By the way, if we compare it to the analogue days: 36 mm x 24 mm film is estimated between 4 and 16 million pixels depending on the type of film used. Source: http://en.wikipedia.org/wiki/Digital_versus_film_photography
At the top end of the estimate, the difference is even smaller.
My partner in Building Panoramics was in at the dawn of digital imaging business so I know a little about this. I haven't looked at the wiki link, but to all intents and purposes 6 to 8 mp is about equivalent to good 35mm film in terms of resolution. You can scan more meg but you end up recording grain.
The 4-16 megapixels are based on findings by Dr. Roger Clark. If you don’t know who that is, please follow the link this time http://www.clarkvision.com/rnc/
Try taking 5 shots at 1/20 on a 35mm focal length hand held with no support. You will inevitably find that one or two frames have IQ damaging blur when viewed at a reasonable enlargement. ( For me it would be four out of five). You may say these are acceptable odds but when that one frame is important it becomes unacceptable.
I didn’t say 1/20, I said 1/40
For (slow) moving subjects like people at a wedding you need at least 1/60 to 1/100
The point I tried to make is that for moving subjects most photographers should be able to get the job done at those shutter speeds with a 35mm lens on a full frame camera without image stabilization. The IS will help a lot if you go down to 1/20 or 1/10 but those shutter speeds will only get you sharp images of non-moving subjects.
Because a f/1.4 lens is a full stop faster than a f/2 lens you can shoot wide open with double the shutter speed or half the iso and that’s a substantial difference in low light situations. That’s why I prefer my 35mm f/1.4 over a f/2 with IS
I read many people on here claiming that the new IS primes are aimed at video, but how many people are 'serious' movie makers wanting these primes compared with the amount of still photographers ?
I can’t speak for other people but I didn’t say the wide angle IS primes are aimed at video, I said “stabilization is nice if you like to shoot video”.
Other than video, image stabilization on wide angle prime lenses will only help you with still images of static subjects at low shutter speeds where you can’t use a tripod.
Where I live the Canon f/2 IS dropped 30% in price after about half a year. Compare that to the 8 year old Canon EF 35mm f/1.4L USM for which you pay about the same as when it hit the market in 2006. To me that says something about the lack of success of the 35 f/2 IS.
The EF 35L was introduced in 1998, so it is sixteen years old. No doubt this info isn't on Roger Clarks website but I'm sure you will find it on wiiki somewhere.
The principal of a 1.4 lens being 'better in low light' is a risky one to hang your hat on. Good exposure, lower ISO and less shake are of little use if your dof is woefully inadequate, and given the focal length of the 35mm and likely distances 'in low light' this is likely to be the case.
Also in days of old you might buy a 1.4 lens to be better at F2 than an f2 lens, but with modern lenses this isn't the case anymore. Seeing as you like web links I have copied photozone's results for the two lenses and you can see that although the 1.4 lens is sharper in the very centre it is way behind mid and edge of frame, and this continues up to f4.http://www.photozone.de/canon_eos_ff/516-canon35f14ff?start=1http://www.photozone.de/canon_eos_ff/847-canon35f2isff?start=1
It's pretty typical of very fast wide lenses compared with slower ones, and why for someone wanting good mid / corner resolution they might well chose a slower lens. ( Though this is changing with the likes of the Sigma 1.4 and Otus ).
There are situations where a faster aperture is a valid reason for low light photography. Take the 135L, it's often sited as a low light advantage, and given the distances of say indoor sports and the focusing on an individual then that is plausible - assuming you nail focus and ignore the high ISO performance of modern FF cameras.
In real terms the 35L is cheaper than it was sixteen years ago. http://financial-dictionary.thefreedictionary.com/Real+terms
Of late Canon have been adopting an EOP marketing strategy; I think these new IS lenses have been caught in this; after all they were the first wide IS primes to be introduced. http://www.investinganswers.com/financial-dictionary/businesses-corporations/early-adopter-2959
In time they will come to be appreciated as what they are - really good lenses. Look at the crap the 70-300L took on forums such as this at the time of it's introduction. Now it is highly regarded by many.
Regarding shake - try it at 1/20 or 1/40 or 1/80. It's the principle I am referring to. The amount of frames with shake will reduce as the speed increases, but you will find that even 1/80 on a 35mm focal length from an unstable platform is no guarantee
of a shake free shot.