We observe that one of the recent trend is "High-ISO". Is it just a marketing campaign or you actually need higher ISO and why ? Do you need it for your dark life photography ? Or for high speed sport shots ? Or, are you one of those who believe that the camera that can do High-ISO will also do better in low ISO ?
Or, you don't need but don't mind having it ?
I shoot sports in dark gyms and often struggle to get 1/250 at 2.0 and 3200. Same thing for wedding ceremonies and receptions .. not as bad because the required shutter speeds are not as high as sports but still can be a struggle .. I shot a wedding this Saturday and the reception ambient was 3200, 1.8 and 1/60.
So I welcome good quality high ISO files, not a marketing ploy at all for me. Now live view and video, that's another story.
i often shoot in dark churches and wedding halls, with my 28-70 and primes. if i want sufficient aperture for DOF and a fast enough shutter speed, the ISO has to give . unfortunately, the breaking point is around f/2.8 (in most of my cases) and that's usually when i have to get up to ISO1600+.
Most of my shooting is for local newspapers which means I get sent to many caves like high school gyms with awful light. Sometimes I light it, others I go for a fast prime and crank up the ISO. I don't like having to go to such high ISO sometimes but places like that there is little choice and the image quality I get is outstanding anyway, even up high. So I guess I fall into the need it category but I don't mind at all if that means better low ISO too when I can actually use it :-)
I prefer to shoot with natural light so as the sun drops below the horizon or in dimly lit moonlit nights, moonless nights, snow covered areas or wildlife in the shadows areas. I don't always carry a tripod at night so it is nice to shoot at higher ISOs. Pictures very grainier and not sharp but they have their own unique look. Nothing like walking in a forested area shooting at ISO 3200 and the 50mm at F1.0 or 85 at F1.2 and underexposing 2 stops.
I'm another cave photographer (READ: local newspaper assignments in high school gyms, community centers, and un-lit "creative arts centers"). I do not have the chance to light my shots. Although I recently broke my budge to purchase faster glass (f/2.8 with IS), high ISO with reasonable noise suppression/avoidance is crucial. The amount of noise I get with my 40D really kills me.
High ISO is definitely not a marketing ploy as far as I'm concerned. I actually found myself using live view for the first time last week and re-discovered the utility in being able to acurately frame a shot without looking through the viewfinder. I think by far the most useless feature on Canon's camera is the direct-print link - I mean, when would you EVER actually print directly from the camera without bothering to upload to a harddrive?
i completely understand that great high ISO does not always = clean low ISO.
I however, do most of my shooting at night, in low light conditions, hand-held.
Bird photography in routinely dull, overcast weather (the NE coast of England) - I'm at 1600 ISO with depressing regularity sometimes, to keep the shutter speed up to catch fast-beating wings, for example.
. unfortunately, the breaking point is around f/2.8 (in most of my cases) and that's usually when i have to get up to ISO1600+.