any way to increase the amount of shots to be taken with adv bracketing?

Started by Bill Santos, August 08, 2013, 10:07:46 PM

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Bill Santos

New to ML use and I think I'm getting a hand on advanced bracketing feature, but I have a question:  Right now, I have adv bracketing set to take the 9 image maximum with my Rebel T3, but is there any way to increase the amount of shots taken?  Obviously, I can manually change the exposure compensation either above or below where I currently have it, but I was wondering if the software could do this in any way as I'd rather avoid touching the camera.  I tried experimenting with the ISO change, but the number of shots were still the same. 

Thank you,
Bill   

a1ex


Bill Santos

Yes, I'm finding that the nine shots aren't enough to capture the full dynamic range of some of my images.  Right now, I have the EV increment set at 1.5 EV.  I could increase this to 2 or more if I had too, but I'd rather change exposure compensation so I can keep the EV the same between shots. 

a1ex

Can you post an example?

You can generate the intermediate steps from the existing CR2 files, no need to kill the shutter.

Bill Santos

I can't really post any images because I've gone back and corrected them.  I'm fairly new to HDR imaging, but noticed a problem with blown highlights on my final HDR's.  Some reading suggested that not enough of the lower ranges were captured, at least not enough to have a true image where some part of the image didn't have a blown highlight.  Obviously, going from the simple 3 images my camera offered to the 9 ML offers is a tremendous improvement, but I was still getting some blown highlights in some of my tests earlier.  The only way I see to increase the range, if not taking more shots with a different shutter setting, was increasing EV, which I may end up trying just to see what happens. 

With the final HDR's I created, I already did go back and correct the blown areas but this is tedious to do manually. 

Just thought ML might be able to offer an increase in shot amount taken.  Perhaps a script could do the job, but that is out of my ballpark to set one up.   

a1ex

Try the auto bracketing or use the raw histogram to check whether you are capturing everything you need.

If the darkest image doesn't have any overexposed areas, something's wrong with your workflow.

Bill Santos

Thanks for the auto bracketing suggestion.  That seemed to do the trick and I actually ended up with 10 images.  The resultant HDR was a lot easier to work with.  Still needed a slight correction, but only contrast boost really and almost no highlight adjustment.  Only thing I find with the auto setting is that I am assuming that starting has to be exactly at 0 EV and, if not, it won't take the correct exposures(?).   

Audionut

Use the raw histogram to find the exposure setting that pushes your highlights to the right without overexposure.

Set the sequence in Advanced Bracket to (0 + ++)

Set the number of frames and EV increment dependent on the amount of dynamic range needed.

Most new Canon cameras have a dynamic range of around 10.5EV @ ISO 100.  Lets play it safe and say that they have 8EV of dynamic range before noise becomes intolerable.  9 bracketed shots 1.5EV apart increases dynamic range to over 20EV.  That's snow under sun down to subjects under full moon.
And more dynamic range then the human eye.

Bill Santos

Tried the auto select for number of shots, and then manually set the number at 7.  I felt auto did ok, but sometimes not enough shots taken, so then I went to 7. 

The images continue to come out better with this greater dynamic range of input, but I am noticing that often times, out of the 7 shots, I am ending up with 2 or 3 that have identical exposures.  Any reason why this is happening?

Walter Schulz

Exposure time in these shots is not 1/8000 s by any chance?

Ciao, Walter

Bill Santos