I don’t know how many times I have heard people ask what the best lens to buy is. A reasonable question for a newbie maybe as they simply do not know. Part of the problem though is the do not know what they do not know! What do I mean by that? Well frankly they likely do not even know what type of photography the are interested in performing, and without that essentially piece there is no way one can even begin to recommend a starter lens, never mind the best lens.
You see different photography types requires different lenses, landscape, portraiture, architecture, wildlife, birds, insects, flowers, astrophotography and on and on. Some require exotic lenses with very unique design, some require lenses with long reach or high magnification, some super sharp and minimal distortion and others very wide broad view.
And even if one narrows it down a bit there are differences in options, capabilities and price points. Let’s look at a common Nikon some ask about, the 70-300mm versus the 70-200mm lens and which is best to buy. Well the 70-300mm looks like a logical choice as it is more versatile, it actually comes at a lower price point and is much lighter and easier to carry around. All logical reasons to jump on it.
Well lets look at a few items on each and compare.
First the focal length, yes the 70-300mm has more magnification and allows one to zoom more closely on distant objects. But longer zoom lenses are always a compromise, each focal length has an optimal design which changes quite dramatically from longer focal length to shorter ones. This means it is very difficult to design lenses which have huge variance between the shortest and longest focal length and as a rule of thumb one should never look at lenses which have a ratio between shortest and longest of more than 2 to 3 times as the compromise gets too large and the distortion and soft focus in images becomes much more apparent. So what is the difference between these two? Well the 70-200mm has a zoom ratio of 2.85 or lets say 2.9 which is almost the upper limit! The 70-300mm has a zoom ratio of 4.28 or lets say 4.3 which is well over the generally acceptable limit meaning this lens likely has a soft focus and distortion problems going by a general rule of thumb.
Next is the speed of the lens or the widest aperture. The 70-300mm has a variable aperture, which accounts for a lower cost as it is a much simpler design. The aperture on this lens varies from f/4.5 at 70mm to f/6.3 at 300mm. Now this is not that fast a lens as you are going to need a bit of light at f/6.3 and some cameras may struggle a bit with focus if in dim lighting conditions. The 70-200mm is a constant f/2.8 across all focal lengths, this means the difference being between 2 1/2 to 3 1/2 stops! Each stop needs twice as much light, meaning at the 70mm range the 70-300mm needs over six times the amount of light and at 300mm will need even more to operate as well. That is a huge difference in performance.
Now the 70-200mm is a much larger and heavier lens, which can make it more award to use, that however is a result of physics and what is required to make a lens that has wider aperture and is better in low light. Performance comes at a cost. Yes a cost, both in size, weight and dollars spent.
As far as physical build the 70-200mm is a monster and far more robust, much better able to handle the bumps of daily use. But that is to be expected as this is a professional grade lens. It does however also show in part why the weight and cost are much higher.
Auto focus performance is much better with the 70-200mm as well, it is faster, performs better in low light and is simply much better overall.
Image sharpness, as can be expected with all things listed above can be expected to be quite a bit better with the 70-200mm lens and frankly it is.
Now this was not meant to be a full review or even to really say one is that much better, but to help show that the best lens is difficult to state. Yes the 70-200mm does operate faster, does focus better, does take sharper images in much more challenging conditions and is far more robust in design. But, having said that, the 70-200mm also weighs perhaps twice as much, is physically larger and costs a heck of a lot more.
So even in this situation one of these may be better suited for one person and the other for another person. Each may be satisfied with their choice, even though they are totally different lenses. Not everybody needs or wants the very best or sharpest lens, the fastest lens or the one with the longest reach. It depends on your specific needs, your ambitions and expectations and of course your budget. If you are just starting out get a low cost budget lens often referred to as a “kit lens”. Maybe even two of them. Again in the Nikon crop camera world this may be something like the 18-55mm and the 55-200mm lenses as a pair. Some will say you need primes lenses, you need faster lenses, etc.. etc.. blah.. blah.. blah.
Fact is you DON’T – get those two to start. They are sharp enough, take fantastic images and work well. They are inexpensive and cover a very wide range in focal length. You may well be satisfied with those two for the rest of your life, or you may decide you want others as your hobby grows, but at least you will then know what you need and be able to make that decision on your own versus getting input from others who neither know your needs and often don’t even really know what they are even talking about!
Enjoy and take lots of photos!