IS in wide-angle lenses?

[dan_vidal]

IS is a wonderful thing. I shoot a lot at night and tend to ignore the 580EX

flash in my back pocket (ST-E2 in the hotshoe), and my 28-135 IS does wonderfully.

 

I also like utilizing a 15mm Sigma 2.8 for some wide shots of the venues I shoot

in. The downside is, of course, no IS. What I noticed is that Canon's IS

offerings peter out at 17mm, and that lens is an EF-S mount. I shoot with a 30D,

so I can use EF-S, however I'm not 100% confident in it yet until it gets

another few years under it's belt...

 

With that being said, my curiosity is, why isn't there IS in wide-angle lenses?

What technical hurdle prevents this, or is it just that there's no real market

for such a lens?

[greg_moss2]

Just my opinion, but it use to be that the rule of thumb for handholding a specific lens was using the focal length as the slowest shutter speed you could effectively handhold. eg. 15mm lens=1/15 of a second. IS will usually gain 2-3 stops in slower shutter speeds. Would you really want to handhold a 1/2 second shutter? OR maybe the IS doesn't work for shutter speeds that slow. Surely it is easier to stabilize an image for 1/100 or second or so versus stabilizing that same image for 1/2 a second.

 

Just my 2 cents...

[mars c]

The efs 17-55 and the 17-85 IS USM are wide, but for FF, those range are ultra wide, But not compatible with aps sensor.

 

I guess Canon decided they dont have to make FF ultra wide with IS, not because They cant, But because they think people dont need IS on wide ultra wide angle.

 

There is no technical reason to prevent them, but only economical.

[mars c]

sorry, I mean, those efs lens are not compatible with FF sensor body.

[squareframe]

it is as simple as the requirement isn't there and diminishing returns when the focal-length is short.

[steve_dunn2]

<p>It may be interesting to remember that, at least for the 28-135, Canon claims that IS works better at the long end; they claim 1.5 stops at the wide end and 2 stops at the long end. The 28-135 has the first generation of IS; the 17-55 has the latest. For the 17-55, they claim 3 stops, without referring to any change at different focal lengths, but the example in <a href="http://www.canon.com/camera-museum/tech/report/200605/200605.html" target="_blank">this document</a> only discusses a shutter speed at the wide end <em>two</em> stops below what you'd need without IS. Hmm.</p>

 

<p>I have a guess, and it's purely a guess, so take it with a grain of salt. If you try to hold an object as still as possible, and we measure how much it moves over a variety of durations, I think it's likely that the maximum deflection will tend to increase with duration. To put it another way, in 1/8s (which would be a two-stop improvement over the 1/30s you'd normally need at the wide end), you'd be likely to move the camera farther than you would in 1/30s (which would be a two-stop improvement over the roughly 1/125s you'd normally need at the long end). The more motion, the greater the challenge for the stabilizer, and therefore the more difficult it is to stabilize a wide-angle lens.</p>

 

<p>Like I said, purely a guess.</p>

 

<p>If you want an IS wide-angle lens for your 30D, well, you only have two choices, and they're both EF-S. You're not marrying it; it's a tool. If you end up upgrading to a full-frame body later, you can sell the lens. Yes, you'll lose money on it, but when was the last time you sold a used EF-mount lens and got back the same amount you paid for it in the first place? So if you want an IS wide-angle lens, buy one, and enjoy taking pictures with it.</p>

[matthias_meixner2]

A simple experiment will explain why IS works better with telephoto lenses. Take a telephoto lens and a wide-angle lens and shoot two pictures of a ball with each lens: One with the ball in the center and one with the ball near the corner of the image. Now look at the pictures. The ball on the telephoto picture will be round in both cases. But on the wide-angle photo it will be round only in the center and look egg-shaped near the corner.

 

Image stabilization can be considered equal to moving the sensor to compensate for camera shake (Canon moves the image by some additional optics instead of moving the sensor, but the effect is the same). This works perfect with a telephoto lens, since the subjects always have the same shape wherever they are in the image. But with a wide-angle lens camera shake results not only in a movement of the image but also in a distortion of the image (the ball became egg-shaped near the corners). This cannot be compensated by moving the sensor, i.e. image stabilization is less useful.

[robin_sibson1]

A mathematician writes ... "As any fule kno" (although Molesworth probably dropped out long before hitting projective geometry) the image of a spherical object is an ellipse with its major axis postioned radially, not an egg-shape, and it is circular if and only if the object is on the lens axis (assuming the lens axis is a right angles to the image plane). The eccentricity of the ellipse increases the further it is from the axis (in terms of angle), which is why you notice this with a WA lens but tend not to with a long-focus lens. The amount of movement arising in the camera-shake/image-stabilisation situation is far too small to make any material change in the eccentricity of the ellipse, and this has nothing to do with the relative effectiveness of IS with different focal lengths.

 

Just for the record, Canon's widest IS lens is the 24~105 used on FF, not the 1.6-factor-only EF-S 17~55 or 17~85, which are approximately equivalent at the wide end to 28mm on FF. Even 28mm is reasonably wide, and 24mm even more so, and plenty of users have said they find IS valuable at these focal lengths.

[perttu_luukkanen1]

I recently acquired the EF-S 17-55 f2.8 IS and have used a few longer lenses with IS. My gut feeling is that IS probably saves more of my regular shots in the long end (where shake is more of an issue) and in the WA end it just gives an opportunity to take shots I'd never try before, like at night ISO 800 17mm f2.8 1/2s, which would be doomed to fail without IS. Just something I didn't think about before getting the lens.

[matthias_meixner2]

Robin you are right if you refer to a perfect lens. But most lenses suffer from pincushion or barrel distortions. And, therefore, you will most likely see something egg-shaped and not an ellipse.