R.G. Loc: Scotland

Some situations are more demanding than others. For example shooting fast-moving sports in less than ideal lighting. When things are tight, the best course of action is often determined by the answer to the question "What has the greatest potential to spoil the shot?". If the answer is motion blur then shutter speed is the main priority. If the answer is insufficient depth of field resulting in large out-of-focus areas, then aperture is the main priority. If the answer is noise and/or limited dynamic range, then ISO is the main priority. We need to be able to determine what is the greatest hazard in each difficult situation that we find ourselves in so that we can make the appropriate choices.

And having determined what the main priority is, we then need to prioritise the remaining two factors. Very often that is determined by the answer to the question "What is the most acceptable compromise?" For example is motion blur/camera shake more likely to be a shot spoiler than ISO noise? (If the answer is yes then ISO is the most acceptable compromise). Fortunately it's unusual for things to be that tight. Usually it's just a case of determining what the main priority is. But being pressurised on all three fronts is a great learning experience that teaches us a lot.

Linda From Maine Loc: Yakima, Washington

You have a well organized (organised), analytical mind, R.G. Many thanks.

BboH Loc: s of 2/21, Ellicott City, MD

I'll add a second to your comment

R.G. Loc: Scotland

Thanks both of you. Organised?!? You should see my living space ,

Linda From Maine Loc: Yakima, Washington

You have your priorities right; that's what counts I have little tolerance for clutter but a great deal of tolerance for dirt. Even Trixie doesn't want to eat off my kitchen floor anymore. (TMI?)

CamB Loc: Juneau, Alaska

A battle in our house. My wife hates dirt, doesn't mind clutter. I hate clutter but can live with a little dirt.
...Cam

Linda From Maine Loc: Yakima, Washington

Oh oh

aubreybogle Loc: Albuquerque, NM

My wife is Ms Neat Freak, but you should see my office. She finally gave up trying.

Linda From Maine Loc: Yakima, Washington

Methinks this topic has run its course... mea culpa for mentioning my dirty apartment

I'm greatly appreciative to all who participated. Along with the public praise, I received a couple of pm's from folks who enjoyed the discussion. I hope others will consider hosting non-gear talk topics where we can continue to share ideas in a friendly and cordial manner. There are a lot of great people on this forum. Many thanks!

topcat Loc: Alameda, CA

Late to the party, but I sometimes use auto ISO in manual mode.
That allows me to pick the SS and Aperture and let the ISO vary up to a certain limit.
This is on a Nikon, but I don't know if the other cameras have the same ability.

Linda From Maine Loc: Yakima, Washington

Thanks for your information and interest in the thread!

rehess Loc: South Bend, Indiana, USA

Pentax has a 'TAv' mode, which has user select shutter-speed and aperture, then camera selects ISO that makes this work, within limits set by user.

Bipod

We are talking about three different things:

1. How the camera determines normal exposure for a give scene.
This depends primarily on metering mode. Whatever and however it meters, it will try to render it as middle gray.

2. Translating that Camera EV number to aperture/shutter pair (and possibly ISO, if not fixed).

3. The photographer's intentions and how things really look (which usually means exposure compensation).

So whether you let the camera figure it out or you figure it out yourself, normal exposures is just the starting point.

If you let the camera determine normal exposure, then you better know how it does it, because no matter what the camera's "rule" is,
some scenes will break it---and cause the camera to guess wrong about normal expoure. Automated methods for determining
normal exposure all assume an "average" scene--though each method has different strengths and weaknesses.

A well-known example is how a backlighting breaks average metering and causes center-weighted metering to under-expose. Matrix
metering (and P mode) does a pretty good job of dealing with most backlighting -- but not other problems, such as a scene that is unusually
dark toned or unusually light toned.

Your camera will render a snow field as middle gray. You probably don't want gray snow.

Also, the camera knows nothing about moving subjects, subjects requiring depth-of-field, confusing backgrounds that would benefit
from bokah, etc. So if you let P mode pick the Aperture & Shutter speed pair, it will just avoid extremes.

Enabling Auto-ISO is a statement that the photographer cares nothing about image quality. That might be reasonable for a photojournalist
or someone doing surveillance work. But in most other photography, it's just a sign of being lazy.

ISO choice depends on how you are going to use the image. For most uses, there is a certain ISO -- maybe 400, maybe 200, maybe 100 --
above which the image will be too degraded for its intended use. (Given that all consumer digital cameras are miniature format or smaller,
you don't have a huge amount of resolution to throw away. You are shooting the same format as a Kodak Instamatic, or even smaller.)

There are really very few uses for an image taken at ISO 1600 --except if it's a photo of Big Foot.

Everything the photographer does -- what camera and lens he selects --where he goes to shoot -- is determined by the final image he is trying
to achieve. There is no other rational approach.

When you go hunting, everything is determined by the type of game you are trying to bag. Same reason.

Talking about an "exposure triangle" is like talking about a food triangle: meat, vegetables and nicotine. If you consume enough nicotine,
it will kill you. Perfectly usable images can be created at the extremes of the aperture range and at the extremes of the shutter speed range.
Buy one always pays a price (in terms of image quality) for turning up the ISO.

The photographer has to take charge because he is the only piece of "gear" with a brain. The tripod doesn't have one, and neither does the
lens or camera. The camera is capable of executing algorthims contained in firmware, but it has limited information. It doesn't know what
it's looking (and if you want proof--or a good laugh--try enabling face recognition). It doesn't know how light- or dark-colored anything
actually is -- only how they appear in a given light.

You know that snow isn't gray. The camera says "what is snow?"

Linda From Maine Loc: Yakima, Washington

Thanks for your far-ranging essay, Bipod. Use of auto ISO seems to trigger silly arguments and criticisms in the vein of raw vs. jpg and sooc vs. pp.

Here is what pro Steve Perry says: https://backcountrygallery.com/manual-mode-with-auto-iso/

I'm pretty sure if it's good enough for him (in certain circumstances), others who use it need not feel ashamed.

cjc2 Loc: Hellertown PA

They way I look at this issue is as follows. I've been in this game for 51+ years. I know how to both estimate and measure exposure. My modern cameras have several 'computer' chips and are much faster at calculating than I am. I'm a sports guy. I shoot wide open, whatever that happens to be, and (usually) 1/1000th. I'm very comfortable in letting my camera select the ISO. There are situations where I go manual everything, but I'm not unwilling to let my camera perform the functions it was designed for. I, for one, find AUTO ISO a godsend on many occasions. Given the right set of circumstances, other camera automation features are also very useful. Best of luck and happy holidays to all!