Tutorial: Sharpness – Part 1

I realized that there are a lot of factors that go into getting a nice sharp landscape shot, things that I now do automatically without even thinking about them. I thought I would try to capture them all in a couple posts to share with those of you still learning about depth of field and sharpness. Of course, many of these items will also apply to other types of photography…

  • Tripod – For the landscape photographer this is a hugely important piece of equipment. I shoot about 99% of my photos from a tripod. Usually a landscape photographer is shooting at the beginning and end of the day, when the light is best but not strong enough for really fast shutter speeds. Plus you will be shooting at smaller apertures (more on this below). For a nice clean image you’ll want to be using a low ISO setting; so all of this adds up to shutter speeds that can easily be a second or longer, making a tripod necessary. Plus it’s nice to have the peace of mind that the camera didn’t shake during the shot. If you’re just shooting around your home, have a rental car, etc. then weight isn’t too much of an issue. But if you’re travelling or hiking a lot I would recommend something lighter such as carbon fibre or a small travel tripod. A ball head would be recommended, I find them much easier to use than a pan/tilt head. Don’t worry, they’re easy to attach.
  • Aperture – Simply put, the smaller the aperture that you use (the bigger f number, so for example, f11 is a smaller opening than f4) the more you will get in focus from near to far. Keep in mind though, that as the aperture gets really small there is an optical effect called diffraction which will actually make the photo less sharp. It is a trade off; you “stop down” the lens to get more depth but you will trade some sharpness at the pixel level. You might be able to recover some of the lost sharpness with post processing sharpening. Each lens will have an optimal aperture where it is sharpest, often around f8. Check your specific lenses on a lens testing site to see where they are sharpest. I like to use www.imaging-resource.com (look for the “lab tested” lenses) and www.photozone.de. Youtube also has some good reviewers; I like Christopher Frost’s reviews: https://www.youtube.com/user/christopherfrost.   optimal for lens and setting for depth of field.
  • Focus Point – When you focus on something at a certain distance you get a zone of sharpness; about 1/3 of that zone is in front of the focus point and 2/3 of it is behind the focus point. The best spot to focus on, given the distance of the closest object and the size of your aperture, is called the Hyperfocal distance. You can find charts to calculate this or download an app, but a general rule is to focus 1/3 of the way into the scene. Some say focus on something that’s at the 1/3 point of the frame. Or, an even simpler rule that I use, is to focus a little bit past the closest item you want in focus (see the photo below). Also, if I’m having trouble getting sharpness from near to far, I’ll focus a bit closer to ensure that the objects closest to the viewer are sharp for sure.

 

Oct15_2013_6D_1123 - edit-edit-edit-3-edit-2
An example of which area I would focus on in this scene. The red lines indicate roughly three zones of elements that are at near/middle/far distance. The circle is my area of focus; while I probably could have focused a bit further into the scene I sometimes focus a bit closer to make sure the elements closest to the viewer are in focus for sure.

 

  • Mirror Lock-up – If you have a digital SLR there is a mirror inside that flips up when the exposure is made. This can shake the camera and cause a loss in sharpness. There will be a setting which allows you to first flip the mirror up (called mirror lock-up), wait for any vibrations to subside, then take the photo. If you have a mirrorless camera this isn’t an issue, but you can even set some cameras to have an electronic first curtain setting, which basically means nothing moves until after the end of the exposure.
  • Self-timer or Remote – Further to avoiding vibrations from the mirror, you also don’t want the cause vibrations from your hand pressing the shutter button. You can either use the self-timer set to a short duration like two seconds, or you can use a remote (with a cord or a wireless one) to take the photo. I would recommend just getting a cheap one off ebay, they work just as well as the expensive name brand ones.
  • Focus Stacking – Sometimes using a small aperture isn’t enough to get sharpness from near to far. Focus stacking it a technique where you can set the lens to a nice optimal aperture for maximum sharpness, like f8, then take a series of photos focused on progressively further parts of the scene, and combine them later with software. Some people use automatic software while some people prefer to do this manually by hand using layers in Photoshop. Something to keep in mind though is that you have to keep the exposure elements the same; use manual mode to ensure the aperture and shutter speed don’t change, and make sure the white balance doesn’t change either by using the Kelvin scale or by choosing one of the presets like “daylight”.
  • Tilt-shift Lenses – Another option is to use a tilt-shift lens. This is the name Canon uses; I think Nikon uses the term “perspective control” or PC lenses. These are for more advanced users. Basically what happens is that you tilt the focal plane. Think of focus like a wall at a certain distance with everything at that distance in focus. Then you use a smaller aperture to get more things in focus in front of and behind that focus point. But, a tilt-shift lens lets you take that focus “wall” and tilt it forward so that the focus plane is lying along the nearby foreground element and extends to the mid-ground and further to your background, like a mountain range or something. Since the focal plane is tilted you don’t need to use such a small aperture. So you can pick the best aperture of your lens, say f8 for example, and get everything in focus.

That’s it for now, check out Part 2 for more sharpness information.

 

 

 

Advertisements

Comments are closed.

Create a website or blog at WordPress.com

Up ↑

%d bloggers like this: