Is "IS" that important?

[joseph_wisniewski]

<p>That depends on what the meaning of "is" is.</p>

<p>(OK, somebody had to say it).</p>

[dan_south]

Joseph Wisniewski, everyone! Joseph will be performing at Caesar's all next week!

 

 

:-)

 

 

It IS what it IS!

[John Crowe]

<p>No. Also consider the Canon EF 70-210mm f3.5-4.5 USM. Good image quality, very light, very fast autofocus, and very quiet.</p>

[philip_wilson]

<p>IS is another really useful tool and it all comes down to a financial decision. IS does not add much to a lenses size and weight (and although it reduces battery life this is not a big deal) but it can add a lot to the price. In general it becomes a very desirable feature in lenses over 100mm and slower than F4. With faster lenses or shorter ones it is a nice to have feature and it's importance depends on what you shoot. So for example my 70-200 f4 is the IS model but my 70-200 F2.8 is not - this is a personal decision but for me I mainly shoot sports with the F2.8 lens so I don't miss IS. On the slower lens IS is more important as it is my general purpose lens and IS adds a lot of flexibility. Would IS be nice on the F2.8 - sure but it almost doubles the lens price (although I have had my F2.8 lens for a very long time).<br>

The 70-200 F2.8 IS II costs $2400, the F2.8 non IS is $1400 and the F4 IS is $1300. So the decision here would be spend and extra $300 and get two lenses which gives you a lightweight option as the F4 lens is half the weight - or take the convenience of the F2.8 IS single lens solution. This is a difficult decision which depends on what you need them for.<br>

In the case of the EFS 75-300 / 70-300 IS the difference is $200 vs $550 so again it really depends how much you need the lens. IS will make this lens a lot more useful but it is over twice the price so if you only plan to use it occasionally you may not need to get it.<br>

Canon's IS pricing is very interesting - their EFS kit lens is only $160 and includes IS but on most of their better lenses IS can add $500 - 1000 or more. I know the optical quality of these lenses is higher but it does seem to be a case of Canon being a long way from cost based pricing here!</p>

[g dan mitchell]

<p>I haven't read the whole thread, so I'll have to imagine the hornets nest I might be stepping into...</p>

<p>Aside from price, there isn't really any downside to getting the IS version of a lens - you can always switch it off if you think that is necessary.<br>

As to how important it is, that depends on what and how you shoot. It is probably very clear by now that IS can help with certain types of blur but won't help with others. It compensates for certain types of camera motion that you'll get when you hand hold the camera. So if your issue is that the camera moves and causes blur, then IS can reduce this problem. As others point out, it may perhaps be most useful on longer lenses where the camera vibration is effectively amplified. However, it can also be useful on lenses with shorter focal lengths since it is not impossible to find yourself, say, needing to shoot slower than 1/25 second on a 24mm focal length.</p>

<p>And, yes, IS does not help when the problem is subject motion rather than camera shake/motion. For that you simply need a short enough shutter speed - or electronic flash. In some ways, relying too much on IS could get you into trouble when you shoot active subjects if you don't remember that the shutter speed needs to be higher if you goal is to "stop" motion.</p>

<p>I'm often amused at those who will post and tell us that they can hand hold their 200mm lens at 1/25 second. How wonderful for them! And so what! Most people can't, and even those who can will be able to shoot with a bit less fussiness about keeping the camera still and will get a higher percentage of sharp images with IS.</p>

<p>I probably do 90% of my shooting from the tripod, so I don't usually need IS. However, on more than one occasion having it has made the difference between getting (and in some cases, subsequently selling) the shot or not.</p>

<p>Dan</p>

[zack_zoll]

<p>IS reduces image quality (especially in the out of focus areas), but not nearly as much as camera shake would reduce image quality. If shooting stationary (or slow-moving) subjects, the rule of thumb is that your shutter speed ought to be above your focal length. In other words, if you have a 200mm lens, your shutter speed should be above 1/200th of a second to avoid camera shake.</p>

<p>If you're shooting sports or other fast-moving subjects, you generally need a shutter speed of 1/250th to avoid motion blur from the subject. This means that for most conditions and most lenses, IS will usually not be terribly useful for fast-moving subjects. I find myself turning off the VR (IS) on my Nikon 70-200 VR very frequently.</p>

<p>I think what it boils down to is that if the lens would be good for you without the IS, and the IS version is in the budget, then buy the IS version. It helps sometimes, so why not? If the lens doesn't suit your needs, then adding IS isn't going to fix that. Since many excellent lenses of all shapes and sizes aren't even availible in IS versions - including many pro lenses - it's safe to say that the IS isn't a good enough feature that you should be selecting a lens just because it does or doesn't have it.</p>

[JDMvW]

<p>read what people say</p>

<blockquote>

<p>The rest of them don't have it because they are relatively ancient designs predating the availability of modern IS</p>

</blockquote>

<p>and the rest....</p>

[bob_himmelright]

<p>you guys all missed the big picture. He's asking about a <strong>EF</strong>55-200, not a <strong>EF-S</strong>55-250<strong> IS</strong>. Apparently it's one of the worse lenses canon has made in EF mount.</p>

[NimArt]

Hi

But I really think the IS has no mean , I have a 70-200LF4 IS USM on 7D

ok, you if you shoot at 200mm ( on my camera 320 ) you need to be at 1/200 sec or more than that for proper and fixed ( sharp ) image, then in that speed you won't need IS , cause the speed itself make the image to be fixed. and if you shoot at 200mm but lower than 1/200sec shutter speed then as I take it the IS won't help you to fix the scene, or just in some few moments..

[OPK]

<p>for me IS is unnecessary cost and I'dont need it. there's just need to bear in mind that your shutter speed should be at least equal to focal lenght. that's it.</p>

<p>so, as long as you shoot at 200mm on FX, shutter speed ought to be 1/200th or 1/250th</p>

[dan_south]

One over focal length is a bare minimum for managing camera shake. It doesn't ensure sharp images. IS can

improve sharpness up to four times the shutter speed depending on conditions. 1/30th with IS can have the camera

motion supressing power of 1/250th. But even at 1/250th, IS can improve sharpness.

 

 

 

Of course IS has no effect on the movement of objects within the frame. Only shutter speed or flash can freeze

subject movement, but I think that's well known.

[zack_zoll]

<blockquote>

<p ><a name="00YwbU"></a><a href="../photodb/user?user_id=1115203">Bob Himmelright</a> <a href="../member-status-icons"></a>, Jun 24, 2011; 11:06 p.m.</p>

</blockquote>

 

<blockquote>

<p>you guys all missed the big picture. He's asking about a <strong>EF</strong>55-200, not a <strong>EF-S</strong>55-250<strong> IS</strong>. Apparently it's one of the worse lenses canon has made in EF mount.</p>

</blockquote>

<p>No, we got that. We just thought it would be more useful to answer his question than to say, "That's a crap lens! You're an idiot!"</p>

<p>

 

<blockquote><a name="00Ywfg"></a><a href="../photodb/user?user_id=2071900">Dan South</a> <a href="../member-status-icons"><img title="Frequent poster" src="../v3graphics/member-status-icons/3rolls.gif" alt="" /></a>, Jun 25, 2011; 07:11 a.m.</blockquote>

 

 

<blockquote>

One over focal length is a bare minimum for managing camera shake. It doesn't ensure sharp images. IS can improve sharpness up to four times the shutter speed depending on conditions. 1/30th with IS can have the camera motion supressing power of 1/250th. But even at 1/250th, IS can improve sharpness.

</blockquote>

 

 

That's the theory. The counterpoint to that is since IS is altering an already-focused image, the quality of that image will suffer; the fact that bokeh is instantly improved by switching off IS is clear, but the in-focus areas are subject to variations. But since I lack the physics expertise to produce a chart of what lenses will suffer camera shake on what bodies, what shutter speeds, and from what people, I figured it would be easier to just go with the general rule :)

 

 

<blockquote>

 

 

<a href="../photodb/user?user_id=2071900">Dan South</a><a href="../member-status-icons"><img title="Frequent poster" src="../v3graphics/member-status-icons/3rolls.gif" alt="" /></a>, Jun 25, 2011; 07:11 a.m.

Of course IS has no effect on the movement of objects within the frame. Only shutter speed or flash can freeze subject movement, but I think that's well known.

 

 

</blockquote>

 

 

You'd think so. But as they say, common sense isn't very common.

 

 

 

</p>

 

[g dan mitchell]

The "1/focal length" so-called rule needs some clarification, based on what I am reading here.

 

First, this "rule" is more of a "rule of thumb" or a starting point estimate. It is a rough estimate of a shutter speed that

might be OK for typical shooters, in typical circumstances, using a 35mm film camera, and probably not trying to

achieve the highest level of sharpness. It also exists perhaps because it is an easy formula to remember as much as

because it is objectively accurate or ideal.

 

Using this "rule" does not, by any means, guarantee that you'll make the right shutter speed choice. For example, if

you have steady hands and careful technique and know a few tricks you can sometimes shoot successfully at

considerably lower shutter speeds than those predicted by the "rule." On the other hand, if you are working quickly,

under pressure, while on the move, or very casually, the "rule" shutter speed may leave you with blurry images. At

best, the "rule" could be a fine place to begin conducting a few careful experiments to find out what works best for you.

You may discover that your work and shooting style requires higher shutter speeds or that it tolerates lower speeds,

and so forth.

 

Keep in mind that a rule that might work for full frame or 35mm shooting needs to be modified if you shoot a different

format. For example if you shoot a 50mm lens on a 1.6x cropped sensor camera and the 1/focal length rule works for

you on 35mm or full frame, you need to incorporate the crop factor into your calculation and assume that 1/80 second

would be your baseline. (I will spare everyone the full explanation, but a bit of thought will make you see why ths is

so.)

 

All the forum theorizing in the world about what should happen means little compared to knowledge of what actually

does happen in the field. Attentive photographers eventually pick this up through their photography, but you can

accelerate the process by doing a bit of careful experimentation. There are many possibilities. For example, go out and

make 50 exposures at shutter speeds determined by the rule and inspect them closely, or photograph several scenes

at a variety of shutter speeds and compare.

 

Also, recognize that in the field things are often less cut and dried, and that multiple tradeoffs need to be made. In a

marginal light situation you might have to decide what combination of larger aperture (shallower DOF, soft corners,

need for more critical focus, need to use prime rather than zoom), ISO (possible concern about noise and dynamic

range), flash (can't shoot as rapidly, alters lighting radically, equipment complexity, hard to be discreet), shutter speed

(risk of blur from subject and/or camera motion) is the best compromise. In one case a bit of motion blur might be best,

while in another a bit more noise might be OK.

 

In the end, IS can be another useful tool for many types of shooting. Having IS capabilities has few serious

disadvantages and there are situations in which it makes the difference between getting the shot or not.

 

Dan

[philip_wilson]

<p>Dan - the only disadvantage I see with IS is the Bokah (which does suffer wide open with IS on) - but of course you can always switch it off!</p>

[marc_bergman1]

<p>Can someone post examples of Bokeh worsening with IS on vs. IS off?</p>

<p>I have never heard of this but am always willing to learn new things.</p>

[dcstep]

<p>IS has no impact on the quality of bokeh. Bokeh describes the quality of the OOF areas caused by shooting with a wide aperture. Really "smooth" bokeh will display almost no detail, but take on the color of the BG.</p>

<p>The smoothness of the bokeh has more to do with shallowness of the DOF and the number of leafs in the aperture than anything else.</p>

<p>Here's smooth bokeh, taken with IS on:<br>

<br>

<a title="Proud robin with cricket by dcstep, on Flickr" href=" src="http://farm3.static.flickr.com/2580/5840534835_db4849983e_b.jpg" alt="Proud robin with cricket" width="683" height="1024" /></a></p>

[William Michael]

<blockquote>

<p><strong><em>Can someone post examples of Bokeh worsening with IS on vs. IS off?</em></strong><br>

and<br>

<strong><em>IS has no impact on the quality of bokeh. </em></strong></p>

</blockquote>

<p>One nice shot with IS turned on, does not dis-prove that there could be a "difference" in Bokeh, if the IS were turned off.<br>

The theory of why Bokeh might be DIFFERENT when IS, is turned on compared to the same shot, for when IS is not turned on, is explained quite well, here: <a href="http://www.bokehtests.com/Site/Stabilization_and_Bokeh.html">http://www.bokehtests.com/Site/Stabilization_and_Bokeh.html</a></p>

<p>WW</p>

[faysal]

<p>I find that I have absolutely no need for IS because for my needs, larger aperture usually solves the problem.When I owned a 70-200f/4 IS, the IS was necessary because I was trying to shoot at f/4..... YMMV.</p>

[zack_zoll]

<p>David, you have nothing in the background for the IS to affect. Your background is so empty that there IS no bokeh; it looks like a Photoshop gradient. Bjorn has several examples on his reviews page of the Nikon 70-200 with VR on and off, and William's link is excellent.</p>

<p>When there are details in the OOF areas, IS will generally cause the bokeh to appear 'busier' and more geometric. You may also get some weird sharpness on the edges of well-defined areas like tree branches that are out of focus.</p>

<p>I'm not saying that this always happens with every photo and every IS lens; just that like the shutter speed thing, this is a 'rule of thumb', and will generally work that way.</p>

[dcstep]

<p>Zack, there are trees behind the bird, in the bottom half of the picture, with blue sky in the top half. That's true bokeh, not some stupid PS effect.</p>

<p>The link was INDEED excellent and news to me. I don't think it's anything to worry about as a practical matter. If you don't hold the lens steady at all and the IS is working to extremes, then there may be some impact, but compared to what would happen without IS, the IS is probably the better option.</p>

<p> </p>

[philip_wilson]

<p>I will take a sample - I probably notice it the most with my 100 f2.8 L IS. I find it is the worst if there are bright points in the background that are very out of focus. For example sunlight streaming through the trees in a portrait shot of someone standing in front of them.</p>

[William Michael]

<p>I believe that the "difference" in Bokeh is a Practical Matter, for some Bird Photographers, mainly those who use quite long FL Lenses (> 400mm).<br />But as Bokeh is Subjective, whether it is "worse" (or not), is a matter of opinion.<br />Also how much emphasis placed on Bokeh, in the first place, is relevant.</p>

<p>WW</p>

[zack_zoll]

<p>David, I didn't say you did it in Photoshop. I said that the detail is so muddled up (on my monitor I can't make out anything but a gradient, hence the anology) that you can't really use it to describe bokeh quality, as there is nothing to describe. Even if you had used an 18-55 IS (which is not known for its stunning bokeh), the background is so out of focus that it would still render smoothly.</p>

<p>You may have a perfectly valid point; all I'm saying is from that image, we can't really draw any conclusions.<br /><br />WW does make a good point about subjectivity too. Certain scenes or types of photography will make bokeh more or less of an issue. Below this text box I'm looking at an excellent photo of a wildflower by Nima Koochek Shooshtari. It has very smooth, although not 'benchmark' bokeh. There are lenses that may be smoother, but I suspect not a lot of them. In this image, a busy bokeh would be much more distracting, as the colours and shapes are similar, and are closer to the subject.</p>

<p>I'm also looking at a race car image by John Crowe. This image has a dark background, with the only other object behind the car being the track itself. Even if the bokeh on this image was the worst in the world, it probably wouldn't affect the picture quality.</p>

[g dan mitchell]

Are we really imagining that there is a real and significant (and heretofore unheard of) negative effect on bokeh that

comes from using IS? Seriously!?

 

"One nice shot with IS turned on, dues not disprove that there could be..."

 

And one photograph of a clear blue sky with no visible flying objects does not disprove the existence of little green

men from Mars. Be careful out there!

[William Michael]

<p> . . . no (my quote which was cited used) was discussing the possibility of a “difference” in bokeh and linked to a page which outlines quite clearly the theory as to why there would be such a difference.<br>

Also I went on to mention that the goodness or badness of Bokeh, is subjective, as indeed is the relevance that each of us places on bokeh in the first place.<br>

The metaphor and comparison of my statement about dis-proving something, to little green men, is just silly and appears beneath the author’s usual high standard of articulation and thinking.</p>

<p>WW</p>