Using ASA Options

[colliewalker1]

The default ASA setting for the 300D/DRebel is 100; when I was using film I always chose 200 asa as a reasonably fast film but still offering fine grain One of the obvious benefits of a fast film of course is that it helps to avoid camera shake.

I would be interested to know if other members stay with the default ISO setting - unless lighting conditions definitely require a faster setting.

[Tom W]

I tend to change ISO/ASA setting a lot. Its a good tool to help you achieve the shutter speed and aperture that you want. With the 300D, while 100 is your cleanest setting, you can move between 100 and 400 with no normally noticable noise/grain. Even 800 is pretty clean when you need it. Above that starts to get fairly noisy, but if you expose well, its not too bad to deal with. There is noise reduction software available to help clean up those high-ISO shots.

[picture-this]

I thought ISO just controled light sensitivity, your saying it controls movement also?

[Tom W]

No, just light sensitivity of the sensor (or film in the old days). But higher ISO will allow you to use a faster shutter and/or stopped down aperture if you need that for your shot. I probably should have worded my reply better.

[robertwgross]

Some shooters use ISO settings more actively, but you may be limited with that camera on how much control of ISO you have yourself. All other factors being equal, if you set ISO low (e.g. 100), then that is the least sensitive. That will tend to force apertures more wide open, which limits your depth of field more.

If you shoot a scene with the depth of field too severely limited, you might have a real problem image that really can't be corrected in editing. If something is really out of focus, it can't be fixed.

On the other hand, if you had to go to higher ISO settings to get a correct exposure, about the only problem you will get is high color noise. The modern color noise reduction programs can take out most of that problem.

---Bob Gross---

[CyberDyneSystems]

As moving objects tend to be my subject matter I rarely have the Cameras I use set at anything lower than 400 ISO

When working in low light I'll be at 800-1600 no problem.

[thomascanty]

I tend to change the ISO a lot too, depending on conditions. As long as I'm outside in normal daylight conditions though, it pretty much stays at 100. In fact, I really wish my 10D and 20D has a 50 ISO setting like my PowerShot S330 and Olympus C-8080WZ do.

[Jim_T]

AFAIK, there's no 'default' ISO setting in any of the Canon EOS digitals..

When you first turn the camera on, it's set to 100, but it always stays where it was last set... If you switch it to 400, then it stays at 400 until you want something else.

Setting the ISO is much like setting the shutter speed, aperture or exposure compensation.. What any of these are set to depends on the shot you're taking and the desired effect. Of course, just like film, there is grain introduced in the form of noise as the ISO increases.

Just as there is no default aperture or shutter speed for a lens, there really isn't a default ISO for a digital camera... (There isn't a default ISO for film either).

I generally try to use the lowest ISO possible.. If I'm shooting landscapes outside on a bright sunny day with a lens set to f/1.4, then I'll choose ISO 100. If I'm taking action shots at dusk with a lens set to f/5.6, then I'll bump it up to 400 or 800. I won't use 100 because it just won't work.

[Bodog]

Wow! ASA! Been awhile since I've seen that acronym used. :D
Up until the last month or so, I've been a "lower is better" shooter. But I'm beginning to feel that is a carry over from film that is best left in the past. I find that leaving the setting at 400 gives you a lot more choice in aperture/shutter speeds with no really noticable degrading in quality, as long as the exposure is good. Even when exposure is a little under, noise is easily dealt with. Just my opinion...

[scottbergerphoto]

Re: Jim_ T
In the fully automatic (non creative) modes, you cannot manually set the ISO.
Scott

[Citizensmith]

I'm still on slow as possible with ISO and tend to leave it on 100 unless otherwise needed. I don't hesitate to push it out to 3200 when need though. The only problem is when I go back outside and forgot that I set 3200. :)

Incidentally, changing the ISO does not change the sensitivity of the sensor, it just changes how much the single from each photosite is amplified. Consequently the noise in this instance is Bias Noise and is repeatable. Which is where the noise reduction software steps in.

[scottbergerphoto]

Incidentally, changing the ISO does not change the sensitivity of the sensor, it just changes how much the single from each photosite is amplified. Consequently the noise in this instance is Bias Noise and is repeatable. Which is where the noise reduction software steps in.
For the rest of us, that's the same as changing the sensitivity of the sensor. ;)
Scott

[Tom W]

Wow! ASA! Been awhile since I've seen that acronym used. :D
Up until the last month or so, I've been a "lower is better" shooter. But I'm beginning to feel that is a carry over from film that is best left in the past. I find that leaving the setting at 400 gives you a lot more choice in aperture/shutter speeds with no really noticable degrading in quality, as long as the exposure is good. Even when exposure is a little under, noise is easily dealt with. Just my opinion...

I tend to shoot between DIN 21 and DIN 27 most of the time, though I'm not impartial to DIN 30 or 33 or even 36 if it is needed. :)

[forrest64]

I would be interested to know if other members stay with the default ISO setting - unless lighting conditions definitely require a faster setting.

I almost always use ISO 400 (on my 10D) just as I did in my film days. It allows me reasonably fast camera settings and gives me crystal clear images. You should try it and compare it to your ISO 100 or 200 setting pictures. I think you'll notice little difference.

Mark

[Jon]

The default ASA setting for the 300D/DRebel is 100
I tend to shoot between DIN 21 and DIN 27 most of the time, though I'm not impartial to DIN 30 or 33 or even 36 if it is needed.
I almost always use ISO 400 (on my 10D) just as I did in my film days
Anyone still use Weston, BS, or GOST?

[thomascanty]

Anyone still use Weston, BS, or GOST?

I think a lot of people here are pretty free with the B.S. :lol: :D

[bluepxl]

How long ago did the name change from ASA to ISO? I just think it's funny that it's still so entrenched that people actually say ASA/ISO when they're the same exact thing.

Not meaning to offend anyone, I'm just enjoying myself over here :) Just an observation.

[Alexia]

What is the point of ISO on a digital? Already have shutter speed and aperture. :confused:

[Jon]

Shutter speed and aperture control how much light is allowed to hit the sensor. ISO controls how much the signal from the sensor is boosted. So, you can be shooting at 15 sec. f/1.2 at ISO 100 in the near-dark, or you can amplify the signal coming out of the sensor a bit to get 1/2 sec. at the same f/ 1.2 but ISO 3200 (5X amplification, gaining you 5 stops).

[Tom W]

How long ago did the name change from ASA to ISO? I just think it's funny that it's still so entrenched that people actually say ASA/ISO when they're the same exact thing.

Not meaning to offend anyone, I'm just enjoying myself over here :) Just an observation.

I only say both when the subject material calls for it - since the original post mentioned ASA, I thought I'd make it clear that they are the same (without actually saying it).

Same reason I mentioned DIN in another post - that used to be a standard as well and is included on the film-speed dial opposite the ASA setting on my old FT camera.

Not to worry - we're all enjoying ourselves here. :)

[stoneylonesome]

I change my ISO a lot, but through laziness I set it at 200 and have kept it there unless I have a really bright day out. but I do tend to go to 400 or even 800 if it's needed. Lately around where I live it's been needed a lot. sun never seems to come out and when your lens is 5.6f and if you want a little more DOF you need all the help you can get.

[Tom W]

What is the point of ISO on a digital? Already have shutter speed and aperture. :confused:

ISO adjustment gives you a lot more flexibility in choosing the right aperture and shutter speed in various light conditions.

While both aperture and shutter speed control the amount of light that gets to the sensor, both have other features and drawbacks.

With aperture, wider gives you more light for your exposure, but at a smaller, tighter depth-of-field. Sometimes, that is the effect you want, other times, you want the deepest possible depth-of-field that you can get.

Shutter speed has its own effects. While you may want a slower shutter to allow more exposure, you also have to consider the blurring effect of too-low a shutter speed. Sometimes, this can be an advantage, but more often than not, you want a shutter speed that will stop action so that you don't get a fuzzy picture.

On a bright sunny day, these two adjustments may be all you need to get the image you want at ISO-100 - stopped down for great depth-of-field, and a fast-enough shutter to capture the image without motion blur. But if its cloudy and you're trying to capture a soccer game, or a bird in flight, you'll want a faster shutter speed. Or, if you're in a dark room where you can't get a shutter faster than 1/15 second even at f/1.4, you need some way of gaining enough shutter speed to capture moving people. You need to go beyond ISO-100.

In this case, you would raise your ISO setting to 200, 400, or even 800 to make the camera more sensitive to light so that you can get the shutter speed and aperture you want at less-than-ideal lighting. The tradeoff is that you increase noise in the image, but the benefit usually outweighs the consequences, particularly on today's low-noise DSLR cameras.

Now, you may be thinking that you can just brighten up (or darken it if overexposed) the image in post-processing. A little experimentation will show you why that isn't a good option. Yes, you can move an image over a small range, but there is only so much data a camera will capture. Plus, the noise sacrifice is much greater when you try to increase an underexposed image in post-processing (especially JPG images) rather than have the right exposure coming out of the camera.

Anything that comes out of the camera as totally black is lost shadow detail - you cannot recapture it in post-processing. Likewise, anything that comes out of the camera as totally white is lost highlight detail - it also cannot be recovered. Even shooting RAW with its wider gamut of intensities, once a pixel reaches full output (white) or zero output (black), it cannot be pulled back into the detail.

[Alexia]

ISO adjustment..... WOW! :shock: Thank you so much! I declare sticky material!

[Cadwell]

Because I shoot motorsport in Britain it is a rare and blessed day when I get to shoot below ISO 400. 400 is usually a starting point and I will wander up as needed.

[BDM]

A long time ago I saw many comparison shots using a tripod mounted Nikon F3 film camera then the same shots with the same camera hand held. The difference in sharpness was very significant.

So - - - the rule I try to follow is use the slowest practical EI (not ASA which is a film sensitivity concept) and a tripod whenever possible (certainly for most landscape shots) if you want the maximum performance your lens is capable of offering. The effect of camera shake or subject movement is the same whether shot with a digital or film camera.

If you are shooting action shots and can't even conveniently use a monopod, then by all means up the EI to allow the use of a shutter speed which is at least the reciprocal of the lens focal length and faster than that if the subject movement demands.

As noted, the higher the shutter speed the less depth of field you will have. And the higher the EI, the more opportunity for noise. But a shallow depth of field and/or increased noise are in my opinion far less troublesome than shots blurred by camera shake and/or subject movement. Shots with a shallow depth of field and a bit of noise may even be deemed "art" but shots which are just blurred all over are usually just junk - - - at least in my opinion.

Bruce

[colliewalker1]

How long ago did the name change from ASA to ISO? I just think it's funny that it's still so entrenched that people actually say ASA/ISO when they're the same exact thing.

Not meaning to offend anyone, I'm just enjoying myself over here :) Just an observation.

Using the term ASA was a mental aberration on my part - an unintended throwback to the days of film!

I have tried the 400 ISO setting - combined with integral flash ( set at -2: thanks to Wasia Hack!) - taking a photo of the cat - copy attached. Could that be a trail of noise from L to R acrosss his midriff - and if so why there only? In Photoshop I tried 'Noise/Despeckle' and it disappeared leaving what I think is quite a reasonable picture for a black cat, which is a difficult subject. I have to admit to using Curves to adjust the coat until enough texture was shown.