Auto ISO - Yay or Nay

[sovietdoc]

There is so much absurdity in this thread, such a high level of confusion concerning the most basic principles of exposure and measurement and how the light meter functions, that there really isn't much here to discuss.

On the contrary, if there is confusion perhaps you could help clear this up.

 

[unpopular]

I can, and did. But it crashed. I'll write more later. Gtg get the kiddles.

 

[belial]

I say shoot which mode you're most comfortable with for your type of shooting and strive to understand and learn all the modes. Too many people use full manual because they think it makes them a better photographer just because it manual. Using any auto setting is ok IMO as long as you pay attention to what the camera is doing and understand how it's going to affect your work.

 

[unpopular]

I chose this post by Greystar to illustrate some of the common misconceptions about metering. This isn't meant to out Greystar as a poor photographer - I am sure he may be plenty capable within AE. But there are a lot of technical issues here that can be addressed. It is very likely that nobody here will be surprised by what I am saying, with camera control there is a kind of "ah ha!" moment where it just kind of clicks. You can intellectually know everything that is required to intuitively use your equipment in manual mode, but getting it all to fit together is another challenge.

Well, I've never believed that controlling exposure was in any way intuitive, but to your point I would say that the "intuitiveness" of exposure settings depends on the approach and point of view of the person.

All cameras measure and record light in a similar way, meter modes differ only in the scope of area which they measure.

Averaging modes, such as weighted, average and the like use a very broad area, while spot modes such as spot and evaluative use a very narrow area. I say evaluative uses a very narrow area because it, as others have said is akin to a manual user making several meterings and using the collective information to choose the 'best' choice (or an average of two or more choices) according to how the camera was programmed to best suit a widest array of circumstances.

This approach assume that there is an absolute proper exposure for every scene regardless of subject. Perhaps the specular hilights are more interesting than the shadows. In such a case you'd need to compensate for less exposure such that the detail in the specular remains unclipped and as full as possible, at the expese of shadows. Without some kind of exposure compensation, the cameras auto exposure will not compensate this correctly. This is of course why we have EC in auto mode.

However, if you use EC in auto mode and you are in a Tv program, then DOF will be affected. If it were the shadows you were interested in, and you were in Av program, then shutter speed might be drawn down so far you risk camera shake. You could use AE ISO, however you risk affacting effective latitude and noise level.

In manual, I can more or less use the camera in Av but I can also decrease shutter speed only to a certain level, and only then start adjusting aperture - preview the DOF and expose with a moderate aperture and shutter speed without affecting ISO unless I absolutely need to.

My process is to first set exposure, and then I set aperture/shutter for the effect I want. So exposure is purely an exercise in EV, and the selection of shutter or aperture is purely an exercise in effect.

For example, lets say it's a Sunny 16 day. That's 14 2/3 EV. So my first step is to lock in my exposure at 14 2/3 EV (using any number of methods...metering clear blue sky, the gray card in my pocket, spot metering my palm and setting +1 EC...whatever.) Once that's locked in I allow my camera's auto modes to maintain that exposure while I manipulate the setting of interest. I want a shallow DOF, so I set A mode and open up the aperture. I want to pan subjects in motion for motion-blurred backgrounds, so I set S mode and 1/120s. At this point aperture and shutter are not controls for exposure, but controls soley for effect. And while I'm changing my desired setting, the camera is changing the setting under its control to maintain the locked exposure that I set. I simply change one control, directly to where I want it, and I'm done. In manual mode I would now have to manipulate the other control to restore the exposure.

I don't like questioning people's process, but I think that this is a weird way of looking at exposure. Cameras do not record available light, which I am sure you already know, they record reflected light.

You can certainly preset exposure to a specific reference and everything will be 'correct' based on that reference. The problem is that cameras have only finite latitude. If something you are interested in is beyond that latitude it will either not record at all (clipping) or the data will be unusable (floor noise). Provided you have the opportunity, it is much better to view every scene as a unique exposure with the intent to maximize the data recorded. For this reason I always meter off the hilights and in the least place them accurately by adjusting exposure, if not placing the brightest region at the upper end of latitude range - opening up shadows. You'd be surprised of seldom HDR is actually needed.

By all means you can do this in Av or Tv modes using EC, but when each and every scene becomes a unique exposure it is very easy to loose track, and adjusting only shutter speed is really no different or faster than adjusting exposure compensation in Tv mode, however, manual does not lock down other camera controls according to a predetermined program, either, and I can adjust any control on-the-fly when they are needed for given the circumstances and subject.

This gives me tremendous freedom to experiment because it's so easy to change settings. I've been able to take 5 shots and 5 different apertures in about 7 seconds...

I am unsure that using manual is any different. I can set an aperture with a specific shutter speed, adjust aperture, increase shutter speed by a factor of two. I have little doubt that I could make a similar bracket in less than 30 seconds. Perhaps not 7 seconds, but who cares.

and all had the same consistent exposure. And this is also where Auto ISO comes in (at least for Nikon cameras...other cameras need improvements in this area.) With Nikon's Auto-ISO I simply set a minimum shutter speed for the current subject matter. If, while stopping down my aperture, the exposure calls for a shutter speed slower than I'm willing to use, the Auto-ISO function will increase the ISO in order to maintain my minimum shutter speed. So with one turn of a dial I can change three settings. But the important thing to realize is that the settings I end up with are exactly the settings I would have set myself in manual mode. It's my exposure, my shutter speed, and my aperture. The camera isn't deciding anything for me...it's simply carrying out my instructions on how it should manipulate the controls

I truely have no doubt that AE is useful for a select number of subjects, especially sports photography. I guess I can see your point about auto ISO, but if you're within +3EV of your minimum exposure speed at minimum aperture, it is my opinion you should just preset your ISO one stop greater rather than relying on the camera to make a choice on your behalf.

The reason for this is because I know at ISO 200 (where I normally shoot) I have a latitude of -4/+2 1/3ev, at ISO 400 I have a slightly less latitude on the shadows, and at ISO 800 floor noise becomes pretty aparent at -3 and hilight latitude starts to decline. At ISO 1600 hilight latitude is greatly affected - I admit that it's an older camera, and a notoriously noisy one at that, but analog gain will always affect effective latitude. If you're within +3ev of your lowest possible shutter speed at a given minimum aperture, you'll always be away of the consequences of the specified ISO.

So no. I just don't recommend auto ISO. there just isn't any real need for it, IMO.

while I concentrate on the subject and composition. That's the power and freedom that you get from using auto modes.

It is a very common mistake to believe that exposure is not part of composition, and that it is a purely technical element with no creative flexibility. Nothing could be further from the truth, and I would encourage you to read "The Negative" by Ansel Adams.

I can assure you that if people spent time really appreciating the Zone System, views on exposure would change - and yes, exposure control becomes intuitive.

 

[unpopular]

I was not aware that the reference between evaluative/spot and average differed. But I also know enough that it doesn't much matter provided that you are aware of the difference. The issue is entirely beside the point.

But don't go telling people that I have misconceptions when you don't even know how your camera works!

This coming from someone who doesn't find exposure control intuitive.

But whatever. If you understand manual, you'll understand AE. The same cannot be said the other way around.

 

[unpopular]

WHat is there to understand? Exposure compensation adjusts exposure according to a given program.

I just don't understand why you're making this huge deal out of it. AE is nothing special, and does nothing which you wouldn't be doing in manual, only that in auto the camera's computer does it. I prefer manual because I can choose how EC is conducted, rather than being fixed to a specific program. I can adjust exposure by time, aperture, sensitivity or a combination of all three. When one translation isn't suited, I can use another without changing AE mode.

There is also a difference between instinctively and intuitively. You can intuitively read, but that doesn't mean you didn't have to learn it ... Reading becomes intuitive, despite it having been hard at one time.

Perhaps if I used average metering more, I'd know more about it's reference. It's an interesting tidbit perhaps that average mode meters at one reference while spot modes at another (something I have never heard of, mind you) but its really of no consequence if you meter exclusively in one over the other - and I cannot think of any circumstance when average mode would out perform spot mode, including evaluative modes; at least not once you have a good handle on exposure compensation, manual or otherwise.

Finally, until you can decrease shutter speed by a factor of two, aperture stopped down by three, and increase ISO from 200 to 400 within the same AE mode, I'll stand by my belief that you don't have full control. Perhaps your camera can do it, and I agree my camera is limited, but I have yet to know of a camera which can arbitrarily adjust all controls in auto mode in order to meet specific conditions.

 

[unpopular]

Oh. And how I learned was in the darkroom. And yes, it did just make sense, and rather quickly. I was shooting in some stables at the Park Co., WY fairgrounds with the view camera, and it just kind of came into focus what the meter was doing and how it related to the negative and how the film ought to be processed. I of course had been taught, but it did become intuitive.

 

[MTVision]

Correct...a difference you weren't aware of. Which is pretty much the theme here...you making proclamations of things you are unware of.

No, that issue IS the point...you're condeming processes that you don't understand. If you aren't aware of how things work then how can you make definitive statements about those processes? The only definitive statement you can make is the one you just made..."I was not aware."

Merriam-Webster says "intuitive" means "known or perceived by intuition." M-W says of "intuition"; "quick and ready insight" or "immediate apprehension or cognition." Considering the number of photography books and classes available, and the number of questions on camera use we see in forums and other places, I find it difficult to imagine anyone coming to the conclusion that using a camera is intuitive.

So, what...did you pick up a camera, point it at a scene, and say, "oh I get it...the meter is averaging everything to mid gray so I guess I should overexpose light objects and underexpose dark objects."? I serious doubt that's how it happened. Tell us the story of how you learned to determine exposure.

Once again, that's your (unintuitive) perception because you don't understand how to use the auto-exposure systems of your camera. Obviously...OBVIOUSLY...being able to take pictures in manual mode does NOT mean you understand auto-exposure operations. If it did we would never have had this pointless exchange, and we would all be chuckling at newcomers who insist that they want to shoot in manual mode for "full control" of their cameras.

But we are having this exchange because you and others (like Megan, who readily admits to not having learn any other way to use her camera) don't know how to use the AE systems of your cameras...yet somehow you've determine with absolute certainty that AE operation doesn't provide full control over the camera.

Must have been your intuition.

I NEVER once said that you were wrong (or at least I don't remember saying so). I believe I said that it doesn't matter how you choose to shoot as long as you get the shot you were going for. I don't think manual is better then any of the other semi-auto modes or vice versa. I know for a fact that I never said that you only have full control of your camera when shooting in manual mode.

I learned (and am still learning) how to shoot in manual. I haven't had my camera for very long so no I haven't gotten around to learning the other modes. But just because I haven't fully learned how to use them properly doesn't mean that I won't. Or that I don't see the value.

 

[table1349]

QUOTE=Graystar;2583452]
The big difference is that the shutter/ISO changes happen instantly for me, whereas a person shooting manual mode would be fumbling with three controls. This gives me advantages in speed and fluidity of shots.

I get it now. I finally understand what you are trying to explain.

You don't really understand your equipment and can't operate the camera smoothly so you let the auto modes do it for you. Your arguments make a heap of sense to me now.

 

[MTVision]

No, you understand so little that a cheap insult is all you have to counter my explanations. That's pathetic.

This is what I meant by my earlier comment about this argument being stupid. Not that what you or the other people were saying was stupid. Just that it's kind of like the Nikon vs canon debate. People have their preferences and nothing anyone says is going to really change their opinion. I think a lot of your points are valid. Like the thing about the guy fumbling with his settings so his dad sat down. I'm sure I've missed shots doing that exact thing.

I am still more comfortable with manual mode (that's not saying much since I haven't been doing so very long) but because of this thread I have been using aperture priority more.

 

[belial]

I shoot in manual aperture and shutter. I agree with graystar that in aperture and shutter you maintain full control. Can't see ever using program though as I feel I'd be giving up creative decisions of dof and stop motion. One thing I like to do is have manual and aperture set to drastically different settings because it allows me to switch between different types of creative exposures with one click of a dial (the camera saves the last setting on each mode other than iso of course)

 

[coastalconn]

Wow, I can't believe this thread has been going on for so long. Anyways, my only contribution is that auto iso has saved me many times with BIF... I shoot in A mode and my D90 has a great implementation of auto iso. Lately if I have tons of light I shoot 1/1000 to 1/1600th of a second with iso on base 200 max 1600. I don't think anyone (maybe I am wrong) can change ISO fast enough and track a bird like this cormorant taking off from the shade underneath a bridge into bright sunlight. I think in more controlled shooting that auto iso isn't nearly as important and turn it off when I'm not chasing birds around...

 

[TheBiles]

I only ever use auto-ISO in manual mode when I'm in a low-light situation and I want to maintain max aperture and a set minimum shutter speed.

Sent from my Galaxy Nexus

 

[unpopular]

f5.6 -> 8 = 1/60 -> 1/30 is a Tv program
likewise 1/125 -> 1/250 = f11 -> f8 is an Av program

If an exposure translation is conducted in a relative to another value, then it is in accordance to a program.

And no. I don't fumble, because I understand how the scene relates to exposure, and how exposure control relates to the image data. I preset aperture, adjust exposure time - just as anyone would in Av mode. Only instead of dialing EC, I directly dial in the shutter speed. If I change the aperture, I just double the exposure time.

But if I need to translate the exposure by three stops, I have the option to split that translation between aperture and shutter. Say i needed +3ev, I can stop down once and decrease time by a factor of four. I can open aperture by one stop and double exposure time. I can increase ISO by 1ev and leave aperture alone while increasing shutter 2ev. I could decrease shutter speed by 3ev. I could open the aperture three stops. I could increase sensitivity 3ev. It just depends on what I need at the time.

 

[ClintBalsam]

Auto ISO is fine, and a useful feature.