Jump to content

Problems using polarizing filter for sports


dan_sisken

Recommended Posts

<p>I just bought a Canon T3 and used it with the kit lens and a polarizing filter to take pix at a swim meet. The photos turned out disappointing. It looked like the filter noticeably softened the focus (although the colors were nice). Am I correct that this is likely the filter and not some issue with the lens, which I have not tested without the filter as this was my first shoot with it.<br>

Thanks for any discussion.<br />Dan</p><div>00Z5Sz-382851584.jpg.5f3c3dfe8b31847d4e08eff931dd9128.jpg</div>

Link to comment
Share on other sites

<p>Poor quality or low brand polarizer can degrade picture quality.<br />Polarizers take away about 2 or 3 F-stops, forcing you to use slower shutter, or higher ISO, or open aperture wider, ... all depending on exposure mode you used. Possibly your polarizer is OK, but the light loss of few F-stops forced different exposure parameters.</p>

<p>Make sure your shutter is fast, and aperture allows sufficient depth of field.<br />Explore EXIF data of your pictures with polarizer and without, and see any exposure difference ?</p>

Link to comment
Share on other sites

<p>Was this indoor or outside swim meet? If indoor, why did you want to use the polarizer? As Frank S. noted, the loss of maybe 3 stops resulted in slower shutter speed than necessary. <br>

show us the exif data.<br>

Another thing is that kit lenses do not , for the most part, focus as quickly as more expensive pro lenses. Even more so in lower light(caused by use of polarizer) situations. </p>

Link to comment
Share on other sites

<p>Thanks Frank and Steve,<br>

I used the auto-sports mode. The ISO was 250. Speed 1/800. F 5.6. <br>

The meet was outdoors in bright, sunny conditions (and around 100 degrees!) .<br>

Some of the pix in the group turned out ok, but none were sharp. This included pix of people standing around watching.<br>

The camera I had hoped to be upgrading from, a non-SLR Sony DSC-H2 12x optical zoom, so far is winning the contest by a mile (even though the auto focus is broken).</p>

 

Link to comment
Share on other sites

<p>When you say polariser do you mean a circular polariser (one where the front rotates)? If so you need to make sure that you have the polarising filter set correctly in relation to the suns position. As well as that polarisers work by blocking reflected rays depending on where the sun was in relation to your position and camera angle it may not of had much if any effect.<br>

There are plenty of tutorials on the web bout polarisers you should probably have a read og one or a couple to make sure that you get the basics correct for next time.<br>

When you say that your shots were not sharp that could be a function of focus (or lack thereof), the quality of the lens and the in camera settings that you have applied or whether you have shot in jpeg or RAW. You must remember that by default p&s cameras tend to have a lot (usually too much) in camera sharpening applied to images to trick people into thinking that they (the cameras) take good photos. DSLR's by default usually have less in camera sharpening and if you shot in RAW maybe no sharpening at all applied. You will need to learn your camera and it's settings which unfortunately involves something boys don't do, reading the owners manual and then taking the same shot of a scene with various settings applied and seeing what works best for you. Canon kit lenses unfortunately aren't renowned at the best lenses available and it is possible that you may want to upgrade the lens at some stage once you have experimented with in camera and post production techniques. Most of us probably started somewhere along the way with kit lenses and then realised that we were on a treadmill which involved spending money to reach the next step forward as skills and perceptions increased</p>

Link to comment
Share on other sites

<p>Dan - it'd be easier to judge if you could post the original unsharpened image side-by-side with the one you tweaked in PS.</p>

<p>Richard wrote</p>

<blockquote>

<p>...you need to make sure that you have the polarising filter set correctly in relation to the suns position.</p>

</blockquote>

<p>While this is true for using a pol filter in general it should have no impact on the image's sharpness.</p>

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

Henry Posner

B&H Photo-Video

Link to comment
Share on other sites

<p>Hmm, the softness doesn't appear to be an effect of the quality of the polarizer (it could be, but...)-it looks as though eitehr nothing shown was captured in focus or the overall image is soft due to movement. I believe it is a result of a combination of the following factors: <br>

1. Shutter speed of 1/800 might be too slow to capture the action if you're using a long lens (200mm+) on a cropped body without IS. Even with IS, it's going to be marginal at 250mm+, meaning it could take several shots to ensure a cleaner capture. Some will argue this point, however it is a lesson I learned the hard way. While some Polarizers can absorb as much as 3 stops of light, there are others that only absorb 1.25-2 stops. A bit more expensive, but i will give you an extra stop or two on the shutter speed. Just make certain you're using a circular for digital work.</p>

<p>2. Non L lenses (not proposing you NEED an L lens at all) are slow to focus, and your T3's focusing system isn't optimized for tracking moving subjects. I have the 60D, (same system) and it's tracking ability is less than satisfactory for good keeper rates. You might want to start pre-focusing on a spot and letting your swimmers enter that zone before taking the picture (manual focus), or start honing your manual focusing techniques for these events to improve keeper rates.</p>

<p>3. Possible you're using the wrong AF setting- AI servo is the best for moving subjects, combined with a single focusing point. Trick is to make certain you keep the curser on on the target as it will hunt otherwise and you will get soft images as a result.</p>

<p>4. Even under ideal circumstances, AF is not perfect and will never result in 100% accuracy, even on static subjects. Always try for multiple frames to increase your keeper rates.</p>

Link to comment
Share on other sites

<p>Polarizers generally reduce the amount of light that reaches the sensor by a stop or more. Therefore, your shutter speed was likely cut in half and its not an unsharp photo due to poor optics or bad focus but its likely to be motion blur. I only use a polarizer for landscapes. My CPL will fit my long lenses, but since it has so much of an impact on shutter speed the advantages do not outweigh the disadvantage. </p>
Link to comment
Share on other sites

<p>Thanks to everyone on their responses. I will do some more testing. Also, if this is of interest, I could post more photos (without sharpening) so people could see what I'm talking about (although having to compress jpegs makes this difficult).<br>

<br />Dan</p>

Link to comment
Share on other sites

  • 3 weeks later...

<p>A polarizer can soften your photos to some extent. I was shooting into the sun, with a polarizer at a motorcycle race, and I couldn't <em>buy </em>a sharp photo. Removed it, and the pixes improved greatly. I was using the polarizer as a ND filter that day, just to see.<br>

I'd forgotten that the greatest effect of the polarizer is in reducing non-metallic reflections, or darken the sky at 90 degrees to the angle of the sun. Thus, it doesn't have much effect on automotive or cycle paint. <br>

Experiment # 238...busted! Now, I know.</p>

Link to comment
Share on other sites

<p>A polarizer can soften your photos to some extent. I was shooting into the sun, with a polarizer at a motorcycle race, and I couldn't <em>buy </em>a sharp photo. Removed it, and the pixes improved greatly. I was using the polarizer as a ND filter that day, just to see.<br>

I'd forgotten that the greatest effect of the polarizer is in reducing non-metallic reflections, or darken the sky at 90 degrees to the angle of the sun. Thus, it doesn't have much effect on automotive or cycle paint. <br>

Experiment # 238...busted! Now, I know.</p>

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...