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Equivalent Focal Length and Field of View

Nov
12
2010
November 12, 2010
By 39 Comments

When it comes to focal lengths, it seems that many photographers get very confused by “equivalent focal length” and “field of view” jargon that is often used to describe lens attributes on different camera sensors. To help fully understand these terms, I decided to write a quick article, explaining what they truly mean in very simple terms.

1) True Focal Length

What is the true focal length of a lens? This one is extremely important to understand. Focal length is an optical attribute of a lens, which has nothing to do with the camera or the type of sensor it uses. The true focal length of a lens is typically what manufacturer says it is on the lens. For example, the Nikon 50mm f/1.4G lens (below) has a true focal length of 50mm, irrespective of what camera you use it on.

Nikon 50mm f/1.4G AF-S

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Telephoto Lens Focal Length Comparison

Aug
7
2010
August 7, 2010
By 10 Comments

Although I have already done a focal length comparison from 12mm to 500mm focal length before, I decided to do it once again for telephoto lenses. I receive quite a few emails from our readers, asking about telephoto lenses and focal lengths, specifically whether a focal length of a lens is going to be sufficient for bird and wildlife photography. The below images should give you a pretty good idea about field of view when using particular focal lengths, from 70mm all the way to 1200mm:

70mm-400mm FoV

600mm-1200mm FoV

The above images are not cropped in post-production and represent equivalent focal lengths relative to 35mm. The longest field of view of the 1200mm shot was captured with the Nikon 200-400mm f/4.0 + TC-20E III TC @ 400mm (800mm effective) on a DX body, which is equivalent to 1200mm. The shortest focal length was captured with the Nikon 70-200mm f/2.8G VR II at 70mm.

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How to Obtain Maximum Bokeh

Feb
5
2010
February 5, 2010
By 27 Comments

In photography, the term bokeh represents the quality of the magical out-of-focus blur that makes it look like the subject is isolated from the background. It is visually appealing for us to see a photograph with a soft, creamy and beautiful background. It helps concentrate our eyes on a single area and creates a sense of depth and dimension on an otherwise flat-looking image.

Let me share a few tips on how you could obtain maximum bokeh from your camera setup.

1) Use a large aperture

Bokeh is not created by the camera – it is your lens and its optics that are responsible for rendering the out-of-focus areas. Therefore, the first thing you should do is set your lens aperture to its lowest value, also known as “maximum aperture”. You can do this by changing your camera mode to “Aperture Priority” and setting the “f” number to the lowest value your camera will permit. On Nikon DSLR cameras, this is typically done by rotating the front dial towards the left (counter-clockwise).

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What is EXIF Data?

Dec
4
2009
December 4, 2009
By 11 Comments

This article is about the Exchangeable Image File Format (EXIF) and the methods of reading EXIF Data from photographs. Back in the film days, photographers were forced to carry a pen and a notepad with them to record important information such as shutter speed, aperture and date. They would then use this information in the lab, going through one picture at a time, hoping that what they wrote actually corresponds to the right image. It was a very painful process, especially for newbies that wanted to understand what they did wrong when an image didn’t come out right. Nowadays, every modern digital camera has the capability to record this information, along with many other camera settings, right into the photographs. These settings can then be later used to organize photographs, perform searches and provide vital information to photographers about the way a particular photograph was captured. This stored data is called “EXIF Data” and it is comprised of a range of settings such as ISO speed, shutter speed, aperture, white balance, camera model and make, date and time, lens type, focal length and much more.

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Focal length comparison on Nikon DX (1.5 crop factor) cameras

Jan
8
2008
January 8, 2008
By 7 Comments

This test shows focal length comparison on a 1.5 crop factor camera (all Nikon DX cameras) from 12mm to 500mm. All images were taken on Nikon D300 with ISO 200, f/10. The focal lengths are not 100% accurate because of different lens sizes and mounts (when short lenses such as the 50mm f/1.4 were used, the camera was mounted on the tripod, while zoom lenses had to be mounted via lens collars). The tripod was never moved (just slightly re-adjusted to focus on the top-left portion of the blue ornament). The 420 and 500mm shots are a little soft because of slight vibration and use of a teleconverter.

The shots were taken indoors because it was too cold outside :)

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