Auto ISO. Do you use it.

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Auto ISO seeks the lowest ISO possible, at the "expense" of other parameters.

For example: I shoot BIF with Tv set at 1/1250, and ISO set to a minimum of 400 to try and achieve an aperture stopped down to at least F8.

When using Auto ISO in this situation, the camera will open the aperture to it's widest setting in order to achieve the lowest ISO possible with the selected shutter speed, sacrificing DOF, & prevent using the lens at a "sharper" aperture.

Auto ISO would be far more useful if you could select a minimum ISO, or better yet; if you could set a combined Shutter/Aperture Priority, and have Auto ISO select an ISO to achieve the correct exposure.

Leigh

http://www.crscrk.com

what if your subjects constantly moved from well lit, dim lit, mid lit then back to well lit environment? how can you adjust ISO manually in such a fast pace scenario?

Leigh A. Wax said:

or better yet; if you could set a combined Shutter/Aperture Priority, and have Auto ISO select an ISO to achieve the correct exposure.

Leigh

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This sounds exactly manual mode with autoISO including exposure compensation. But exposure compensation is missing at the moment.

No need for ranges or limitations for autoISO values, all values from minimum to max.

This would be much more useful than Av or Tv if you really want to control your camera.

jitteringjr said:

I don't have it but I have never found myself craving it either. How many people use it and in what situations. Do you shoot basic or creative modes when you use it?

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After upgrading to a 7D from a 20D, I ignored auto ISO for the first few months. I thought the idea was silly, since I absolutely want to control the ISO I am using. However, I got bored and gave it a shot, and realized that for 75% of my photos, it automatically does what I was doing manually in the past. So I am starting to turn it on from time to time.

Most of my shooting is in Av mode. I choose an aperture to achieve a desired DOF. But shooting handheld, I need to make sure the shutter speed is fast enough. So I frequently twiddle the ISO, aiming for the lowest ISO that gives me a shutter as fast as the "rule-of-thumb" suggests (I use 1 / (1.6 x focal length)). Lo and behold, I learned this method of choosing ISO is exactly what the Auto ISO feature does, even taking in to account your focal length. (have you noticed the auto ISO increases as your focal length increases? Nifty feature!)

I definitely do not plan to use Auto ISO in the following situations:

• When I am using an IS lens or tripod and can tolerate a much slower shutter speed than Auto ISO assumes.
• When I really need a faster shutter speed than Auto ISO assumes (for freezing motion, for example) and am willing to crank up ISO to achieve this.
• Indoor flash photography in M mode (it will always go to ISO 3200 to brighten my background, otherwise)
• When I am taking a series of pictures and feel I don't want ISO changing from frame to frame.

But I would say 75% of the time Auto ISO does precisely what I want, and I know which 25% of shots it does not work for. When it's applicable, I think I am going to try to use it more often to help me cut down on time spent futzing with controls.

GammyKnee said:

Hardly ever used it on my 40D & 50D, but I do find it very useful on the 7D when shooting in M mode in changeable conditions. I can pin the aperture and shutter speed, and let the camera square them up with auto iso.

Some say this can lead to more noise (.e.g when the camera picks an "in-between" or "fake" ISO). I've no idea if this is true, but with action shots it doesn't bother me either way.

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That is not true. General rules memorized in one context do not always apply in another.

You get exactly the same SNR in ISOs 160, 200, and 250 with a fixed manual exposure. The only difference is that 250 is going to be about 1/4 stop missing highlights (none that would normally be used by a JPEG or DPP, but other converters may use it.

--
John

Wayndom said:

GammyKnee said:

Some say this can lead to more noise (.e.g when the camera picks an "in-between" or "fake" ISO).

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I've never understood this argument. Unless there's some strange quirk of electronics I'm not aware of, it doesn't make any sense.

An ISO isn't a thing, it's simply a measure of how much light is falling on the sensor, and therefore, how much amplification the camera should apply. There are no fake ISO's, any more than there's a fake speed of your car, or a fake volume setting on your stereo.

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"Fake" might not be the best name for them, but they are produced by a cheesy shortcut on the camera, with detriment to shadow areas and DR with the 125/250/500 series.

There are different meanings of ISO in regards to digital cameras and exposure, and ISO SETTINGS on cameras are very real things, even if the number assigned to them is somewhat arbitrary. ISOs 100 and 125, and 200 and 250 both with HTP, use the same gain as each other, but a different gain than ISOs 160-200-250 and 320-400-500 w/HTP, all six of which use the same gain.
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John

jitteringjr said:

Jovo said:

The reason? I would rather have a bird photo with noise than a photo that is blurred because the shutter speed was too low!

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Sure but if you are just worried about blurred birds, you can shoot TV and manually select ISO. It only takes a second to bump ISO if you are AV limited.

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A second is an epoch shooting birds. A bird jump in and out of the sun 5 times in a second, and take 5 poses in each one.

jitteringjr said:

Why didn't you shoot with auto ISO with your 40D and 50D?

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They only had auto-ISO in name. It was completely worthless, for most uses. Even the 7D's is stripped down and only partially useful. Canon treats their users like dirt.

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John

kohan said:

I would use autoISO and manual mode all the time but I am missing exposure compensation. It seems that Canon is missing one wheel more.

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Just need to combine one of the wheels with a button for that.

kohan said:

Now if I use manual optics with aperture ring I have Tv, autoISO with exposure compensation. But the function is like manual mode, autoISO with EV correction.

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Ironic that it's possible with other people's lenses, but not with Canons, ha?

--
John

KariP said:

I can imagine that auto ISO could be great in serious action photography - reporters in warzones or something like that - things you can not ask people to do again. In a place where you really want the photo and some extra noise or lower resolutions means nothing.

Traveling , nature , some macro, landscapes etc are my basic subjects - auto ISO could ruin my shots ! I want to know exactly what the image quality will be.

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You have some serious misconceptions about auto-ISO. Auto-ISO does not make images noisier, in general. One exception is that in auto ISO in Av mode, an IS lens will get a faster shutter speed than may be necessary for still subjects (or any lens on a tripod, but if you're shooting still subjects, you probably don't need auto-ISO). Other than that, auto ISO does not use unnecessarily high ISOs; that's a myth.

--
John

Leigh A. Wax said:

Auto ISO seeks the lowest ISO possible, at the "expense" of other parameters.

For example: I shoot BIF with Tv set at 1/1250, and ISO set to a minimum of 400 to try and achieve an aperture stopped down to at least F8.

When using Auto ISO in this situation, the camera will open the aperture to it's widest setting in order to achieve the lowest ISO possible with the selected shutter speed, sacrificing DOF, & prevent using the lens at a "sharper" aperture.

Auto ISO would be far more useful if you could select a minimum ISO,

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(putting limits on f-stop and shutter speed would probably address such concerns more directly.

Leigh A said:

or better yet; if you could set a combined Shutter/Aperture Priority, and have Auto ISO select an ISO to achieve the correct exposure.

Click to expand...

The 7D and 1D4 do that, and I assume, all future Canon DSLRs.

--
John

jitteringjr said:

... Do you shoot basic or creative modes when you use it?

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My camera (40D) has a limited version of Auto ISO, but I never use it. Only ever shoot in Av, M, sometimes P, rarely Tv.

Even if Canon had the enhanced Nikon or Pentax version, I still don't think I'd use it.

For panos, macro, etc. it's not necessary or even desirable.

However, in certain situations I would use it if I could set a max ISO based on the current conditions.

John Sheehy said:

KariP said:

I can imagine that auto ISO could be great in serious action photography - reporters in warzones or something like that - things you can not ask people to do again. In a place where you really want the photo and some extra noise or lower resolutions means nothing.

Traveling , nature , some macro, landscapes etc are my basic subjects - auto ISO could ruin my shots ! I want to know exactly what the image quality will be.

Click to expand...

You have some serious misconceptions about auto-ISO. Auto-ISO does not make images noisier, in general. One exception is that in auto ISO in Av mode, an IS lens will get a faster shutter speed than may be necessary for still subjects (or any lens on a tripod, but if you're shooting still subjects, you probably don't need auto-ISO). Other than that, auto ISO does not use unnecessarily high ISOs; that's a myth.

--
John

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.......

I have just been quite happy with all those auto-things i already use . I did not know i need more...

Perhaps it comes from my film - years. It was important to know what film was in the camera.

High ISO number CAN cause image quality compromises when i do not need them, of course it is then a user error... But absolutely - in some situations i will use it . If i must - i just imagined a reporter in a war zone. But why should i use it in everyday photography ?
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Kari
SLR photography started in 1968, 40D since 2007
60.21 N 24.86 E

KariP said:

I have just been quite happy with all those auto-things i already use . I did not know i need more...

Perhaps it comes from my film - years. It was important to know what film was in the camera.

High ISO number CAN cause image quality compromises when i do not need them, of course it is then a user error... But absolutely - in some situations i will use it . If i must - i just imagined a reporter in a war zone. But why should i use it in everyday photography ?

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Your reply sounds like you didn't even read what I replied to you the first time.

Auto-ISO does NOT tend towards higher ISOs than necessary. Quite the contrary, the camera often leans in the other direction, too low an ISO, with an open lens or slightly compromised shutter speed (1/EFL is a little slow for 18MP for many people).

The only exceptions are when you are using an IS lens or a tripod, with Av or P with auto-ISO - the camera may choose too fast a shutter speed, raising ISO. You probably don't want to use Av with aISO in those situations, unless there is so much light that it doesn't matter, and the extra speed is nice for subject freezing.

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John

Of course i read your text and even understood it. I think.

In certain situations auto ISO is surely useful , but i am not so sure if i WANT to use it. And there are certain people and styles that see it as a blessing. And they should use it. Some people shoot with all manual , some Av , some Tv, P , some use the green all-auto thing ...etc

The question was : do YOU use auto ISO .

Answer was : not because I.... My statement was only a personal opinion. Absolutely NOT better than others.
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Kari
SLR photography started in 1968, 40D since 2007
60.21 N 24.86 E

kohan said:

I would use autoISO and manual mode all the time but I am missing exposure compensation. It seems that Canon is missing one wheel more.

Now if I use manual optics with aperture ring I have Tv, autoISO with exposure compensation. But the function is like manual mode, autoISO with EV correction.

Click to expand...

Can't you compensate exposure in manual mode? That seems like the ideal way to do EC. You select aperture and/or shutter speed to get what you want. In manual mode without auto ISO how would the camera know to apply EC? I must be missing something.
--
A bird in the viewfinder is worth...

clk_walker said:

kohan said:

I would use autoISO and manual mode all the time but I am missing exposure compensation. It seems that Canon is missing one wheel more.

Now if I use manual optics with aperture ring I have Tv, autoISO with exposure compensation. But the function is like manual mode, autoISO with EV correction.

Click to expand...

Can't you compensate exposure in manual mode? That seems like the ideal way to do EC. You select aperture and/or shutter speed to get what you want. In manual mode without auto ISO how would the camera know to apply EC? I must be missing something.
--
A bird in the viewfinder is worth...

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Make thinking one step forward.

You set shutter, aperture and autoISO is made by your camera for correct exposure but EC is missing. Mode like Tv or Av if you are not using autoISO.

clk_walker said:

Can't you compensate exposure in manual mode? That seems like the ideal way to do EC. You select aperture and/or shutter speed to get what you want. In manual mode without auto ISO how would the camera know to apply EC? I must be missing something.

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Unfortunately you can't... in M mode the Auto-ISO will bring it back to normal grey.
Pitty, indeed!!

--
BigGis

kohan said:

clk_walker said:

kohan said:

I would use autoISO and manual mode all the time but I am missing exposure compensation. It seems that Canon is missing one wheel more.

Now if I use manual optics with aperture ring I have Tv, autoISO with exposure compensation. But the function is like manual mode, autoISO with EV correction.

Click to expand...

Can't you compensate exposure in manual mode? That seems like the ideal way to do EC. You select aperture and/or shutter speed to get what you want. In manual mode without auto ISO how would the camera know to apply EC? I must be missing something.
--
A bird in the viewfinder is worth...

Click to expand...

Make thinking one step forward.

You set shutter, aperture and autoISO is made by your camera for correct exposure but EC is missing. Mode like Tv or Av if you are not using autoISO.

Click to expand...

Varying the ISO does not affect exposure. Exposure is a measure of the amount of light irradiating the sensor. If you need EC and are in manual mode just change the aperture and/or shutter speed.
--
A bird in the viewfinder is worth...