Whats depth of field all about?

Depth of field is an indispensable creative tool — but what exactly is it, and how can you control it?

Depth of field, or DoF for short, is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in a photo. We say ‘acceptably sharp’ because only one point will be truly razor-sharp in your pictures, as your lens can only focus at a single distance. However, the sharpness falls off gradually both in front of and behind the point you’re focusing on, and the depth of field is a measure of how far this

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SIGMA

35mm f/1.4 DG ull frame 35mm wideangle le

HSM £699

Sigma’s new 35mm f/1. If that sounds a little vague then let’s cut straight to the bottom line: this is simply one of the very best lenses currently available.

Unzipping the padded case reveals a broad manual-focusing ring filling the front half of the barrel with a focused-distance window and a focus-mode switch in the rear half. The lens feels a little weighty but very solidly built.

A really nice little touch is the white panel that is unveiled when the lens is switched to AF mode, saving the user

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Lens basics

Choosing a lens can be tricky for new users. That’s where our beginner’s guide comes in…

The beauty of investing in a DSLR or CSC is that you can swap lenses, giving you a whole new perspective on the world and allowing you to get really creative with your photography.

Being able to change lenses allows you to select a lens often more suited to your subject and by adding lenses to your camera bag, you build up a much more versatile camera set-up. In many ways, lenses are a more important consideration than the camera, as a lens will

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DIGITAL PHOTOGRAPHERS NOTEBOOK

Bokeh Is Japanese for Blur

Bokeh is the often-mispronounced term for those wonderful round, out-of-focus highlights that we love floating throughout the backgrounds of photographs. So just what is photographic bokeh and how does it differ from a blur of the same name made in Photoshop? The answer this time in the «Digital Photographer’s Notebook.»

There are three factors that make pleasing bokeh: pinpoint highlights, a lens with a longer focal length than normal for the camera, and a large aperture. Surprisingly, the most beautiful bokeh is not always with the widest f-stop. Oh, by the way, Japanese speakers say

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Depth Of Field

By varying the aperture on your camera lens, you can control the image brightness, as well as increase the range of objects that will appear sharp at a single focus setting. This band of sharpness is called depth-of-field.

In SLR cameras, you can observe the lens diaphragm change as you vary the aperture. Aperture, as has been mentioned earlier, is shown in f/numbers or f/stops. This is an internationally accepted number scale that runs as f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f//11, f/16, f/22 and so on. When a lens has an aperture of say f/1.4, it is termed a

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All About… Dobsonian telescopes

There is a lot of misunderstanding about Dobsonian telescopes; what they are and what they can do. This should help clear it up…

The Dobsonian telescope is a Newtonian reflecting telescope on an altazimuth mount. It is the mount that distinguishes it from any other type of Newtonian reflector and this was popularised in the Sixties by avid amateur astronomer John Dobson. It’s thought that Dobson invented the design for the mount, but as he freely admitted, the idea had been around for many centuries as cannons were mounted in such a way and wars fought using them. However, he

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Booster Boom into orbit remote sensing satellite Kondor-E

Today, from the Baikonur Cosmodrome, a pad 175/59 at 20:53 MSK started by conversion booster "Boom" satellite remote sensing of the earth "Condor-E."

SC separation from the carrier occurred in 21:18:35 MSK.

The satellite was put into a circular orbit at 504.7 km and an inclination of 74.75 degrees.

 

Small Spacecraft (ICA) "Condor-E" with a synthetic aperture radar (SAR) is designed to receive, store, and transmit to ground stations for receiving and processing of high resolution of remote sensing (RS) in the microwave range of the electromagnetic spectrum.

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Upgraded Il-38N

Not so long ago the Russian Navy was the first modernized sea plane-Scout Il-38N. Since both Sludge-38N entered the armament eleven years ago, it was made a few updates. It was a major upgrading of the aircraft in service since 1960. Recent upgrades to the aircraft allows it to detect ships at a distance of 320 km. It also posted a new heat (thermal) sensor more massive computers and increased the ability of all sensors.

Available Il-38N able to detect aircraft and submarines at a distance of 150 km. Aircraft equipment includes synthetic aperture radar / reverse synthetic aperture

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