Using polarizer w/ Cokin ND grad filter? (Galen Rowell style)

Considering the amount of frames I've shot, I have a somewhat embarrassing newbie type question regarding using a polarizer with the Cokin P type ND grad filters at the same time. I know Galen Rowell used the ND grads extensively to get his slides to have correct exposure in the sky...while bringing out the detail in the (darker) land below. I am slowly learning to do this as well, and match the needed density to the sky.

Does anyone know if he (or please share what you do?) stacked a large Cokin style round polarizer filter in the filter holder behind the ND grad(s)? Or is it better to get a smaller screw-in Hoya type Polarizer filter of say 62mm for my favorite lens, and then screw the Cokin adaptor ring into the polarizer filter that's already on the lens? I'm not sure if that would cause too much vignetting or other problems?

Hope that makes sense what I'm asking...kind of confusing, I know.
Thanks,
Jed

You'll find that a polarizer will produce un-even sky exposures; 6 additional glass surfaces, front and back, will cause flare (due to light reflecting between surfaces - loss of contrast), loss of transmitted light, and loss of image resolution. Are you willing to sacrifice?

Thanks for the reply on this.
The degradation of image quality may not be acceptable to me. Perhaps he never used a polarizer stacked with ND grad, maybe just one or the other? I will have to experiment a little on this.
Is that degradation in quality from just the polarizer itself, or only when you stack with an ND grad? As far as I know, the ND grad filter shouldn't reduce quality too much - and it seems pretty necessary when shooting color positives - I have found that out the hard way, at least.
As far as circular polarizers go, is there anything to really consider other than "multi-coating" versus standard coating? Would a higher end Hoya be "good enough"?
If it's not advisable to stack them, then perhaps it would be better to just get a screw-in type filter over a Cokin style.
Thanks for any discussion on this,
Jed

I've been using polarising filters with grads and warm up filters for years. I use the Cokin P system holder mounted to the lens via the appropriate adaptor ring, the Cokin polariser in the holder and then followed by the grads etc.

As to image image degradation. Well it depends how anally retentive you want to be. Use a lens hood, try not to shoot directly into the sun and you will avoid flare. The polariser will not of its self cause any degradation. As to the comment of uneven exposure, well for a polariser to work properly the lens access needs to be at right angles to sun. Using lenses wider than 28mm introduces a wider angle and you are seeing patches of un-polarised sky.

Many photographers far more fastidious about image quality have been using these techniques for years.

This was written by Galen and is on Vividlight.com

If we cross paths on a trail where I'm off for a day hike or climb, I'll likely have my 13-ounce N65 with a 7-ounce 28-80mm f3.5-5.6D zoom in a Photoflex Galen Rowell Chest Pouch. A zipper pocket holds a couple of Singh-Ray graduated filters cut down to fit the small Cokin "A Series" holder, plus a polarizer, and film. An attached lens pouch can add an 11-ounce 80-200mm f4.5-5.6D zoom and the new 18-35mm f3.5 zoom. Built-in Velcro tighteners stop them from rattling around. Total weight: 3 pounds.
The main compartment also houses my Nikon SB-26 flash. Its SC-17 remote cord and Rosco gels fit in a side pocket with tiny Photoflex soft gold and white reflectors plus a Litelink slave unit for remote TTL wireless flash. Other pockets hold 5 Singh-Ray Galen Rowell graduated filters with a Cokin P holder and adapter rings, 3 screw-in 81A filters (2X skylights to correct deep shadow or overcast), 2 Singh-Ray circular polarizers (rotate in a Cokin holder for use with an ND grad-one standard, one warming with built-in 81A color correction), 1 Nikon 52mm polarizer (solves 20mm vignetting), 4 lithium AA batteries, 4 AA rechargeable Supercells (for flash), a cable release, a chamois cloth (to wipe off water), and a tiny lens cloth.
Tucked away in another bag for occasional drive-by shootings are the 80-400mm Nikon Vibration Reduction zoom and the 18-35mm zoom. I bring along a larger Lowe PhotoTrekker bag only where I need very special-purpose lenses, such as my rectilinear 15mm f3.5 (renders straight lines), my 16mm f2.8 (slightly fish-eyed), my 28mm f2.8 PC (corrects parallax), or my fast 35mm f1.4 and 85mm f1.4 lenses (great for aerial photography in low light). For wildlife or sports, I add a 300mm f2.8 or 500mm F4 with TC-14B (1.4X) and TC-301 (2X) teleconverters. For commercial work, I add assorted flashes, reflectors, and soft boxes.

Thank you, it seems the stacking will not be so much of a problem, then. Enjoyed the article, thanks for posting it. I had read some of his before, and have enjoyed a couple of his books from the library, but don't remember the titles off hand. I purchased the Galen Rowell A Retrospective book when it came out as well...many wonderful images there.
I suppose in the end I will have to get both kinds of polarizer. Haven't really used filters too much, just played with the ND grads last fall and getting the hang of it. Used to have regular polarizers for my manual cameras, but since getting the AF gear, haven't invested in any circular polarizers yet.
All the best,
Jed

Paul.A said:

I've been using polarising filters with grads and warm up filters for years. I use the Cokin P system holder mounted to the lens via the appropriate adaptor ring, the Cokin polariser in the holder and then followed by the grads etc.

As to image image degradation. Well it depends how anally retentive you want to be. Use a lens hood, try not to shoot directly into the sun and you will avoid flare. The polariser will not of its self cause any degradation. As to the comment of uneven exposure, well for a polariser to work properly the lens access needs to be at right angles to sun. Using lenses wider than 28mm introduces a wider angle and you are seeing patches of un-polarised sky.

Many photographers far more fastidious about image quality have been using these techniques for years.

Click to expand...

Paul,

Image degradation is synonymous with the enhancements you speak of but if the results you get satisfy you, then that's all that really counts.

I moved up to MF because 35mm looses noticeable detail when blown up larger than 5x7 print format. Leica owners may not agree.

Regards,

From another Paul.A

I regularly enlarge 35mm up to 42 x 29 cm, but I concede that film choice, lens quality and tripod use has a big part to play. I use the same methods of controlling subject brightness range on MF and LF as well. I've found that you are most likely to see any aberration at small apertures and this is at the point where you will also see refraction from the lens its self. Cokin used to recommend for best results that you don't use too small an aperture, I don't know if they still do or not. So I think at times a compromise has to be made to get a shot especially when being paid for it.

Paul.A said:

....I think at times a compromise has to be made to get a shot especially when being paid for it.

Click to expand...

Yes, this is absolutely true. Some of my published (text book) photos were from 35mm color transparencies - bought on the basis of subject matter instead of image quality - they remained as small pictures on the pages. Unfortunately, the demand today is more for digital files, but again, if the subject of the photo is what the book designer needs, they'll accept film.

Something I found interesting in theoretical physics: Why a glass surface will always reflect 4% of the light striking it and transmit the remaining 96% is one of the strangest mysteries in physics. A deep study of this phenomenon is found in a book by Richard Feynman; QED:The Strange Theory of Light and Matter.

Yeah, if you were going to do it, I would get the Cokin polarizer. Threading into a filter would extend the filter holder out from the end of the lens even more and might produce some vignetting on super wide angle lenses. But I seldom have had the need for both filters simultaneously.