Even though the weather is dreary this time of year, the past couple of months were the start of birding season here in the Greater Vancouver region. This is the time of year when the bald eagles return, and there are multiple spotting opportunities along the waterways. Of course birding means long lenses, and the rule of thumb is that you can never get close enough with the lens that you have. By it's very natural, bird photography is an expensive hobby. This is where the Sigma 150-500mm enters. It's still not an inexpensive lens, but it's much less expensive than any other lens of a similar focal length. Compared to the "Bigma" 50-500mm, the 150-500mm is a more focused device for long range photography.
Updated July 2014: Added comparison sample with Nikon AF-S 80-400mm f/4.5-5.6G ED VR
Build and Design
The 150-500mm predates the Global Vision refresh, but nonethless maintains the appearance of a serious lens. Tolerances are tight, with no wobble in the barrel or control rings, both of which turn with a user-friendly amount of resistance. There tripod collar is sturdy and locks the lens solidly in place. There's a fair amount of heft to this lens, but in terms of size and weight, it's probably the smallest lens on the market that reaches 500mm.
In terms of features, this falls into the category of being a "modern" lens, as it has both OS image stabilization and in-lens HSM focusing motors. Both greatly add to the usability of the zoom lens, but neither performs as well as the best implementations in either Nikon or Canon camps. Focus speed is quick not not the fastest; it's nowhere near as quick as the AF-S version of Nikon's 80-400mm for comparison. The OS image stabilization system takes a bit of time to settle in, approximately up to a second or so. You have to let the image stabilization system settle in to properly use it; when it does there's a noticeable "snap" to how the image settles down in the viewfinder. The behaviour of the system is quite abrupt compared to how the Nikon and Canon systems work. Letting the image stabilization system settle is good practice for all stabilized lenses, but it's especially true for this one.
In adequate light, you could shoot with this lens hand-held, but it's not really a good idea. Usually, manufacturers' claim 3-4 stops of shutter speed advantage with their image stabilization systems, but it's bets to be conservative and to shoot around the assumption that system provides only two stops at best. As will be discussed further, the optical quality of this lens is good but not great; however, if you insist on shooting without a tripod or monopod, chances are that there will be more loss of detail due to handshake than because of the optics.
Here are the vital stats for crop and full frame use:
|Focal Length (mm)||Crop Field of View, Degrees||Full Frame Field of View, Degrees|
Naturally, the best use of the long focal length of this lens is to use it on a crop-sensor body given the pixel density of the smaller format. Visually, here is that the field of view looks like on a Canon EOS 70D (JPEG, out of camera):
On the EF-S Canon bodies, the reach is the equivalent of 800mm on the full frame boy. it's a challenge to hand-hold this lens full-extended. Assuming a conservative estimate of a two-stop advantage with the OS image stabilization system turned on, the minimum safe shutter speed for a non-moving object without a tripod or a monopod would be 1/200s. This is quite challenging in low light conditions, as the maximum aperture of the lens is f/6.3 at 500mm. Note the loss on contrast as you zoom in, the black curtain becomes progressively lighter and the saturation in the red's goes down. That said, it's rescuable in post processing.
On a 5D Mark III, this is what the lens looks at at various focal lengths. For reference, the figurine is approximately 4-5" tall. Note that "bokeh" is essentially irrelevant at the longer end of the focal length scale when focusing on objects at near-to-middle distances. The perspective compression of using a longer focal length "magnifies" the blur in the background, making everything behind the plane of focus look creamy.
The vignetting wasn't an issue on the crop body, but it is apparent on full frame.
If you think that something is amiss in the above samples, then you would be correct. The magnification of the figurine is less than what you would think that the focal length should produce. The 150-500mm exhibits what is known as "focus-breathing" In other words, the effective magnification is reduced when you shoot at objects that closer to you than the infinity-focus distance. You only get the full effect of 500mm when focused at far distances. In all fairness, all lenses do this, and it's seen on the Canon 100-400mm as well.
Like most lenses, this one isn't as good at the extremes of its use as it is in the middle. In other words, 500mm is nice, but the lens is at its best below 400mm. This is also true of the Canon 100-400mm and the AF-D version of the Nikon 80-400mm. The results are "merely okay" with the lens wide open, but the Sigma 150-500mm is capable of producing decent results when stopped-down. In terms of handling, anecdotally, the Sigma has better image stabilization than the Canon, and is sharper at 400mm than the AF-D version of Nikon. However the Nikon AF-S 80-400mm is in another league compared to all of these lenses, both in terms of overall performance and price.
Sigma 150-500mm f/5-6.3 DG OS HSM APO vs Nikon AF-S 80-400mm f/4.5-5.6G ED VR
The following sample were taken on a Nikon D7100, out of camera JPEG, handheld at 400mm (600mm full frame equivalent). Though not ideal testing conditions (and not equivalent apertures and exposures), there is one thing that immediately jumps out from a subjective image quality standpoint (click to view at a larger size):
|Sigma 150-500mm, ISO 1600, f/6.3, 1/100s|
|Nikon AF-S 80-400mm, ISO 1600, f/5.6, 1/100s|
Though there's 1/3 of a stop's indicated difference, the exposure is equivalent in terms of what the D7100 metered it at. (All lenses meter differently depending on their optical efficiency.) There is a slight variation in where the plane of focus fell; with the Sigma it's a little bit in behind (on the crucifix) and on the Nikon it's a little bit in front (the bikini). In terms of detail, the Sigma isn't that much worse than the Nikon under these conditions, but where the Nikon is clearly better is in overall contrast and colour saturation. Colours are deeper all around, and if you look at the texture of the skirt, the Nikon pulls out just a bit more in terms of crispness.
What the sample images don't tell you is how these two lenses handle. Both are similar in terms of size and weight, but the Nikon is quicker to acquire focus and has the faster and more reliable image stabilization system. You have to wait longer for the Sigma OS system to settle in before taking the shot; the Nikon achieves stabilization in a quicker and smoother manner.
The Sigma 150-500mm isn't a top-quality exotic, but it does fulfill the niche for an affordable longer-lens that's under-served by Canon and Nikon. For the mainstream manufacturers, there's a big jump in price from the consumer oriented 70-300mm lenses towards either the Nikon 80-400mm or the Canon 100-400mm. For either company, the 70-200mm lenses aren't the best choices for distance work as they don't provide enough reach for truly long-range applications on full-frame systems, and are shorter than the cheaper 70-300mm lenses for the more consumer-focused crop systems.
There is a temptation in thinking that if the Sigma 150-500 has a slow maximum aperture, then why not just throw a 1.7x teleconverter onto a consumer-grade 70-300mm lens? The problem is that it's not possible. Teleconverters aren't compatible with these lenses because their rear elements run the risk of butting into the glass of the converter. However, it is possible to use a 2x converter on either Nikon or Canon's 70-200 f/2.8 zooms, which creates the equivalent of a 140-400mm f/5.6 lens, but this is not the "cheaper" choice that many would hope for. Once again, it bears repeating: there's no way to photograph birds and not spend lots of money...
Theoretically, it is possible to shoot with one of Sigma's teleconverters on the 150-500mm, but it hardly seems like a wise practice considering that the optical performance doesn't allow much if any room for the degradation that a 1.4x or 2x converter would introduce. In either case, both converters would introduce AF issues at the longer end of the zoom range because the effective aperture will exceed f/8, the limit of most AF systems.
There's also the issue of having loads of reach and a fast aperture, but lenses of that calibre exceed the scope of this blog. It would be nice to if the Sigma 150-500 was both cheaper and just as good as its competition, but that just isn't the case. This is a lens that doesn't fit in with the rocks/sucks discourse that happens too often on internet forums; it's value proposition is more nuanced than that. Overall, owners seem to have a love-hate relationship with this lens, but like all good relationships, it's one based on understanding. The understanding part of the equation is that you get what you pay for, and that the unique selling proposition with this lens is the cost savings compared to the equivalent Canon or Nikon. The Sigma is good for what it does at the price that it asks of you. As with most cases: cheaper, better, faster; pick two but you can't have all three.
With thanks to Broadway Camera.