Understanding exposure, aperture and shutter speed

October 16, 2012 at 12:14

I’ve found two great resources to help me understand how exposure parameters (ISO, aperture and shutter speed) affect the final picture.

The first one is an icon representation of the effects of the three parameters. Take a look to the original article here.

And the second resource is an online SLR camera simulator.

With this simulator it’s possible to play with the different controls you could find in any SLR digital camera and view in real time your result…amazing! It’s time to practice!

 

Lens hood

September 19, 2012 at 17:06

Len HoodI remember unpacking my Sony NEX C3K a few months ago: objective, camera, strap and random-shape-black-plastic piece. Despite I studied colour theory and processing and I know a lot of details of image processing algorithms, I barely know about lenses and optics.

So, what was that black piece included in the package? Obviously, a lens hood. A lens hood has an important mission: avoiding lens flare and lens flare is an image artifact caused by light scattering into the lens. It’s usually caused by very bright light sources in the image or by shining from light sources that are not appearing in the image itself and, more often than not, it’s an unwanted effect.

Lens hoods are usually smaller in wide-angle lenses to avoid vignetting (unwanted reduction of brightness in the corners of the image) and the geometric shape is optimized taking into account final image shape and aspect ratio.

In Barcelona I deal very often with unwanted brightness in pictures and my solution until now has been to change the picture angle. But in my future photo-walks I’ll try to practice a little how to use a lens hood.