Auto iso

[Roy C]

So does Auto ISO give you the classic focal length/shutter relationship, 1/50th for 50mm, 1/300th sec for 300mm for example, or does it multiply by the crop factor too?

Canon's (or at least the 7D) take into account the crop factor in Av mode. So with a 400mm focal length it will return 1/640 (+/- 1/3 of a stop).

 

[irelanst]

I think that fact that it will adjust ISO to increments much smaller than a full stop is an advantage when shooting in manual in changeable conditions e.g. if in full manual you shoot at ISO100 to get a correct exposure but in auto it might go to ISO120 to get a 'better' exposure.

 

[Oggy]

I use it on my Pentax as you can set minimum and maximum values. As far as I can see you cannot do so on the 1D of 7D.

 

[irelanst]

You can set the maximum auto ISO on my 550D so I assume you can do that on any of the higher spec Canon bodies. I can't set a minimum, but can't think of any reason to do that anyway.

 

[tijuana taxi]

Afraid you can't set a max value on the 7D, think you can on the 60D though

 

[Roy C]

Afraid you can't set a max value on the 7D

Quite right although it only uses up to ISO 3200.

 

[Chris Primadona]

Does anyone use auto iso?

I personally think that the iso is the last thing you should leave to a camera to decide. I let mine control apeture sometimes and shutter speed on rare occasions but I mostly see my iso as a last resort "emergency" option for when I would otherwise miss a shot and use it sparingly.

 

[God]

I have it kick in when my shutter is going to drop below 1/125 capped at 6400

Rather a grainy image than a blurred one

Heard this mentioned a few times, does anyone know whether it can be done on Canon bodies? :shrug:

 

[Chris Primadona]

On the 1d mkIII its C.Fn I-8-2 "Enable ISO safety shift" then C.Fn I-12-"Enabled" and set your min/max shutter speeds.

 

[God]

On the 1d mkIII its C.Fn I-8-2 "Enable ISO safety shift" then C.Fn I-12-"Enabled" and set your min/max shutter speeds.

Got it, Im yet to check the 1dsii but the 5D doesnt let you choose a min/max ISO. Shame

 

[Martyn...]

I personally think that the iso is the last thing you should leave to a camera to decide. I let mine control apeture sometimes and shutter speed on rare occasions but I mostly see my iso as a last resort "emergency" option for when I would otherwise miss a shot and use it sparingly.

Same as anything, you need to learn how to use it to your advantage, for wildlife shooting it is a superb tool to have.

 

[DuncanDisorderly]

Got it, Im yet to check the 1dsii but the 5D doesnt let you choose a min/max ISO. Shame

If you are only shooting to print at A3+, then Auto ISO is fine.
Max ISO is 3200 and looks a bit rubbish at 100%, but will produce a clean A3+ print with accurate colours straight from the camera.

 

[Chris Primadona]

If you are only shooting to print at A3+, then Auto ISO is fine.
Max ISO is 3200 and looks a bit rubbish at 100%, but will produce a clean A3+ print with accurate colours straight from the camera.

Noise won't really be a problem at that size, but won't the images be very soft? :shrug:

 

[DuncanDisorderly]

Noise won't really be a problem at that size, but won't the images be very soft? :shrug:

Good point
My 60D - softer than ISO 100, but the prints look very acceptable
My 5DII - the 5DII retains loads of fine detail even at ISO 3200, way more than needed for an A3+ print

 

[Gauntey]

Like everything on my camera i use it when i need it, i often use it when walking around and just snapping and looking for new shots, but also use manual for when doing a propper shot or etc....... but then again i normally go full manual for this also.