Lens Review: Sigma 50-500

Something I’m going to do now and then is post some of my equipment reviews on this blog. All of my lenses are reviewed for their Sony Alpha/Minolta Maxxum mounts, naturally. If you’re interested in my thoughts about them, then read on. I’ll post one every now and then for your perusal.

The Sigma 50-500 f/4-6.7 EX RF

compared to:
* Minolta 70-210 f/4
positive:
* Built like a tank.
* Extremely useful range.
* Great image quality for the range.
* Sigma gives you nice stuff when you buy it.
* Fast (enough) AF on 5D, very fast AF on a700.
negative:
* Attention getter.
* You better be in shape.
* “Fair weather” lens.
* Requires sturdy tripod or monopod.

The Lens also known as Bigma.

The Sigma 50-500 has a well deserved reputation. For the price, it has unrivaled build and image quality. It also has a few caveats. If you can accept the caveats of the lens, you’ll gladly welcome it into your stable.

* BUILD QUALITY *

Huge. Absolutely huge. It’s not called Bigma for nothing. This is how a 10X zoom should be made – imagine if those 28-200 or 18-200 zooms had the kind of build quality as this beast. Four pounds of glass and metal combine to a shoulder-straining experience. A good tripod/monopod and head are a requirement for this lens. Handholding at 500mm is nearly impossible, antishake or not. Your arm just gets tired from holding it. The included protective case and lens strap are nice touches.

Sigma’s lens caps still bother me. Everyone but them (and Canon I think) is doing the center pinch gig and they need to follow suit. I shouldn’t have to buy a third party (hard to find) 86mm center pinch cap for a lens of this caliber.

Materials are nice. Finish is great (would be even better if it was white!), rubber is smooth and grippy, and the magnesium tripod collar is extremely sturdy. Match it up with a Bushhawk, gimbal head or other such apparatus and you’re pretty much set. Sadly, I have none of those things yet!

* ZOOMING AND FOCUSING *

The zoom is very stiff until about 100mm. You could theoretically use the lens in a push-pull fashion but I’m not sure how well that would impact on the internals. Just point it towards the ground while zooming out that first “hump.” After about 100mm it zooms well enough.

Manual focusing has a few oddities due to the lens’ initial design for a focusing motor and subsequent transplant onto a mechanical AF train. You must make sure the lens is set to the AF mode when attaching the lens to the camera, turning the camera on and off, or when AF is enabled on the camera. If you don’t do this, the focus motor will just keep spinning until it times out.

This has the side effect of not spinning the focusing ring while the camera AFs. When you do want to manual focus (even with DMF activated), you must pull the ring towards the lens mount and then turn it. This engages the manual focusing clutch. You can even do this while the camera is in AF mode, but when you half-press the motor will just spin and spin. Keep this in mind when using the lens. Keep it on AF at all times unless you have MF set specifically.

There is a zoom lock to keep the lens from extending while stored or when you don’t want it to move. This lock also keeps the lens to a 100-500 zoom range if using a Sigma teleconverter. Sigma TCs also disable autofocus.

Autofocus is fast enough thanks to a rear focusing design (think Minolta 28-135 f/4-4.5). It can hunt in low contrast situations on a 5D, but then, most lenses do. Note that if you have a flash for AF assist attached, the AF assist beam stops working around 300mm. Autofocus is fast and confident on a700.

* IMAGE QUALITY *

Two things are evident from most Bigma pics – little to no chromatic aberrations, and a high level of sharpness for a superzoom. After some initial dopeyness on my part, I managed to get the Bigma into some shooting, and several things were made apparent to me.

1. This lens needs a lot of light. The slow maximum apertures (You’re at f/6.3 at 200mm, f/5.6 at 100mm) demand either high ISO, a lot of light, or both. When the clouds come out, the Bigma might have to come off if you like higher shutter speeds.

2. Slowness also means less bokeh flexibility. The tele-ness of the lens helps in this regard, but a 500mm f/4 would kill this lens in that regard.

3. Mirror lockup is also extremely useful but is out of the equation when shooting moving subjects.

4. Remote shutter cables and a tripod are helpful too. At 500mm, vibrations are magnified many more times. Your images will not be ruined by the lens’ softness, but more often by your moving it.

As long as you keep the shutter speeds as high as they can go, you’ll probably find a lot of success with the Bigma. It has its flaws (you have to compromise to get a lens like this) but the images will certainly please. There is the risk of some vignetting and pincushion distortion, but that comes with the territory and is not so severe that it cannot be adjusted for. The color cast is neutral-cool, which I tend to adjust towards a warmer side in post.

The Bigma is not an every day lens. I bought it to shoot airplanes. If you don’t know what you’re shooting, this lens isn’t for you. If you’re a nature/wildlife shooter, this lens was built for you. If you’re a street shooter, I wouldn’t reccomend it.

By the way – the lens is very, very conspicuous. Be careful where you aim it, because people might mistake it for something else. Not speaking from experience, but make sure you have a giant indicator that you are a photographer.

UPDATE: I have used this lens on my new a700 with great results. It focuses faster and quieter, and the image quality is still very good. However, the chromatic aberrations that were very hard to see on 6MPX are now quite visible on 12PMX, only because the camera is better at resolving lens flaws. Funny how that works. But comparatively speaking, the CAs are very minor and can easily be corrected in your favorite RAW converter or left alone even.

I also had an issue earlier this year when the small screws in the zoom lock switch came apart and jammed the lens. Sigma repaired it under warranty with no problems. If the switch feels loose or hard to change settings, take a jeweler’s screwdriver, take the switch off the body, and tighten up the two screws holding the switch to the locking tab. Some loctite may also be of use here.

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