As new photographers start growing in their chosen path, they will eventually want to grow their equipment too. And the most popular second item to purchase has always been a longer focal length lens, normally a tele-zoom lens. Somehow, people just seem to want to “reach out” further with their second lens.
Longer?… Longer As Compared To What?…
Well, this comparison takes us back to the good old days, when lenses were always quoted in comparison to the standard lens. So it you are using the 35mm camera system, then your standard lens would be the trusty old 50mm lens.
Longer lenses would be mean anything with longer focal length than 50mm. Prime telephoto lenses like 85mm, 105mm, 200mm, 300mm, 400mm, 600mm, etc. all fall into this category.
Then there are also tele-zoom lenses like 80-200mm, 200-400mm, etc. Of course there are also mid-range zoom lenses that partially cover focal lengths longer than 50mm, but that is a different class altogether, so we shall not discuss them here.
Money Talks… Even In The Photography World
As the focal length increases, so does the price. The longer it goes, the more complex the optical formula, and more glass material is needed to construct them, hence the increased price. But that’s only part of the equation.
The other half of the equation is that maximum aperture is inversely proportionate to the focal length, assuming everything else remains constant. What this means to us – non-mathematicians – is that as the focal length increases, the maximum aperture decreases. Therefore a long lens tends to be a slow lens too.
However, this is not a death sentence. You can design the lens barrel to have a larger internal diameter to compensate for the smaller maximum aperture for a longer lens. That way, you not only get a longer lens, you also get a girthier lens too. But (I’m sure you heard the “but” coming a mile away), in order to get the best of both worlds, there is a price that you must pay… literary… $$$
This combination is known as “fast lens”, meaning large maximum aperture lens. Fast lens are generally grithier than its “slower” cousins. Its girth increases exponentially to its focal length, hence any fast lens longer than the 200mm f/2.8 lens will be too heavy and girthy to be handheld.
It’s Nothing Personal… It’s All Business…
The manufacturers of photographic equipment are all in it for the profit. So in order to maximise their bottom line, it is always in their favour to sell more products. But the hefty price tag of long and fast lenses prohibits the brisk sales at the retail level. So to make up for it, manufacturers advertise all the advantages of the long-fast lens, but sell more long-slow lenses instead, which are priced very much lower than their faster cousins.
So should you break your piggy-bank, and go all out for the long fast lens for your next lens purchase, or do you settle for a more affordable, equally long, but much slower lens instead? Well, the answer very much depends on what you intend to do with it. If you plan to use it to record your globetrotting adventures, and have all the time in the world to arrange and compose your subject, then I would say keep your piggy-bank intact, and go for the cheaper option. You are much better off spending the extra pocket money on your plane tickets instead. Besides, you sure don’t want to haul around the dead weight on top of all your other luggage and personal belongings.
But if your answer is to go into the heat of the action, like maybe shooting motorsports or the like, then you have no other choice but to break your piggy-bank, and go all out for the fastest long lens you can afford. The slower (and more portable) lens wouldn’t cut it when it comes to capturing actions.
Yes, this is the exact combination that you saw in the image right at the beginning of this article. The lens is the Tokina AT-X 80-200mm f/2.8 lens, extended with a Teleplus 7-element 2X tele-converter, essentially doubling the focal length to 160-400mm f/5.6. And yes, it is a pretty fast zoom-lens.
So Are You Saying That Fast Lenses Better?
Hmmm… Not exactly!… It’s faster, meaning they have a much larger maximum aperture. That in turn means you can afford to shoot your subjects with a higher shutter speed at the same lighting condition. So if you don’t mind hauling around all that extra bulk and weight of a faster lens, then it will definitely make your shooting adventure much easier.
But if you are talking about the absolute optical quality, then no, they are not necessarily “better” than a slower equivalent lens. Don’t get me wrong, they are not worse off, just not necessarily better.
Okay, Now I’m Officially Confused…
Generally speaking, the further away you go from the standard 50mm lens, the more complex the optical formula is. Therefore, in order to design a lens that can capture an image as close to its point of origin (i.e. the standard 50mm lens), the more difficult it is to do. This means the longer the focal length of the lens is, the more expensive it will be to manufacture. However, the increment of the cost is more or less linear, assuming that the drop in the maximum aperture is ignored. The longer the lens is, the smaller the maximum aperture becomes.
Assuming that a 50mm f/1.4 lens cost is, I don’t know, maybe a hundred dollars? (Substitute dollar into whatever currency that you are familiar with)
50mm f/1.4 costs $100
100mm f/2.8 cost $200
200mm f/5.6 cost $400
However, if we make the focal length a constant (let’s say a 200mm f/5.6), and we design it to achieve a larger maximum aperture, the increment in cost now becomes exponential instead.
200mm f/5.6 cost $400
200mm f/4 cost $800
200mm f/2.8 cost $1,600
200mm f/2 cost $3,200
Again, this does not mean that the more expensive lens will have a “better” optical quality than its equivalent slower lens. It just makes your photographic work so much easier to live with, as larger maximum aperture comes with a host of benefits, like making it so much more easier to focus with.
So Which Is A Better Choice For A Second Lens Purchase?
Again, it all depends on what you intend to achieve with the second lens, and what you plan to shoot with it. If all you want is to record your travel adventure, then you might as well spend your money on your travels and accommodations, and opt for a cheaper, slower lens. But if you intend to make a living with your photography, then you might as well invest in a fast lens.