Much Ado About Lenses

We need it, we are always wanting more, we sometimes drool over the big fancy ones, and sometimes we can be jealous at what other's are carrying around.  Let's face it, it's not about the size of the lens but how you use it.

Today I am going to provide a detailed brief about all of the important things you need to know about lenses: the basic differences, how to choose the right one, and why you might have to sell a kidney to afford some.  

Many of us have that "dream lens" but another equal portion have no idea what's so special about the seemingly infinite number of lenses out there and how to pick one to upgrade to.  (Don't worry, it wasn't that long ago when I had no idea what an article meant when they were discussing "glass.")  "Kit" lenses, the ones that typically come with your DSLR, will get the job done and you may feel that those are really the only lenses you'll ever need, but prepare yourself for: life after the kit lens.

Sure, the old adage about it's not the camera, it's the photographer is true to an extent, but the lens will "control the image that's projected onto your imaging sensor, and ultimately what photos you are taking home. As such, many photographers would prefer to shoot with an okay camera and a great lens, than a great camera with ho-hum glass attached."  So, what is a great lens? 

First, you need to understand how these different lenses might improve your current photos and finally allow you to take ones that you currently can't.  There are three main categories of lenses: normal (50mm-range), wide-angle/short, (10-35mm), and telephoto/long (55+) and all of those have confusing letters and numbers that provide detailed information such as:

Focal length - expressed in "mm", smaller numbers are wider angles and higher numbers are bigger zooms.  (Reference, the human eye has a focal length equivalent to 30-50mm.)  If the lens has a set of focal length numbers, such as 18-135, that means that it can zoom in and out between those focal angles.  If there is one number, such as 50mm, then this is called a prime lens and it will force you to stop being lazy because your feet will be what zooms it in and out; it forces you to think more about composition and perspective.

Maximum aperture - The lens aperture is shown in several ways, but "whether it's f/2.8, F2.8, or 1:2.8, it all means the same thing and refers to the the maximum amount of light which the lens can gather" at its widest maximum aperture.  You will see lenses with very small numbers such as 1.8, 1.4, and I have even seen 1.2, and this just means it is capable of letting in a huge amount of light through the camera aperture so you will likely have to work with a very fast, maximum shutter speeds to get a good exposure when using it.  They differ in low-light capture abilities, weight, size, close-focusing range, and price and give you that incredible selective focus with shallow depth of field called bokeh.  

There is also a variable maximum aperture meaning that it changes depending on the focal length.  Take, for example, an 18-200mm f/3.5-5.6 lens.  It would have a maximum aperture of f/3.5 when it is at 18 mm and would be maxed at f/5.6 when zoomed out to 200mm; as you zoom in, less light gets to the sensor.  Variable-aperture zoom lenses lose their ability to transmit a constant volume of light as the lens zooms in and out, which is why a zoom starts off wide at f/3.5, but will max out at f/5.6 as the widest aperture.

Constant-aperture lenses, which maintain a consistent maximum aperture, regardless of the focal length, tend to have the wider maximum apertures.  Constant-aperture zooms lenses also tend to be larger, heavier, and typically more expensive.

Lens mount type - Plain and simple, you can't mount a Canon lens on a Nikon camera and vice versa.  This is because of their mount type.  Yes, you can buy adapters, but for now let's just stick to the basics.  An example of the common lens mount types for DSLRs are the Nikon F-mount, Canon's EF or EF-S, the Pentax K, and the Sony Alpha (A) mount.  This is your camera's special receiving end for the lens you will mount to it.  

Format type - (This is where it tends to get complicated so hang on!)  There are about seven different formats but I will cover the most common two: full frame and crop sensor format types.

Canon:  EF lenses cover both full frame and APS-C sensor DSLRs and EF-S lenses are specifically for APS-C "crop" sensor DLSRs such as the 70D, Rebel 2Ti.  

Nikon:  FX lenses cover the full frame sensor in full frame DSLRs like the D610, D810 and DX lenses cover the APS-C "crop" sensors in DSLRs such as the D90, D3200.  The sensor/format difference can be seen in the image below.

Lens manufactures give a 35 mm-format equivalent on lenses designed for cameras with smaller sensors, therefore, if your camera has that smaller APS-C (DX) sensor, you will need to consider the following calculation when deciding which lens you need:

"If you're using a full frame camera there's no calculation needed, a lens will give you the field of view you'd expect from its number. If your camera has an APS-C sensor it has a crop factor of 1.5 - meaning you multiply the lens focal length by 1.5 to get its equivalent 35 mm-format focal length. For Canon APS-C cameras that number is 1.6." (Wilkinson)

Ok, so how do you choose what's right for you?  Ultimately you need to consider how set you are on your current DSLR.  If you plan to upgrade from an APS-C to a full frame camera body sometime soon you should consider upgrading to a lens that's meant for a full frame camera.  Allan Weitz sums up the difference between choosing a prime and variable lens:

"The down side of fixed focal length lenses is that they are not as versatile when shooting subjects that move quickly toward or away from your camera position . . . When shooting with zoom lenses, it's easy to get lazy. When shooting with a fixed focal length lens, you have to physically approach your subject in order to frame the picture properly. With a zoom lens you see something and you zoom in on it. And while there's nothing wrong about shooting that way, one of the benefits of a zoom lens is that it makes it extremely easy to photograph a subject from a variety of vantage points, distances, and focal lengths without having to pause and switch lenses . . . If there were a downside to shooting with zoom lenses, it would have to be that none of them opens up wider than f/2.8, and if they did, they would be quite hefty."

        

For casual photographers, the slower, least expensive 50mm f/1.8 is sufficient for almost every need. For others, including pros who require even better low-light shooting capabilities, the f/1.4, which is a 1/3-stop faster, may be preferable and even still affordable.  That 85mm f/1.4 seems to be high on the dream-list of "portrait" lenses but it comes with a hefty price tag.  It is the Goldilocks of prime portraits lenses; not too wide, not too long - you don't have to be uncomfortably close to your subject, and it won't compress the depth and make your image look flat.  

"Wide angles lenses should be used when prominent foreground objects are present. The primary mistake made by new photographers is to use wide angles incorrectly - by not being close enough, having no interest in the foreground, or by trying to include too much in the scene. Wide angles are also handy in tight areas, like small rooms, cars, caves, etc. They can give volume to the small area. Wide angles have the potential to drastically change your photography." (Berk)

Standard zoom lenses work well as “walk around” lenses.  They offer versatility between wide or zooming, landscapes and portraits.  These are generally your "kit" lenses: 18-55mm, 18-135mm, 24-105mm for example.  Zooms/telephoto lenses allow you to stand back a little like when the subject is not exactly approachable.  These can also be useful for portraiture, but keep in mind Robert Capa’s words, “If your pictures aren’t good enough, you’re not close enough,” as it is easy to get lazy and let the lens do all the work.  These are also excellent for sports, nature, and wildlife.  With sports though, you need to be able to freeze action sharply which requires a fast shutter speed and faster (larger maximum aperture) zoom lenses are required.  "If sports is one of your primary subjects, a telephoto zoom such as a 70-200 f/2.8 is an excellent choice.  If you really want to shoot like the pros, you’ll want a 300mm f/4, or 300mm f/2.8 or 400mm f/2.8. " (Berk)

Long, even extreme focal lengths and large maximum apertures mean bigger and heavier lenses,

which, along with the bigger price tags, is why they are typically used by professionals who can ultimately justify purchasing them.  Build up to these lenses as you grow as a professional so you don't have to sell an organ on the black market just to add one to your collection.  If you think it is a necessary business expense then that is always a justification too.

This post just covers the basics; I could go on for days about lenses.  There are a variety of other special lenses on the market like a macro lens if you like shooting tiny things or a tilt-shift or perspective correction lens for architecture.  There is a lens to suit every purpose so I hope I have been able to provide some good direction when contemplating purchasing a new tool for your photography endeavors.

Works Cited

"85mm Portrait Philosophy." photo. NameMedia, Inc., 21 May 2011. Web. 23 Sept. 2014. <http://photo.net/nikon-camera-forum/00YlSn>

 Berk, Rick. "Choosing Lenses: When to Use Which Lens and Why." digital-photography-school. Digital Photography School, n.d. Web. 23 Sept. 2014. <http://digital-photography-school.com/choosing-lenses-when-to-use-which-lens-and-why/ >

"Black Market." Photograph. Encyclopædia Britannica ImageQuest. Web. 23 Sep 2014. 

<http://quest.eb.com/#/search/115_2729832/1/115_2729832/cite>

"Hispanic boy thinking at school desk." Photograph. Encyclopædia Britannica ImageQuest. Web. 23 Sep 2014. 

http://quest.eb.com/#/search/154_2899196/1/154_2899196/cite

"Hungary, Budapest, Jealousy, 1892." Photopgraph. Encyclopædia Britannica ImageQuest. Web. 23 Sep 2014. <http://quest.eb.com/#/search/126_3739316/1/126_3739316/cite>

"Monarch Butterfly." Photograph. Encyclopædia Britannica ImageQuest. Web. 23 Sep 2014. 

http://quest.eb.com/#/search/149_2081893/1/149_2081893/cite

Weitz, Allan. "The Canon Lens Experience: Everything You Need to Know about Canon Lenses." bhphotovideo.  B & H Foto & Electronics Corp., Aug, 2014. Web. 23 Sept. 2014. <http://www.bhphotovideo.com/explora/photography/tips-and-solution/canon-lens-experience-everything-you-need-know-about-canon-lenses>

Wilkinson, David. "The DX/FX distinction." Photograph. switchbacktravel. Switchback Travel, n.d. Web. 23 Sept. 2014. <http://www.switchbacktravel.com/camera>