Higher ISO What Does It Actually Achieve??

[kbm]

hi
can anyone explain to me the following question. I am an old 35mm slr person whereby the higher ISO you used, meant the faster shutter speed you could use for action shots.

1 - What does Higher ISO's actually do in digital photography?

2 - What is the benefit (not feature) to the final image produced?


I dont understand because i have just seen a series of photos shot at high shutters speeds with an ISO of only ISO80 and they looked perfect.

But when i saw some ISO400 shots they were very noisy

So i am now totally confused.

Can you please help me out?
Thanks Kevin

[cdifoto]

Higher ISO lets you get the shutter speeds you wouldn't get at lower ISO by making the *film* (sensor in digital) more sensitive to light.

Use low ISO when you can still get the shutter speeds you need...since you get more dynamic range(the ability to record shadows and highlights without burning out the highlights) out of lower ISOs.

In short...ISO is the same in film and digital with the same effects and shortcomings versus benefits. You just notice noise more because you see an image at 100% on your screen instead of a developed 4x6 or 5x7 or what-have-you.

[kbm]

thanks cdi
so basically it performs the same as it does in film.
instead of having faster film,
we make the senor more sensitive?
If that is the case can you shoot higher shutter speeds with iso400 than you can with iso80 in digital cameras.

I guess thats why the penalty is more noise, the same as higher iso film?
cheers and thank
kev

[Norm in Fujino]

thanks cdi
so basically it performs the same as it does in film.
instead of having faster film,
we make the senor more sensitive?
If that is the case can you shoot higher shutter speeds with iso400 than you can with iso80 in digital cameras.

I guess thats why the penalty is more noise, the same as higher iso film?

All correct. Raising the ISO in a digital camera means that the electrical "gain" of the sensor is increased. That increases its ability to detect light, but simultaneously it increases the likelyhood (certainty) that the sensor will pick up more extraneous electrons that leak from surrounding circuitry and appear as "noise" (grain) in the photograph. Different sensor designs produce differing amounts of inherent noise, and different manufacturers of sensors and cameras have different philosophies about how to handle what noise is there. Most (?) use some form of in-camera processing to eliminate (some of) the noise, while some leave it for users to eliminate using standalone NR programs (Neatimage, Noise Ninja, Noiseware, etc.).

The rationale of the latter is that a standalone program can use the entire computer's power to perform that processor-intensive task, rather than trying to get it done by a chip in a more rough-and-ready fashion inside the camera. Both systems work to varying degrees.

What's really amazing is what we've come to expect as "normal" these days. Back when using Tri-X, I shot at ASA200 most of the time, cutting back on processing time to produce finer grain. But now we expect shots at ISO 1600 and 3200 to be virtually noiseless.

[cdifoto]

thanks cdi
so basically it performs the same as it does in film.
instead of having faster film,
we make the senor more sensitive?
If that is the case can you shoot higher shutter speeds with iso400 than you can with iso80 in digital cameras.

I guess thats why the penalty is more noise, the same as higher iso film?
cheers and thank
kev

Yep and the awesome part about digital is you can switch ISO on the fly on a shot-per-shot basis...without changing film! :D

Something interesting to note...due to the noise in the image, the filesizes are larger at higher ISOs...so you get fewer shots per memory card with more high ISO photos than low ISOs. My 4GB card can hold well over 1000 pics at ISO100 (not sure exactly how many because the counter can only read as high as 999)...but up it to ISO1600 and the initial count goes to about 960. It always fluctuates though since the counter is just an estimate and each shot is usually a different filesize.

[kbm]

Hi Norm
Thank You very much, that is exactly the type of detailed answer i was after, it now makes alot more sense, having come from a 35mm slr background. The sensors you are talking about, are these the cmos and ccd type?

I also use photoshop alot for my design business, is it easier to use the deicated noise remove programs you mentioned than photoshop, and do they do a better job? I know photoshop struggles with alot of noise and you always loose the sharpness of your iamge dont you.

Thank cdi, that was a big help re the mem cards, so i will be buying a good size card as well.

cheers kev

[wxcloud9xw]

Also it should be mentioned that instead of raising the ISO speed you can open up the aperture wider to let in more light allowing you to achieve a more "noiseless" picture. Certain situations do require a higher ISO though.

[kbm]

wxcloud9xw,
yes very good point, i do have some lea-way by doing that as well, almost forgot that until you brought it up, just need to watch my depth of field, is that right.
thanks so much for all the help.
i can see the light at the end of tunnel getting closer
cheers kev

[cdifoto]

Also it should be mentioned that instead of raising the ISO speed you can open up the aperture wider to let in more light allowing you to achieve a more "noiseless" picture. Certain situations do require a higher ISO though.

Yeah...that too.

Unless of course you need depth of field or something. There are also time when you're struggling so much that even ISO1600 and f/1.8 is barely gets you (read: me) 1/30th shutter speeds. :eek: heh.

[cdifoto]

Hi Norm
Thank You very much, that is exactly the type of detailed answer i was after, it now makes alot more sense, having come from a 35mm slr background. The sensors you are talking about, are these the cmos and ccd type?

I also use photoshop alot for my design business, is it easier to use the deicated noise remove programs you mentioned than photoshop, and do they do a better job? I know photoshop struggles with alot of noise and you always loose the sharpness of your iamge dont you.

Thank cdi, that was a big help re the mem cards, so i will be buying a good size card as well.

cheers kev

Standalone programs like Noise Ninja and NeatImage do a lot better than Photoshop's built-in noise reduction (at least with the outdated PS7 that I have). You still lose detail...that's kind of a given...but it seems to be more of a problem with patterns on fabrics and some textures than edge detail. I can't speak for the newer releases. Those standalone programs often have free trials or are free altogether but with limited features. You can also purchase them and get a Photoshop plugin to use. I forked over the dough for NeatImage with the Plugin. Cost me a pretty penny but was worth it since I do a LOT of ISO1600.

[ReF]

Standalone programs like Noise Ninja and NeatImage do a lot better than Photoshop's built-in noise reduction (at least with the outdated PS7 that I have). You still lose detail...that's kind of a given...but it seems to be more of a problem with patterns on fabrics and some textures than edge detail. I can't speak for the newer releases. Those standalone programs often have free trials or are free altogether but with limited features. You can also purchase them and get a Photoshop plugin to use. I forked over the dough for NeatImage with the Plugin. Cost me a pretty penny but was worth it since I do a LOT of ISO1600.

PS NR still sucks, but the NR in PS RAW is pretty good. i don't have cs2.

[cdifoto]

PS NR still sucks, but the NR in PS RAW is pretty good. i don't have cs2.


Come on Ref. Tell me how you REALLY feel! :eek: :D

Seriously though I figured it still would but hate to draw conclusions based on assumptions.

[ReF]

Come on Ref. Tell me how you REALLY feel! :eek: :D

Seriously though I figured it still would but hate to draw conclusions based on assumptions.

it's so bad that i don't even bother with it, no matter what the situation.

[cdifoto]

it's so bad that i don't even bother with it, no matter what the situation.

Same here with PS7. All it does is muddy up the photo and make it unusable - especially for printing. Puts ya in a worse spot than you were before with all the noise.

[wxcloud9xw]

I've got photoshop Cs2...but I haven't had the chance to try out the NR yet.

[D70FAN]

I use Noise Ninja, and the results are generally amazing, especially when you use the camera profiles supplied for individual dSLR's. Recently, I de-noised the ISO 3200 shot that was posted on the D200 using a D70 ISO1600 profile, and it worked pretty well (reads printable). For $29 it should be in your bag of tricks.

I see equally good results using Neatimage.

[kbm]

hi guys
thanks so much for your input, i really appreciate it.
3 more questions

1- rather than looking at the FZ30 because of the amount of noise, i am now looking at the Canon S2 IS, however it doesnot have RAW or TIFF.
HOW MUCH OF A PROBLEM IS THIS GOING TO BE? And does effect any particular shot range than another?

2- I was looking at some photos on dpreviews from the Canon S2 IS and one of the settings was called: (Meter: 13.5 EV). What does this mean, as they did not show the ISO rating either.

3- When i look at all the previews of noise at ISO400 i can see what they mean by lots of noise, and both the FZ30 and S2 IS seem to have the same amount when viewed at close up shots, but these images are magnified quite alot, or at least they look that way. And yet when i see there images at normal size they both look great. Does that mean they will print okay or not?

I know normal inkjet printing should be fine but keeping in mind i will be using the camera for graphic design where i need finished shots at 300 DPI for professional printing on presses. Anything less than 300 DPI (dots per inch) becomes pixilated as you probably already know.

Once again thanks for all your help in advance

cheers Kev

[wxcloud9xw]

on higher MP digital camera pixalation is hardly noticed..even if you print at 100 Dpi...It depends on how big a print your going to make.... 150dpi at 11x14 will still look very good on an 8mp camera for instance.

99.9% of digital fixed lens cameras/point-n-shoots have a lot of noise at ISO 400.

RAW and TIFF are advantageous for editing, because they are the uncompressed/loseless image data from the camera. RAW is like a digital negative allowing you to make Whitebalance adjustments before converting to TIFF or Jpeg. TIFF is just an uncompressed jpeg at 100% original quality and takes up a lot of harddrive space and memory card space as well. Jpegs are compressed versions of the image that save space. TIFFs and RAW help keep you from being able to see any loss of quality during heavy editing sessions before you convert to high quality jpeg for printing when your done editing.

[kbm]

thanks cloud
\what about this meter ev thing?
cheers kev

[wxcloud9xw]

Just have to wait and see if someone else knows...I'm not sure.

[cdifoto]

I'm not 100% certain but I believe 13.5 EV refers to metering. Evaluative metering that weighs the center 13.5% of the frame more than the outer 86.5%. I could be wrong...and probably am. lol.

[timmciglobal]

EV = exposure value or a measurement of how "Bright" the scene is. The reviews from dpreview have a seperate light meter to show the EV rating of a target to give you an idea if the ISO and exposure is correct. Seeing as most people (myself included) have no clue how many "Ev" per ISO at a shutter speed results in proper exposure it's a mostly useless peice of information, only really used as a term of the ability to focus (some camera focus down to 1 ev, some 1/2 ev, some -1 EV (meaning they use an AF assist light in darkness) and at a maximum EV (how bright before it can't distinguish contrast in a set brightness)

Tim

[cwphoto]

wxcloud9xw,
yes very good point, i do have some lea-way by doing that as well, almost forgot that until you brought it up, just need to watch my depth of field, is that right.
thanks so much for all the help.
i can see the light at the end of tunnel getting closer
cheers kev

Remember too that most digital cameras have a greater DOF for a given aperture and FOV compared to 35mm, so you won't have to stop-down as much to achieve a similar result as the past. Which is just as well beacuse diffraction is a problem below f/11 on many models anyway.

[kbm]

thanks guys
i found out the EV is Exposure Value
cheers and thaks kev

[wxcloud9xw]

I was just reading that a lot of Professionals stick with 100 ISO 99% of the time and just use a tripod in dull dark times of the day and just take longer exposures rather than raising the ISO.

[cdifoto]

I was just reading that a lot of Professionals stick with 100 ISO 99% of the time and just use a tripod in dull dark times of the day and just take longer exposures rather than raising the ISO.

What professionals? I highly doubt that's true. I don't think there are enough pros shooting static subjects with the luxury of time to set up a tripod to be able to come to a conclusion that *most* do that.

Some...but certainly not most.

[timmciglobal]

I think an accurate statment would be most pro's only use higher ISO's when required.

You won't see a "pro" shooting @ ISO 800 just because he can shoot at ISO 800. Image quality is of extreme importantace to someone who makes money from images so shooting at the cleanest ISO possible to get the result he/she wants is what they would do.

However, high ISO is important. Natural light shots even @ F 2.8 are difficult without a clean high ISO on a camera.

Tim

[cdifoto]

I think an accurate statment would be most pro's only use higher ISO's when required.

You won't see a "pro" shooting @ ISO 800 just because he can shoot at ISO 800. Image quality is of extreme importantace to someone who makes money from images so shooting at the cleanest ISO possible to get the result he/she wants is what they would do.

However, high ISO is important. Natural light shots even @ F 2.8 are difficult without a clean high ISO on a camera.

Tim

Exactly. I don't LIKE to shoot ISO1600 at Path Valley but...when the lights come on I have to. Camera goes right back to ISO100 or 200 (not that much difference between those two settings) during the day.

Oops....I said that as if I'm a pro. I'm not. My apologies.

[cwphoto]

I use the slowest ISO I can comfortably get away with, which may mean shutter speeds of down to 1/15s for indoor daylight photography and up to 4s for some wedding night shots.

[MrForgetable]

Yeah...that too.

Unless of course you need depth of field or something. There are also time when you're struggling so much that even ISO1600 and f/1.8 is barely gets you (read: me) 1/30th shutter speeds. :eek: heh.

hmm imagine what a canon 5D at ISO 3200 with a 50mm F/1L could do. that is like, another 2+ stops. you could probably shoot in the dark. thinner than razor thin DOF though.