Prime Time - Why Shoot Prime Lens/Lenses

What is a Prime lens?

Unlike a Zoom lens, prime lens are fixed at a focal length so do not zoom. It’s really as simple as that!

So why use a prime lens?

Creativity

I truly believe that prime lenses force photographers to be more creative. The problem with a Zoom lens is that is allows the photographer to be lazy and learn little about focal length and perspective. Remember photography is an art! Shortcuts just stop us exploring our creativity and learning new skills.  A fixed focal length means you actually have to move your camera to frame your subject and because of this it also encourages the photographer to look at the world from new angles. This along with aperture (that I talk about in a minute) encourages and photographer to introduce the idea of depth into an image.

Bang for your buck



Nikon 50mm f/1.8

Due to having no zoom, prime lenses have far fewer lens elements and moving parts, this makes prime lenses relatively cheap. Here is where I have to mention aperture/speed if you don’t know. A lenses speed has nothing to do with how fast they focus (this trips up most amateurs) but is actually talking about maximum aperture diameter, or minimum f-number. A fast lens has a large maximum aperture diameter, that allows for more depth of field and better performance in low light, as more light can be captured. This along with glass quality is what you tend to pay for in the professional lenses. So back to prime lenses. Because of the simplistic nature of fixed focal length lenses, prime lenses tend to be fast and often have an aperture as wide as F/1.8 or F/1.4 and some even go as wide as F/1.2.

Let’s put this into perspective

A cheap, standard 18-55mm f/3.5-5.6 kit lens at 50mm has an aperture of about f/5.0 and costs around £150.

A more professional lens for example a Nikon 17-35mm f/2.8 can cost around £1000.

In contrast I got my first professional prime lens, the Nikon 50mm f/1.8 for just £95.

What I think

Don’t think that the contrast in price makes the prime lenses anything less on a good professional choice. Prime lenses are an amazing option for anyone looking to produce better professional work. I believe professional, affordable, fast lenses like this are a vital part of my kit. I would recommend to everyone with a DSLR to invest in a prime lens.
Canon EF 50 mm f/1.8 II Lens
Nikon AF NIKKOR 50mm f/1.8D Lens



AlexAndrews

Aperture Shape & Custom Bokeh blur

Have you ever looked at the out-of-focus areas in an image and wondered why all objects and more notably objects like a lights blur in a round shape?  Playing with my Camera Obscura got me thinking about aperture shape and Bokeh blur.  I think it is important to know that the out-of-focus parts of an image actually acquire the shape of the aperture. This got me thinking about creating a custom aperture shape. As I don’t fancy opening a lens up, its possible to mound an aperture modification to the front of a lens much like a filter, just so long as the new aperture is smaller than the original aperture in the lens(if not the shape is clipped by the old aperture). The only real problem is that once the new aperture is mounted, the original aperture becomes obsolete, so control over the aperture is lost. It’s also important to remember the max aperture will be stopped down a few (depending on the size of your shape) as this is now your new aperture. This becomes annoying as this whole project is about creating Depth of Field and out of focus areas.

So where to start?

I wanted to start simple, so just used some card that I cut to the size of my Cokin filters. This way I was able to mount them easily. In the center for each card, I cut my new aperture shapes and then could just slide them into my Cokin Filter Holder.

Bokeh Filter and Standard Bokeh Shape

Let’s Take Some Shots

I found that my 50mm f/1.8 was the best choice of lens and simply whacked it out-of-focus and took some photos of some old Christmas lights.

What I Found

1.       The more out-of-focus an image is, the larger the shape shows. This allows you to control the size, but only when none of your image needs to be focused. Obviously ,when shooting with part of your image in-focus, depth of field controls/limits this

2.       Using a Cokin filter holder is a good way to mount the aperture filters

3.       As the filter becomes your new aperture exposure and DoF will be affected

4.       It’s worthwhile to make nice filters once and keep them in your bag

While searching online I also came across some pre made “creative aperture kits” like this one below. I Have not had a chance to try them yet but defiantly worth a look.
Lensbaby Creative Aperture Kit

AlexAndrews