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QT Luong
22-Nov-2006, 17:40
I am wondering if anyone uses a polarizer on a wide-angle lens fitted with a CF filter. I am thinking of the 110 on 5x7, which is quite wide. Currently I use either the CF or polarizer but not both because I do not have a polarizer of diameter large enough. Besides the loss of 3-4 stops of light (gulp !), any other potential problem ? The CF has a larger front element than the lens filter size. Would that be enough to prevent vignetting if I use a polarizer of the CF front element size, or would I need a super-expensive wide angle polarizer with a front element even larger ?

Tuan.

Eric Leppanen
22-Nov-2006, 18:08
I occasionally use a polarizer and CF with my WA lenses, with no problems other than the challenge of slow shutter speeds and the usual caution of uneven sky polarization.

I use the Lee filter system with a 4x4" square linear polarizer, and my FK100 press-on filter holder with spacer ring fits snugly onto the SS110XL CF without vignetting, even with movements (I use only two filter slots on my FK100, however). Regarding conventional round polarizers, I vaguely recall discussions (perhaps with Schneider?) that a slim (no front filter thread) 86mm polarizer is required to avoid vignetting with the CF. But I can't swear to this.

roteague
22-Nov-2006, 18:47
I sometimes use a polarizer and CF on my 80 XL. I've never run into issues of vignetting, however, I also haven't gone to extremes on movements with this setup. I don't always use the CF; I don't use it in flat light or scenes with little contrast. FWIW, I shoot 95% transparencies (4x5).

Daniel Geiger
22-Nov-2006, 19:10
I have used the combo on a 90XL. First put the the CF on, then view the polarization effect just through the filter (not camera), mark the position going straight up using the lettering on the outside rim of the Pol filter, and place the filter on the inside rim of the CF, and lighly secure the Pol filter with tape around the outside rim of the CF. I use a 105 mm B&W circ POL that is usually on the Lee system.

It only works if the lens is more or less vertical; be careful not to scratch either the CF or drop the Pol. Yep, +3.5 f-stops.

Also, I can not use a proper lens shade, so resort to shading the lens with a piece of cardboard if necessary.

I have been thinking how I could use the two better secured, but have not found an answer. I think the CF should be right against the lens as if you put it at a greater distance, then angular values of the CF will change. As the CF is very oversized on the outside rim, there is no way I can fit the Lee system around it. The 90XL CF has an outside thread of 110 mm, and B&H does not list any step-down rings (110 -> 105) in that size. That would mean custom work, but with the added distance, vignetting could well become a problem. So the balancing act seems the best option and I don't use it that often anyway.

roteague
22-Nov-2006, 22:25
I have used the combo on a 90XL. First put the the CF on, then view the polarization effect just through the filter (not camera), mark the position going straight up using the lettering on the outside rim of the Pol filter, and place the filter on the inside rim of the CF, and lighly secure the Pol filter with tape around the outside rim of the CF. I use a 105 mm B&W circ POL that is usually on the Lee system.

Keep in mind, the 110 XL uses the 3B filter, which only as an outside diameter of 86mm. FWIW, I've had a tough time finding a polarizing filter at this size. I have not tried putting the polarizer on the lens first, I've always seen Schneider recommend the CF as the first filter - I should give it a try and see how it works.

Struan Gray
24-Nov-2006, 05:50
Could you put a smaller polariser on the back? You'd have to align it by the index mark, but it would solve vignetting problems.

aporodagon
24-Nov-2006, 11:02
I found that the hasselblad 93 POL filter (inner thread of 86mm) works on my CF with the 110. This filter is extremely thin and the inner threads just (fortuitously) happened to fit. Still an expensive proposition, but I already had the filter for the Hasselblad kit.

John

roteague
24-Nov-2006, 11:09
Could you put a smaller polariser on the back? You'd have to align it by the index mark, but it would solve vignetting problems.

I don't have a problem with a polarizer vignetting on a wider lens, so it shouldn't be a problem with the 110. However, Schenider recommends that the center filter go first., which would make sense since you would get an uneven polarizing effect if you put it under the center filter. I have to admit, I haven't tried it.

JW Dewdney
24-Nov-2006, 15:43
I agree with Daniel - that the CF is really designed to be in a very specific position relative to the optical assembly. The OTHER issue supporting this - and it's something you should generally consider with ANY photographic setup... is that the Polarizer is the one cutting out a lot more stray light than the CF is - so it should really be the first thing in the chain. This way you're preventing flare, however minor the effect.

QT Luong
20-Dec-2006, 22:11
I used to do balance the polarizer too, but once it feel and rolled straight into a steep
slope. Now I settle for the slightly reduced movements of a well-secured wide-angle filter. There are a fair amount of choices for a 86 pol at b&h. I chose the heliopan slim because it has the markings and no front threads.

C. D. Keth
20-Dec-2006, 22:30
I don't have a problem with a polarizer vignetting on a wider lens, so it shouldn't be a problem with the 110. However, Schenider recommends that the center filter go first., which would make sense since you would get an uneven polarizing effect if you put it under the center filter. I have to admit, I haven't tried it.


It's not so much that as the design of a center filter. The center filter has to be in a particular place in relation to the lens to exactly counteract the falloff of the lens. If it's put closer or further from the lens, strange things might happen.

QT Luong
18-Sep-2007, 14:07
I got the Heliopan 86 slim polarizer (no filter threads) and it worked just fine with 110 XL + Rodenstock 0.45 CF on 5x7. No vignetting, but so far I did not use a lot of movements.

JPlomley
18-Sep-2007, 15:18
I would like to add that the same polarizer on a Schneider IIIb CF mounted to a 55mm APO Grandagon does unfortunately vignette. I am going to try an 86/105 SUR mounted on the CF next with my B+W F-Pro Warm Tone (KR 1.5) polarizer (not a slim mount). I just need to find a supplier that actually carries the 86/105 SUR. This stuff is just impossible to find anymore.