Canon has trouble implementing IS with large lens elements?

[slashbinslashbash]

Just thinking over the latest lens announcements from Canon.

1) 24-70 has no IS. Even with its recent diet, this is still a substantial lens.
2) 24mm and 28mm with IS are only f/2.8, while previous non-IS lenses of similar focal length were much faster (e.g. 28mm f/1.8).

Add to:

3) Existing IS lenses are either relatively slow (kit lenses, 24-105 f/4) or have relatively small elements deep inside where the IS works its magic as compared to the hefty glass in the front elements (telephoto f/2.8 etc.).

Now, thinking purely of the physics of IS, of course you can't have very effective correction if the IS motor has to move a lot of mass around. It makes perfect sense; for the motor to be quick and responsive, it needs to move around the smallest/lightest elements in the lens. So the answer to the question in the title is kind of "No duh."

But, that being said, I really didn't think we'd be up against the limits of it this soon. Only f/2.8 in a 28mm? Really? Does this mean we'll never see IS in any of the fast L primes, e.g. 35mm f/1.4? If so, it really is too bad. If the 24mm or 28mm were, say, f/2.0 then that could be a pretty compelling purchase. As it is, I've already got an f/4 zoom that covers both 24mm and 28mm, with IS. One stop of light isn't worth the trade.

 

[Anubis]

umm the large zooms (300-600) have massive lens elements in them, they still have IS. or am i reading what you mean wrong?


short length primes dont benefit as much from IS which is why you dont see it in them. nikon does not have many either. + you can handold a 24mm at extreamly slow shutter speeds and get great results

 

[slashbinslashbash]

http://www.canon-europe.com/support..._educational_tools/en/ef_lens_work_iii_en.asp

Look at "The EF Lens World (Single Focal-Length Lenses)" and scroll down to e.g. the EF 300mm f/2.8L IS USM. There are plenty of smaller lens elements and groups near the middle and rear of the lens. If I'm not mistaken, that is where Canon implements the IS mechanism, not in the large elements at the front.

 

[slashbinslashbash]

Thinking about this a bit more. I guess a part of it is the size of the stabilized lens elements vs. the size of the lens body. In a 600mm lens, there is already a lot of bulk, so the IS doesn't take up that much size/weight proportionally. In a 28mm lens, the lens barrel is short and narrow. If too much of that volume is taken up by glass (as it would need to be, if the lens were faster) then there's no room for the IS mechanism.

Which leaves Canon with a dilemma, to either increase the overall size of the lens or to decrease the size of the glass inside. Which again is a bit of a "duh" but I'll say that I'm surprised that they hit the compromise where they did, i.e. in the direction of making the lens fairly compact.

 

[RobDickinson]

The trick with IS elements is to have them far enough forward you dont have to have too many oversized elements ahead, but not so far forward the IS elements themselves are huge.

The MTF chart for the new 24-70 seems to suggest its worth it and IS obviously would be too much (compromise, weight, price , whatever) the target market isnt so bothered about IS when you can bump your new body up to ISO 25600 or whatever.

 

[iGas]

Canon EF 400mm f/2.8 L IS USM -- 11.8 lbs

Canon EF 600mm f/4.0 L IS USM -- 11.8 lbs

Canon EF 800mm f/5.6 L IS USM -- 9.9 lbs

Canon EF 500mm f/4.0 L IS USM -- 8.5 lbs

 

[slashbinslashbash]

Canon EF 400mm f/2.8 L IS USM -- 11.8 lbs

Canon EF 600mm f/4.0 L IS USM -- 11.8 lbs

Canon EF 800mm f/5.6 L IS USM -- 9.9 lbs

Canon EF 500mm f/4.0 L IS USM -- 8.5 lbs

Your point? AFAIK the IS in all of those lenses takes place towards the rear of the lens, where the smaller elements are.

 

[iGas]

Your point? AFAIK the IS in all of those lenses takes place towards the rear of the lens, where the smaller elements are.

My point is that Canon doesn't have problem with it.

IS is not the problem. There is more problem associated with auto focusing of large elements. In the past large telephoto and fast lenses auto focus was slow, but Canon has over come that hurdle. As for IS, it doesn't warrant the additional cost or weight of lens to have IS for wide angle.

I use to shoot/handheld my 24mm at 1/30s to 1/60s and get good result, and I tend to shoot it at f/5.6~f/8.

 

[slashbinslashbash]

My point is that Canon doesn't have problem with it.

IS is not the problem. There is more problem associated with auto focusing of large elements. In the past large telephoto and fast lenses auto focus was slow, but Canon has over come that hurdle. As for IS, it doesn't warrant the additional cost or weight of lens to have IS for wide angle.

I use to shoot/handheld my 24mm at 1/30s to 1/60s and get good result, and I tend to shoot it at f/5.6~f/8.

Obviously it warrants having IS for wide angle lenses when they just introduced it on 24mm and 28mm primes. However, I am disappointed that they are both only f/2.8.

 

[RobDickinson]

For large lenses you put the focus elements at the back. This works well but you have focus breathing issues.

 

[iGas]

Obviously it warrants having IS for wide angle lenses when they just introduced it on 24mm and 28mm primes. However, I am disappointed that they are both only f/2.8.

Distortion and flares are hard to control with wide angle, specially at fast aperture, and most people would shoot it at stop down aperture for depth of field and entire field sharpness, that associated with the beauty of wide field of view (tend to be mostly landscapes, and architectures).

http://improvephotography.com/2449/what-is-the-sharpest-aperture-on-a-lens/

http://www.luminous-landscape.com/reviews/lenses/24-vs-24.shtml

There is nothing stopping you from picking up the 24mm f/1.4 L if fast aperture is your uttermost important criteria.

 

[corkyg]

Lots of information. I have used my 70-200 f/2.8L lens for several years and found no IS problem. On the center barrel are two switches for IS - On/Off and Mode 1 and Mode 2.

 

[magomago]

I'm going to disagree with you guys here saying that there is no point for IS on the short end. Coming from in body IS, its awesome to have it anywhere, and I can get great results even with a much slower shutter speed. I've seen great results from others where they do take beautiful images handholding using IS-style systems (ie: think standing still on a busy street in NYC while everyone walks around you)

This is one of those things where you'll tell yourself you don't need it if you don't have it and find ways to rationalize it, but you'll appreciate it and find creative uses of it if you do have it. So lets not pretend its pointless on the short end.

 

[RobDickinson]

IS at any length is a very useful too.

I have hand held shots at 25seconds with the 17-55IS at 17mm. Bring it on.

It can produce some iffy bokeh if active but rather that than a blurry subject.

 

[Sp12]

Sounding like Sony/Pentax shooters, rationalizing IS as a useful feature just because you don't have to pay a premium for it.

 

[slashbinslashbash]

IS at any length is a very useful too.

I have hand held shots at 25seconds with the 17-55IS at 17mm. Bring it on.

It can produce some iffy bokeh if active but rather that than a blurry subject.

25 seconds? Really? I assumed that at such lengths, there would be such large movements that there's no way that IS could compensate. Maybe, propping the camera up against something. But 100% handheld? Your body would rock back and forth too much. At least that's my assumption. But if IS on a wide-angle could really compensate even up to 1/2 second or so, I would be happy with it.

 

[RobDickinson]

I was braced, and it was one shot out of a dozen that came out. (Canon 17-55 on 7D), this is the shot, its not perfect though:

 

[foghorn67]

Lots of information. I have used my 70-200 f/2.8L lens for several years and found no IS problem. On the center barrel are two switches for IS - On/Off and Mode 1 and Mode 2.

This. Emphatically this. A whole lot of words, when this post negates the rest.