Someone please give me a straight answer about ISO!!

[flinch13]

Hey everyone,

There are a lot of talented photographers who post on this forum and I'm honored to be able to ask questions to you guys. Here's one that's been bugging me for a long time... what ISO values should be used in the real world?

I have had a Rebel XT (my first DSLR) for the past three months and have kept the ISO down to 100 to reduce noise. I have been relatively happy with the results, but I'm just a newbie, and for all I know I could have ruined some perfectly doable shots by sticking to such a low sensitivity. What do you guys use and in what situations? What do you notice as far as image quality reduction and noise? Anyone have particular experience with the XT? Also, is there anyone out there who also keeps their ISO down to 100 all the time? I may just continue doing that if it's what you guys do. Thanks so much, any help at all would be greatly appreciated.

 

[Abstract]

I use whatever ISO gives me the shutter speed required to take the shot. I'm not afraid of noise, and I'm not afraid of using a high ISO if it gets me a good shutter speed that will allow me to take a non-blurry photo. Blurry photos definitely look worse than a slight amount of noise.

You don't have this on your XT, but on my D300, I care so little about ISO that I just leave it on AUTO ISO. It'll increase the ISO every time the shutter speed goes below 1/40th of a second. Generally, this is good enough. If my shutter speed is below this, then the ISO increases until I can shoot at a minimum of 1/40th seconds.

 

[OreoCookie]

First of all, any modern dslr will have lower noise than film which is rated at the same ISO. I usually switch back and forth between ISO 100 and 400/640 without a second thought. ISO 800 still gives very good results (IMO the noise is still less pronounced than on Ilford FP4 Plus, for example). If I have to use ISO 1000 or above, then it's a conscious decision `making the shot vs. not making the shot.'

Noise is IMO overrated, IMHO it's much more important to be able to take pictures. Especially with the crumby kit lenses, you have to use higher ISO values for many indoor shots.

 

[Hmac]

Generally use whatever ISO gives you the shot you want with the exposure you want and with acceptable noise levels. I usually leave my D3 on auto ISO, and set to top out at 6400. If I have noise that intrudes on the image, I run it through noise reduction on Capture NX, or if necessary I use Noise Ninja.

 

[flinch13]

Very interesting... looks like I'll have to try out some new techniques! If only the ISO weren't so annoying to set... grr...

As for auto-iso, I know the rebel xt doesn't have it, but some higher-end canon dslr models do. Does this work in manual mode? I'm usually in manual mode, so an auto-iso feature that you can set a ceiling value would be awesome, though only if you could enable it in manual. Anyone know of any canon models that do this?

 

[Doylem]

Keep the ISO as low as is compatible with getting your shots. That is: if you're setting ISO 100, and getting sharp results, then you're doing the right thing. I set ISO 100 for 99% of my landscape shots - using a tripod for when I would otherwise 'up' the ISO...

 

[Edge100]

First of all, any modern dslr will have lower noise than film which is rated at the same ISO.

While I agree that one should, on a modern DSLR, use the lowest ISO sensitivity possible and should not worry about using high ISO if required, let's not confuse the noise created by a DLSR with the grain produced by high-ISO films. Film grain can be a wonderful effect, especially on very nice high ISO film. It is distinct from noise, especially chroma noise which is, in my opinion, the bane of the DSLR.

 

[rogersmj]

As for auto-iso, I know the rebel xt doesn't have it, but some higher-end canon dslr models do. Does this work in manual mode? I'm usually in manual mode, so an auto-iso feature that you can set a ceiling value would be awesome, though only if you could enable it in manual. Anyone know of any canon models that do this?

I'm afraid I don't know the answer to your question, but I find it funny that you ask that because that's the opposite of what I want with my Nikon. I normally shoot in P mode with Auto ISO enabled (and I love Auto ISO in most situations). But I find it annoying that when I switch to full manual for a special shot, even if I set the ISO manually, auto ISO is still enabled until I go into the menu system to turn it off! In my opinion, auto ISO should NOT function in full manual mode...hence "manual" mode and not "auto" (or the camera should remember the setting for each mode...that would be GREAT).

 

[snberk103]

Another thing to consider

Not to confuse the issue, but changing the ISO doesn't just change noise and sensitivity.... it also changes the depth-of-field (in an indirect way of course ). Try this experiment..... Choose a scene with stuff that ranges in distance from close to you to far away. Keeping your shutter speed the same, change your ISO from lowest to highest - shooting at those ISOs plus one or two in between. You will end up changing your f/stop in order to keep your exposes correct. If you have chosen your scene well, you should see a change in the depth-of-field.

Traditionally, we talked about the 2 controls for exposure - shutter speed and aperture. We never talked about ISO being a "control" because, with few exceptions, once someone had chosen the ISO by loading the film, it really wasn't changeable. Then when the digital cameras first came out, the range of useable ISOs was limited. But now..... well, if I had a modern DSLR with 4 or more stops of ISOs, I would be changing the ISO setting on a constantly.

Yes, you have to watch out for noise - but good photography is not always about being sharp as possible.

Good luck...

 

[OreoCookie]

Changing the ISO does not change the depth of field, this is incorrect.
If you crank up the ISO, your sensor is `more sensitive' to light and you can choose either faster shutter speeds or smaller apertures.

But the depth of field is solely determined by the focal length of the lens, the aperture you've chosen and the distance to the focal plane.

Edit: I know what you're trying to say, but your explanation will only add to the confusion in my opinion.

 

[SpaceMagic]

Seriously. I recommend this book 100%. Covers dSLR too.

Taught me all I needed to know about everything. My shots are amazingly better now than just 1 month ago!

http://www.amazon.co.uk/Understanding-Exposure-Photographs-Digital-Camera/dp/0817463003/ref=sr_1_1?ie=UTF8&s=books&qid=1211988155&sr=8-1

 

[ChrisA]

Traditionally, we talked about the 2 controls for exposure - shutter speed and aperture. We never talked about ISO being a "control" because, with few exceptions, once someone had chosen the ISO by loading the film, it really wasn't changeable.

No, "Traditionally" ISO was always changable. because you got to choose the film. 35mm film was only popular for the last three decades of the 20th century. Before and after that period photographers would select the ISO (or maybe "ASA" or "DIN") to match the subject. Photography is 16 decades old. Only 3 of those 16 were in the 35mm film era and even then most of the "serious" work other then sports or journalism was done with cameras that allowed one to select the film for each expose either by swapping backs or using sheet film.

Even with 35mm film cameras people could do something like changing the ISO. Many photographers had a set of neutral density filters. I think I had a 2 and a 4 stop filter. So if a really needed a long exposure with a wide aperure in daylight I could used a 2 stop filter and in effect devide the ISO by 4.

 

[snberk103]

Changing the ISO does not change the depth of field, this is incorrect.
If you crank up the ISO, your sensor is `more sensitive' to light and you can choose either faster shutter speeds or smaller apertures.

But the depth of field is solely determined by the focal length of the lens, the aperture you've chosen and the distance to the focal plane.

Edit: I know what you're trying to say, but your explanation will only add to the confusion in my opinion.

You are of course correct. I was only trying to point out that changing the ISO allowed one to change the aperture, which is what changes DoF. Perhaps I wasn't clear enough..... But - I do stand by my assertion that one should at least think about changing the ISO for reasons other than amount of light.

 

[snberk103]

No, "Traditionally" ISO was always changable. because you got to choose the film. 35mm film was only popular for the last three decades of the 20th century. Before and after that period photographers would select the ISO (or maybe "ASA" or "DIN") to match the subject. Photography is 16 decades old. Only 3 of those 16 were in the 35mm film era and even then most of the "serious" work other then sports or journalism was done with cameras that allowed one to select the film for each expose either by swapping backs or using sheet film.

Even with 35mm film cameras people could do something like changing the ISO. Many photographers had a set of neutral density filters. I think I had a 2 and a 4 stop filter. So if a really needed a long exposure with a wide aperure in daylight I could used a 2 stop filter and in effect devide the ISO by 4.

This is my day for mea culpas (hope I got that right ). I should have known this, as I have shot sheet film in the past - and a MF camera with interchangeable backs. Time for me to get back to basics, again.

Can I keep some dignity and say that I assume the OP probably has no experience with anything other than digital and perhaps a bit of 35mm?

 

[Doylem]

No, "Traditionally" ISO was always changable. because you got to choose the film. 35mm film was only popular for the last three decades of the 20th century. Before and after that period photographers would select the ISO (or maybe "ASA" or "DIN") to match the subject. Photography is 16 decades old. Only 3 of those 16 were in the 35mm film era and even then most of the "serious" work other then sports or journalism was done with cameras that allowed one to select the film for each expose either by swapping backs or using sheet film.

Even with 35mm film cameras people could do something like changing the ISO. Many photographers had a set of neutral density filters. I think I had a 2 and a 4 stop filter. So if a really needed a long exposure with a wide aperure in daylight I could used a 2 stop filter and in effect devide the ISO by 4.

Yes, "you got to choose the film"... but that meant that the next 24 (or 36 shots) had to be shot with the same ISO setting. That was the reality, for 95% of photographers, during the 'film years'.

What's changed, with digital, is the ability to change ISO frame by frame... so ISO can now join 'aperture' and 'shutter speed' as one of the principal camera adjustments... not just another option buried away in a nested menu.

 

[OreoCookie]

But - I do stand by my assertion that one should at least think about changing the ISO for reasons other than amount of light.

Yes, and in that you are correct. I just think that the wording of your comment was a bit misleading.

 

[termina3]

mea culpas (hope I got that right )

I'm only responding because you seem be interested in "being right." Technically, it's meis culpas (feminine ablative plural of each), but for all the non-Latin's it's probably better to leave it as you had it originally. It's become a heavily used part of the English language, ergo it assumes English characteristics/syntax.

Oh, and fyi, mea maxima culpa (or meis maximis culpis, pl.) translates best as "my greatest fault."

 

[genshi]

No, "Traditionally" ISO was always changable. because you got to choose the film. 35mm film was only popular for the last three decades of the 20th century. Before and after that period photographers would select the ISO (or maybe "ASA" or "DIN") to match the subject. Photography is 16 decades old. Only 3 of those 16 were in the 35mm film era and even then most of the "serious" work other then sports or journalism was done with cameras that allowed one to select the film for each expose either by swapping backs or using sheet film.

Even with 35mm film cameras people could do something like changing the ISO. Many photographers had a set of neutral density filters. I think I had a 2 and a 4 stop filter. So if a really needed a long exposure with a wide aperure in daylight I could used a 2 stop filter and in effect devide the ISO by 4.

I may be reading this completely wrong (I just woke up) so please forgive me if I've missed something but, 35 mm film for still photography was introduced in 1913 and was popularized in 1925 with the release of the first Leica camera. Masters of photography like Henri Cartier-Bresson only shot with 35 mm and continued to make it popular since the 1930s all the way through the 1990s before digital really began to over take film. So not even counting the introduction of the Leica in the 1920s, that's still at least 6 decades I count (60 years) not 3 and certainly not just the last three.

As for ISO; someone else mentioned earlier that there is a difference between digital noise and film grain and that is very correct. IMHO, I think some people don't place enough emphasis on the importance of avoiding noise (preferably before you shoot, by using low ISO whenever possible.) They seem to think that it's no big deal and they'll fix it in post, which is fine if you are just showing your photos on a web site, but disastrous if you are printing for a show or magazine or something. But high film ISO and it's resulting grain can be quite beautiful and artistic.

With digital, I generally always shoot at 100 ISO and so far, I have never needed to increase it, but I also generally use a fast 50 mm f1/4 prime lens (for what I shoot) and that also helps for low light situations. I was recently commissioned to shoot a fashion design and manufacturing house "Reportage" style and there were several low light situations where I thought I would have to finally increase my ISO for the first time, but I didn't and it all came out fine:

With film, I recently used expired Delta 3200 Pro (which is actually rated at 1000 ISO I think) in my Holga and got fairly nice and grainy results that lent itself well with the subject matter:

 

[snberk103]

I'm only responding because you seem be interested in "being right." Technically, it's meis culpas (feminine ablative plural of each), but for all the non-Latin's it's probably better to leave it as you had it originally. It's become a heavily used part of the English language, ergo it assumes English characteristics/syntax.

Oh, and fyi, mea maxima culpa (or meis maximis culpis, pl.) translates best as "my greatest fault."

.... at the moment, I think mea maxima culpa is not leaving well enough alone! Thanks - its good to learn something new each day.

 

[eddx]

My straight up answer for you

ISO 100 all of the time, BUT...

...if the image you take is blurred because the camera isn't getting enough light, you can't use flash and don't have a tripod or other camera support - I have been known to push it to ISO 400 or 800 but it is always as a last resort in my professional experience.

 

[flinch13]

Wow, all of these wonderful answers! Thanks everyone, this helps tremendously.

 

[sonor]

My straight up answer for you

ISO 100 all of the time, BUT...

...if the image you take is blurred because the camera isn't getting enough light, you can't use flash and don't have a tripod or other camera support - I have been known to push it to ISO 400 or 800 but it is always as a last resort in my professional experience.

This sounds rather too restrictive nowadays. It might be true with the lower end bodies (I don't know how good the OP's Rebel XT is), but the best top end DSLRs - Nikon D3 & D300, Canon 1D MkIII and 5D - are remarkably good at high ISOs.

Wedding photographer Neil van Niekerk has just written about this on his blog...

http://planetneil.com/tangents/2008/05/24/even-higher-than-befor/

...and he's happy shooting at 3200.

The Nikon D3 is the reigning champion of high ISO shooting and many of the images I've seen look fantastic up to 6400 and certainly useable if there's no choice up to 25,600.

Rob Galbraith has a page of D3 images from 200 to 25,600...

http://www.robgalbraith.com/bins/multi_page.asp?cid=7-8745-9153

I'd say it's best to get to know your own camera and see how it performs at high ISOs. It's also worth investigating noise reduction software such as Noise Ninja and Neat Image.

 

[NeXTCube]

I find the noise on my EOS 300D (original 6MP Digital Rebel) is acceptable up to ISO 400, and too much for 8x10s above that. OTOH, noise on my Canon S2IS is unacceptable at anything above ISO 100. I find that color saturation and accuracy are much better at lower ISOs as well.

So my answer will mirror the rest here - use the lowest ISO that gives you the exposure (shutter/aperture) you need. Don't fear ISO 400, but avoid it if you can.

Noise from the Tri-X Pan I use in my Mamiya/Sekor DTL1000 is always acceptable, however!

 

[AxisOfBeagles]

I find the noise on my EOS 300D (original 6MP Digital Rebel) is acceptable up to ISO 400, and too much for 8x10s above that. OTOH, noise on my Canon S2IS is unacceptable at anything above ISO 100. I find that color saturation and accuracy are much better at lower ISOs as well.

So my answer will mirror the rest here - use the lowest ISO that gives you the exposure (shutter/aperture) you need. Don't fear ISO 400, but avoid it if you can.

Noise from the Tri-X Pan I use in my Mamiya/Sekor DTL1000 is always acceptable, however!

I used to love the effect of grain in B&W film ... when my son was born, many many years ago, I had my trusty Nikon SLR at hand, and shot Tri-X, which I pushed to 1600 by using H&W Maximal processing. The resulting soft grain made for some beautiful shots at his birth, which are still on the wall, printed 11x16

 

[66217]

You don't have this on your XT, but on my D300, I care so little about ISO that I just leave it on AUTO ISO.

Abstract, can you use Auto ISO while in complete manual mode?

For some reason it won't let me use the Auto ISO in my D40x while being in Manual mode, nor in the Aperture or Shutter priority.

Is this a feature exclusive for the D300?