A Simple Explanation On How Aperture Impacts Depth Of Field (And Why Pinholes Are Always Sharp)

lenses-pinholes

There is a Seinfeld episode where George loses his glasses, yet he is able to spot a coin on the floor by squinting. Without knowing the team at Seinfeld made a very elegant scientific experiment comparing lenses to pin holes.

A Lens makes things sharp by focusing rays of light coming from a source so the rays converge on a single sport.

A pinhole, on the other hand, only allows light to enter from a single direction thus not letting it blur.

Both aspects are very clearly explained in this video by MinutePhysics.

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Is Depth Of Field Affected By Focal Length? A Practical Test

The fact that the depth of field varies depending on focal length seems pretty straightforward, doesn’t it? Matt Granger however says that wide angle lenses don’t necessarily have a smaller depth of field when compared to longer telephoto lenses:

To understand any of this, you have to know what depth of field is: (Yes, this is very basic) Depth of field is basically the depth of your image that is in sharp focus, it is usually about 1/3 in front of your focus and 2/3 behind it.

In his video, Matt conducts a test to prove his point: He takes the same shot with the same framing and only changes the focal length and the position of the camera. The aperture was kept the same – f/2.8 – throughout the shoot. Of course when changing the focal length of your lens you’ll have to physically move the camera if you want your final result to have the same crop.

Here are the results:

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Your Aperture Is Sort Of Lying To You: When Is An Aperture Of F1.2 Not Actually A F1.2?

tstop

When Is An Aperture Of F1.2 Not Actually A F1.2? By the time the light gets to your sensor, that’s when.

One of the first things we learn as photographers are F stops and how we can use them to properly expose a photograph, but there is also such a thing as T stops and we don’t always give them the attention they deserve. Of course, a T-stop may not be essential knowledge on every photo you take, but understanding what a T stop is will give you a better understanding of light, which is never a bad thing for a photographer to have. (It’s also helpful information to have in your bag if you’re going to be lens shopping soon!). And Matt Granger does an amazing job of explaining the difference.

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Apple Finally Makes It Official: Aperture is Dead

aperture

For a while now, Aperture has been Apple’s signature professional photo management app, similar to what Final Cut Pro and Logic Pro have done for video and music. After WWDC, however, things looked a bit bleak for the software after Apple announced its rollout of its new Photos app – the keynote went by with no mention of any updates on Aperture itself. Today, it’s been confirmed by the company that development on the software has officially ended.

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New Chemical Iris Technology Aims to Innovate Smartphone Camera Aperture

As advanced as smartphone cameras are today, they’re still limited by the size they need to be. As a result, most smartphones have a fixed aperture to save space; the iris itself is mad from fixed blades that set the aperture for each camera. But as always, in a time where mobile devices are so engraved into the modern lifestyle, technology is constantly reaching higher ground. In this case, that higher ground is reached by a new type of iris – one made of chemicals that eliminate the need for physical blades.

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Back to Basics – Depth Of Field

depth_of_fieldAfter discussing exposure in great detail, I would like to turn to a different kind of control – Depth Of Field (A.K.A. DOF). OK. Don’t jump – you are right. Depth Of Field is not a real control, but more of a result of how you used the aperture control.

In simple words Depth of field is the term you use to describe what is inside the focused area of your image and what is left outside of the focused area (and will stay home alone, and eat dry bread and drink stale water. Sorry Jewish mom syndrome…)

As I said before the control that has the most impact on depth of field is aperture. Bigger apertures tend to provide shallower depth of field. That means that if you open a wide aperture (say f/1.8) you will have a narrow location in your image which is focused. If you set your aperture to a small value, say f/22, you will have a huge focused area. The other two controls you can employ to control depth of field are Zoom focal length and camera to object distance. [Read more...]

Back to Basics – Aperture

Aperture tutorialAperture is one of the three main controls you can use when you are taking a picture. Along with shutter speed and ISO, aperture controls how light will hit the sensor (OK, old schoolers – hit the film).

In very simple words, aperture is the “size” of the hole the light goes through when it passes the lens. So large apertures will let more light go through then small apertures. Going back to the pipe allegory analogy, we can see the following: If we use smaller aperture, then to keep our exposure unchanged we have to use longer shutter speed, or higher ISO.

Sink image by Andrew Mason. [Read more...]