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SwissDot

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Wondered why camera manufacturers are so concerned about putting ISOs at higher and higher speeds but yet nothing much slower than 100 ISO.

Back in the olden days, I remember seeing film at 25 ISO, and the max on my Minolta XG-M was 800 ISO, which seemed to be as fast as you'd ever need.

Why is this? Does anyone take pics at the hyper-fast speeds? :shrug:
 
That's a really good question. It must be something to do with the electronics but I've never really understood the finer details. Someone will be along any minute to explain it all to us..................
 
SwissDot said:
Why is this? Does anyone take pics at the hyper-fast speeds? :shrug:
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Having the ability to shoot at extremely high speeds is nice, but that's not the main point. Think of it more like driving a fast car. You don't need it to be able to drive at over 100mph, but the fact that it can gives you better performance at lower speeds.
 
Film grain is closely linked to ISO, and the finest grain was - and still is - achieved with the slowest film, ISO 25. 30-40+ years ago, colour film didn't come much faster than this anyway - if you wanted to shoot in low light, you'd need a fast black & white film.

Digital SLRs are capable of essentially noise-free pictures at anything below ISO 400, depending on the sensor, so there's really no need to put in ISO settings below 100. (Nikon have ditched the 100 setting on the D700 - the lowest on this model is ISO 200). If you need a very low ISO setting for long exposures, large apertures in bright light etc., you'll need a ND filter.

At the other end of the spectrum, being able to shoot good quality images at ultra-high ISOs is a boon for any photographer, and something that just wasn't possible with film - at least not to the same extent. Apart from anything else, it means you don't need a flash to shoot indoors!

and the max on my Minolta XG-M was 800 ISO, which seemed to be as fast as you'd ever need.
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Reminds me of Bill Gates's comment about 640kb being enough memory for anyone ;)

A.
 
Would IQ be any better or different at ISO's lower than 100? Or is the interest in taking longer exposures?
 
I'm a bit confused about linking very low ISO to hyper-fast speeds. You get a faster shutter speed with a higher ISO not a lower ISO. The drive for higher ISO performance comes from the sports world where you need to freeze the action with a fast shutter speed in a dimly lit stadium, so you need 1/800th or more and when your lens wont open any more than f/2.8 the only remaining adjustment is to increase the ISO. I routinely use ISO4000-5000 for my floodlit or indoor sports stuff these days.

Anyway, the 1D series goes down to ISO50 which I sometimes use if it is a very bright day and I am doing a very long exposure like 4 mins or so of a seascape, and a 10-stop filter isn't enough.
 
ryanyboy said:
That's a really good question. It must be something to do with the electronics but I've never really understood the finer details. Someone will be along any minute to explain it all to us..................
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I recall some one doing so about 10 months ago. The explanation was mostly lost on me, but it was to do with sensor technology.

Some day the technology will exist to greatly expand ISO range with noiseless images. The D3s has already pushed the upper boundary well out.
 
SwissDot said:
Wondered why camera manufacturers are so concerned about putting ISOs at higher and higher speeds but yet nothing much slower than 100 ISO.
Click to expand...

Possibly because there's nothing that you need ISO25 for? If you want to use slower shutter speeds then you just use a ND filter.
 
I believe the camera sensors are based on 100 ISO sensitivity and as far as picture quality is concerned that is as good as it gets for that sensor. Reducing the sensitivity to 50 ISO on the same sensor only adjusts the exposure value and does not increase the picture quality (unlike film)....the only advantage that I can see is it can enable you to get an extra stop slower on the shutter speed.

I kept wanting to write ASA instead of ISO when I wrote it in the previous sentence, must be an age thing :D

Paul
 
It would still be god to be able to use the ISO to reduce the shutter speed rather than the aperture value. the only other alternative is filters.
 
hollis_f said:
Possibly because there's nothing that you need ISO25 for? If you want to use slower shutter speeds then you just use a ND filter.
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I'm much rather have ISO25 or ISO50 than a base ISO of 200 and a 3 stop ND filter.
 
A number of canon DSLR's have a ISO of 50, which I find useful on occasion, particularly when you want to slow the shutter speed down , on flowing water/waterfalls for example.
I much prefer this method than adding extra filters.

It was one of the reasons (a number of years ago) for chosing a Canon DSLR over a Nikon DSLR, as at that time the minimum ISO on a Nikon was 200
 
I've always fancied getting an old Kodak SLR/n or SLR/c as it can do ISO6.
 
Most cameras that offer 50 ISO are only using a boost to get it that low, in this case 100 ISO is better.
 
Yeah, it'd be great to have ISO 12 or ISO 6.

IIRC correctly it would require extra signal amplification to get say ISO1600 with a lower base ISO. The higher the base ISO the easier it is to achieve generally higher ISO. Perhaps this is why Nikon used ISO 200 for base ISO?
 
Andy said:
Most cameras that offer 50 ISO are only using a boost to get it that low, in this case 100 ISO is better.
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From Canon's website in relation to ISO50:

Some customers claim that they see less noise at ISO 50 than ISO 100 on a EOS XXX, but both settings are about equally noiseless. There is approximately a stop less dynamic range in the highlights at ISO 50, which is the reason why this setting is normally locked out.

I can easily live with that :)
 
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