Tuesday, March 27, 2012

Ultrawide Portraits with the Sigma 10-20

This is a hands-on review of the Sigma 10-20 f/4-5.6, an affordable ultrawide lens for crop sensor cameras.

This lens has been around for a couple of years and has already been reviewed in detail in several websites.  If you would like to know how about its sharpness, distortion, chromatic aberration and so forth, check these reviews:


Instead, this review will focus on what it's like to use this lens in the field, particularly for people photos.  In Part 1 of this post, we'll have a look at some of the ways an ultrawide can be used for shots of people.  In Part 2, we'll discuss some characteristics of ultrawides to make better use of them.  In Part 3, we'll talk about the Sigma 10-20.



BACKSTORY
Prior to getting the Sigma 10-20, I saw little need for an ultrawide lens.  I thought that an ultrawide would be more useful for real estate photography, architectural photography, landscapes, cityscapes, and special effects.  I, on the other hand, take photos of people 95% of the time.  With photos of people, it's generally a good idea to be several feet away from the subject, hence the popularity of focal lengths between 85 to 105mm as portrait lenses.  If the subject is too close to the lens, the subject's face will seem distorted or the nose will appear disproportionately large.  Using a wide lens was furthest from my mind for taking portraits.

Recently, I decided to get an ultrawide anyway to take establishing shots (the ones you take to set the scene).  Having gotten one, I started using it for people shots and found it to be both challenging and exciting.  Here are some of the reasons I love this lens for people shots.



I.  Why I Love An Ultrawide for People Shots

1.  In the Middle of the Action
With an ultrawide, you can (and probably should) get very close to the action, and not surprisingly, it makes the viewer feel like they are part of the action, not a passive observer.

In this shot, the viewer feels like he's in on the huddle (but the little girl seems to mind :) ).
In the shot above, I was only a couple of feet away from the kids.  If I had been using a normal focal length, I would have captured only the faces of the two girls in the middle.  And if I had stepped back to capture the group with the normal lens, the perspective would have been very different, and would have created a different feeling.



2.  Dramatic Shots.

As a general rule, wide angle lenses do not distort the subjects any more than do telephoto lenses.  The usual distortion that we associate with wide angle lenses is due to perspective distortion when the camera is thisclose to the subject, near objects seem even closer/larger, and far objects seem even farther/smaller.

However, ultrawide lenses do have distortion on their sides.  Rectilinear lenses (the kind of ultrawide where straight lines appear straight) tend to have sides that stretch to the edge of the frame.  Fisheye lenses tend to have sides that cause straight lines to bend around the middle of the frame.  Both kinds of ultrawides don't have a lot of distortion (if any) toward the middle of the frame.

The distortion from ultrawides is not a bad thing per se.  It's just something to be aware of and take advantage of.  One effect of the distortion is that it can make a shot look more dramatic.

Here is a shot of my son at an almost normal focal length (28mm on APS-C, 42mm equivalent):

And here is a swing shot at the same location at 10mm (15mm equivalent):

3.  Being Pulled Into the Scene
The stretching from a rectilinear wide angle lens tends to create leading lines to the middle of the frame, which can also give a sensation of pulling the viewer into the scene.

Come on up my rocket ship!

4.  Emphasize a Subject
With an ultrawide, you can get very close to a subject, emphasizing that subject among other potential subjects in the scene, even if they are at similar distances.


5.  Environmental Portraits
Well, duh. :)

II.  Ultrawide Quirks
Here are some of the things I've learned about using ultrawides.

  • As mentioned before, it's generally a good idea to get very close to the subject when using an ultrawide.  Yes, it can be a bit intrusive (as the little girl would attest), but I just do it really quickly.  If I can't (or don't want to) get that close myself, sometimes I thrust the camera closer and shoot blindly.
  • An ultrawide is very sensitive to tilting vertically and horizontally, and to a slightly less extent rotationally (around the z-axis).  When an ultrawide is used perfectly straight on, it doesn't have that much distortion except at the edges.  But when it's tilted vertically or horizontally, things get crazy real fast.  And if you think that's wild, just think of how much fun you can have when you combine tilting angles. :)
  • In my opinion, using an ultrawide requires a very deliberate artistic intention.  It's not something you can do with just your left brain (apologies to left-handed readers).  If you use it as an information-gathering tool ("getting it all in") rather than an artistic instrument, your shots may look very boring.
  • Because an ultrawide can capture so much of the scene (including the sun or other light sources), flare and ghosting are significant concerns.  Some lenses tend to be more flare-resistant than others.  I read on a forum that Zeiss lenses and lenses with fewer elements are more flare-resistant, but I have no experience about that so I can't confirm either way.
  • My cameras usually have dependable automatic exposure modes (P, A, S).  However, with an ultrawide, my cameras seem to underexpose more often (possibly because the shot includes much of the sky or overhead lights).  I just have to pay closer attention to exposure. 
10mm (15mm equivalent)


III. Sigma 10-20 f/4-5.6 EX DC HSM I got the Sigma 10-20 f/4-5.6 because it is one of the most affordable ultrawide lenses, and it has decent performance and a useful focal length range.

1. Build Quality.
The Sigma 10-20 has Sigma's "EX" designation, which means it has a higher build quality than their other lenses.  Although the Sigma 10-20 is not an expensive lens, it feels substantial and well-made.  It also has a metal mount.

2.  Focal Length.
I love the focal length range of this lens.  At its widest, the Sigma 10-20 is deep in ultrawide territory at 15mm equivalent.  I thought that the 15mm equivalent would be too wide for people photos, but I've been using it most often at its 10mm focal length and have occasionally wished it be even wider.  So, no, 10mm is not too wide.  On the other hand, at its longest, it is almost a normal lens (30mm equivalent) with none of the distortion usually associated with ultrawides.  It thus functions both as a specialty lens and a general purpose lens.
20mm
3.  Aperture Range.
The Sigma 10-20 is a slow lens with a variable aperture.  When used traditionally outdoors, the smallish aperture presents no issues.  When used indoors, it requires me to push the ISO to the camera's limit.  I honestly expected to use this lens primarily to take photos of scenery and locations, when I can use a tripod.  In retrospect, I would have found it useful to have a faster aperture, like that of the Tokina 11-16 f/2.8.  However, I find that I can sort of get away with slower shutter speeds because of the extreme wide angle, so it's not a dealbreaker.

4.  Focus speed and accuracy
With a wide angle lens, I have a fairly deep depth of field therefore focusing accuracy is not critical.  That said, I find that Sigma 10-20 focuses quickly enough that it doesn't interfere with getting the shot.  In terms of accuracy, I would say it focuses accurately, although sometimes I still get a slightly blurred subject because the shutter speed was too slow, or because the autofocus picked the wrong spot to focus on.

5.  Image quality
I find the Sigma 10-20 to be sharp.  The limiting factor in the sharpness of my images tends to be my slow shutter speed rather than the lens sharpness itself (evidenced by having sharp parts of the picture where there is not much motion).  One concern is flare resistance.  When the sun is in or near the frame, there is noticeable flare. Otherwise, I find flare resistance to be reasonable.




OTHER LENSES TO CONSIDER:

Crop sensor:
  • Tokina 12-24 f/4 - Sharper than Sigma 10-20 according to dpreview tests. Prone to flare and CA.  Has version I and version II.  Competitively priced.
  • Sigma 10-20 f/3.5 - Updated version of the Sigma 10-20 f/4-5.6.
  • Tamron 10-24 f/3.5-4.5 - Slightly wider aperture and longer reach.  When used wide open, the Sigma 10-20 is sharper.  But when the Tamron is stopped down to f/5.6, it is sharper at 10-15mm.  From 15mm to 20mm, the Sigma is sharper.  The Sigma 10-20 has less CA throughout.  Use the dpreview lens comparison tool to compare it with the Sigma 10-20.
  • Tamron 11-18 f/4.5-5.6
  • Tokina 11-16 2.8 - Among the sharpest lenses, even when used wide open, although prone to flare and CA.
  • Canon 10-22 - If I had a Canon, I would be very interested in this lens because of its flare resistance.
  • Nikon 12-24 f/4 - Nikon's first crop-sensor ultrawide.
  • Nikon 10-24 - Lower cost model released after the Nikon 12-24.
  • Sigma 8-16.  Currently the widest rectilinear lens for crop sensor cameras.  Very sharp.
Full frame:
  • Sigma 12-24.  Great focal length for full frame, but not that wide on a crop sensor.
  • Nikon 16-35, Nikon 17-35, Nikon 14-24 - They're out of my budget (for now ;) ).

CONCLUSION

Some photographers say that an ultrawide is the most challenging type of lens to use, and I tend to agree.  It definitely takes a lot of getting used to.  But with a little persistence I was rewarded with some shots that I could not have gotten with any other lens.


WHERE TO BUY
If you'd like to get a Sigma 10-20, you can support this blog by buying through these links to Amazon.  It will not increase your cost but you'll be helping us:
Sigma 10-20 4.5-5.6 for Nikon or Canon