_MSP9571 What does it mean to find the sweet spot of a lens?  All lenses are not the same.  And even at different apertures on the same lens, you can see a difference of sharpness.  Lenses tend to lose sharpness because of diffraction.  This is a very technical term that means the light tends to split-up at either end of the aperture range.  Lenses tend to be sharper in the middle of the aperture range.  Say f 8 or so.  But that's just a rule of thumb.  How do you know exactly what the sweet spot is on your lens?  I know some people will say that my lens is sharp all the time in all apertures, but after the sweet spot test you'll see that it isn't.  All lenses are not the same even if th ey are the same brand and make.  If you have a Kit lens, this is a great way to figure out how to get the sharpest image out of it.  Here is an easy way to test your lens and find out what the sweet spot is on your lens.  First, you'll need a few things.  A tripod, a wall that has a lot of texture in it so you can see if it's sharp or not (like a brick wall or a wall that has lots of details in it), and some sort of photo editing software like Lightroom.  Set your tripod up and get your lens focused on the wall.  Put your ISO on say 100 or your native ISO for your camera and put your camera on aperture priority shooting mode.  Open up to your widest aperture, say f2.8 or whatever your widest aperture is, and take a shot.  Then go through all of your apertures to the most closed down ones.  After you've taken all of your photos, put them into Lightroom or some other software and start to compare the sharpness of the different shots.  Then before long you'll come up with a clear winner, or at least a couple that are almost identical in sharpness.  I'm not a big supporter of pixel peeking, but in this case it's what you want to do.  Make sure you look in the corners and all across the frame.  When you have your winner, you'll know what your sweet spot is.  You can do this to all of your lenses, and the sweet spot will be different on those lenses.  You can record the results or just remember them for future reference.  Now why is all of this important?  Knowing what aperture your lens is the sharpest can come in handy.  For me, when I know what the sharpest is, I tend to leave that lens at that point for general photography like just walking around.  And when sharpness really matters I know where to put my lens.  Knowing your gear and how it works, from your camera to your lenses, will save you money in the long run.  22730511_10210704932196387_7018311079726609722_n You won't have to spend that extra money to buy the more expensive lens because it's supposed to be sharper.  You can stick with your old lens because you know how to make it sharp.  The same can be said with our camera bodies.  We probably only use 10% of our camera's potential just exploring the menus and reading the manual can help you become a better photographer and utilize the camera that you have, not the one that you lust over.  And I am as guilty of this as anyone else.  Always wanting the next best thing.  So save yourself some money and find the sweet spot of your lenses for sharp photos.  And as always keep shooting!