nxb
I think I'm mixing up TV and AV. I was in between a 2 part gig so I wrote without thinking. I was using shutter priority and instead of taking shots at 1600 iso, it was taking them at 100. So you would get a black photo. Right before it was using 1600... as soon as I zoomed the lens in to 5.6 it screwed up. When I used a different lens that was F2.8-4.0 I had the same problem. Changing minAV one step higher than lens minimum seemed to solve the problem. Also the problem showed up between lens changes when new minimum was too low. I need to find a way to reproduce this issue reliably.
In Tv mode, AutoISO kicks in (raises the ISO) when the camera selects an aperture greater than the "Max Av" parameter; but the camera will never set an aperture out of range for the lens, and thus AutoISO will never kick in if you select a "Max Av" value out of range for your lens (next version will not let you do that, BTW). For example, in you have a f/4 lens and set "Max Av" to f/2.8, then AutoISO will raise the ISO when the camera sets f/2.8, but the camera will never set f/2.8, because that value is out of range for your lens.
Zoom lenses are a bit more complex, as there are different maximum apertures. With a f/3.5 - f/5.6 lens, "Max Av" at f/4 will work only on the wide end of the zoom (where max aperture is f/3.5), but not on the tele end (where max aperture is f/5.6). This is all expected behavior (well, at least expected by me 😉), but your post made me think that AutoISO could also try to avoid underexposures, not only look at aperture values; will investigate on this.
nxb
As for flash, it seemed to not account for it at all. I was shooting 1/90 and f8 in close quarters. This is the point of flash... so I don't have to shoot at 1/30 + wide open + 1600/3000. The subjects came out flash "painted" and I had to turn the exposure down anyway.
Ok... I just picked up the camera and tested flash in M mode. Iso stays the same whether you use flash or not. In P mode at first it jumps to ISO 1600 when you raise flash... then after a couple of half presses it drops the ISO below what it was when flash was closed.
Yes, AutoISO does not account for flash, just like Av / Tv modes do not account for it when calculating shutter speed or aperture; and I do not think I could change this, even if I wanted. Think that AutoISO is trying to produce a good exposure for the background (where the flash does not reach), and let the camera adjust the flash intensity to expose the foreground (where the flash does reach).
In these situations, I would not use AutoISO, or try to compensate down the exposure.
nxb
In TV mode, autoiso closes up the aperture but ISO stays the same.
Not exactly: AutoISO just raises the ISO, then the camera compensates by closing the aperture; I think this is explained in the manual.
nxb
In AV mode it randomly tries a couple of things when you raise flash but it does appear to lower the ISO with a few tries.
Problem is that I don't see the ISO in the viewfinder so I'll only see that it screwed up after I look down 🙁
Raising the flash should not affect AutoISO at all, but I'll have a look at this later.
nxb
P.P.S Jump button needs a setting to jump through all ISOs not just intermediate in that range. Otherwise it is 2+ button presses to change iso. I'm glad this feature is back in some form though. :lol
Point taken.
