If there’s one aspect of a lens that is more discussed than any other, it’s sharpness. In wildlife photography, sharp photos are especially sought-after, with just a few exceptions. Fine feather detail in bird photography is one of the first things I look for in my own shots, personally. But how much does a lens’s sharpness really matter in wildlife photography?
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What is Lens Sharpness?
In short, a lens’s sharpness is its ability to resolve detail on the subject. But lens sharpness isn’t just a single metric – the same lens that’s sharp in some cases may be below average in others. For example, let’s take a look at our sharpness measurement from Imatest for the Nikon Z 50mm f/1.8 S lens:
This is actually one of the sharpest lenses we’ve ever tested in the lab, but even so, you can see that the sharpness depends on the aperture and the portion of the frame that you’re considering. The Nikon 50mm f/1.8 S behaves like most lenses: It is most sharp in the center, and it has a “sweet spot” of the sharpest aperture values (in this case, around f/2.8 to f/5.6).
The sharpness or resolving power of a lens is dependent on the optical formula of the lens. More modern and complex designs often – but not always – result in better sharpness and fewer aberrations.
In general, expensive and exotic telephoto lenses (like 300mm f/2.8 lenses, 600mm f/4 lenses, etc.) tend to be among the sharpest optics of any lens today. But there are plenty of cheaper telephoto lenses on the market, too – some of which are not as strong optically. Does that matter? Well…
A Sharp Lens Does Not Mean Sharp Photos!
When people use the term “sharp photo,” they are actually referring to the presence of detail. This detail depends upon much more than just the sharpness of the lens.
In other words, don’t expect to pick up the latest 600mm f/4 and automatically get beautiful, razor-sharp wildlife photos. There are many other factors to consider first.
One of the biggest ones is subject distance. If the subject is closer, detail such as bird feathers will be larger relative to the frame, and thus you’ll capture more detail on them. Plus, being closer reduces the distortion effects from atmospherics.
There’s also the focal length of the lens. If your subject is far away, the world’s best 400mm lens will not compare to an average 800mm lens in the detail you’re resolving, since the 800mm lens magnifies the subject so much more.
This is one reason why it is so dangerous to judge lens sharpness purely on sample photos, especially if you’re not seeing the original Raw files. For example, a nearby bird photographed with a cheap 70-300mm zoom will appear sharper than a bird far in the distance photographed with a high-end 300mm f/2.8.
There are other factors, too, including:
- Shutter speed and subject movement: Pick too slow of a shutter speed, and you’ll get motion blur – a huge culprit behind sharpness loss!
- Missed focus: Front-focus or back-focus can make a $10,000 lens look worse than a point-and-shoot camera lens.
- Sharpening in post-processing: This won’t magically create lost detail, but it can make existing detail more apparent.
- Image noise: Shooting in low light and high ISOs is a recipe for losing details. Proper noise removal can help, but overdoing noise reduction can make the problem worse.
In other words, the final level of detail present in your photo depends on a lot more than the pure resolving power of your lens.
A Below-Average Lens Does Not Mean Blurry Photos!
It’s obviously true that sharp lenses can resolve more detail (at least if you do everything else right). This helps for things like cropping your photos or printing a bit bigger.
But, if you’re filling the frame with your subject and you have plenty of light, you’ll capture surprisingly similar levels of detail with a budget telephoto compared to a super-sharp exotic lens, so long as your print size is reasonable. I’ll put it like this – if you’re getting blurry photos with any modern lens, it is unlikely that the lens’s resolving power is to blame.
Recently at Jardim Botânico São Paulo in Brazil, I managed to get very close to a Southern Lapwing with my Nikon 70-300mm AF-P DX lens. This is a $400 entry-level telephoto zoom, and although it’s perfectly acceptable, it’s not going to be in the same conversation as Nikon’s exotic primes. Yet because I had proper focus, a fast enough shutter speed, a low enough ISO, and a subject filling the frame, the photo is very sharp up close. The limiting factor for making a large print is my pixel count, not the lens at all!
Granted, these were close to ideal conditions. For more difficult subjects or extensive cropping, the 70-300mm would have shown its weaknesses more clearly. But it goes to show that a basic – or even a below-average – telephoto lens is not a fatal blow to sharp wildlife photos. It’s better to fill the frame with a cheap lens than to crop extensively with something expensive.
Should You Upgrade to a Sharper Lens?
Whether you should upgrade is a tricky question. When you get a more expensive or higher-performing lens, sharpness is far from the only thing that will improve. For example, going from the Sony FE 200-600mm f/5.6-6.3 G to the Sony 600 f/4 GM does not just give you more sharpness, but faster autofocus and an f/4 maximum aperture. Frankly, these improvements matter more to the photo’s overall sharpness, compared to the difference in resolving power between the two lenses.
In my own wildlife journey, I used to shoot with the Tamron 150-600mm G2 lens and later upgraded to the Nikon 500mm f/5.6 PF lens. In this case, the faster autofocus and lighter weight of the lens were the most noticeable improvements, and both had direct impacts on the sharpness of my photos. Yes, the 500mm f/5.6 is the better of the two lenses in lab tests, and that shows up sometimes in the field – but it was the other features that made a bigger difference to me.
Not to mention that most of the time, the problems in a wildlife photo run deeper than sharpness (whether lens sharpness or otherwise). It’s much more important to focusing on lighting and composition (gasp!) than pixel-level detail. And even when the problem specifically is insufficient detail, the most likely culprit is that you need to get closer to your subject.
That brings me to another point: the degree of the upgrade. To bring up one common situation, if you’re currently shooting with a shorter lens plus a teleconverter, switching to a lens with a longer native focal length will usually be a nice upgrade in terms of sharpness (especially if it’s a prime lens).
On the other hand, the differences in sharpness narrow once you climb the ladder of high-end lenses. If you’re still not getting adequately sharp photos with some $2000+ telephoto prime lens, you better not be blaming the lens, unless you dropped it off the ladder.
I remember that Libor surprised a lot of people when he noted that the Nikon Z 400mm f/4.5 (a $3250 lens) is basically as sharp as the Nikon Z 400mm f/2.8 TC (a $14,000 lens). There are good reasons why pros will buy the f/2.8 prime – mainly the wider maximum aperture and built-in teleconverter – but sharpness measurements in the lab are probably not among them.
Finally, there is no doubt that lenses are getting better with time. Modern lenses, even the budget ones, are much better than a typical lens of ten years ago. I would have no issue using modern telephoto zooms like the Sony 200-600mm, Nikon 100-400mm, and presumably the upcoming Nikon 200-600mm. The sharpness of those lenses may be worse than a high-end prime in the lab, but in the field, those differences will often disappear.
So, how would I answer the question I posed in the title of this article? I’d say that lens sharpness doesn’t matter too much beyond a certain point, and we’ve mostly reached that point with modern lenses, even cheaper ones. But paradoxically, upgrading to a sharper lens can still be worthwhile for sharpness-obsessed photographers! That’s because the sharpest lenses on the market (usually the exotic primes) have other features that matter more. They have wider maximum apertures, faster focusing speeds, better image stabilization, and so on. Those features can directly lead to sharper photos. So if you switch from a 70-300mm f/4.5-5.6 to a 300mm f/2.8, you’ll definitely get crisper photos, but probably not for the reason you were thinking.
And as a final note, let’s all take a step back if possible. It can be kind of silly how much photographers obsess with sharpness these days – and I’m guilty of it too. I love prints that look razor-sharp up close. But some of the best wildlife photos I’ve seen still have a few issues when your nose is up against the glass. Before you spend a fortune upgrading your lenses, make sure you know what you’re gaining and exactly how it will help your photography.