The D(i)S(ney)LR Series: Lenses
Prime. Zoom. Fixed. Variable. WHAT'S IT ALL MEAN? How do I choose? What's better?
My favorite non-committal answer: it depends. But it's true.
PRIME VS ZOOM AND COST
A prime lens has a fixed focal length, a zoom lens has variable focal length. That's the primary difference between the two. Which is better? Well, what are you shooting? Prime lenses are limited in their perspective: you get one only. In general, a prime lens provides a slightly sharper and crisper image. The reasoning is simple: prime lenses have fewer pieces of internal glass than a zoom lens that the light must pass through before the image is captured. The quality of the image has NOTHING to do with the maximum aperture capabilities (although people love to toss around that f stop like a badge of honor, it's not. Side eye.).
Prime lenses (with their fewer internal mechanics than zoom lenses) can be produced at a lower cost for comparable characteristics (such as fstop). A 50mm f 1.8 prime lens is a lens of exceptional quality that can be purchased new for under $200. Remembering that 50mm is human perspective, so it is the least complicated to duplicate in production, thus making for the lowest cost. Primes of higher and lower focal lengths will increase in price accordingly as well as depending on their maximum aperture capabilities.
Most entry-level zoom lenses allow for versatility but at the expense of low-light shooting capabilities as well as a few other bells and whistles that might be lacking. These starter lenses usually have variable fstop capabilities, depending on their focal length (a listing such as 18-200mm, f 3.5-6.3, etc.). The lenses tend to be very light weight, substituting less expensive glass and plastic wherever possible to reduce cost. This is not to say that these lenses are not 100% functional and practical, merely that they are limited.
Zoom lenses that do not have variable apertures, such as the Nikkor ED Zooms (24-70mm f 2.8, etc.), tend to be some of the most expensive photography lenses in production (unless you start looking at specialty brands, such as Zeiss). They also provide for some of the most pleasurable shooting experiences I've ever had.
Nikon (Nikkor) and Canon make a wide variety of lenses and price ranges. The Nikkors I've worked with have proven reliable, versatile, and generally worth the price tag. Within the brand itself, there are higher and lower tiered lenses. Yes, you get what you pay for.
There are a number of third party brands (Zeiss, Tamron, Sigma, Rokinon) that produce lenses of varying quality, reliability, and cost. Tamron, Sigma, and Rokinon tend to provide lenses of similar features to Nikkor/Canon but at a reduced cost. Your best bet is to research the specific lens (not just the brand) to decide if it's a worthwhile investment to you. I have a Tamron 28-105mm f2.8 that I acquired secondhand for an absolute steal and that has proved a versatile and valuable addition to my lens bag. With that said, it has some quirks in the glass that may or may not be in keeping with your own photography aesthetics. Do. Your. Research.
Keep in mind when purchasing lenses to check that the lens itself is compatible with your camera body. All Nikkor lenses from pretty much any year of production ever will operate in some capacity on my camera (it may not have automatic functions, it may not interface with my camera's meter, but it will attach and take pictures manually), but NO canons will. The mount is different. So make sure when researching third party brands that you are buying a model that built to work on your system.
SENSOR AND LENS
Camera bodies will feature either a Full Frame or Cropped sensor. Full Frame sensors have the same dimensions of 35mm film. A cropped sensor has smaller dimensions (yes, exactly how it sounds). Cropped sensor cameras are less expensive to make and purchase.
Among other differences, cropped sensor camera feature a reduced Field of View. This leads to a multiplier factor that must be a attached to the focal length of any lens attached to a crop sensor body. The multiplier factor depends on the specific brand. Nikon's DX series, for example, has a 1.5, Canon's is 1.6. What this means is that unless you are attaching a lens to your crop sensor camera that is SPECIFICALLY made for crop sensor use (ie, Nikkor DX lenses), you should take the focal length of that lens and apply the multiplier factor to it in order to get a more accurate representation of the field of view that will be provided by said lens. For example, if I attach a 50mm Nikkor to a Nikon d90, the lens will mimic a 75mm lens field of view.
I don't generally recommend investing in crop sensor specific lenses. Lenses are an investment (I have primes in my bag that were made in the 70s and are still fantastic) that generally last beyond your camera body. Should you ever decide to make the upgrade to a full frame sensor, you'll be glad you have full frame lenses. There's also a larger variety of lenses available for full frame than for cropped sensor (even though, ironically, there tend to me many more crop sensor variety camera bodies available than full frame).
Other "add-ons" that can drive up the price (and quality) of your lenses include...
Silent Autofocus- On Nikkor, you'll see the term SWM. SWM lenses not only run their autofocus motor with little to no sound (great if you're shooting with newborns, wildlife, etc.), but it is FAST at shifting between focus points. The lens that I consider my "baby" when it comes to shooting at WDW, the 28-300mm ED, features a SWM and it's the #1 thing (other than the focal length range) that really made me fall in love with this lens. A SWM lens will shift focus points silently and in the blink of an eye, whereas most of my primes that do not have this feature will be a bit noisy and slower.
Most lenses require you to flip a switch and offer either full manual or full autofocus. A small group of lenses allow you to, while in autofocus (without flipping a switch) then fine tune with your manual focus. It's helpful, but not necessary with most on-the-fly shooting that occurs at WDW (it's not particularly useful with fast moving subjects like in shows or parades).
I'm a fan. On Nikkor look for the VR. Image stabilization offers a sharper image when handheld shooting at slower shutter speeds. The downside is that the VR CAN run down your battery a little faster, but the trade off of being able to shoot a 1/80 at a 300mm and have it still come out in focus? That's priceless.
If you're concerned about your battery, you can always turn the VR off with a flick of a switch anytime you're shooting at faster shutter speeds or on a tripod.
SO... WHICH ONE??
90% of my Disney trips, I take my baby and that's it. I don't like hauling around a massive backpack full of lenses in addition to the many trimmings of parenthood and womanhood.
Most of my shooting at WDW is outdoors with plenty of natural light, but even for more challenging lighting levels (fairytale hall, the grotto), my camera has high ISO capabilities, and I have no fear of cleaning up a decent RAW file in Lightroom. Still, that lens is not cheap, nor is it nearly as versatile when attached to a crop sensor, so...
Bring your stock zooms. Probably both of them, depending on what you want to shoot. The wide zoom (18-55mm) is great for character interactions while the long range zoom (50-200mm) will be useful for parades and shows.
Should you bring a prime? MAYBE. I like a 35mm 1.8 on a crop sensor (that multiplier factor makes it look more like a 50). You can take some really sharp, pretty portraits with that lens. With that said, if you are not used to PHYSICALLY MOVING A LOT while you shoot, you will probably NOT enjoy a prime. I should also warn you that, on my own adventures shooting with a 50 on my full frame in the hall, there will be shots that you literally can't get far away enough to shoot (like full body shots, etc.). You will be limited to... well... mostly portraits. If that's what you want? Groovy. Primes are actually at their most useful on dark rides and for the dreaded NIGHT PARADES (such as Boo To You). To date I've had my most success shooting Boo To You Parade with my 85mm f1.8.
So given all that, take the lenses that will be the most helpful to you based on what you want to shoot. I carry an over the shoulder sling bag with adjustable velcro compartments that has enough space for my camera with a full zoom attached, as well as room for one or two additional primes AND the basic necessities that make carrying a purse in addition unnecessary.
We're still just scratching the surface. Up next? Why and how to shoot RAW with your DSLR.