Wednesday, April 10, 2013

Nikon 24-120mm f/4 lens
Hands on review

Nikon considers the 24-120mm zoom to be a consumer lens, but I know many pros, me included, who use it for its convenience. It covers a focal range that make it a popular choice when you want to carry around only one lens. This lens cannot compare with the optical quality and build of the professional 24-70mm f/2.8 lens, but the added range up to 120mm make it an attractive alternative.

The Nikon 24-120mm f/4 zoom lens shown here on a Nikon D800.

This version of the lens is a vast improvement over the older f/3.5-5.6 lens of the same focal length. In fact, I found the distortions of that lens to be bad enough to make it unusable. The current version has been vastly improved optically, and with its fixed f/4 aperture it is a full stop more open than the older lens at full 120mm length. The VR (vibration reduction) of the new lens is purported to be good for 4 stops making the f/4 maximum aperture less of a problem in low light.

This is a great focal range to have when you do not know what photographic situation you will face.
 The resolution is very good in the center but sharpness drops off noticeably in the corners. It takes an aperture of around f/8 or more to bring the corners back to an acceptable level. How important this is to you depends upon how you plan to use the lens, and how objectionable you find the softness.  For instance, I use the shorter range of this focal length -- 24mm to about 35mm -- when shooting landscapes, particularly up close where the foreground needs to be in sharp focus. So for me this lens is not acceptable for that particular use. I tend to use it more as a general carry around lens for travel photography when I need to cover a broad focal range mostly in the middle zoom range where the performance of this lens is at its best and the corners do not matter so much.

This is typical of how I take many landscape photographs with a wide angle lens and close focus on the foreground. The focal length here is 28mm, but even at an aperture of f/16 you can see that the bottom corners of sand are noticeably soft. Click here to download a high res version of this image.

The four images below demonstrate the optical performance of this lens from f/4 to f/11 at 32mm. You can download the full res images using the links below the images. The corners show softness that doesn't fully go away until the lens hits f/11. In addition there is chromatic aberration present in the corners.  This was easily cleared up entirely with Photoshop but I left it in for purposes of this demonstration.

f/4 click here to download a high res version.

f/5.6 click here to download a high res version.
f/8 click here to download a high res version.
f/11 click here to download a high res version.
 The lens zooms by moving in and out and it does tend to drift out by itself when I carry the camera slung over my shoulder.

Filter size is 77mm, which fits in nicely with the standard for most Nikon pro lenses. Internal focus makes for quick autofocus with manual override.

This is the 24-120mm f/4 (lens on the left) compared in size to the Nikon 24-70mm f/2.8. In the right photo the 24-120mm is at full extension. the 24-120mm weighs less at 1.47lb (670g) versus almost 2lb for the 24-70mm. Both take 77mm filters. Although longer in focal length, the 24-120mm is more compact and lighter to carry.
Because this it is considered an up-scale consumer lens by Nikon it is not built to the same rugged standard as their pro lenses. Nonetheless, it does seem to have a very solid build to it and I don't envision having any problem with it not being able to stand up hard use over time. It price of around $1300 puts it toward the higher end between a consumer and pro lens.

At 38mm and f/8 this lens is close to the best performance range for this lens. This image has been corrected in Photoshop to show what the real usage results would be.  Click here to download a high res version of this image.
 Close focus is a handy feature in an all-around lens. This lens focuses as close as 1.5' for a magnification of .24x (1:4.1 reproduction ratio).

Racked out to 120mm focal length, at 1.5" this is the closet this lens can go, which is very good for an all-around zoom.
 Conclusion:

At first I was skeptical about using a lens like this for professional work, but the convenience of its focal length tempted me to give it a try. Now I find myself using it quite a bit, particularly when I want to walk around with only one lens. It does have limitations -- corner softness, chromatic aberration -- but they do not become much of a problem for general shooting, and the fringing is easy to fix in post-processing. I don't even mention vignetting or linear distortion because they, too, are routinely corrected in post-processing.

This lens is intended for FX cameras, but its performance would be much better on DX cameras, where it would have a focal length equivalent to 36-180mm, and many of the problems I mentioned above would disappear because you would be working in the sweet spot of the lens. 

Image quality from this lens is not up there with the exceptional abilities of Nikon's top pro lenses, but it is good enough -- particularly in the center area of the frame -- for professional shooting where you know the occasional limitations of the corners and can work around them. I have been using this lens since it first came out in 2010. It is my most used focal length for general outdoor shooting and travel.  I guess you can say it is an all around workhorse, which explains both why I like it and how I use it.



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