Last week, I reviewed the Sony Nex-6 camera body. One of the interesting features of this line of Sony cameras is the large selection of third party lens adapters available, making it possible to mount almost any mount system lens. While most of these lenses will use the camera’s auto focus (or any other “auto” features for that matter), they will work perfectly well in manual focus mode. There is some “quirkiness,” though. Neither the camera’s onboard information, nor the embedded EXIF information will give you the aperture value, the focal length or the shutter speed value. I used the manual metering system and the on-screen “real time” histogram feature to estimate exposure. And, it appears that on the lenses which do not have physical aperture settings, the camera will default to the smallest aperture and there does not appear to be any way to adjust that. On lenses with aperture rings, you will be able to set the aperture. Sony does make an adapter for its own lenses (i.e., the A-mount series that mounts on its DSLR cameras) that will pass the autofocus and exposure information through to the camera body and vice versa.
I purchased the Rayqual adapter for Nikon “G” series lenses (these lenses do not have a physical f-stop selector ring, but are instead all chosen by one of the camera’s “command” dials). The G adapter will work with any existing compatible Nikon “F” mount lens (or any lens fitted to the Nikon F mount). There are a number of manufactures that offer adapters, and reviews seem to suggest that quality of manufacture is all over the place. The Rayqual was recommended to me by my pro friend and I thought it made sense to go with something known. The guy at Cameraquest was very accomodating.
Of course, the camera’s “APS” sensor means you will have to apply the 1.5 field of view factor to the lens. But there are some very sharp, fully manual, older lenses out there (i.e., the venerable 50mm f1.8). I played around with a couple of my own Nikon lenses and found that in reasonable light conditions, focusing (either on the back LCD or in the viewfinder) is relatively easy.
My primary motivation for purchasing this Nex-6, though, was to find smaller, more convenient setup to use while traveling and while out walking around, that would give me image quality like I have grown to expect from my DSLR setups. The NEX has the promise of doing that, in my view. But using an adapter and manual older lenses may defeat that purpose. While they are fun to play around with, I don’t want to be doing that when I am on vacation in new places. I want to shoot and have reliably good quality results.
For that reason, the Sony E SELP16-50 F3.5-5.6 PZ OSS zoom is a very attractive lens. The 35mm equivalent of approximately 24-75mm is a pretty useful range for “street” shooting and “walking around.” Of course, 28-300 would be nice (and they do offer that option), but it comes at the expense of size, weight, and … well, expense (the E-mount 18-200 is over $800). I don’t intend for this camera to replace my D800 DSLR. It is a significant upgrade replacement to my Canon G12, though and will undoubtedly get lots of use. As such I really wanted the 16-50 to be acceptable. It didn’t have to match up to the performance of my f2.8 Nikkors.
I am pleased to say, I am pretty impressed, given the challenges the lens faces. The lens, fully retracted, measures only 1 1/2 inches long (there is a serious typo in the dpreview literature – though it would be amazing to have a zoom of this range that measured only 3/16 inches 🙂 ). The overall depth of the Nex-6 with this lens attached is a mere 2 1/2 inches! The lens is image stabilized (OSS), with a minimum focus distance of just under 10 inches. Its minimum aperture (depending on zoomed length) is between f22 and f36. It is a very lightweight addition to an already comfortably light and small body. The barn above, was shot at 50 (75) mm at f16. You can see that at those specs, the lens produces a relatively sharp, edge to edge result. But how does it do at wider apertures, and at other focal lengths? You can see in the image below of the white house that, stopped down, the lens performs nicely at its wide end (note that this was distortion-corrected in ACR using its lens database). For daylight images, I cannot think of a reason not to stop the lens down to its “middle” ranges (f8-11-16), unless trying to obtain a specific DOF result.
I will leave the technical specifications, like resolving power, distortion measurements, and other things to the technocrats and pixel peepers. My criteria was whether I was going to be able to bring home some “wall hangers,” using this lens. I think I can.
My non-scientific testing involved setting the camera up in my basement, mounted on a tripod using the same image, from a stationary position. I also used the IR remote to ensure no camera movement was involved. I am still trying to master the settings and particularly the AF technology on this little unit. To the best of my observation, the IR remote did not cause the camera to try to re-focus (which is a good thing). However, as I glean more knowledge about the AF technology in this camera, I wonder if that is really what is happening. From what I read, the default AF system in the camera works with “contrast detection” (as opposed to “phase detection” on most DSLR cameras). What I am learning this means, is that the camera, when set to its AF setting, is constantly searching for a sharp exposure. So, it may just be that in good light, the AF performance is just that good, and and locked on when the remote triggered.
What I generally concluded was that there is little difference in sharpness from wide to small aperture and from short to long focal lengths. This is particularly true (as might be expected) in the center of the lens. But I am pleasantly surprised at the edge to edge performance. Granted, this combination is not going to be an architectural setup. Nor will it be up to the standards I generally expect from a “grand landscape” image shot with a “pro-specs” lens. But for its intended use, the results were very acceptably sharp and pleasant. All images were at 100 ISO.
Since a common concern is whether these lenses are sharp at their longest lengths, I started there. I then tried some additional, varied settings of the same image:
Other reviewers have noted that this lens suffers from significant distortion and some vignetting, particularly at the wide end. The “before and after shots” here confirm this. Both images were adjusted for contrast in my ACR raw image converter (Adobe Camera Raw), run through Dfine’s noise software and the default settings Pixel Genius’ “capture sharpening” engine. They are otherwise uncorrected except that I applied the “lens correction” facility (again at its default settings) in ACR before opening it in Photoshop. Some of the curvature can, of course, be attributed to the user. A higher camera position would help here, if possible. But you can see the pronounced curvature in the first image and the somewhat “tamer” curvature in the corrected version. You can also see noticeable vignetting in all 4 corners of the first image and essentially no trace of it in the corrected image (no filters were used in this example, by the way, so this is the “bare” lens being demonstrated). Sony is aware of this issue. Again, I am not an engineer (and the world is a better place because of that 🙂 ) but it is my understanding that this is a design issue that cannot be overcome at this point (somebody will figure it out some day). This is physically a very short lens for its zoom range, and also small, working on a larger sensor than many of these smaller lenses have used in the past. To “combat” these issues, Sony has firmware in the camera that “corrects” for this. For Nex users that are using one of the earlier models (Nex-3, 5 or 7), it is my understanding that it will be necessary to upgrade the firmware to take full advantage of this. Caveat: the Sony firmware correction will only work on jpg files. For those of you shooting jpg (there is a 10-step program for you out there 🙂 ), I understand from what I have read, that this works very well indeed. For the rest of us, some correction in post-processing will be necessary. Adobe has done a great job of incorporating lens correction algorithms in their Light Room and ACR modules, including this lens. I don’t have any familiarity with other raw converters or post-processing software, but it would not surprise me to find something there. I consider the “corrected” image somewhat “normal” for this type of image, at the selected focal length of 16mm (24mm at 35mm-equivalent).
For the few who don’t already know this, the word actually comes from the Japanese, “boke,” and refers, in loose translation, to blur. For photography purposes, it is usually referred to as the aesthetic quality of the out of focus areas rendered by the lens. With regard to this particular lens, I can only really refer to the last 2 letters of the word in describing my reaction to the 16-50’s Bokeh: “eh.” :-).
Seriously, as I have said previously, it is a multi-purpose zoom in which Sony is trying to accomplish an awful lot of engineering, including a wide focal length range, reasonably wide apertures, and above all, very small footprint. Given its modest price and versatility, I think they have done admirably well. I think it would be unrealistic to expect it to stack up again virtually any prime lens and particularly the Zeiss glass or any of the Leica, Nikon, Cannon, Zuiko, Voightlander, or other “legacy” lenses that can be fitted via an adapter. As part of my overall purchase, I picked up the pair of Sigma-manufactured e-mount f2.8 primes (19mm and 30mm). When I get a chance to get in the field and do some real world testing, I hope to report on them. for now, here are two “test” examples. Images are not very exciting, but given the time of year here, they are what I have to work with :-). The first image is at the widest end of the lens, wide open. The second is at the longest focal length, again, wide open. I did not do any sharpening on these two images, so they are pretty much what you see is what you get (other than whatever PS did during the jpg conversion and resize, and I can say they looked pretty sharp on my screen as they came out of ACR).
I used the same default “capture sharpening” using Pixel Genius’s “Photokit Sharpener,” and identical contrast and local contrast adjustments in ACR on all the illustrated images. I did not do any other sharpening.
While the light was not quite as nice on the final image, I wanted to include it to show that the lens is decently sharp at the wide setting and its wide-open aperture, too. With appropriate “creative” sharpening in post-production, I can see that this lens will produce very acceptable images.
Filed under: EQUIPMENT REVIEWS, PHOTOGRAPHY | Tagged: Andy Richards, APS, Bokeh, Cameraquest, distortion, DSLR, exposure, Light, LightCentric Photography, NEX Adapter, Photoshop, Rayqual, sensor, sharpness, Sony 16-50 zoom, Sony Nex-6 |