Manglesphoto Loc: 70 miles south of St.Louis

I set the ISO on manual

WessoJPEG Loc: Cincinnati, Ohio

sueyeisert Loc: New Jersey

To understand what your camera does and the exposure triangle, I would practice all in manual including ISO. Once you feel comfortable with your camera and setting f stops and shutter speed then I'd use auto ISO. In my camera I can set an upper and lower limit for auto ISO.

DonSmith

I like to select the iso value, keeping it as low as possible. From time to time I use auto iso, see nothing wrong with letting the camera do its thing for some shots. Don't think about what others do. Learn how to operate your camera settings to obtain the pic You want. Play with ISO, ss and ap. Take some bad pictures, with practice you'll start taking great shots.

jerryc41 Loc: Catskill Mts of NY

If you're shooting Manual, go all the way. Decide what ISO you want and then select A and S.

windshoppe Loc: Arizona

Precisely! This is the primary circumstance in which I use auto ISO. I shoot in manual mode in order to control shutter speed (generally 1/500 or higher) and depth of field (depending on whether I want to isolate the subject from background or to do a more environmental shot). The auto ISO feature IMHO is invaluable for such circumstances. In landscape work and travel I rarely use it, but then I rarely use manual either in those instances.

dave.m

Wow! didn't realise this was such a dangerous topic, so at great risk will add my 5 pence worth :)

ISO really matters with film - the lower the ISO the finer the silver grains, so the better the resolution. Increase the grain size, will allow lower light levels to be captured because grains are bigger, but with less grains the resolution will be less. With enlargements from film there is a very noticeable difference between same-size enlargement from ISO100 and ISO800 for example - and the fall off is non-linear (inverse square law applies to grain size where double the size of the grain for more sensitivity reduces the area coverage and hence resolution by a factor of 4.)

With film of course you fix your ISO for the next 20 or 36 frames the moment you put a film in and you can only adjust Aperture and/or shutter speed to control exposure.

One of the greatest benefits of digital cameras is that many of the constraints of film no longer apply in the same way and ISO is an example.

With a digital sensor the pixel size and total pixel count remain the same no matter what ISO is selected. Digital ISO is therefore an electronic adjustment of sensitivity. Make it lower and it allows more light to be 'gathered' for given Aperture and shutter speed, and vice versa.

So the resolution doesn't change as 24Mpx is still 24Mpx. The downside is that increase ISO to very high values and the 'gathered' light is insufficient to determine exactly what the pixel is recording - is it red , blue, green etc and we get Noise

The best analogy I ever read was visualise each grain or pixel as a cup:
with film we change the surface area and hence the volume of the cup, and pack more or less in. The'volume' of light captured changes accordingly and so does the resolution depending how tightly packed they are.
With a digital sensor the surface area never changes, we just change the 'volume' of the cup. Resolution is unchanged, but quality of recorded light increases or degrades.

Who cares?

I use most of the camera settings - aperture and shutter priority, and manual as needed.
Typically I use Aperture as I want to control DoF on a landscape or a portrait. I keep an eye on shutter speed to ensure it is reasonable to reduce camera shake (using the rule of thumb it should be equal to at least 1/focal length of lens as a starting point) and let ISO take care of itself.

Similarly with fast moving subjects - birds, aircraft etc I fix shutter, and keep an eye on aperture.

I only use manual when A or S priority doesn't give me what I want - a 20 sec f2.8 exposure for a night scene; an aircraft if I want motion blur in the propellers, etc. In these cases the need to specifically set aperture and shutter speed in manual mode, means I need to set ISO also to get what I want

My view is a modern camera is not unlike a car: 50 years ago (from personal experience) you had to use the choke, accelerator, gearstick, clutch, wave your hand out of the window to indicate, to get from A to B. Similarly a camera - you HAD to understand the relationship between aperture, shutter speed and ISO (or ASA as it was then.) Nowadays the modern digital camera can do as much as or little as you want. My greatest challenge has always been composition. A modern digital camera is almost liberating in that it frees me to focus on the most difficult part (for me.)

Or as an renowned expert I once saw said 'always using a digital camera in manual mode is a bit like having a car and running alongside'

Please flame courteously

rafikiphoto Loc: Spain

There is on my 5DS R and Mk IV... and Leica SL.

Photomia

I set the ISO in most situations - 200 in well-lit places, 400 when overcast, 800 when needed, etc. I find Auto ISO helpful when photographing my active grandchildren when they are running around in an area where the light changes, i.e. in and out of sunlit and shaded areas.

Jcmarino

The one time I used auto ISO was when documenting a family reunion and the sun was in and out. Drove me nuts. I wanted a specific shutter speed 125, and low aperture 2.8. Saved me a lot of grief. Other than that I have not used auto ISO, too much of a control freak I guess.

WessoJPEG Loc: Cincinnati, Ohio

I like your quote very much. The best I've read. I believe the same way you do. Thank you.😃

anotherview Loc: California

Using Auto ISO in manual mode, I have found, allows the shooter, with a modern DSLR, to put his attention more usefully on adjusting Aperture and Shutter Speed.

Of course, the situation may arise where the available light could jump the ISO too high in Auto mode, introducing unacceptable noise. The shooter then might wish to set the ISO at a fixed amount while setting one or both of the other two adjustments for a good exposure.

Overall, the conditions and the shooter's intention together will prompt which way to use ISO, whether in Auto mode or in Manual mode.

Note that with a Canon DSLR, setting the ISO to Auto mode allows the shooter to adjust Exposure Compensation for a proper exposure. Otherwise, with all three adjustments in Manual mode, EC becomes unavailable.

I understand that unlike Canon DSLRs, the Nikon DSLRs allow use of EC even with all three adjustments in Manual mode. Thus, the shooter could fully set Manual mode while having EC available to adjust exposure.

Being a Canon shooter, however, I cannot say how the Nikon option of EC in Manual mode affects the Exposure Triangle. Others here may explain this arrangement.

I hope this explanation helps.

dsmeltz Loc: Philadelphia

Jaackil Loc: Massachusetts

It seems per usual this thread took a right at the lights and kept going. Let me try to directly answer your question without telling you if you use auto ISO you are not in manual mode. Whether I use auto ISO or not depends on what I am shooting. If I am shooting sports or anything fast moving with changing lighting conditions I will use it. I keep my camera set on auto ISO with an upper limit of 3200 when it is in my bag for those times a shot appears before me so I can just grab and shoot. It's easier for me to adjust the shutter speed on the fly in those quick shot cases too. Better to get a well exposed noisy shot than not get the shot. That said in any situation where the lighting is constant or I control it(using flash) I set ISO my self. I set the ISO myself when I have the time to control all of the settings like when shooting portraits.
Here is the disadvantage of Auto ISO to me You potentially lose some control over the amount of noise entered into a picture depending on the upper limits you set in the ISO. The other disadvantage is the camera is not perfect. Sometimes your eye is better than the camera deciding what the correct exposure is. Here are the advantages to me. It gives you a better chance of getting the exposure correct in many cases. It also allows you to get ISO numbers you can not get manually. So let's say you are setting it manually you can get 100, 200, 400, 640, 800 etc. But let's say you set the upper limit at 400 limit in auto ISO for the scene you are shooting but given the exposure it does not need 400 it might give you 260 or 340, both are ISO numbers you can not get to manually. So it will only give you the the ISO needed to make the shot. So it also helps give you the lowest ISO needed for a scene. As you are new to shooting manual use it and learn from it. When you are reviewing your images note the ISO and what you think of the exposure learn from it so that in the future you have a better understand of how to set the ISO manually yourself. For me one of the best ways to learn the exposure triangle is to experiement with the settings. Good Luck Shooting.

camerapapi Loc: Miami, Fl.

Good photography is all about control. To me the best control is achieved when the camera is set to manual and the ISO is also set manually set.
The camera can also be controlled in AUTO mode but I prefer going manual.