High ISO Weirdness?

[1750Shooter]

Maybe I just don't get it, but I keep hearing whining about noise in digicams at ISO's over 6000 or so. Wikipedia says ISO=ASA, so you're talking about "speeds" higher than anything commonly available in film. I've used Tri-X pushed to 1600 & Ilford 3200 & expected grain. I don't understand the need for these high ISO's except for tricks. I've seen lots of dim, poorly lit, & badly composed photos taken at amazing ISO's but not much good stuff. Thanks for any explanations & apologies to anyone offended.

 

[jsrockit]

Well, if you search for garbage, you get garbage. The internet is full of bad photography, but also, there is more good / great photography available than ever.

High ISO allows for faster shutter speeds, more depth of field based on using smaller apertures, and of course extreme low light photography. It may not be necessary for your photography, but I have relatively clean 3200 and 6400 ISO photos from the Fuji X series that are completely usable and I am happy these ISOs are available and usable.

I don't look at high ISO as something that allows you to photograph a ninja in a cave. It just allows for more versatility (shutter speed / aperture combos) in low light.

I think high ISO is just like super wide angle lenses... a few people know how to do it well, and a lot of people do it badly.

 

[Dogman]

I shoot most of my photos in the 100-200 ISO range. But I can appreciate the ability of a camera to make photos with excellent image quality at high ISOs even though that feature is only of limited interest to me.

 

[willie_901]

People who shoot sports for a living can never have enough ISO.

It's sometimes useful to have no DOF restrictions and use a reasonable shutter speed.

I use ISO 800 for my interior photography. This lets me get the most out of the small stobes I use to light the interiors. I can use several small battery powered strobes instead of large, heavy AC powered studio strobes. I have more flexibility to blend ambient with strobe light. The image quality is similar to ISO 400 from 3 - 4 years ago.

For non-commerical work I use ISO 1600 for ambient, lo- level lighting. I rarely use ISO less than 400 because I prefer to use the highest possible shutter speed for hand-held shots.

There may be a reason why many ultra-high ISO photos look bad. There are two ways camera makers increase ISO. Electronic amplification of the signal is what most people think of when it comes to ISO. But very high ISOs, say greater than 1600, are achieved by digital multiplication of the in-camera raw data before it is written to the memory card. So ISO 6000 would almost certainly be from an image that was actually underexposed by 3 to 4 stops and pulled to the higher ISO using in-camera software. Underexpose always creates a inferior digital image (regardless of the ISO) so sensor noise and limited dynamic range is particualy noticeable in very high ISO images.

 

[Bill Clark]

ISO (ASA) is different with film as compared to digital.

With digital the sensor doesn't change speed, the output (amplification) does to get to the higher ASA.

Haven't tried any of the new high ASA digital cameras but I haven't the need or desire to.

Agree with your second to the last sentence.

 

[Paul Luscher]

Guess I'd have to say I do a lot of my shooting at ISO 1600 (no-flash live concert work), going higher on occasion when needed. So I'm happy to have ISOs running that high. But since I do come from the age of pushed Tri-X and TMax 3200, I find all the complaining about noise at 1600, etc, amusing. To me, my shots taken at those ISOs look amazingly grainless. This applies to my M9, which I have seen users bitching about as having "too much noise" at ISO 1600. To those whingers I say: you don't know how good you have it.

 

[Bill Clark]

Interesting Video on digital stuff:

http://www.youtube.com/watch?v=WEApLA-YNko

 

[dmc]

For me, I shoot digital different than film. With film I am locked into the ISO so I select shutter speed and aperture based on the speed. With digital, I allow my ISO to float, by using the Auto ISO setting, and then choosing the shutter speed and aperture based on what I want out of the composition. Depending on the light, my ISO may vary from 200 to 6400. While I do love shooting film, I do enjoy the luxury of being able to select Auto ISO and use whatever combo of shutter/f-stop I want.

 

[jsrockit]

For me, I shoot digital different than film. With film I am locked into the ISO so I select shutter speed and aperture based on the speed. With digital, I allow my ISO to float, by using the Auto ISO setting, and then choosing the shutter speed and aperture based on what I want out of the composition. Depending on the light, my ISO may vary from 200 to 6400. While I do love shooting film, I do enjoy the luxury of being able to select Auto ISO and use whatever combo of shutter/f-stop I want.

Yes, the best thing about modern digital cameras. I think of it as a hybrid manual technique.

 

[Peter_wrote:]

Wikipedia says ISO=ASA, so you're talking about "speeds" higher than anything commonly available in film. I've used Tri-X pushed to 1600 & Ilford 3200 & expected grain.

by the way, you cannot always say digitalISO=analogASA . at least with my canon digicam (powershot g11) iso/2=asa. so with e.g 400iso i get about the same time/aperture as with 200asa film for a correct exposure.

i once saw a chart somewhere, which confirmed that fact. every manufacturer seems to have its own politics in this issue.

 

[Terry Christian]

The terms ISO and ASA are regardless of analog or digital technology. ISO is simply the name for the newer standard. If your digital ISO doesn't equal your analog ISO, then either your metering methods differ or one of the meters is seriously off.

 

[Peter_wrote:]

both cameras meter correct.

Films exposed to light and developed produce fogged images that can be read with a densitometer. This reading determines the ISO for a specific film. Unfortunately, this method can not be used to determine the ISO of a digital sensor. Digital ISO must therefore be determined by methods different from those used to determine film ISO. The methods for determine ISO are described in detail in the following document: Photography – Digital still cameras – Determination of exposure index, ISO speed ratings, standard output sensitivity, and recommended exposure index; ISO 12232:2006.

it is meant, that they should be somehow equivalent. but most manufacturers seem to trick a bit.

and i saw a chart somewhere which underlined my own experience. unfortunately i can't find it anymore. but for canon it said something like 2/3 * canoniso= filmiso


but i just found this in the chdk (alternative firmware for canon compacts) wiki:

"The values entered in the ISO override are not exactly equivalent to the values in the Canon UI and exif. Canon uses different values for calculation ("real" ISO) and display ("market" ISO). The CHDK override works on "real" values. The "real" value is lower than the displayed value, so an override to 50 will result in a "market" value of around 80. The exact relationship isn't well specified."

this shows that there is some space for the manufacturers how to interpret the iso-specification. in this case even for same camera you have two different iso-values.

 

[willie_901]

There are five different approved methods measuring the sensitivity of digital sensors and be complient with ISO (International Organization for Standardization) standards. Japanese camera manufacturers use yet another standard of their own that is defined by the Camera & Imaging Products Association.

Camera reviewers like DxO use a different definition that measures sensitivity based on the light intensity required to saturate the sensor. This definition typically results in a lower number than the other ISO/CIPA standards.

The goal of all these standards is to have an EV that is similar to film and give consumers and manufacturers a way to compare cameras.

Of course the methods used to determine film ISO are completely different. ASA was obsolete and was replaced by a film ISO standard decades ago. Then, the ISO definition was intended to match the ASA sensitivity.