High ISO Performing Bodies: Why not Auto ISO?

With the significantly higher ISO capabilities of the new bodies – me: 5D3 – is Auto ISO a consideration in BIF?

With Auto ISO, I still choose creative settings: Av and Tv are fixed, e.g., f/8 and 1/2000 during the day.

The ISO will shift according to the tonal values within the pattern. When tracking a BIF the background typically varies as you move the camera (and thus what is in the pattern). Is this BAD?

Auto ISO only affects sensor sensitivity so that, for example, if the sun momentarily popped behind a bit of cloud and the lighting slightly changed Auto ISO would for the moment make the sensor more sensitive so that you would obtain - as far as the camera "thinks" correct exposure and at the same time you still apply the chosen DOF and Speed to the capture?

Before someone says "I do not want to rely on the camera's meter" remember that you did rely on the camera's meter when you made your initial settings, made the first image, and checked in the LCD to determine if you did in fact ETTR.

Thanks,

Mr. Questioning

Dear Questioning ( :p ),

I tried auto-ISO on my 7D for a while and was actually relatively pleased with the results, although it would overshoot sometimes and choose higher ISOs than I was comfortable with. Especially in the early morning hours, there can be a huge shift in available light from an overhead shot to a bird flying in over the water in the shaded pond and that is hard to keep up with without some fancy fingerwork or an auto function. I haven't downloaded the new Firmware yet that allows me to designate a Maximum ISO in auto ISO mode, but I'm looking forward to trying that.

You should play with it.

I have been using auto iso with my D300 and my D800 for a while now and like it, particularly with the D800! One problem for non Nikon shooters is that supposedly you don't have the exposure compensation capability ( plus or minus from the camera's pick). For sure Canon does not have this feature. Here is a quote from Robert Otoole "Nikon bodies allow you to apply Exposure Compensation in manual mode (which is impossible with other camera brands." I wonder if Canon shooters could use shutter priority plus auto iso and have the exp comp available? This might allow you to pick your shutter speed at least?

PS. The disadvantage is the obvious camera pick of a very high iso but the advantage is that sometimes you are surprised at a very low iso pick! Also, a high shutter speed at least bags you a nice record shot!

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Originally Posted by Dan Brown

I have been using auto iso with my D300 and my D800 for a while now and like it, particularly with the D800! One problem for non Nikon shooters is that supposedly you don't have the exposure compensation capability ( plus or minus from the camera's pick). For sure Canon does not have this feature. Here is a quote from Robert Otoole "Nikon bodies allow you to apply Exposure Compensation in manual mode (which is impossible with other camera brands." I wonder if Canon shooters could use shutter priority plus auto iso and have the exp comp available? This might allow you to pick your shutter speed at least?

PS. The disadvantage is the obvious camera pick of a very high iso but the advantage is that sometimes you are surprised at a very low iso pick! Also, a high shutter speed at least bags you a nice record shot!

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Dan, I do not shoot Nikon but applying EC when you are in full Manual mode makes absolutely no sense to me. In Manual Mode, what variable is being changed when you apply EC? Are you increasing or decreasing speed, aperture, or ISO? If in full Manual, how does the camera know which variable you want to change? Confused!!

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Originally Posted by Jay Gould

Dan, I do not shoot Nikon but applying EC when you are in full Manual mode makes absolutely no sense to me. In Manual Mode, what variable is being changed when you apply EC? Are you increasing or decreasing speed, aperture, or ISO? If in full Manual, how does the camera know which variable you want to change? Confused!!

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In auto iso, the camera picks the iso, I pick aperture and SS and EC. EC affects the iso to compensate. So, lets say zero EC = iso 400, I apply +1 stop EC, the iso jumps to 800. Make sense?

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Originally Posted by Dan Brown

In auto iso, the camera picks the iso, I pick aperture and SS and EC. EC affects the iso to compensate. So, lets say zero EC = iso 400, I apply +1 stop EC, the iso jumps to 800. Make sense?

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Makes total sense now that you are saying you are in Auto ISO; I will check my Canon to determine if you can apply EC in Auto ISO. Cheers,

Jay- There are many reasons to use Manual exposure setting but the poster child has to be birds in flight. As you say and then ask- "When tracking a BIF the background typically varies as you move the camera (and thus what is in the pattern). Is this BAD?". The answer is usually yes. You may find yourself in a situation where the BG is constant no matter where you point the lens but usually as you track the bird, the BG tonality changes. You generally want to expose for the subject not the BG so you set an ISO, shutter speed and f-stop for the subject in Manual mode and shoot away. Regardless of the mode, exposure compensation does not generally work in these situations because the relative tonality of the subject and the BG may vary from + to - and one compensation is not going to work in all situations.

I can see at least one situation where auto ISO with birds in flight might work- the bird is flying in and out of different light, say full sun and shade- and you want to capture both. Shift to spot metering and keep the spot on the bird. This will not work for black and white birds for obvious reasons.

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Originally Posted by Dan Brown

In auto iso, the camera picks the iso, I pick aperture and SS and EC. EC affects the iso to compensate. So, lets say zero EC = iso 400, I apply +1 stop EC, the iso jumps to 800. Make sense?

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Dan- I don't think Canons allow you to dial in an EC in Manual mode, with or without auto ISO set. You can micro adjust the exposure settings but that would be a real phaf.

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Originally Posted by John Chardine

I can see at least one situation where auto ISO with birds in flight might work- the bird is flying in and out of different light, say full sun and shade- and you want to capture both. Shift to spot metering and keep the spot on the bird. This will not work for black and white birds for obvious reasons.

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John, I did exactly this while shooting White-tailed Kites a while back. I set the SS at 2000, aperture at f7.1 and auto iso +.3, spot metering. It worked beautifully! But, for general BIF, I am more comfortable with total manual including iso.

Hi Jay,

Note that ISO does not change sensitivity of a digital camera. See the what is ISO thread in the science of photography forum. Digital sensors have only one sensitivity. ISO only changes the range of signals that are digitized,

Roger

Jay, I shoot auto-ISO in manual mode almost permanently on my D3s and D7000...
Works great and you can adjust EV as it then adjusts ISO.
I trust these cameras to deliver at just about any ISO setting, even the D7000 surprises me!
I read somewhere that Canon have included EV compensation on for auto-ISO on the new bodies.

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Originally Posted by Morkel Erasmus

I read somewhere that Canon have included EV compensation on for auto-ISO on the new bodies.

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I had the pleasure of shooting with Doug Brown in early July and at that time, his new top of the line Canon body did not have the EC capability. He spent a half hour on the phone with Canon pro services trying to figure it out and they flat told him the camera didn't have the capability!

FYI, you can set a high iso limit if you want to. With my D800, I have set a high of 6400. The body is pretty good up there and delivery's good record shots at least!

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Originally Posted by Dan Brown

I had the pleasure of shooting with Doug Brown in early July and at that time, his new top of the line Canon body did not have the EC capability. He spent a half hour on the phone with Canon pro services trying to figure it out and they flat told him the camera didn't have the capability!

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True story! But the conversation was limited to adjusting exposure while using auto ISO in manual mode on the 5D3. There is no way to quickly adjust your exposure while shooting with that combination of settings. It's quite unbelievable! You have more creative control with auto ISO when shooting in a priority mode than you do in manual mode.

Canon really need to bring this feature into their cameras (exposure compensations in Auto ISO mode). I wonder if it's a firmware "thing"?

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Originally Posted by John Chardine

Canon really need to bring this feature into their cameras (exposure compensations in Auto ISO mode). I wonder if it's a firmware "thing"?

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For some it might be a reason to switch "thing"!

Doug is right; it is "quite unbelievable".

Given that I have recently changed all my lenses after buying the 5D3, if I thought it through I might have made the jump to the D800. Not now!! Too costly.

Auto anything is the kiss of death when shooting BIF against changing bgs. If you want consistantly correct exposures for BIF against changing bgs in the same light you MUST either shoot in manual mode or use exposure lock which is essentialy the same thing. If you only want some of your exposures to be the best exposure possible, thats what you will get with P, AV, TV, or auto ISO.

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Originally Posted by Jay Gould

For some it might be a reason to switch "thing"!

Doug is right; it is "quite unbelievable".

Given that I have recently changed all my lenses after buying the 5D3, if I thought it through I might have made the jump to the D800. Not now!! Too costly.

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It's not a reason to switch Jay. Trust me on that one.

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Originally Posted by Jim Neiger

Auto anything is the kiss of death when shooting BIF against changing bgs. If you want consistantly correct exposures for BIF against changing bgs in the same light you MUST either shoot in manual mode or use exposure lock which is essentialy the same thing. If you only want some of your exposures to be the best exposure possible, thats what you will get with P, AV, TV, or auto ISO.

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This is mentioned in pane 7 above Jim.

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Originally Posted by Jim Neiger

Auto anything is the kiss of death when shooting BIF against changing bgs. If you want consistantly correct exposures for BIF against changing bgs in the same light you MUST either shoot in manual mode or use exposure lock which is essentialy the same thing. If you only want some of your exposures to be the best exposure possible, thats what you will get with P, AV, TV, or auto ISO.

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Jim, shooting in auto iso, you are also in manual mode, setting the shutter speed and the aperture. The iso varies but nothing else.

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Originally Posted by Dan Brown

Jim, shooting in auto iso, you are also in manual mode, setting the shutter speed and the aperture. The iso varies but nothing else.

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No Dan, auto ISO in manual mode is an automatic exposure mode and the problems associated with this in BIF situations, as explained in panes 7 and 17 above, pertain.

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Originally Posted by John Chardine

No Dan, auto ISO in manual mode is an automatic exposure mode and the problems associated with this in BIF situations, as explained in panes 7 and 17 above, pertain.

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I see your point, the exposure on the subject would change with a varied bg in auto iso. Auto ISO plus manual mode seems to be working ok except under the most extremes in contrast between subject and bg.

As for being the kiss of death for BIF, it's just a peck on the cheek, (compared to AV anyway!) IMO because your SS is still high, freezing action and the missed exp can be rescued in ps if needed unless it's way off. Having said that, I agree that Jim's method is the best way to go.

A few points from extensive use of three cameras-5dIII, 1dx, and 7d

5dIII

When in Africa, I rented a 5dIII for my wife who has a good eye but does not want to understand the more technical issues. (My wife normally shoots a t2i and the auto iso performance there was not something that was worth the risking against the investment of 3 weeks in Africa....So on the 5dIII, I had her in manual mode and would take periodic readings usually off the grass...Then I would periodically set/change the ss and av early morning, late morning, late afternoon and near dusk-all using Auto ISO with limits at 12800. I can tell you many of her images were terrific and often at much LOWER iso than 400 or 800 so as you know it works both ways. (She has some really fine shots at less than 200 ISO)...

After looking at her images, I actually started selectively using Auto ISO myself in some situations such as the rapidly changing light on the wildebeest crossings... where they often went quickly from partial shade to sun to shade etc....or as a strategy as we approached dusk which also was when we saw some real activity .....worked very well.....Once on two cheetahs just before dusk that tried to ambush a giraffe and a few zebras...would have missed the shot otherwise.....Sun goes down fast near the equator

Now I know it does not answer your question about Bif. When I spent 5 days shooting eagles in Alaska, I did not use auto iso much...but did in some situations where the backdrops tended to change but the desired capture point was consistent....i.e...bird coming across from bright sky that I wanted to capture against some sheer rock.

1dx

While in Africa for 3 weeks, I experimented with spot metering tied to the selected focus point and was very, very pleased. Of course, mammals can be much different than BIF. So for full disclosure, I tried it only briefly on some BIF vultures.... but not sure that test would be conclusive as they tended to fill a good part of the frame when I was doing it....But blue wing teal, whistlers and some geese are starting to show up in Louisiana now so I will be experimenting with it the next two weeks. That will be a much better test . I am somewhat optimistic though as the dual processors work so fast....in fact I am going to experiment with the image priority in AF servo as the initial image which I have set to release almost always seems to snap in focus...worth an experiment anyway


7d

I tried the auto ISO when I first got the 7d and was disappointed for the most point. The ISO values were often very high and nothing any nr could really help........I still use the 7d and need to install the firmware with the limiters to see if that might make it a bit more viable as I could make other adjustments on the fly to get proper exposure.

Auto ISO only works in fluctuating light when the tonal values in the meter pattern remain the same. Otherwise, you will need to apply exposure correction whether you are in Manual or Auto priority modes.

Chas in BC

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Originally Posted by Charles Glatzer

Auto ISO only works in fluctuating light when the tonal values in the meter pattern remain the same. Otherwise, you will need to apply exposure correction whether you are in Manual or Auto priority modes.

Chas in BC

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No doubt that auto ISO is not a panacea....why I said above that "many" of the images my wife took were terrific.....it obviously failed when exposure correction was needed.....but in her case, it was vastly superior to the auto mode as we could get two variables generally right and hope for the best....and in some cases, it simply was worth rolling the dice

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Originally Posted by Steve Uffman

No doubt that auto ISO is not a panacea....why I said above that "many" of the images my wife took were terrific.....it obviously failed when exposure correction was needed.....but in her case, it was vastly superior to the auto mode as we could get two variables generally right and hope for the best....and in some cases, it simply was worth rolling the dice

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Steve,

Agreed

In your/her case the odds were better stacked in her favor using Auto ISO, as most of the images she was taking contained similar grass tonality.

Chas

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Originally Posted by Dan Brown

I see your point, the exposure on the subject would change with a varied bg in auto iso. Auto ISO plus manual mode seems to be working ok except under the most extremes in contrast between subject and bg.

As for being the kiss of death for BIF, it's just a peck on the cheek, (compared to AV anyway!) IMO because your SS is still high, freezing action and the missed exp can be rescued in ps if needed unless it's way off. Having said that, I agree that Jim's method is the best way to go.

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Hi Dan- The "missed exposure" will of course be the same in Auto ISO and Av/Tv modes. The difference in tonality between the shadow side of a bird and bright water or sky might be several stops so unless your intent was a silhouette, the subject's exposure will be way off and not usually salvageable.

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Originally Posted by John Chardine

Hi Dan- The "missed exposure" will of course be the same in Auto ISO and Av/Tv modes. The difference in tonality between the shadow side of a bird and bright water or sky might be several stops so unless your intent was a silhouette, the subject's exposure will be way off and not usually salvageable.

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John, for me, the missed exp on the dark side would yield a more usable image with auto ISO/manual (high ss picked by me) than a dark miss in AV (low ss picked by the camera), unless I am wanting a blur!

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Originally Posted by John Chardine

Hi Dan- The "missed exposure" will of course be the same in Auto ISO and Av/Tv modes. The difference in tonality between the shadow side of a bird and bright water or sky might be several stops so unless your intent was a silhouette, the subject's exposure will be way off and not usually salvageable.

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John, there is a difference between any mode that changes exposure time or f/stop and ISO. Changing exposure time or f/stop changes the amount of light delivered to the sensor (and thus how much light is recorded by the sensor). Changing ISO only changes the range and precision the signal from the light is digitized and has nothing to do with recording more or less light. At low ISOs, a low signal (e.g. the shadows) might be affected more by fixed pattern noise. But as ISO increases, especially above 800, there would be little to no loss in the shadows. At high ISOs, underexposing by shutter speed or f/ratio means less light, but ISO will digitize just as well, so no detriment at all, just boost in post. Of course if one overexposes to saturation by any method (exposure time, f/ratio or ISO), there is complete loss of image information.

Roger

Boosting the ISO in post should be avoided with Canon cameras including the latest 1DX/5D3. The ISO is the premap gain and transport is fully analog in Canon CMOS design, if the gain is set too low the signal will drop below the noise floor of both the CDS and the ADC. The shadows will look beyond terrible when raised in post and result in poor IQ even after NR.

Nikon is a different story.

I never use/recommend auto ISO to Canon shooters.