Lee filters advice

[eskil_hess]

Hello

 

I'm finally stepping up my a game and investing in lee filters. I have some questions I hope you can answer:

 

1. Do anyone of you use the wide hood holder? Is it worth it ? How do you mount the 105mm polarizer ? Can you turn the polarizer with

the hood extended, or do you have to minimize it ?

 

2. Which filters would you reccomend ? Which grads? I already have a big stopper from hitech, I thougt I would be using this as well.

 

3 is it really important to clean your filters with cloths before taking a shot? I some times get this circles on my shot I beleive come from

dust on the filter

[lex_jenkins]

<blockquote>

<p>"... is it really important to clean your filters with cloths before taking a shot? I some times get this circles on my shot I beleive come from dust on the filter"</p>

</blockquote>

<p>You're probably seeing either dust on the sensor or ghosting flare from the filters. Dust on the filters wouldn't be visible in most practical situations. <em>(A rare exception would be using a macro lens at minimum focus, or other lenses with extension tubes and minimum focus setting. The only time I can see dust on the front of a lens or filter is when I try to use an extension tube with a 24mm lens - the lens can virtually focus on its own front element, so it's not practical for any purpose other than to focus on the dust on the front element.)</em><br>

<br>

Sheet filters like the Lee, Singh-Ray, Cokin, etc., present a lot of surface, especially when stacking filters for special effects. Hoods or some effective method to shade the filters from sun and other flare inducing light sources are a must. I use stacked Cokins with snap-on modular hood for infrared and flare is a constant challenge. In the field I use my hat for additional shade. A good bellows hood or matte box would be better but those are very expensive.<br>

<br>

Dust on the sensor usually is fairly small, irregular, with well defined edges when the lens is stopped down. It's less noticeable with fast lenses used wide open. It will be visible regardless of lighting - check by using a bright diffused light source, including a sheet of white paper over the lens. Adjusting the angle of the lens relative to the light source won't affect the position of the dust on the sensor (unless the dust is really loose and moving around).<br>

<br>

Ghosting flare tends to be larger in diameter, with edges matching the shape of the iris/diaphragm. Most lenses used wide open will produce nearly perfectly circular ghosting flare artifacts, although off-axis flare will be more oval, and some teardrop and/or piston shaped artifacts may be visible as well. With the lens stopped down the main ghosting artifacts will take on the shape of the iris/diaphragm blades. Changing the angle of the lens relative to the flare-inducing light source will change the position of the flare artifacts in the frame.</p>

[eskil_hess]

http://i.imgur.com/MF1fZec.jpg

 

Here's an example of the spots. This is the first time I used the filter.

[lex_jenkins]

<p>That looks like flare - note the multi-sided iris shape in some of those artifacts. I get similar ghosting flare artifacts in my infrared photos using Cokin resin sheet filters (see attached example, upper left corner). In the attached sample photo the single desk lamp was out of frame and not in the path of the front of the filter - but the Cokin clip-on hood allowed stray light *behind* the filter, which produced the flare.</p>

<p>By the way, was this a day-for-night effect? In other words, photographed in daylight and exposed/edited to simulate a nighttime effect? If so, bright reflections of sunlight off the water and surroundings may have produced the flare.</p>

<p>If you don't already have a hood you can try making one from matte black construction paper, taped into a cone shape or more elaborate rectangular or petal shape. Repeat some exposures in similar flare-inducing conditions and see if it helps.</p>

<hr />

<p>*<img src="http://d6d2h4gfvy8t8.cloudfront.net/17881266-md.jpg" alt="Demonstration of ghosting flare artifacts using Cokin sheet filters." width="450" height="680" border="0" /><br /><em>Similar ghosting flare artifacts with Cokin resin sheet filters in this infrared photo</em>.</p>

 

[eskil_hess]

<p>It was photographed during the day, but during the wintertime, so was a dull light.</p>

<p>But that must have been really bad luck? Several people never saw this happen once. I guess if I actually purchase the Lee Filter holder with the Lee Filter wide angle adapter, this will prevent this, or at least be better. The Hitech holder even appeared with dark vignetting on 17-20 mm on the 17-40 lens.</p>