For many photographers, especially those starting out, deciding which lenses to buy can be a daunting task. One of the fundamental questions we often ask ourselves is “Should I buy prime lenses or zoom lenses?” Chat rooms on the internet tend to reveal some very strong opinions on this subject, with a few assumptions often coming into play. Ultimately the decision really is one of personal choice based on a number of factors.
Note: a few images have been added to this article to provide visual breaks. Click on them to enlarge.
Let’s consider lens sharpness. DxOMark defines sharpness as the visually perceived quality of details in an image. This is associated with both the resolution and contrast observed in the details. Many proponents of prime lenses will cite lens sharpness as one of the primary reasons, if not the most important reason, to choose a prime lens over a zoom lens.
They often claim that a prime lens is always sharper than a zoom lens. But, is this always the case? The simple answer is – no. We need to remember that a lens does not operate in a vacuum. The images we create are produced by the combination of camera body and lens we use and performance can vary. We also need to remember that lens technology has been advancing at a considerable rate and the design age of a particular lens can be a significant factor in terms of its sharpness on more modern camera bodies.
For example, if we look at the Tamron SP 24-70 f/2.8 Di VC USD zoom lens mounted on a Nikon D800 its sharpness is rated at 17P-Mpix by DxOMark. A Nikon 58mm f/1.4G mounted on a D800 is rated at 18P-Mpix, and the Nikon 50mm f/1.8G is rated at 16P-Mpix on that same body. So there is very little difference between these three lenses. What about something like the Zeiss Planar T 50mm f/1.4 ZF2? 13P-Mpix.
There certainly are prime lenses that are much sharper than a zoom lens that covers the prime’s focal length. The Carl Zeiss Distagon T* Otus 1.4/55 ZF.2 is one such lens. On a Nikon D800 it is rated at 29P-Mpix, which is phenomenally sharp. But, before shelling out $4,000 or more on such a lens we need to ask ourselves if we can justify this kind of expense for one lens.
Let’s look at the Nikkor 85mm f/1.8G. It is a reasonably affordable lens and many Nikon shooters love this lens, often claiming it is ‘uber-sharp’. On a D800 it is rated at 19P-Mpix. The Tamron 70-200 f/2.8 Di VC USD on that same camera body is rated at 22P-Mpix, while the Nikkor 70-200 f/2.8 VRII is rated at 20P-Mpix, and the Nikkor 70-200 f/4 comes in at 21P-Mpix.
It is also important to keep in mind that lenses will perform differently based on the body on which they are mounted, and those differences can be noticeable. As an example let’s look at the Tamron 70-200 f/2.8 noted earlier. While it is rated at 22P-Mpix on a D800, it scores at 28P-Mpix on a D800E/D810 which is a significant difference. While the Tamron performs marginally better than the Nikkor 70-200 f/4 on a D800 (22P-Mpix vs. 21P-Mpix), it falls behind the Nikkor lens when it is mounted on a D800E as the Nikkor lens scores 30P-Mpix vs. 28P-Mpix for the Tamron – but it is still close.
So, rather than assume lens sharpness, it is far better for us to do our homework and look at specific camera body and lens combinations so we can make informed decisions based on independent test results.
We need to be aware that when we take the time to compare prime lenses of the same focal length produced by different manufacturers we may discover that there is simply no benefit in buying the more expensive lens in terms of sharpness depending on the camera body we are using.
For example, if we are shooting with a Canon 5D Mark II using a $900 Sigma 35mm f/1.4 DG HSM, it produces a DxOMark sharpness score of 17P-Mpix. Switch the lens on that camera body to an $1,850 Zeiss Distagon T* 35mm f/1.4 ZE and the sharpness score drops to 15P-Mpix.
Many proponents of prime lenses also claim that they are absolutely needed to deal with low light situations. This is only partially true. If we are shooting in low light where our subject is in motion we will need to shoot at a higher shutter speed to avoid image blur of our subject. In this type of situation a prime lens that shoots at f/1.2, f/1.4 or f/1.8 can be an excellent tool to use, especially if we are also trying to shoot at the lowest possible ISO to help limit noise.
However, many prime lenses do not have vibration reduction which limits the shutter speeds at which they can be successfully shot hand-held, unless our camera body has in-body image stabilization. In situations where we are shooting a stationary subject in low light and at a lower ISO, a zoom lens that has effective vibration reduction may do a good job for us if our hand-holding technique is sound.
Some folks go as far as to state that shooting with a zoom lens makes a photographer lazy and limits their creative development. They claim that using prime lenses makes a person become more involved with their subject, and by forcing them to move around physically to get proper image framing, it makes them become a better photographer. I think this is hogwash. The root of composition is in the mind of the photographer and the lens used is simply a tool to help bring that vision to life. If we don’t have the capacity to see the images we want to capture in our minds, the lenses we use won’t make one bit of difference.
What about bokeh? It is true that shooting at a more wide open aperture like f/1.4 or f/1.8 can produce smoother, and more pleasing, ‘muted’ backgrounds that help to isolate an image subject. We need to remember that background blur is a function of more than just the f/stop used, as the distance of the camera from the subject and the distance from background details also come into play.
Prime lenses are generally smaller, lighter and less expensive than zooms so many folks will choose primes from budgetary and portability considerations.
So, where does all of this lead? At the end of the day all that really matters is the quality of the images that we capture and produce. The route we use to get there in terms of our choice of lenses is secondary.
If we can avoid cropping our images whenever possible, and use as much of our camera’s sensor – the more details our images will contain. Shooting at the lowest possible ISO given conditions will allow us to take full advantage of the dynamic range and colour depth of the sensor in our camera, producing the best possible images from that particular make/model, regardless of what we happen to own. Using a tripod or developing very good hand-holding technique will help reduce camera shake and help lead to better quality images. Shooting in RAW and learning how to use whatever software we have to its fullest will also help us create better quality final images. Whether we choose to use prime lenses, zoom lenses, or a combination of both types isn’t as important as these other factors in terms of the final images we create.
Technical Note: All images in this article were taken hand-held with a Nikon 1 V2 and a Nikon 1 10-30 f/3.5-5.6 VR zoom or Nikon 1 30-110 f/3.8-5.6 VR zoom kit lenses. The manufacturer’s suggested list prices of the lenses at the time of writing this article were $219.95/$279.95 Canadian. I’ve included pricing information to reinforce the idea that good quality images can be achieved with cameras with small sensors like the Nikon 1 V2 along with modestly priced lenses.
Images were produced from RAW files initially processed through DxO OpticsPro 9/10. A DNG file was then exported into CS6 and Nik Suite for additional adjustments as required.
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