By Mike Zawadzki, Technical Consultant
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The good news is if you shoot a camera with a crop sensor, you have many more choices than a full frame shooter. Canon, Nikon, Sigma, and Tamron all make great ultra-wide lenses. However Sigma has now officially produced the widest lens (non-fisheye) for crop sensor cameras, the 8-16mm f/4.5-5.6 DC HSM.
The Overlap Factor
The majority of "kit" zoom lenses that come with DSLR cameras have a range of 18-55mm. Yet most ultra-wide zoom options have a range of 10-20mm, 10-24mm, or 12-24mm depending on the manufacturer. While any of these lenses are perfectly suitable for ultra-wide angle applications, I applaud Sigma for creating a lens that does not overlap the 18-55mm focal range of a standard kit lens. The 8-16mm matches up almost perfectly with a standard 18-55mm kit lens or a more advanced 17-55 f/2.8 lens which is the standard mid-range zoom lens for crop sensor cameras.
8mm vs. 10mm
All other ultra-wide lenses start at either 10, 11, or 12mm. In terms of arbitrary numbers, this doesn't seem like a big deal. After all 10mm is "only" 2mm longer than 8mm. However in terms of focal measurements this is a big deal. Every last millimeter of focal range at the ultra-wide lens makes a difference. At 8mm you are getting an angle of view of 114.5 degrees compared to 102.4 degrees at 10mm. Lot's of numbers, I know, sorry. To illustrate this, here are a couple photos.
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| Ramapo Valley Reservation D300s at 8mm f/4.5 ISO800 |
8mm vs. 10mm
All other ultra-wide lenses start at either 10, 11, or 12mm. In terms of arbitrary numbers, this doesn't seem like a big deal. After all 10mm is "only" 2mm longer than 8mm. However in terms of focal measurements this is a big deal. Every last millimeter of focal range at the ultra-wide lens makes a difference. At 8mm you are getting an angle of view of 114.5 degrees compared to 102.4 degrees at 10mm. Lot's of numbers, I know, sorry. To illustrate this, here are a couple photos.
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| Straight out of the camera at 10mm |
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| Straight out of the camera at 8mm |
Note: The opposite is true for telephoto lenses, which is why you don't see a 70-200mm zoom (just an example) competing with a third party 70-205mm. It just wouldn't change the angle of view dramatically enough to notice.
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| Ramapo Valley Reservation D300s at 8mm f/4.5 ISO640 |
SPECIFICATIONS
Sigma's Alphabet Soup
HSM: Hyper Sonic Motor allows the lens to focus fast while making minimal noise while functioning.
DC: Indicates the lens is exclusive use with smaller sensor APS sensor cameras
FLD: Although not in the lens name, this lens has at least one element which is made of fluorite glass, which Canon uses in their L series lenses. This helps reduce chromatic aberrations.
Aspherical: Aspherical lens elements help correct distortion in wide angle lenses. Additionally reduced coma at wide apertures and elimination of other lens aberrations are benefits of Aspherical elements. This lens has two aspherical elements and two glass mold elements.
Construction: 15 Elements in 11 Groups. Four elements are FLD glass and two are Aspherical.
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| Lens diagram for the 8-16mm. |
Effective Focal Length: 8-16mm
(This would be equivalent to about 12-24 on full frame) This is the widest lens available outside of fisheyes for a digital camera. No surprise here, Sigma also makes a 12-24mm lens for full frame cameras.
(This would be equivalent to about 12-24 on full frame) This is the widest lens available outside of fisheyes for a digital camera. No surprise here, Sigma also makes a 12-24mm lens for full frame cameras.
Angle of View: 114.5° - 75.7°
Maximum Aperture: f/4.5-5.6
Don't be fooled by this "slow" range. This lens is tack sharp wide open where other faster lenses in this category show their flaws. This also allowed the lens to be very small and lightweight. If you shoot on a tripod most of the time, save yourself the money and get this lens instead of a more expensive/faster option.
Don't be fooled by this "slow" range. This lens is tack sharp wide open where other faster lenses in this category show their flaws. This also allowed the lens to be very small and lightweight. If you shoot on a tripod most of the time, save yourself the money and get this lens instead of a more expensive/faster option.
Minimum Aperture: f/22
Minimum Focusing Distance: 9.4" from the sensor.
The actual front element will be much closer to the subject. Lots of great things you can do using an ultra-wide at close focus distance. Fill the frame with your subjects!
The actual front element will be much closer to the subject. Lots of great things you can do using an ultra-wide at close focus distance. Fill the frame with your subjects!
Maximum Magnification: 1:7.8
Aperture Diaphragm: 7 Blades
Filter Thread Size: None.
One of the downfalls of this lens is it's lack of being able to put a filter on it, just like the Nikon 14-24mm f/2.8G.
Lens Hood: Built in petal shaped shade.
Lens Pouch: Nice Nylon padded zipper case with a loop on the back for attaching to belts. Much better than the cheap garbage Nikon or Canon give you in this price range.
Dimensions: 3.0x4.2"
One thing I loved about this is the small size. I was much happier walking around with this little guy instead of my giant 14-24 Nikkor.Weight: 555g / 19.6oz.
Mounts: Available for Canon, Nikon, Sony, and Pentax
PERFORMANCE
Overall: At first I was hesitant about using such a slow lens. If this was a full frame lens I wouldn't have worried as much because of better high ISO performance of full frame cameras. However I was quite pleased with the photos I was making when shot wide open. I couldn't see a difference in sharpness when stopping down.
Focusing Speed: The Autofocus is not as fast as a Nikon 14-24 f/2.8G, but it is still fast enough for all applications. Again don't let the slow f-stop range fool you.
Focusing Accuracy: Very accurate. With these types of lenses, focusing accuracy is usually not an issue, it's more of a matter of where you focus. There are certain compositions which will require you to manually focus or focus and recompose because the lens is so wide that an area in the foreground you may want to focus on will certainly not be in the range of the camera's selectable AF points. Again one of my biggest gripes with current AF systems in DSLR cameras is that they do not extend to the furthers edges of the frame. There is probably a technical reason for this, but I still don't like it!
Manual Focusing: Smooth and easy to grab and just turn whenever you feel like switching to manual focus. As I just said above there will be situations when you need to do this. However this is also one situation where I don't like the slow aperture range of the lens. Manual focusing would be much easier with a f/2.8 lens.
Focusing Accuracy: Very accurate. With these types of lenses, focusing accuracy is usually not an issue, it's more of a matter of where you focus. There are certain compositions which will require you to manually focus or focus and recompose because the lens is so wide that an area in the foreground you may want to focus on will certainly not be in the range of the camera's selectable AF points. Again one of my biggest gripes with current AF systems in DSLR cameras is that they do not extend to the furthers edges of the frame. There is probably a technical reason for this, but I still don't like it!
Manual Focusing: Smooth and easy to grab and just turn whenever you feel like switching to manual focus. As I just said above there will be situations when you need to do this. However this is also one situation where I don't like the slow aperture range of the lens. Manual focusing would be much easier with a f/2.8 lens.
Distortion: As expected, there is pretty intense complex barrel distortion at 8mm. No one else even makes a lens this wide, so... Just correct it in Photoshop later if it has a negative impact on your photos. Beyond 10 or 12mm I saw little to no noticeable distortion. If measured I'm sure you would find some, but someone isn't going to pick up a print you've made and say "WOAH CRAZY BARREL DISTORTION TRY +1.3 IN PHOTOSHOP LENS CORRECTION FILTER!"
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| As you can see there is some pretty whacky distortion at 8mm. Instead of whining about it on dpreview, try to use it to your creative advantage! |
Falloff/Vignetting: Just like any other ultra-wide lens, there is light fall off when shooting with the Sigma 8-16mm. It is most severe when shot at 8mm and wide open at f/4.5. Although I mentioned sharpness is high throughout the zoom and at all apertures, stopping down helps get rid of some of the fall off.
Sharpness: Very good across the entire zoom range. I have to say I was impressed, I expected this lens to be slightly soft when shot wide open (f/4.5) at 8mm. However it exceeded my expectations and the MTF charts here published my Sigma back up my claims. This level of sharpness shot wide open at 8mm is an optical achievement/benchmark by Sigma. Bravo to them.
Remember to take these charts with a grain of salt. Some manufacturer's create these charts based on theoretical, not measured resolution. I am not sure if Sigma measures or not. Either way, you need to see how a lens acts in real life to give it a fair assessment. So in addition to these MTF charts which don't tell you about real world lens performance I have included a shot bellow with a 100% crop from the center and corner. (Click to enlarge any of the images.)
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| A shot from the trail at Ramapo Valley Reservation Nikon D300s at f/4.5 8mm ISO640 |
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| 100% crop from center |
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| 100% crop from top left corner |
f/4.5-f/11
Corner sharpness slightly improves as you stop down to f/8. This lens’s “sweet spot” is around f/5.6 or f/8. I still wouldn't be shy about shooting this lens wide open most of the time. Unless you are in bright sunlight you will probably need to anyway. Thankfully Sigma's design has allowed for excellent performance in this range. Also based on how diffraction sets in (see bellow), stop down with moderation please!
f/16-f/22
Diffraction sets in and contrary to popular myth, you lose sharpness when stopping down this far, especially stopped all the way down to f/22. Shooting at f/8 with this lens on a crop body will be enough to get everything to appear in focus (greater depth of field) unless you are using the lens at a the minimum focusing distance to your subject.
Corner sharpness slightly improves as you stop down to f/8. This lens’s “sweet spot” is around f/5.6 or f/8. I still wouldn't be shy about shooting this lens wide open most of the time. Unless you are in bright sunlight you will probably need to anyway. Thankfully Sigma's design has allowed for excellent performance in this range. Also based on how diffraction sets in (see bellow), stop down with moderation please!
f/16-f/22
Diffraction sets in and contrary to popular myth, you lose sharpness when stopping down this far, especially stopped all the way down to f/22. Shooting at f/8 with this lens on a crop body will be enough to get everything to appear in focus (greater depth of field) unless you are using the lens at a the minimum focusing distance to your subject.
BOKEH
You weirdos out there (I still love you) who describe Bokeh as if it were some bizarre fantasy, keep your pants on. You shouldn't look to this lens for it's Bokeh rendition. Like most other ultra-wides it's hard to get anything to appear out of focus unless you focus very closely. Throw in the fact that this lens has an maximum aperture range from f/4.5-5.6 and is for use on crop sensor cameras... This isn't your grandma's Canon EF 50mm f/1.0L. However this is actually an advantage for those looking to take architecture or landscapes where everything appears to be razor sharp and in focus.
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| Just to prove my point I shot this at 16mm and f/5.6 An interesting perspective and the Bokeh isn't bad at all. |
COMPARED TO
SUMMARY
| Sigma DC 8-16mm f/4.5-5.6 HSM | Nikon AF-S DX 10-24mm f/3.5-4.5G ED | Canon EF-S 10-22mm f/3.5-4.5 USM | Tamron Di-II 10-24mm F/3.5-4.5 SP AF LD | |
| Focal Length | 8-16mm | 10-24mm | 10-22mm | 10-24mm |
| Max Aperture | f/4.5 | f/3.5 | f/3.5 | f/3.5 |
| Max. Angle of View | 114.5° | 109° | 107° | 108° |
| Min. Focusing Distance | 9.4" | 9.48" | 9.48" | 9.4" |
| Filter Thread | NONE | 77mm | 77mm | 77mm |
| Mount | Canon, Nikon, Sony, Pentax | Nikon F-Mount | Canon EF-S | Canon, Nikon, Sony, Pentax |
| Weight | 555g/19.6 oz. | 460g/16.2 oz. | 385g/13.6 oz. | 406g/14.3oz. |
| Price (08/2010) | $699 | $819 | $789 | $499 |
As you can see above a lot is similar between the ultra-wides that different manufacturers make. However the Sigma 8-16mm offers something that none of it's competitors do. It is the widest rectilinear lens available for a digital SLR camera. It's sharp at every focal length and aperture. It has good distortion characteristics considering how wide the lens really is.
It's biggest drawbacks are the slow aperture and inability to use standard threaded filters. If you can deal with these drawbacks, this is the lens for you. If I still shot primarily with a crop sensor body I would buy myself a Sigma 8-16mm.
If you happen to own a Sigma 8-16mm f/4.5-5.6 HSM DC I would love to see some of your photos and hear feedback from you. Were your experiences with the lens similar to mine? Feel free to comment here or e-mail me mikez@uniquephoto.com
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