Auto-ISO - inadequately implemented?

[Mike Buckley]

Surely you do not need to go into the menus to change Auto ISO?

That's not a requirement of later Nikon models but it is a requirement of earlier models.

If you press the ISO button on the top of a Canon, the front scroll wheel lets you choose any ISO, including Auto ISO (it comes at the low end of the ISO range) instantly.

Does that method also allow you to configure the minimum shutter speed and the maximum ISO, both of which are parameters of Auto ISO?

[MrB]

AS mode, as I proposed, or "TAv" as it is apparently implemented by Pentax means you manually choose an Aperture and a Shutter speed and the camera uses the meter (and any EC offset chosen) to set the ISO to achieve correct exposure.

That is correct, Dave. If anyone is interested, there is an explanation of all the Pentax Modes here:

http://www.dpreview.com/reviews/pentaxk7/7

Pentax not only have TAv Mode on the dial, but also Sv Mode, and a versatile (and possibly unique?) implementation of P Mode.

Cheers.
Philip

[Dave Humphries]

Does that method also allow you to configure the minimum shutter speed and the maximum ISO, both of which are parameters of Auto ISO?

No Mike, it is near the bottom of the Shooting Menu on my D7100.

Each photographer is likely to set and leave the Maximum ISO at the figure they can tolerate - I chose 6400.

However, regarding the minimum shutter speed, there is an "Automatic" option, which, with CPU lenses, takes account of the focal length to determine what it thinks the appropriate minimum shutter speed should be. If you don't like that, you can bias the Automatic choice faster (if shaky) or slower (if your lens has VR), or of course, you can select a preset shutter speed to use regardless of other factors.

The Nikon front wheel on/off method is quicker to do than the Canon method Adrian relates, since you don't need to scroll down through all the ISO values to get to it - this was actually how I had assumed it worked before Christina enlightened us all.

Casual playing (not thorough testing) in Manual mode Iso-Auto has shown that there doesn't seem to be a way to set the minimum ISO you (might?) want it to use. If you use the rear wheel to set say, 2000 iso, switch to Iso-Auto, then frame a scene that would be too bright, it indicates it will go down to 100 iso.

[Venser]

On my D700, turning auto ISO is embedded deep in the menus.
On my E-M1, I can set it to a dial, like any other setting. I see no reason why Nikon couldn't implement something similar. It's really useful when I'm shooting street and I know the aperture and shutter speed of a scene I want to shoot but still need something to determine the exposure. Love the fact I can simply spin the dial on the fly, like I do for pretty much everything else on that camera.

[Brownbear]

Hi Dave,

Thank you. It is especially nice to know that I was helpful, especially regarding a mechanical feature of how our cameras operate. I likely figured it out, out of sheer need.

I have yet to try BBF, likely intimidated just by the thought, but will do after watching Richard's video.

Hi again Christina,



I have just had a play with this method this morning and I can see it working for me

I am used to changing ISO quickly using that button with the rear command wheel, but like Bill, I hadn't realised that the same button, with front command wheel, very easily turns off/on "ISO-Auto".

The press (hold) a button and rotate the front wheel one click is the same action I use to switch from DX to 1.3x crop mode (aka "24 - 16" to "18 - 12") on the fly, so I don't think it will take me long to learn it in conjunction with the ISO button.

Many, many thanks for the help, Dave

[Dave Humphries]

Regarding Nikon D7100:

One apparent disadvantage of using M + Iso-Auto (to my previous way of working/habits), is that in M mode, the wheels obviously now control Aperture (front) and Shutter Speed (rear) - I have lost quick access to EC.
Previously, shooting in Aperture Priority mode, I had the camera set for "Easy-EC", meaning I didn't need to hold down the +/- button to change EC. I found that a great way to rapidly alter exposure compensation should a new 'target' (aka bird of a different plumage) appear which required a different EC to the previous target.

So now I will have to press that button for EC in M + Iso-Auto
OR:
I will have to try Iso-Auto in Aperture priority mode (and set the Iso-Auto Minimum Shutter Speed to be say 1/1600)

I am not complaining - yet
Just something new to try an see which method works best.

Further playing:

With Aperture priority + Iso-Auto, it does now seem to obey the minimum iso set manually, at least, up to a point. I also have easy access to EC again.

However, if you give it a dark enough subject and it reaches the 6400 maximum I set, it seems to lower the shutter speed below the manually hard set 1/1600. In these circumstances it does seem to flash the "ISO-AUTO" in the viewfinder (and on top LCD) to indicate it is being naughty though.

Much to experiment and learn - perhaps better done in more realistic situations than me 'waving it around pointing at defocused room lights'

Stuff to do, more tonight or tomorrow.

Thanks all, Dave

[jprzybyla]

Hi Dave, once you get used to it the +/- EV button is as quick and convenient as Easy ISO. Same wheel, push the +/- EV button count the clicks (I have mine set in 1/3 step increments). 3 clicks clockwise is +1, 3 clicks counter clockwise is -1 etc. Once familiar with it you can do it without looking. I normally set it as a flying bird is approaching or as I am approaching a perched bird. Once set you then have your wheels for shutter speed and aperture.