Stacking filters

<p>Anyone have any experience stacking B+W ND filters and/or Circular Polarizers? how about with a Cokin P holder in addition?<br>

<br />At what focal lengths should I expect vignetting to be an issue in those circumstances? my lenses are predominantly in the <strong>55</strong>mm to <strong>58</strong>mm<strong> filter thread</strong> range, would getting a <strong>77</strong>mm filter avoid the vignetting?<br>

<br />Grateful for any advice, thanks.<br /><br /></p>

<p> </p>

<p>I have used two ND filters and a polarizer on my Pentax medium format camera without experiencing any vignetting, and these weren't the extra slim filters. I've no experience with Cokin filters. <br>

Basically, I think you need to experiment with your camera and lenses. Are you using a DSLR? Just put the filters in front of the lens, play with the aperture and inspect the results and draw your conclusions from there. </p>

<p>The vignetting point depends on many variables, but it is something easily ascertained at home. Just point the camera at a blank wall or ceiling and make two exposures, one at infinity and one at the closest focus available, at the smallest aperture on the lens. With a zoom, use the widest setting.</p>

<p>thanks for the replies, I shoot DSLR. </p>

<p>Actually I'm trying to decide what size filter I should purchase, I understand larger can be more universally applied with help from a step-up ring. But I wanted some opinions first, especially whether the size increase has the added benefit of mitigating vignetting.</p>

<p> </p>

<p>If it matters, larger filters will be more expensive. But, if you go the step-up ring route, then you buy a ring for each lens that fits a filter of, say, 77mm, then vignetting will be much less of an issue, as only the step-up ring will be in a possible position to cause vignetting.</p>

<p>I would not use a Cokin holder <em>in addition to</em> a screw-on filter with or without the step-up. If you see yourself using square filters a lot, it's probably better to go that route (not to mention cheaper! 77mm B+Ws add up!). One adapter with one holder will usually get you 2, sometimes 3 filters in front of the lens. I have the "P" system, and I can get a Cokin Circular Polarizer and two other filters in one holder, as it has one slot for a rotating filter (PL or star, etc.) and two for the "square" filters. You can rotate the CPL independently of the rotation of the other filters, so you could use a grad ND with it.</p>

<p>The downside to using square filters exclusively, is you can't then use the lens maker's custom hood for that lens. Cokin (and, I'm sure, others) have hoods that adapt to their system, though.</p>

<p>I ended up with both. I have a 77mm B+W Kasemann thin CPL for my Canon 17-55 and 100-400, another for my Tamron lens, and the Cokin "P" system with a variety of filters (CPL and mostly NDs and grad NDs). The CPL goes everywhere with me, the Cokins not so much, but your photography may dictate a different path...</p>

<p>I put a three stop ND filter on the lens plus two further filters in the Cokin holder ....YUK :-)</p>

<p>You may find this illuminating:<br>

<a href="http://www.lensrentals.com/blog/2010/12/the-glass-in-front-of-your-glass-all-about-filters">http://www.lensrentals.com/blog/2010/12/the-glass-in-front-of-your-glass-all-about-filters</a></p>

<p>Henry Posner<br /><strong>B&H Photo-Video</strong></p>

<p>How wide is the lens you want to stack all these filters on?<br>

On a telelens with 55mm front thread, I wouldn't worry too much about stacking some filters (when it comes to vignetting at least). On a wide angle lens, I'd avoid it seriously.</p>

<p>Thank you for your input Larry, it resolved a lot in my mind, also Henry for the link (Roger Cicala is a sage) and everyone else for their opinion. I don't expect to go Ultrawide, but if that's the best lens for the job so be it.<br /><br />I was concerned about the situation where I might want to use a Circular Polarizer to bring out the blue and cut out glare, an ND to slow down the shutter, and a Gradient ND to normalize the exposure between the sky & ground. I imagine stacking all of that would be highly impractical (and borderline silly), but wanted to know what others thought of it or whether anyone has done it.</p>

<blockquote>

<p>I was concerned about the situation where I might want to use a Circular Polarizer to bring out the blue and cut out glare, an ND to slow down the shutter, and a Gradient ND to normalize the exposure between the sky & ground. I imagine stacking all of that would be highly impractical (and borderline silly), but wanted to know what others thought of it or whether anyone has done it.</p>

</blockquote>

<p><em><strong>That</strong> </em>is where the Cokin and other "square" systems prove their worth. P adapter threaded onto the lens, the P holder clipped onto that, the CPL in the rearmost (closest to lens) slot, the solid ND in the middle slot, and the GND in the outermost slot. You could swap the two NDs, but the CPL has to go in the rear slot, as it's the only slot that can hold a round filter.</p>

<p>So, to use, you would rotate the entire filter holder to line up the horizon with the GND, and - optionally - slide the GND to match the horizon ("square" GNDs are actually rectangular so you can slide them up and down and not see the hard edge of the filter in your image). Then you would rotate the CPL to achieve the desired result with that, and take the shot. With all that stuff limiting your light, you're hopefully using a tripod. You may also have to set up the CPL and the GND separately, and add the regular ND last, else you might not be able to see much of anything through the viewfinder!</p>

<p>that is perfect! wonderful! I had no idea that round filters can be slotted into the cokin holder =)<br /><br />would you know which round filter size fits that rear slot on the cokin P?</p>

<blockquote>

<p>would you know which round filter size fits that rear slot on the cokin P?</p>

</blockquote>

<p><br />The <em><strong>only</strong> </em>filters that fit there are COKIN round filters. They fill the available space, and have a thin, edge that fits in the very thin slot, and it is serrated so you can turn it in the slot. Cokin makes three types of round filters for that slot:</p>

<ul>

<li>Polarizers (Circular for most Digital and Linear for film and a very few digital cameras)</li>

<li>Star (2, 4, 8 & 16 points) These give you a star like pattern from small or point light sources</li>

<li>Diffractors (3 models) Similar to stars, but the pattern is diffracted as from a prism</li>

</ul>

<p>I don't know whether other square filter systems (Lee, etc.) also have round filters, though I suspect they would.</p>

<p>Thank you Larry for clarifying that for me. I did a little research and it appears the cokin CPs are not so well regarded, BUT it appears that Singh-Ray offers a drop in CP that fits the holder. Its pricey (as all things Singh-Ray are), but I may consider investing the extra 100$ over the B+W just to rid myself the annoyance of fiddling with the filters.<br /><br />My appreciation again Larry, you've been a tremendous help! </p>