Emulating auto ISO with ISO safety shift in 1D(s) MKIII

Les McLean

Les McLean

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I've been a bit envious of the auto ISO facility in the current crop of Canon's DSLR's , The ability to set a fixed shutter speed/aperture in manual mode, and let the ISO take the strain to enable a correct exposure, could be very useful in such situations like rugby/football where the action can move from good to poor light very quickly.

Looking through the 1Ds III Manual, I think you can emulate something similar.

For some time Canon have utilised a safety shift (C.Fn1-8), so the camera will automatically change the exposure settings to obtain a correct exposure if the brightness goes outside the shutter/aperture parameters.

They have also introduced an ISO speed safety shift, so once again if the brightness goes outside the set aperture/shutter settings the camera will automatically change the ISO to enable a correct exposure.

The way I see it, by enabling the ISO safety shift, and then restricting the lens aperture range (CFn1-13) and using shutter priority mode should result in something similar?

So for example if I was shooting Rugby, I could set the shutter speed to say 1/1000 sec, restrict the aperture range of my lens from f2.8 to f5.6, and enable auto ISO safety shift.

This means that all my shots will be at 1/1000 sec @ f2.8-f5.6 with a variable ISO.

Am I reading this correctly, has anyone tried it, or am I being a bit dim, and my understanding of this is all t'pot?
 
That's pretty much spot on :) Might want to keep it at f2.8 for sports though.. just to keep those backgrounds lovely and smooth :)
 
purpleclouds said:
That's pretty much spot on :) Might want to keep it at f2.8 for sports though.. just to keep those backgrounds lovely and smooth :)
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Phew...pleased about that, wasn't sure if I was having a blond moment or not :bonk:
 
That's the problem with reading the manual, ;) you can actually find out how your camera functions :lol:

Not a dig at you Les, I know it is usually 'a man thing' to dive in and not read the manual fully at least once, but it always surprises me how many people are unaware of what their camera can do, and when someone says I have found this great, function, mode, etc, loads of others then post to say how useful it is and how they wished they had known sooner.

RTFM fully at least once and you might have :p
 
Thanks Ed , in my defence ,I've only had the camera a short while and have been concentrating on basic functions [via the manual] I'm now digging a bit deeper, and wasn't sure I understood what I thought I understood, hence the query.
 
Les McLean said:
The ability to set a fixed shutter speed/aperture in manual mode, and let the ISO take the strain to enable a correct exposure, could be very useful in such situations like rugby/football where the action can move from good to poor light very quickly.
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Sounds great doesn't it.. unfortunately auto ISO on the 5D mk II won't work in manual mode, for some reason understood only by Canon engineers - it defaults to ISO 400. I can't speak for other Canon models..

There is a petition around somewhere for Canon to incorporate auto ISO in manual mode in a firmware upgrade.

In the meantime, you could always use shutter priority mode with auto ISO. The camera would tend to use the largest available aperture, which you'd probably want to do anyway, and bump up the ISO to maintain your selected shutter speed.

A.
 
Anorakus said:
Sounds great doesn't it.. unfortunately auto ISO on the 5D mk II won't work in manual mode, for some reason understood only by Canon engineers - it defaults to ISO 400. I can't speak for other Canon models..

There is a petition around somewhere for Canon to incorporate auto ISO in manual mode in a firmware upgrade.

In the meantime, you could always use shutter priority mode with auto ISO. The camera would tend to use the largest available aperture, which you'd probably want to do anyway, and bump up the ISO to maintain your selected shutter speed.

A.
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On the 1D/s3 bodies though you have the option to set your max and min apertures and your max and min shutter speeds in custom functions so even in an auto mode you can have what is effectively an auto manual mode and it is this that Les is thinking of using with ISO safety shift to give him his optimum range of exposure settigs for his subject whilst maintaining an appropriate shutter speed and aperture.
 
Les McLean said:
I've been a bit envious of the auto ISO facility in the current crop of Canon's DSLR's , The ability to set a fixed shutter speed/aperture in manual mode, and let the ISO take the strain to enable a correct exposure, could be very useful in such situations like rugby/football where the action can move from good to poor light very quickly.

Looking through the 1Ds III Manual, I think you can emulate something similar.

For some time Canon have utilised a safety shift (C.Fn1-8), so the camera will automatically change the exposure settings to obtain a correct exposure if the brightness goes outside the shutter/aperture parameters.

They have also introduced an ISO speed safety shift, so once again if the brightness goes outside the set aperture/shutter settings the camera will automatically change the ISO to enable a correct exposure.

The way I see it, by enabling the ISO safety shift, and then restricting the lens aperture range (CFn1-13) and using shutter priority mode should result in something similar?

So for example if I was shooting Rugby, I could set the shutter speed to say 1/1000 sec, restrict the aperture range of my lens from f2.8 to f5.6, and enable auto ISO safety shift.

This means that all my shots will be at 1/1000 sec @ f2.8-f5.6 with a variable ISO.

Am I reading this correctly, has anyone tried it, or am I being a bit dim, and my understanding of this is all t'pot?
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Had a try at this this morning as I rarely use TV, and it works exceptionally well. It only works within the normal ISO range though so 1600 on the 1Ds3 is the top ISO (even with H enabled).

I set a shutter speed of 1/250 in TV set the aperture range to f2.8-f4 and the ISO at 100. As the light changed the ISO increased proportionately.

Not something I would personally use often in TV mode, but have had ISO safety shift set for a while.
 
I use that method myself from time to time, but it can be a bit hit-and-miss depending on what and how the camera is metering. There is a danger it can bang the ISO up too far and overexpose a shot of a player against a dark background for example.

When I do use it, I'll set min and max aperture to f/2.8, put it in Tv mode at say 1/1000th and leave the ISO to sort itself out. The most common time I'll use it is when there is sun on one side of the pitch and the other side is in shade, and I'll usually have centre-weighted average metering on. It generally avoids making a hash of things, and allows you to follow the play quite effectively, but you do have to watch out if the background is v.dark or in shade.
 
Tobers said:
I use that method myself from time to time, but it can be a bit hit-and-miss depending on what and how the camera is metering. There is a danger it can bang the ISO up too far and overexpose a shot of a player against a dark background for example.

When I do use it, I'll set min and max aperture to f/2.8, put it in Tv mode at say 1/1000th and leave the ISO to sort itself out. The most common time I'll use it is when there is sun on one side of the pitch and the other side is in shade, and I'll usually have centre-weighted average metering on. It generally avoids making a hash of things, and allows you to follow the play quite effectively, but you do have to watch out if the background is v.dark or in shade.
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Yep its very handy i used it for the first time at Derby County Vs Notts Forest last month, there were a couplr of times where it bumped the iso to 3200 in daylight :cuckoo: but overall its very very usefull
 
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