Bracketed shooting and Auto ISO

I don't shoot bracketed that much any more, so this may be old news to many but it's something I've not noticed before. As I shot a 3 image sequence yesterday (+/-3 EV) my camera was in Aperture priority mode with Auto ISO on. Auto ISO was set so that the shutter speed was at the "FASTER" end of the range, so 2 clicks above the Shutter Speed = 1/Focal Length spot. When shooting in fixed ISO, which I used to do almost exclusively when I was doing a lot of HDR, the camera would keep the aperture and ISO constant and vary the shutter speed, but not so with Auto ISO on. For my 3 image set shot (with the 24-120mm at 34mm) I wound up with...

0 EV: 1/80sec, f/5.6, ISO 250
-3 EV: 1/250sec, f/5.6, ISO 100
+3 EV: 1/80s, f/5.6, ISO 2000

Now, with the D610 I have to say that the high ISO stuff worked just fine, particularly since the shadows I needed to pull weren't that severe. The nice thing is that I never had to worry about movement in the long exposure.

My point in posting is that if you wind up with an exposure set you want to shoot but just can't seem to get a steady bright shot and don't have a tripod, consider switching Auto ISO on if you don't use it. A little noise is better than a blurry image you can't use.

You shoot base exposure and then +3 stops and -3 stops? This is a little extreme for only 3 exposures when doing HDR. +/- 2 is better for capturing both highlights and low values given the relatively narrow exposure range of digital, compared to negative film. If you wanted to go up and down 3 stops you might want to shoot 5 instead of three.

That's interesting, great idea for wind/fast clouds!

STM said:

You shoot base exposure and then +3 stops and -3 stops? This is a little extreme for only 3 exposures when doing HDR. +/- 2 is better for capturing both highlights and low values given the relatively narrow exposure range of digital, compared to negative film. If you wanted to go up and down 3 stops you might want to shoot 5 instead of three.

Click to expand...

It depends on what you're looking for and how you're doing the blending. Natural looking HDR, perhaps. But when I've got the DR of a D610 I can pull 4-5 stops out of the '0' image without even needing add'l images, so I'm just looking to fill in the extremes. Like I said, since getting the D600/610 and a D800 I hardly ever shoot brackets any more which is why I stumbled onto this in the first place.

That's a good tip, Jake. Haven't tried brackets with Auto ISO, as I was afraid of introducing the noise. As long as ISO doesn't get too high, noise is manageable, and the faster shutter would help prevent ghosting.