DPReview.com is closing April 10th - Find out more

Auto ISO : 40D (0) vs 1D mkIII (1) vs Nikons (1) - Convincing Canon?

Started Feb 6, 2008 | Discussions thread
Flat view
Sylvain G Regular Member • Posts: 416
Auto ISO : 40D (0) vs 1D mkIII (1) vs Nikons (1) - Convincing Canon?

Prior to 40D release, I hoped very much to see the next batch of Canon finally arrive with AutoISO*(cfr.infra) for the masses. So when 40D was announced with AutoISO I was quite excited until reviews detailing how it worked started to appear and a friend let me try it for a few minutes. Having followed with attention Nikon's implementation on last models, I can't tell you how much I was disappointed. As far as I'm concerned, I think that what we now have on the 40D is useless.

Because we don't have any control on it:
-set arbitrarily on 400,
-not available in M mode,
-the way it variates is not user defined
-variates only between 100-800 iso, leaving 1600 & 3200 unused.

From my very short tests, it seems that it start worrying about changing ISO speed only at 1/8s ? If anybody can communicate his findings (possibly with several lenses), we might learn how Canon implemented it more precisely.

I thought the only convincing implementation was on high end model Nikons. There you can set a minimum shutter speed as well as the ISO range, that is ISO lower limit and higher limit. But what I thought was a costly benefit of 4 digits $ cameras is in fact available starting from the D40 and it's been like this for a while it seems (D40,D40x,D50,D70,D70s,D80,D2X,D2Xs,D2H,D3,D300,D200,D100...correct me if I'm wrong).

Could it be then that Canon just doesn't get the idea? I don't think so and I recently discovered an article where the author mentions the thoroughbred 1D mark III has this functionality available by combining three custom functions.

C.Fn I -8 Safety Shift + C.Fn I-12 Set shutter speed range + C.Fn I-13 Set aperture speed range

-- hide signature --

C.Fn I -8 Safety Shift

This works in the shutter-priority AE (Tv) and apterture-priority AE (Av) modes. When the subject’s brightness changes erratically and the correct autoexposure cannot be obtained, the camera will change the exposure setting automatically to obtain a correct exposure.
2: Enable (ISO speed)

This works in the Program AE, shutter-priority AE, and aperture-priority AE modes. When the subject’s brightness changes erratically and the correct autoexposure cannot be obtained, the camera will change the ISO speed within 100-3200 automatically to obtain a correct exposure.

---C.Fn I-12 Set shutter speed range
Disable:The settable shutter speed range will be 1/8000 sec. to 30 sec.

Enable : The settable shutter speed will range from the highest shutter speed to the lowest shutter speed set with [Register]

Register : The highest shutter speed can be registered within 1/8000 sec. to 1/250 sec., and the lowest shutter speed can be registered within 30sec. to 1/60sec. After entering the settings, select [Apply]

---C.Fn I-13 Set aperture speed range

Disable:The settable aperture will range from the camera-attached lens’ maximum aperture to minimum aperture.

Enable : The settable aperture will range from the smallest to largest aperture set with [Register]

Here I quote the author Pekka Saarinen from his review of the mkIII telling us how combining those Custom functions achieve auto ISO.( http://photography-on-the.net/1DmarkIII/ )

"(...)When you combine this with custom settings for limiting shutter speeds and apertures you can set up a shooting environment with some insurance for success. For example I have set minimum shutter speed to 1/60, set ISO safety shift on, set ISO to 1600 and Tv mode to about 1/160. Now what happens when I shoot a live event is that when selected shutter speed is not possible with ISO 1600 Mark III raises ISO to 2000, then 2500 and 3200. When in Av mode and ISO 3200 is reached, it starts lowering shutter speed - but not below 1/60, this I have set to ensure reasonable stopping of movement without photographer having to change all settings during shoot. Now all we need is M mode ISO shift.(...)"

This is indeed a different than Nikon's but looks very flexible already. Or am I missing something?

Hey, but I recall seeing safety shift on the 40D ! Let's see...
C.Fn I-6 Saftey Shift

This works in the shutter-priority AE (Tv) and aperture-priority AE (Av) modes. If the subject’s brightness changes suddenly and the current shutter speed or aperture becomes unsuitable, the shutter speed or aperture is shifted automatically to obtain a suitable exposure.

No #2: Enable (ISO) here and no Min Shutter C.Fn or Min Aperture C.Fn...

And now we're reaching the end of the post : "why oh why did he bother us to dwelve into those manuals?"

Simple. I WANT these custom functions (or any real improvement of the autoISO) on my 40D and I want other people to start voicing their opinion on this as well.

It seems a lot of people haven't realized yet what flexibility this simple feature can bring to action photography with rapidly changing lighting conditions. Michael Reichmann from Luminous Landscapes went even further and proved how useful it was on a simple candid shot ( http://luminous-landscape.com/reviews/cameras/nikon-d3-d300.shtml ).

I'm no Canon firmware engineer but I somehow feel we could have it pretty easily (same generation cameras, digic III, etc...). Canon has to start improving its cameras through firmware someday.

What do YOU want?

Thanks for hanging on this far!


Just for the kicks : "Coming up next,
-Why does our 3" LCD only display tiny embedded low resolution jpegs?

-Why wouldn't Canon implement 450D liveview phase detection focus to the 40D firmware?"

The principle of Auto ISO would be, if I'm not mistaken :

-On aperture priority, when a lower limit shutter speed is reached and exposure cannot be insured -> push ISO to reach or surpass that minimum shutter speed at the selected Av.

-On shutter priority, when a desired shutter speed cannot be reached with maximal aperture -> push ISO so that desired shutter speed can be reached.

-On Manual, when both aperture and shutter speed don't allow for exposure -> push ISO to allow for exp.

Flat view
Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow