Should I get IS lenses? Crystal-ball gazers needed.

[Mihai]

Details? Which body?
M.

 

[table1349]

Something to think about here.

1. Are you going to upgrade bodies every few years or lenses? IS lenses go from camera to camera. Can't take IS out of the body and put it in your older backup body.

2. Yes this is from Canon.
Some of Canon’s competitors have chosen to use in-body image stabilization. The technique involves moving the image sensor in a controlled fashion, based on signals from movement detecting sensors in the camera body. The obvious advantage of this system is that users have some sort of stabilization available with almost any lens they connect
to the body. Short focal length lenses require smaller sensor deflections; 24 or 28 mm lenses might need only 1 mm or so. Longer lenses necessitate much greater movement; 300 mm lenses would have to move the sensor about 5.5 mm (nearly 1/4”) to achieve the correction Canon gets with its IS system at the same focal length. This degree of sensor movement is beyond the range of current technology. Short and “normal” focal length lenses need stabilization much less often than long lenses, so the lenses that need the most help get the least. Further, in cameras with smaller than full-frame, 35 mm film size sensors, equivalent focal lengths become longer, by a factor of 1.5 or 1.6, exacerbating the problem by making all lenses longer.

 

[boris152]

Might as well heap my two cents in too. At this point Sony is the only camera maker I know of that uses in-body IS on dSLRs, and it was Konica-Minolta that turned the technology over to them. That's great for them; they don't make any film cameras. Canon however has been making IS lenses since long before they were heavy into dSLRs. All their EOS equipment and accessories (minus the EF-S lenses) function at full capability on both their digital and film bodies. "What's the point?" some would say. Maybe I'm one of the few these days, but I have a Canon ElanII film body I bought used for less than $40. I love my 350D, but it's nice to have the "full frame sensor" option for only $40 and the cost of a roll of film, and still get to use the IS in my 28-135mm lens.

 

[Alex_B]

All their EOS equipment and accessories (minus the EF-S lenses) function at full capability on both their digital and film bodies. "What's the point?" some would say. Maybe I'm one of the few these days, but I have a Canon ElanII film body I bought used for less than $40. I love my 350D, but it's nice to have the "full frame sensor" option for only $40 and the cost of a roll of film, and still get to use the IS in my 28-135mm lens.

Same here I too like my film body and it works with my IS lenses :=)

 

[Mihai]

Yes, the argument for backward compatibility is correct. But think that in the future Canon (and everybody else) will make 99% of their money from selling digital cameras, not film. At that time it will make no sense to insist on IS on the lens, especially if some nimble competitors (Sony?) will come with a better solution.

The only thing that makes me not jump on the Sony DSLR is the uncertainty in their future: I don't want to invest in a company that may not be in the DSLR business 5 years from now. I know that Canon and Nikon will be here a long time from now. But I think that Sony's solution (Minolta's really) is technically superior to Canon's.

Sony claims that it does 3.5 stops with their IS technology. Reviewers say 2 stops. Even 2 stops is great for now (and I'm sure that it can be done better with better sensors and actuators). This shows that it's techologically feasible (for a variety of focal lenghts).

Now regarding film bodies with IS... I'm not sure that it's not possible. I think that they can do it just as well with a shaking mirror and have the film exposed somewhere else than in the back (e.g., on the right or on the bottom). But the guys that cary film bodies also cary tripods, so they don't need IS anyway .

M.

 

[Alex_B]

well, i use a tripod sometimes for film and for digital.. still i need is ... even on the tripod it can be of use (with the right is that is)

actually i beleive that arguemnt about the tele lenses which are hard to compensate with sensor-is

and it is the tele lenses where you need it most.

 

[Jeff Canes]

Read the manual, IS automatically turns off when the camera is not moving. Do you shake your monopod? Also it is only really helps with low shutter speed

 

[Alex_B]

well, mine does shake.. as it is a light carbon-fibre one for backpacking which even does not stabilise 100% when weights are applied. i agree on sturdy
tripods it makes no sense!

pre-shutter release is the key often as well...

 

[boris152]

Does anybody else wonder if sensor mounted IS would be harder to impliment on a full frame sensor (the kind that only Canon makes)? At least one photo magazine thought so, though I don't have the one in hand to make the reference. Of course, just because so-and-so read it somewhere sometime doesn't make it true.

 

[Iron Flatline]

I think you guys are thinking about IS and it's future in a slightly off way. The solution wil not come through better motion compensation, but through considerably more sensitive and powerful sensor chips. We are still in a paradigm in which we are emulating film technology, and the inherent exposure methods and shutter speeds are just working with chips to act like film - ISO vs. ASA. We will probably begin seeing shutter speeds and sensor chip sensitivity far exceeding our current abilities, and will be able to compensate for exposures that require longer exposures and are thus more sensitive to camera shake. The solution will not be in-lens or in-body IS or VR, it will come from a very different place. Once we're done faking film photography with digital components will we see true technological innovation... and that may, or may not, come from Canon, Nikon, a company like Sony, or a completely unexpected corner of the market.

 

[Mihai]

This is a really interesting idea. However, I think that there is a fundamental limit in the sensitivity of a sensor: you'll need at least a few photons to hit each pixel of the sensor. If you have 16 bits of depth you need at least 65536
photons to be able to maintain the range. I don't know if we're close to that or not. But you're right: a super-sensitive sensor (say 102400 ISO) would solve many things.

Regards,
Mihai

 

[boris152]

That would make for some awful short exposures . . . make way for supersonic shutters!

Or the demise of physical shutters.

 

[Mihai]

Physical shutters are over-rated anyway . What I meant was go up to 102400. Of course, when you don't need it, you go down to 100 or 50 or so.


M.

 

[Alex_B]

This is a really interesting idea. However, I think that there is a fundamental limit in the sensitivity of a sensor: you'll need at least a few photons to hit each pixel of the sensor. If you have 16 bits of depth you need at least 65536
photons to be able to maintain the range. I don't know if we're close to that or not. But you're right: a super-sensitive sensor (say 102400 ISO) would solve many things.

Regards,
Mihai

Uhh, now things are getting rather fundamental here. In principle you are right about the fundamental limit.

However, if you speak of photons, 65536 is a wee tiny tiny little number ... and yes, we are way away from sensitivities like that. If you go down to look at small numbers of photons, then you have to also to consider noise on this quantum scale, which is non-trivial and has nothing to do with the sensor, it is there already in the flux of photons hitting the sensor (of course in addition there is the noise of the sensor itself and of the amplifiers!). I remember experimenting with low photon-flux setups on a fundamental scale as a student at university years ago. Noise always was a big issue there. And that is noise on a scale none of you would ever think acceptable in a photographic image

If you work with the police, army or are a hunter, then maybe you know these various night-vision devices. Those which don't rely on an infrared lightsource or on heat-imaging, those actually have very sensitive sensors and strong amplifiers .... and they produce one hell full of noise! Still got one of those in my drawer

Anyway, when constructing a sensor and push it to such limits, then there are plenty of roadblocks in the quantum-world. Of course always some problems can be solved which one would not have thought to be able to solve ever. But progress will be very slow and some things simply will never work.
Sorry for the tech-talk .. but I was in that business for some years (on the fundamental materials science end)

 

[Mihai]

On the contrary, I like tech-talk. I'm on that side as well, although a bit more toward practical things (engineer), but I'm always fascinated by fundamental limits that don't let us push things beyond a certain point.

Are you sure that 65536 is a wee tiny tiny little number? Do you have anything to support this claim? I mean, it should be somewhat easy to figure out if somebody knows how many photons hit a square meter on sunny days each second. Denote this number with N.

Then from an 18% gray, 0.82*N photons will be reflected. Out of those, only 1/(16*16) get into the camera (following the sunny 16 rule).
Then the sensor size is 0.024*0.036 square meters (for a full frame).
Then each pixel is 1/10M for a 10Mpixels camera. Furthermore, if you take an ISO of 400, then the time is 1/400. Then each pixesl only gets 1/3 light (three colors)

So in the end 0.82*N*0.024*0.036/(3*400*256*10^7) will go to each pixel. That comes down to 230*N*10^-18. I was unable to find how big is N, but notice that this comes down to Avogadro's number. I have the feeling that we're not *that* far from the fundamental limit.

M.