Testing

I recently purchased a new lens, Pentax DA  35mm f/2.4 lens.  I’m having a love/hate relationship.

The hate part comes from how wide the field of view is.  I’m a wide angle guy.  Up to this point, my main lens was a Tamaron 17-50mm f/2.8.  Tamaron gets a lot of hate, but I really liked this lens. I thought it was plenty sharp, fairly fast, and it sat on 17mm most of the time.  I mean, 85-90% of the time.  Truth.  I like a wide field of view.

I’ve had 50mm lenses, and obviously I love those for portraits, and pseudo-macro shots.  And that was it.  Either wide angle, or portrait.  For me, 35mm falls into the really weird middle ground that I’m struggling to get a grip on.  Which is a good thing.  A great thing.  I’m always looking for ways to break out of my comfort zone.

So, I got this lens.  Then, a few weeks later, the family and I decided to take a day trip to Death Valley.  Well, I’ll be dammed if I’m going to take pictures in Death Valley without a circular polarizing filter.  I usually shoot with a polarizing filter, especially here in the desert.  I love the way it makes the Nevada sky this deep Cobalt Blue.

I got a hold of a decent Hoya from a local camera shop (shout out to Casey’s Cameras on Tropicana!) and away we went.

After the trip, the filter just kind of stayed on my lens.  I lose a couple of stops because of it, but I’m able to compensate with a slower shutter speed.  I shoot mostly in the bright afternoon, and I usually shoot buildings and parked cars, so a super quick shutter isn’t usually necessary.

But then I started worrying.  You see, I mentioned the hate, but I didn’t mention the love part of my feelings.  I love how sharp this lens is.  It’s not Carl Zeiss sharp, but for a sub-$200 lens, I think it’s outstanding.  But what effect was the filter having on the sharpness?  I mean, it isn’t an el-cheapo $2.50 filter, but it’s not a $100.00 8-layer multi-coated filter with optical glass either.  And any additional layer between your subject and the sensor is going to degrade your image.  So, did I get a great lens only to hinder it with something that’s just going to give me worse images, not better?

I decided to do some testing.  Two of the results below.

Test one Test two

 

These are only two of about a dozen comparisons I did.  Obviously, this is completely amateur methodology.  I simply went out on my lunch hour, took one shot with the filter on, then the same shot with the filter off.  F stop and ISO were constant, the only differences were in shutter speed to equalize exposure.  Images were all straight out of camera, no sharpening, not tweeks, no nothing.

After staring at each comparison for ungodly lengths of time, I came to the conclusion that there was no real, discernible loss of sharpness with this filter.  I was pretty shocked by this, actually, especially after all the horror stories I had heard about filters making your pictures as soft as a pillowcase full of marshmellows, and how you needed to by a $75-$100 filter or more before it would be ok.  I tested, and found out different.

What’s the point of all this?  Why go through all this trouble?  It is to answer this question: how well do you know your equipment?

How well do you know the tools of your trade?

When you buy a lens, what are you doing to get to know that lens?  When you put filters on it, do you know what effect it is having?  If you get a flash, what do you do to test out its full capabilities, especially in different shooting environments?  How well do you know the tools of your trade?

It’s a good question to ask yourself.  Now, go find the answers.

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