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Discussion in 'Panoramic Cameras and Accessories' started by JJB, Oct 7, 2010.
I have seen where one kind of pano camera needed a center weighted nd filter. Do they all?
It's the lens that needs the filter not the camera, so no they don't all need a centre filter, only those using certain wide angle lenses.
For example a 6x17 camear with a 90mm or longer doesn't need a centre filter, a shorter lens like a 75mm needs one particularly for colour work, however with B&W you can get away with out one. I usually have to work hand held (no tripods permitted) so can't afford the speed loss of a centre filter on my 75mm and as I only shoot B&W I can dodge the edges of the negatives at the printing stage.
Thanks for the info Ian. I am doing a bit of reseach with the intention to build my own. Yes, I am crazy...
A 6x17 uses a large format lens, correct?
Yes a 6x17 need lenses that cover 5x4 with room for movements. So while a 65mm f8 Super Angulon just covers 5x4 it's not quite enough for 6x17, likewise a 90mm f6.8 Angulon won't cover 6x17. Some wider more exotic XL Schneider's will cover but are rather expensive.
Well, a lens for a 4x5 should cover a 6x12 without trouble. I can either go in this direction or look to optics for an 8x10.
Nearly all decent 5x4 lenses will cover 6x17 easily, it's a much more interesting format than 6x12
It's only the very wide lenses like a 65mm SA that don't cover 6x17, many users go no shorter than a 90mm which will have loads of coverage.
Nothing crazy there - see my 6x12 link below..... Actually, yes, it is a bit crazy.
Now he tells me!
That's o.k. then.
If you mounted a polariser onto a fuji g617 on top of the centre filter, would you need to stop down another stop, for example @ f11 losing one or two stops, to f16 or even f22?
1 - 1.5 stops for the CF; 2-2.5 for the Polariser. Total = 4 - 4.5 stops. 100 asa ends up somewhere around 5 asa.
So you'll also need to get your head around reciprocity failure as well. I shoot Velvia/Provia in colour and Acros in B&W to minimise reciprocity failure. Shot some film today with a Pol and CF in rainforest. Exposures were around 2-4 minutes...
I use ND filters for my pinhole. I converted a 6x9 zeiss folder and removed the bellows and the arms and then used a piece of sheet metal to cover the front of the camera. The field of view is now very wide because of the short focal distance from the pinhole to the film. Because of this, even with low ISO films my exposure time was relatively fast so to slow it down a little I started using ND filters.