I have a question about the ISO settings. Now I been told that you use a lower number if you have a lot of light and a higher number if there isnt enough light... I have tried different settings and it seems if I use any setting higher then 100 it makes my image look grainy.

how do you know when to change this setting? the settings go from 100, 200, 400, 800, 1600

thanks for ant help :-)

Miranda

I mainly shoot landscapes so only use 100 or 200 rarely, but the other week I was doing a project for a friend indoors and had to change to 400 because I was using only available local lighting. The shots did not show any grain, Canon 10D. From the shots in your gallery I can't see why you would use anything else than 100 ISO.

Basically if you you can acheive the shutter speed and / or apperture that you require for the shot use 100 ISO. Only change to 200 or 400 if there is not enough light. Never tried 800 or 1600 but I might have a go at the weekend just to find out.

I'm sure someone here will point you in the right direction on the technical side.

Hope this helps a wee bit.

Steve

Attached Link: http://www.dpreview.com/learn/?/Glossary/Digital_Imaging/Sensitivity_01.htm

Viewing your photography I say you should stick to 100 or 200 ISO. Using high settings always will result in a lot of noise. If your light meter says you are going to be under exposed,and you can use a flash the do that rather than set the ISO up higher.If you do not want to use flash...and choose a high setting... you can adjust the grain in PSP using the edge preserve filter. I share your feelings on the the effects of grain. I 've tried using up to 1800 for somethig really fast in action and the images looks terrible. Sticking with less than 400 from now on. Many here might say they don't get the graininess much. but on all 3 of my cameras I do, so am quite satisfied with my settings.

"The happiness of a man in this life does not consist in the absence but in the mastery of his passions."

I'm not sure which camera you use, so it may be different than my Nikon D70s. First you have to understand that ISO was first used with film, example film cameras. It expresses how sensitive a particular film was to light. The lower the ISO number, the less sensitive the film to light. For example, you might use a 200 ISO film in the daylight, or use 800 ISO film at night. Now we jump to the digital world.

When we talk about ISO with digital cameras, it gets a little trickier. Keep in mind, in digital cameras, we have a sensor that replaces the film. So one might think if I set the ISO on my camera, I must be setting the sensitivity of the sensor? Maybe yes, maybe no. With my Nikon, the sensor has an equivalent sensitivity of around ISO 200... this cannot be changed. If I set the ISO to anything else, it doesn't actually change the sensor at all, but rather tells the camera to amplify, (increase the exposure) after the picture is taken. This conversion (I call it in-camera postwork), only happens if I'm shooting in Jpeg picture format. I shoot soley in Raw, so setting the ISO has no effect on the pictures.

Now some cameras will actually change the sensor's sensitivity. Perhaps yours does?

Attached Link: http://www.robert-barrett.com/photo/exposure_calculator.html

hi

well...

ISO speed is a standard for expressing the sensitivity of the film or sensor to light.

You'll also see this expressed as film speed (or sometimes ASA) The higher the number, the more sensitive or faster the film.

ISO stands for International Standards Organization

If you look at almost any basic photography book, you'll see some information on how exposure works.

The shutter speed a camera can use for proper exposure depends on the lighting, the film speed (a.k.a., ISO speed) and the Aperture (which is the ratio between the focal length and the diameter of the aperture iris opening).

A higher ISO speed setting, or higher ISO speed film, allows it to be exposed faster (shutter doesn't need to stay open as long for the same aperture).

With a digital camera, when you increase ISO speed, you amplify the signal from the sensor. Each time you double the ISO speed, the camera can use shutter speeds twice as fast for proper exposure in the same lighting, at the same aperture setting.

This amplification can cause noise (similar to film grain). When the light is low, not as many photons hit each photosite on the sensor (allowing the photosites for each pixel to generate a stronger signal before being read),

So, when you try to increase ISO speed, it can be like trying to turn up the volume on a weak radio station, only instead of hum, static and hiss, you get image noise.

But, you may need higher ISO speed to get shutter speeds fast enough to prevent blur from camera shake or subject movement in many conditions. So, it's often preferrable to have a little noise in the images, versus blur.

When light is good (and/or you don't need faster shutter speeds), it's preferrable to keep ISO speeds set lower for a cleaner image. Most subcompact digital cameras are limited to a maxiumum ISO speed of 400 (although some newer models can go higher now).

Most DSLR models can go to ISO 1600 or higher (their larger sensors can gather more light, since the photosites for each pixel are larger). But, you can't really go by sensor/photosite size alone, as each sensor may have slightly different characteristics.

Here is a handy online exposure calculator that can give you a better idea of how exposure works. Film speed is the same thing as ISO speed.

Note that most subcompact cameras have a largest available aperture of f/2.8 (at the widest zoom setting only), dropping off to a largest available aperture of around f/4.9 or so at their longest zoom setting.

The more optical zoom you use, the lower the light is getting through to the sensor with many models. With other models, you can maintain a larger aperture (smaller f/stop number) throughout their focal range.

So, your lens will also limit what you can do with a camera (you can't set the aperture larger than the lens permits).

http://www.robert-barrett.com/photo/exposure_calculator.html ..

One way to look at it that helped me was to compare them to a glass of water. The light being the water.

50 ISO film is like a large glass of water it (say a quart). It takes so much time to fill it.

100 ISO would be half a quart so half the amount of time to fill

200 ISO would be half again smaller or 1/4 the amount of time to fill compared to the 50 ISO one. And so on.

To continue the analogy...

The apature is like the the size of the faucet. A small faucet (small apature say f22) takes longer to fill the glass than a large faucet (an apature of say f1.4) will fill it much more quickly.

In either case, when the glass is full that equates to when the film has recieved enough light for a proper exposure.

I hope that makes sense to you.

Hugs

Very well put Val.

Steve

OTOH, now, you can use a plugin like Noise Ninja or Grain Surgery or something like that in Photoshop (or PaintShop Pro, IINW) to reduce the grain. BTW, what camera do you have?

-- erlik

I have the Canon Rebel XT EOS

wow so much to take in but I think I am starting to understand (a little) lol

Thank you valouchufy wow that was very helpful thank you so much :thumbupboth:

I have the Canon Rebel XT EOS

wow so much to take in but I think I am starting to understand (a little) lol

Thank you valouchufy wow that was very helpful thank you so much :thumbupboth:

yep...valouchufy xplained it right...all it is, is an amplification...etc....diff cam makes and sensors vary!....have nothing against other makes but that is the main reason why I chose Canon...'cos of the Digic 2 sensor....simple as that!

wow Nameless, you have a very good camera!!!

I know this camera, this quality is complemented with a speed of continuous firing of 32 images at a speed of 4 or 5 fps ( i don't know now), ideal for the capture every decisive moment. With your professional talent and with this Canon, you aren't limits for the creative possibilities. And it's a legendary “series -1” and resistant alloy of magnecio... A very good camera

Before buying the d50 of Nikon, I had already looked thiscamera, but it was too expensive for me :unsure:

very good my friend

good day and Hugs

Thank you :)...BUT... I also believe that knowing and understanding (important I feel)...one's camera helps and the way it works in any given situ!...took a great deal of time on buying the 1D and the 5D...both up for the 'job' ..lol...but getting back to noise, not an issue imo, BUT, also dependable on the weather conditions also!...

exactly Nameless, this camera is professional and you have for her a lot option and my camera is semi-professional and i haven't all option as you ;)

hugs

Quote - I shoot soley in Raw, so setting the ISO has no effect on the pictures.

I don’t know the Nikon system but I don’t understand this statement with regard to the ISO not making a difference in RAW mode.

Good thread, I have to go out but will be back later to read it properly.

Digital noise (grain) is much more noticeable in the shadows and at higher ISO values, the Rebel XT though is very good at handling noise as is the 20D, all my studio work is at 100 ISO but my wildlife stuff us usually at 200 or 400 ISO, I have never noticed a real problem with it

They wouldn’t have made the cane if you weren’t meant to break the rules

I shoot soley in Raw, so setting the ISO has no effect on the pictures.<<

Thanks Simon. That was a case of not typing what one was thinking.

I should have said "The ISO settings have no "bearing" on my pictures, since I always shoot in Raw mode with ISO 200. I adjust exposure with postwork."

Thanks for the heads up.

Quote - my wildlife stuff us usually at 200 or 400 ISO, I have never noticed a real problem with it

200 or 400 is no really high ISO. Even the Olympus cameras that have problems with high ISO don't have problems with those values. The stuff starts to happen at 800 and continues towards higher values.

-- erlik

This photo was shot at ISO 1600 in the RAW format then converted in Capture one with out noise reduction into a tiff.

Camera used is a Canon 350D XT with a Canon 100-400mm L lens

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