Grad ND filter

[michael_g.]

<p>Hi, I am trying to decide on the grad ND filter and while doing the research found that B+W 502 .6 Grad ND filter is not a glass filter but is made of CR-39 resin. Should I be concerned that it is not a glass filter? Also if the lens has multicoated does it make sense to put the CR-39 filter in front of it? Any other recommendations on the Grad ND filters? Thanks! </p>

[howard_m]

<p>depends on how deep your wallet is. there are several lines of glass GND's (mostly german and also Tiffen).<br>

http://2filter.com/4x4camerafilters/4x4ndgraduals.html<br>

but that presupposes you want to spend upwards of $200 on one.<br>

I've cruised these forums a long time and never seen anyone say they own one nor any professional nature photog. say that. 99% stop at the Hitech, Lee or SR brand WRT cost.</p>

[dbcooper]

<p>A few years ago I got a glass Tiffen 77mm .6 ND grad. Good filter, but after I used it a couple of times, I found having the transition area permanently in the middle of the frame very limiting. I now use 4 x 6 rectangular resin ND grad filters with a Lee holder. They cover the 12-24mm wide-angle lens I use, along with all my longer lenses. I also use a Cokin 'P' holder with non-Cokin ND grads when I want to travel light.</p>

<p>Resin filters are optically fine, but they are obviously not as scratch-resistant as glass. They're more resistant to breakage, however. Any filter you put in front of your lens has increased potential to produce/aggravate reflections (ghosting and/or flare).</p>

[david_henderson]

<p>I wouldn't get worried about the CR39 material at all. All the mainstream rectangular grad manufacturers use it; if you wear spectacles there's a very good chance that the lenses are made of it. It probably does scratch a little more easily than glass, though not necessarily more easily than the coatings some people (eg Hoya) put on their glass filters. Using a filter increases the chance of flare, but not all the time and in any case sometimes the risk is worth it.</p>

<p>A much more significant decision is whether to go with rectangular grads or a round screw-in. </p>

[lilly_w]

<p>1) Don't be concerned that it is not glass. 2) I'm not sure what a multi-coated lens has to do with filter usage. When using a filter, ensure that it is high-quality (glass or resin). 3) If needing a grad ND I would much prefer to have the rectangular type (Cokin P style). The fixed position of the grad/non-grad transition in a screw-on mount is very limiting and often an impediment. I use Singh-Ray grad ND's in Cokin P. Standard ND's are 77mm (screw-on) B+W. Cheap ND's risk introducing color-shift.</p>

[JDMvW]

<p>I'll second Lilly on the advantage of the Cokin holder and the rectangular graduated filter. With one of these you can place the transition from light to dark where you want it in the image, not just in the middle.</p>

<p>I will however, say that you can get square graduated ND filters a lot cheaper than Singh-Ray that are optically fine. The standard line of those who spend a lot of money is that the Cokin filters, for example, are not "neutral" in color. I can't see that this is a significant disadvantage (even assuming that it were true) in the days of digital imagery and post-processing.</p>

[michael_g.]

<p>Thank you evrybody for the replies!<br>

How convenient are the Cokin holders if the lens hood is attached? Are the screw-on type more convenient? Choosing between the B+W filters: 501 or 502 is more effective?</p>

[dbcooper]

<blockquote>

<p>How convenient are the Cokin holders if the lens hood is attached?</p>

</blockquote>

<p>You can't use the camera's lens hood with Cokin or Lee filter holders. However, both Cokin and Lee both make accessory lens hoods for use with their filter systems. I recommend going to their websites and looking for yourself to see how filter holders work.</p>

<blockquote>

<p>Are the screw-on type more convenient?</p>

</blockquote>

<p>It depends on your definition of convenient. Screwing on any filter with a lens hood installed is next to impossible. You'll also find screw-on ND grads next to impossible to adjust with a hood on, since they rotate like a polarizing filter. If you don't use the lens hood, then screw-on ND grads are more convenient to install and remove, but the graduation still starts smack across the midline of the frame. Always. Permanently.</p>

<p>There are three parts to install to use Cokin or Lee filters: a) the adapter ring that screws onto your lens (like a screw-on filter); b) the filter holder that clips to the adapter ring; and c) the filter that slips into the holder. The filters and holder will take up more space in the camera bag. In actual use, these are more convenient because you can easily adjust where the ND grad effect begins in the frame, as well as being able to rotate them. They're easier to stack without vignetting, and easier to change if you want to use a different filter.</p>

<p>More conveniences:</p>

<ul>

<li>If you change lenses and the filter thread size is different, you only need the correct adapter ring - the holder and filters will work as-is. With screw-on filters, you'll have to buy a new filter for each thread size you want to use. </li>

<li>With either the Cokin or Lee systems, you can get 'hard' and 'soft' ND graduations (describes the 'suddenness' of the transition to the grad area varies - 'hard' grads are best for scenes with flatter horizons, and 'soft' grads are better for pretty much everything else) Screw-on filters don't offer this. </li>

<li>You can also get 'stripe' and 'reverse' ND grads. Very useful where the horizon area is the brightest part of the scene. </li>

<li>More densities are available (a 1 to 5-stop range). Screw-on filters are a single 'in between' compromise for the transition area, and usually only available over a 1 to 2-stop range. </li>

<li>Extra Cokin 'P' size filters are much less expensive than extra B+W screw-on ND grads, even if you spring for Singh-Ray grads.</li>

</ul>

<p>So in terms of image quality, creative potential, real-world ease of use, and cost over time, IMO, the Cokin or Lee systems are much more convenient.</p>

<blockquote>

<p>Choosing between the B+W filters: 501 or 502 is more effective?</p>

</blockquote>

<p>Neither is more effective. A 2-stop ND grad, however, will be more useful.</p>