luxBorealis Blog

I love my prime lenses and I love the whole approach to using primes: choosing specific focal lengths to capture specific perspectives then moving to carefully compose the photograph to make best use of the film or sensor perspectives. The alternative is a zoom lens.

Zooms have their place too. While travelling around Africa, Europe and the UK, I found my two zooms, which covered the complete focal length range from 24mm to 400mm, ideal for quick hand-held shots in a rapidly changing environment. They were both Zuiko Digital zooms and simply the best combination out there. In fact, the only reason I moved away from them was Olympus’ reticence (or lack of R&D) in coming out with a sensor with enough pixels to emulate the detail I enjoy with 6×7 and 4×5 photography.

However, since switching to the Nikon D800E and prime lenses, I have, on a few occasions, missed having the flexibility of a zoom lens, especially when shooting family snaps and shots around the school. Now, the D800E is definite overkill for snaps – quite often I have it set to capture 9MP jpegs. And, perhaps buying a zoom lens for this camera is a bit dumb as I could buy a decent point and shoot that has greater range for less than the cost of a good zoom. However, it’s also nice to have the flexibility of an excellent auto-focus, zero shutter delay and, if needed, 36mp (which, by the way, is great for cropping sports photos when the action is on the other side of the field – even when using a300mm lens!).

So what did I do? I have a wonderful family who generously assisted with my purchase of the newest Nikkor zoom, an AF-S 24-85mm ƒ3.5-4.5 VRII. The focal range is almost ideal. I would have preferred stretching it to at least 100mm as my previous zoom was a 24-120 Zuiko Digital and it was ideal. The Nikkor is also a bit slow, but when you put it in perspective, this lens covers four times the sensor size as the Zuiko 4:3s lenses, so losing half a stop and 1/3 in focal length isn’t really a big deal. If 85mm isn’t quite long enough, I can always crop with plenty of pixels “to spare”.

But how is the lens quality. I always fell that when you choose a zoom lens, it’s not for quality, but rather for convenience, so I always expect to give up some lens quality. That being said, my primes are not necessarily Nikon’s best: they are all AF-D (older designs) and cheaper builds than the newer ones. I have a 24mm ƒ2.8, a 28mm ƒ2.8, a 50mm ƒ1.8 and a 105 Micro ƒ2.8. So it was against these lenses that I would test the new zoom.

This afternoon, I set up the tripod and electronic release, set the camera to ISO 100 with Mirror Lock-up and full frame raw capture and shot a series with each lens at wide open, ƒ11 (my most-used aperture) and closed down. It was really ƒ11 that is most important to me. I know lenses are a bit mushy at larger apertures and go soft at smaller apertures due to refraction, so those are the details I will show here.

Observations

I’ll not go into a detailed account of each focal length and aperture. You can see for yourself, the differences between the primes and the 24-85mm zoom as I have included a small gallery of comparisons at each focal length at ƒ11, showing the corners only. In the gallery are comparisons at 100% of the top right corner in Lightroom’s “Compare” mode. The files have had no additional processing or sharpening. NOTE: When you look at the gallery images, be sure to click on “View Full Size” in the bottom right of the window that opens.

Needless to say, the centre of each frame is quite good and not significantly different at comparable focal lengths and apertures. What is most important to me are the corners as that is where a lens falls apart. The 24-85mm zoom didn’t disappoint, but it didn’t match the quality of the primes, either. As expected, the zoom showed more light fall-off in the corners, but quite unexpectedly, it did rather well up against the 105mm Micro-Nikkor. I also didn’t expect the 50mm ƒ1.8 to perform as well as it did – it looks great in the corners.

One unexpected difference was in colour saturation and exposure. While the primes had slightly higher contrast (as expected), the zoom has slightly richer colours which may be a result of exposures from the zoom being 1/3 to 3/4 of a stop darker. Not a big problem, but unexpected. Perhaps the stated maximum aperture of the zoom is not as wide as claimed meaning the ƒ3.5 is really a ƒ4 or 4.5. That is one real bonus of prime lenses – they are generally faster than zooms in the sae relative price range and primes are of higher quality at maximum aperture.

So, is the AF-S Nikkor 24-85mm VRII lens good enough to walk around with? Yes it is – just. I am well aware of its shortcomings – which are not too serious, really – and plan to make good use of this lens. However, I will not be using it for my dedicated landscape and nature shots. I will forego the convenience of having a range of focal lengths in one lens and will gladly switch primes when I feel the shot really deserves the kind of quality I can get from prime lenses.