IS or Speed? That is my question.

[unangelino]

<p>So, the standard Canon 18-55 IS kit lens is a good deal slower than the various similar focal length 2.8F offerings from Sigma, Tokina and Tamron. My question is what is really of more practical benefit; a <strong><em>faster</em> </strong> 2.8 lens or a <strong><em>slower</em> </strong> lens with IS?<br>

Yes, yes...I know: The Canon 17-55 2.8 offers both the speed and IS.<br>

But what if I'm not getting any Economic Stimulus Happy Money? <strong><br /> </strong> </p>

[bobatkins]

<p>Faster lens = faster shutter speed and smaller depth of field.</p>

<p>You decide.</p>

[evan_goulet]

<p>IS doesn't allow you to use faster shutter speeds, so your subjects may suffer from motion blur if they are moving fast enough.<br /> Fast lens gives a shallower depth of field (at wider apertures) along with the faster shutter speeds. IS would allow you to handhold a slower shutter w/greater depth of field. <br /> You have to weigh how much your subjects would be moving, and whether you can live with the longer shutter speeds.</p>

<p>Essentially what Bob said...</p>

 

[swede_spoltore]

<p>Remember that the IS feature is great because you can obtain on the average of about 3 extra stops but that is only good if the subject is not moving when you are shooting at a slower shutter speed. I would always opt for a faster lens but also have purchased several lenses that are not 2.8 but 4.0 and have IS. I than boost my ISO and am satisfied with the results. At the same time, I usually find that I have saved money with the 4.0 over the 2.8 as well as usually getting a smaller and lighter weight lens.</p>

[unangelino]

<p>Thanks, Bob & Evan.<br>

Of course, I didn't think of that. I do imagine primarily landscape for the zoom but the DOF issue is one that I had not considered. I have a Sigma 30mm 1.4 and a Nifty-Fifty that I use for most of my portraiture, putting the kit lens on when I go out for landscape photos.<br>

I guess I am just experiencing glass-lust and simply want a Canon 17-55 2.8.</p>

 

[sarah_fox]

<p>It depends on what you're shooting. If you enjoy natural light photography of relatively inanimate subjects in often dim lighting, the IS will be far more useful to you than the higher speed. You'll get a 3-4 stop shooting advantage at the the apertures you prefer for depth of field considerations.</p>

<p>If you shoot rather animated subjects (sports, children, etc.), then you'll need higher shutter speeds anyway. The IS will be rather useless. The higher lens speed will help you to freeze motion. It will also make focusing a bit faster and easier. Much of this benefit is a moot point if you prefer not to shoot wide open (where the lens isn't very sharp anyway). You'll still get the focusing advantage, of course.</p>

<p>Generally, there's a difference in optimization between the faster and slower lenses. Slower lenses (e.g. the f/4 zooms) are better optimized for intermediate apertures where the users of those lenses often prefer to shoot (e.g. f/5.6 - f/11). The faster lenses (e.g. f/2.8 zooms) tend to be optimized wider open and are not as sharp as their slower counterparts when stopped down. This reflects a preference/need for shooting at wider apertures. These preferences can be based either on subject matter (e.g. running athletes, vs. landscapes) or on photographic style (particularly with emphasis on extensive depth of field, compared with emphasis on blurred backgrounds and creamy bokeh)</p>

[unangelino]

<p>Swede:<br>

Which IS 4.0 lenses have you found to give good results?</p>

 

[JDMvW]

<p>Of course in an ideal world it would be IS plus fast aperture. But as in the recent discussion of the supposed EF 1000mm f/1.4 lens, there are technological and financial reasons why this is rarely done.<br>

For objects that don't move much, IS and faster lenses are a toss up.<br>

Action, more difficult. Sometimes motion blur can add to an action picture, but it's nicer to have the choice.<br>

If you buy a slower IS lens, compensate by buying a couple of fast primes for low light work. The primes are often less expensive and optically superior to more costly zoom lenses. Of course the L primes are fairly pricey.</p>

[KenPapai]

<p>I.S. offers exactly one advantage while a faster lens offers <strong>many advantages. </strong> I've always gone the faster lens route.</p>

[sarah_fox]

<p>Ken, JDM, it's not as simple as that.</p>

<p>At slow shutter speeds: An f/4 IS zoom has 3-4 stops stability advantage over the f/2.8 non-IS zoom at any specific aperture (e.g. f/8). An f/4 lens has 2-3 stops advantage over an f/2.8 non-IS zoom when used wide open. An f/4 IS lens is equivalent to an f/1(.2) - f/1.4 lens with regard to stabilization wide open.</p>

<p>At higher shutter speeds: IS is useless.</p>

<p>Paul, your oft-maligned 18-55 IS kit is actually a pretty good lens. It's cheaply constructed but rather sharp. Optically, its only real problem is chromatic aberration, but DPP does a good job of correcting that.</p>

<p>PS I'm impressed by the sudden flurry of responses. Is everyone else here glued to the 'puter, watching the stock market breach the Nov lows? :-(</p>

[rainer_t]

<p>-- "Which IS 4.0 lenses have you found to give good results?"<br>

EF 24-105/4L IS ... EF 70-200/4L IS ... I also would bet that the EF 300/4L IS is a nice lens.</p>

[daniel flather]

<p>You can use the IS to simulate too many drinks; it's fun!</p>

[unangelino]

<p>Sarah<br>

Thanks. The cheaply constructed aspect of the kit lens doesn't bother me at all. What you say here really hits the nail squarely on the you know what: <em>"An f/4 IS zoom has 3-4 stops stability advantage over the f/2.8 non-IS zoom at any specific aperture (e.g. f/8). An f/4 lens has 2-3 stops advantage over an f/2.8 non-IS zoom when used wide open. An f/4 IS lens is equivalent to an f/1(.2) - f/1.4 lens with regard to stabilization wide open."</em><br>

It would seem that for my purposes, the ability to get a shallower DOF would be the prime reason for a faster lens of any focal length. I tend to move more rapidly than most of my subjects...<br>

Cheers.<br>

Pauk</p>

[sarah_fox]

<p>"It would seem that for my purposes, the ability to get a shallower DOF would be the prime reason for a faster lens of any focal length."</p>

<p>Sounds like it. A good compromise approach used by a lot of photographers who have only occasional use for razor-thin DoF is to pick up a a couple of very fast prime lenses to be used in combination with slower IS zooms. Incidentally the lenses Rainer recommends are both excellent. I own the 24-105 and am in the market for the 70-200. However, they're also probably beyond your budget. A slightly cheaper f/4 lens I love is the 17-40, but it's not an IS lens. ;-)</p>

<p>Incidentally, the 70-300 IS is another optically superb consumer lens of somewhat cheap construction and modest price.</p>

[arie_vandervelden1]

<p>Larger aperture gives you an advantage when shooting with flash. A flash pulse is very short in duration, and long exposure times afforded by IS won't increase the amount of light reflected from the flash pulse. With large aperture, your flash will reach further: distance = GN / fstop.</p>

<p>For a given distance, a larger aperture means you have to use less flash power. The same large aperture will also expose more background (assuming same shutterspeed), so in all you get a more mixed-lighting less flashy look.</p>

[mattb1]

<p>Isn't it funny how ISO is never part of the IS discussions?</p>

<p>Paul, note that IS is only good for hand held photos. You should turn it off when using a tripod, otherwise it will soften the images.</p>

[wgpinc]

<p>The IS on the 18-55mm IS lens is not in my experience very effective. I use that lens some but I am using the 17-55mm IS lens more and more. If money was tight I would go ahead and use the 18-55mm IS or spend the $394 at B&H to get the Tamron 17-50mm 2.8. I have used it a little and it is very good. Some say IS some say speed what matters is what you say for your needs and budget. Good luck! </p>

[robert lee]

<blockquote>

<p>My question is what is really of more practical benefit; a <strong><em>faster</em> </strong> 2.8 lens or a <strong><em>slower</em> </strong> lens with IS?</p>

</blockquote>

<p>Switch to a system with in-body IS (meaning not Canon and not Nikon) and you get both.</p>

[marknagel]

<p>This is the biggest advantage of a faster lens (DoF)</p>

<p>http://www.nagelhome.com/phototest/DOFa.jpg</p>

<p>M</p>

[Brad_]

<p>Speed. For creative options with respect to DOF. </p>

[philip_wilson]

<p>For me the fast lens (hence 24-70 F2.8 and 70-200 F2.8 - non IS). It stops motion better (faster speeds) has quicker AF (F2.8 works faster and better on Canons), gives a brighter viewfinder, has shallower DOF and usually better Bokah. If you are a film user I would always go with the faster lens as you have limited ability to raise the ISO. But many people really want IS - I never find I need it (although it does help on my 300 F2.8 - but my old FD300 F2.8 still works fine) but since i spent over 20 years with MF and no IS i learnt how to live without it.</p>

[david_john_appleton]

<p>>>>>>>Switch to a system with in-body IS (meaning not Canon and not Nikon) and you get both.<<<<<< <br>

Not so, in body IS starts to become less effective at 200mm plus.<br /><br>

Its at the longer FL that its is needed, and have you seen the price of Sony lenses, with canon you get the IS for free </p>

<p > </p>

[mphoto gallery]

<p>All good suggestions. You could also consider getting Exposure Plot and use it to review all of your pictures. See what f-stop and shutter speeds you have been using. I did and found a lot of my images were taken using apertures to yield a lot of DOF. A portion of my pictures were taken at the max aperture for the lenses I had at the time. Was that by design or because I needed the light and that was the best I could do? The grouping of slow shutter speeds suggested that I could benefit from more light for some of the pictures and for some, the resulting slow shutter speed was not an issue. </p>

<p>I had missed some opportunities due to blurred movement in the picture. A 2.8 could have helped. I had some images where controlling the DOF would have yielded a better image. The point is that now I know with some degree of accuracy when I could have benefited from a faster lens. Knowing that, I now have three lenses at 2.8 or faster and in addition, I bought the 24-105 as some activities need image stabilization. I hike, take pictures from boats and especially where you are in the middle of a crowd and need to take a quick shot, the IS is very very nice for these purposes. Your mileage may vary.....</p>

[unangelino]

<p><em>And the answer is:</em><br>

The <strong>Tamron 17-50 2.8</strong> . Picked a new one up today at Samy's in Pasadena for 4 Bens & change. Since it's not worth much (cash wise, anyway) I figure I'll just keep the kit lens as a capable back up.<br>

Thanks to everyone (especially you, <strong>Sarah</strong> ) for your advice and insight.<br>

Cheers.<br>

Paul</p>

[richard_muscat_azzopardi]

<p>Can you give us an update now? I'm seriously considering that lens, how are you finding it?</p>