Why is 1DX Auto ISO set at 400 with Flash?

Started Feb 24, 2013 | Discussions thread
John Sheehy Forum Pro • Posts: 19,136
Re: Why is 1DX Auto ISO set at 400 with Flash?

drgas99 wrote:

I think of exposure like a 3 legged stool. Balance is acheived with shutter speed, aperture, and ISO. Shutter speed and aperture give creative expression but ISO, for me, should always be the lowest possible setting to achieve the exposure I am looking for.

Actually, if your absolute sensor exposure is already chosen (f-stop, exposure time, and scene illumination), then the highest ISO that doesn't clip desired highlights is the best noise-wise, or at least the same as a lower ISO.  Low ISO only decreases noise by decreasing absolute exposure.  However, if one shoots RAW and the camera does not have excessive extra absolute noise at base ISO, then everything could theoretically be shot with minimum analog gain (base ISO) for the sake of maximum headroom, and smaller RAW files.  Cameras generally give dark review images, however, when low ISOs are "under-exposed".

Auto ISO does this without flash...but with a flash? Then everything seems to break down.

It doesn't appear to be a limitation in the sensitivity, technology, or computing power of the camera. It clearly has the ability to calculate exposure with 4 variables. It appears to be a simple lack of programming on the Firmware.

But why set it arbitrarily at 400? This is a deliberate move on the programmer's part but it makes no sense to me.

It seems that Canon just doesn't understand the fact that there are people who know what they are doing who want ISO automated.  They seem to think of it as a "newbie" feature, and part of the problem, I think, is that many of the old dog pros that they communicate with are too stubborn to embrace new paradigms.

One of the most revered bird photographers in the places that I shoot used to have the Exif info on his website.  He was shooting his Canon 1D2 at ISO 400 with -1.3 to -1.67 EC in flat lighting.  I've overheard him many times telling people to keep the ISO low, and use negative EC in Av mode to get the shutter speed they want.  Of course all his images and all those who listened to him have images that are much noisier than they would have been at 800 with -0.3 to -.67 EC, or even 1600 at +0.3 EC.  This is the type of person that Canon typically interviews as a pro.

Because I shoot subjects that are moving fast, I would like the assistance of the camera to calculate the exposure I am after...it doesn't seem unreasonable to expect. In addition, there is no reason that with AUTO ISO chosen, I couldn't be able to have Exposure Compensation calculated in Manual mode.

... and you can, if you use a 3rd-party lens with a manual aperture ring (or a fixed aperture), and set the camera to Tv-priority mode, where you will have full use of EC.

For those that want Manual to mean "100% no computer," perhaps have another mode.

No need, really, as simply having "A" as one of the ISO choices does everything for everyone.  Anyone complaining about the presence of "A" on the ISO menu is not being rational, because if such a person is worrying about it going auto against their will, that can not happen as anyone exercising manual control is selecting their own ISO; they are not going to select a, and if they accidentally change the ISO, it is much safer for it to go to A than it is to go completely arbitrary and fixed, where heavy clipping or excessive noise would result.  "A" could just be disabled in the menus, as well.

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