind a MC coated lens flare can occur

[Bob Salomon]

Oh yes,

They also protect the front element of the lens.

[Don Wong]

One instance I've found advantageous for putting filters behind the lens is when using multiple gels to correct artificial light color to match transparency film.

Multiple gels in front of the lens will cause ghost images of bright light sources (such as HID lights in a gymnasium). I use 3" gels for compactness, but they're too small to curve in front of the lens.

Rear lens elements are smaller than front ones, so the 3" gels fit there, with room for some curvature of the gels. The curvature removes the ghosts.

There are problems with this method, but it's the best way I've found to solve that particular ghosting problem.

Don Wong

[Bob Salomon]

Seems like a properly functioning compendium masked to only letting rays that wi ll reach the film would eliminate a ghosting problem.

A lens hood or an improperly extended or / and masked compendium would not.

This is why Linhof builds gel holders into their compendiums.

[Ellis Vener]

I just got a chance to inspect and handle the GLIDE 6x17 panoramic camera this past weekend, courtesy of Jeff Wheeler of QUALITY CAMERA in Atlanta. the camera was equipped with the 72mm XL lens with the center weighted filter (evidently it is definitely needed for the 6x17cm format. The mattebox/filter holder they were using was the new Cokin X filter holder with a self supporting shade made by Camera Bellows, ltd. (and sold by Lee). This holder is designed for 125mm (5") wide filters which are standard in the motion picture industry. There was no vignetting as far as I could tell. The holder grabbed on to the outer rim of the CWF without any adapter as I could tell. The mattebox (filterholder and compendium shade cost US$500.00.

About the GlIDE: it is a fascinating camera. Very smartly designed with many brilliant and innovative, and eccentric features and is truly a work of engineering art. I particularly liked the way Dr. Glide solved the problems of lens movements bi-directional shifts (horizontal and vertical), tilts and focusing, and lens interchangability without having to resort to a monorail or bed, and also shifts and multiformats (6x6, 6x7, 6x12, 6x17) on the body of the camera, and the viewfinder. The design is eccentrically brilliant and the manufacturing quality is superb, of the same level as an ARCA-SWISS F or M camera or that of a Sinar P. It is very extremely pricey at about US$10,000.

[schafphoto]

I've done a quick visual test (no chromes or Polaroids yet) of the 72XL with the Lee FK-100 filter holder. My overall opinion is that Lee has pretty much solved most of the problem of using 4" filters on this BIG piece of glass.

My estimate is that the 72XL without any filters attached allows close to 50mm of rise with the ground glass in "portrait" position before corners start to vignette. With the FK-100 attached and setup for two filters, the worst possible case is loosing about 7 - 10 mm of rise from the outer set of filter rails coming into view. If the FK-100 is configured for only one filter, it didn't appear that you lost anything. I consider the worst possible case to be where the filter holder rails are perpendicular to the major direction of movement. In this case, with portrait format and using front rise, the worst possible case is with the filter rails are horizontal. With most filters this isn't an issue because you can just rotate the holder. It only becomes an issue with grad filters.

(an aside: Filter rail stack height is critical to minimize if your going to get the most coverage with WA lenses. Every millimeter counts. The Lee system uses a fairly non-functional cap piece whose only function is to allow the screws to sit flush. I throw out this piece, and use a hand held wood working counter sink tool on the outer rail pieces to allow the screws to sit flush without the extra piece. Alternatively, you could just get some flat head screws. My preliminary estimates above were with this modification.)

I used the Lee holder you reference on hundreds of photos until the markings of my 72XL started to wear off. (Not really a problem but an annoyance, since the Lee holder mounts with a tension ring around the outer lens barrel.) But since I wanted to quickly interchange my square filters from the 72XL to my other lenses, I had to have two Lee holders with me and move the filters back and forth. I also always felt the standard Lee system was a little plasticy and imprecise. I am reviving this thread to add that I have ditched the Lee holder and have been using the Benro FH100 -- 100mm filter holder for about two years and it fits the 72XL and all the other lenses with one aluminum filter frame, and separate threaded filter rings which I have permanently mounted on all my lenses. It fits the XL with a threaded 95mm low profile ring, that allows for a rotating polarizer to be attached behind the 100mm square filters if that's your jam. I have my holder set up with two filter slots. There are a number of new filter holders on the market competing with Lee now.

223670
Schneider SA 72mm XL with Benro FH100 filter holder (you can see the markings worn off the lens from the Lee holder)

223671
Benro 95mm filter ring

On another note, I use a Schneider Attenuator or Lee Blender graduated 100mm cinema filter to remove vignetting from lens fall off when I think it will be a problem. This way I avoid needing various expensive Center Filters on the lens and all the fiddly bits associated with them. With the large XL image circle on 4x5, I only use the filters when the lens is shifted over 15-20mm from center and into the light falloff area. This happens very often with front rise in HABS work. I find the centered sweet spot of the 72XL image circle to be pretty even in light coverage, just like the center of a Center Filter is pretty even in density until you get to the edges. This may not be exact enough for transparency shooters, but neither is the metering for a heavily-shifted exposure through the less-dense part of a CF. More art than science, I imagine.

[Eric Woodbury]

I use 4" gels (poly) with mine. Either handheld or in a Lee snap holder. Unless you are using f/5.6, then your image rays don't go through all the glass and your filter doesn't have to cover everything perfectly.

[schafphoto]

… Unless you are using f/5.6, then your image rays don't go through all the glass and your filter doesn't have to cover everything perfectly.

How does that work? Are you saying if you use a small hole you only use the middle of the glass?

[Eric Woodbury]

Only saying that as one stops down, the radius of use of all the elements stops down too. At 5.6 you need the full front element. At f/22, the image is no longer in the outer fringes of the glass. Those rays are blocked at the iris. Therefore, filtering those rays does not matter.

Nice to have full aperture to focus, but filters need not be full coverage if you are stopped down. Especially good with gels as you can get them close to front element.

[schafphoto]

...but filters need not be full coverage if you are stopped down...

I am not a physicist. In practice, I find the outer edge of the Image Circle on the 72XL grows a little when I stop down. And the filters I use at the edge of the mechanical vignette at full rise or full shift need to have adequate coverage, which on a 95mm wide lens means a 100mm wide filter. So, it seems logical that the light rays may not use all the glass at the nodal point when stoped down, but they still seem to use the same edge of the very large entrance pupil and smaller filters just add to the mechanical vignette.