58XL for 6x12 Center filter needed??
For 5x4 I know one is mandatory for colour if even exposure is required. However, I am only interested in 6x12, which should not be quite as bad. Has anyone used a 58 on 6x12 for colour and how did they find it? What about monochrome?
While I am at it, what about a 65mm on 612. Basically I am trying to get away with not using one (have not decided on which lens yet), but will face up to it if I have to!
Last edited by Tom Stanworth; 10-17-2006 at 12:41 PM. Click to view previous post history.
I can't help much with the XL but I've found that using a 65mm Grandagon on 6x9 needs a centre filter if I start using much shift on the long axis of the film. I think if I was using 6x12 I would get the centre filter straight away, especially if I wanted to use movements.
In the end I haven't bothered getting one but am careful with shifts beyond about 25mm. I only do B+W and while you can dodge it out this isn't very satisfactory to my mind so I try to avoid the problem. I believe the Grandagon-N design has very slightly better fall-off performance than the XL or the APO-Grandagons which is why I chose it in the first place.
here is a recent handheld 6x12 taken with Kodak Portra 400NC and a 47mm lens, location: Santa Fe NM:
As you can see, it definitely vignettes. Your 58mm is also going to vignette by a similar amount. Yet for some subjects it seems to work. If you were doing precise architectural work however, I'd think your clients might prefer you to use a center filter. However, that being said, I rarely use any filters at all these days as I like the speed (and freedom) one gets with high-speed roll film and a 6x12 back.
J Michael Sullivan
...SOMETIMES I SEE THINGS...
I find I'm always using a center filter with my 55/4.5 Apo-Grandagon, 65/8 Super-Angulon, and 75/4.5 Grandagon-N with anything larger than 6x7. If you don't have one, you can still make interesting photographs, but chances are if you have it, you'll use it all the time (unless you're shooting handheld like Michael).
One good thing, though, is that while it's nice to have the "dedicated" filter, it's not absolutely necessary. I use a Schneider III filter on the 55, 75, and when I need it on the 90/8 Super-Angulon. Technically, I should use the IIIb on the 90, but I've checked and they're only 1/4 stop apart in the center. The Rodenstock filter for the 55 is stronger, so maybe one day, if I'm using the lens a lot, I'll get it.
The reality of the situation is that the center filter only partially corrects for falloff. Bob Salomon mentioned on the LF forum that at one time I think it was Rodenstock used to provide stronger center filters that corrected more accurately, but they were unpopular, because they would eat up 2-3 stops. So even the "dedicated" filters aren't necessarily matched so precisely to the lens, and which one you use is arguably a matter of taste. It does have to fit the filter thread of the lens, though, without any adapter rings or other filters between the center filter and the lens, so I use the dedicated filter for the 65/8 S-A, which takes 49mm filters, and the Scheider III on the other three lenses, which all have 67mm thread.
I was talking to Matt Sampson at Robert White yesterday about the XL range and centre filters. They had a 2nd hand centre spot filter (think it is now sold) as I was just buying a used 80XL. He said that it really was needed for the 58XL but not for the 80XL.
Having used a friends 58 once there wasn't a huge excess of movements on 5x4 and I used the filter after composing the shot. You probably could use it for B+W without the filter if not using much movement, but suspect the darkroom rescue work would become tiresome if you intend using the lens much.
Hope all is well
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I was afraid this would be the case! From my use of 65s on 5x4 for mono I suspected that what gained by the lower coverage required for 612 I would lose when using colout film. Hmmfff. Those CFs are so expensive and none of my filters will fit the external thread either. Maybe I could not use it for mono and use it for colour, for which Idont use any filters in any case (want that reality look).
Couldn't you have lied?
Originally Posted by Baxter Bradford
Having spoken with or communicated with several people that had the Schneider Super Symmar 80mm XL I was informed that with transparencies, the lens almost always has enough falloff to require the Center ND filter. That is why I opted to keep my Rodenstock 90mm f6.8. On the other hand, I just got a Congo WA f6.3 90mm lens from Jim Galli for backpacking and long hikes. Jim has indicated that this tiny lens is a sharp one (I need to test it); it should not need a Center Filter. On the other hand it has very small image circle coverage (only 175mm at f22).
The tinier the lens, the bigger the falloff.
That's very roughly, but mostly true: Miniscule lenses like Angulons and WA Protars have a light fall-off roughly corresponding to cos^4(theta), while bulkier lenses like the Super-Angulons and similar approach cos^3(theta). Of course if (theta) small, the fall-off is small. So a 90mm lens has less need of a center filter than a 65mm lens, since the angle between the light ray to the corner and the lens axis is a lot smaller.
If you compare Schneider's graphs of illumination you will see that the 80mm Super-Symmar XL has a lot more fall-off in the corners (of 4x5") than the 90mm Super Angulon (any version).
-- Ole Tjugen, Luddite Elitist
Thanks Rich and Ole
Will see how I fare with some transparency film in next few days. Not planning to sell old lenses just yet.
I have friends who use it happily without the centre spot. Generally I do not use massive movements with such short lenses, but there is always the possibility........! It is an expensive 'what if' item.
Originally Posted by Baxter Bradford
One of the people that I had communications with had an early lens. I believe his observations were not only due to movement, but the lens has that much light fall off toward the corners, particularly in the sky. He suggested that it was very annoying to the point that he almost always felt the need for the Grad ND Center Filter. However, at least some of the fall off can be corrected in Photoshop or like program. I have had several conversations with Bob Salomon of HP Marketing, US Distributor of Linhof and Rodenstock. He has indicated that he is not too happy with the light fall off characteristics of the new Schneider Super Symmar XL lenses in general.
Also, for me, in addition to my Rodenstock f6.8 90mm Grandagon MC lens I also have the Rodenstock f6.8 75mm Grandagon MC lens. Also, early on I purchased the Heliopan Grad ND Center filter for the 75mm lens. This only has a correction of 1 1/2 stops and is a 58mm filter size.
Last edited by naturephoto1; 10-19-2006 at 12:49 AM. Click to view previous post history.