Exposure Bracketing in Digital Cameras

Im not able to understand what cameras exactly change with exposure bracketing. Like ISO, shutter speed, aperture all have direct physical things that change, don't understand how cameras change exposure, and if the exact process is different in each camera. Is it changing aperture, or shutter speed, or ISO and how to control this or find out.

I don't exactly understand your question. I am going by the assumption, that you want to know how exposure bracketing works in a camera.

My camera doesn't have that feature. If the camera takes different shot, then (logically) I think camera would change shutter speed for exposure bracketing. Changing aperture would give different dof, iso would give more/less noise.

With CHDK, I can pick the one I want aperture or shutter or iso (I haven't tried all at once, so I don't know if I can employ all at the same time).

If your camera takes different exposure and saves all the exposure as separate files, check the exif and see what has changed. If the camera saves just one file, then shoot a question to the manufacturer.

yep. I suspect that these digital point and shoots at least change aperture! I have no clue how to prove it, because I don't know how much the aberrations on my pictures are because of shake or because of dof change.

If your camera does not have that feature, I think it is a very good camera, because that feature is superflous in digital cameras. Think the same effect can be achieved in pp, without relying on a digital camera for exposure bracketing, (no need for multiple photos) if the same logic as film is followed. Need confirmation of this line of thought.

Anorion said:
If your camera does not have that feature, I think it is a very good camera, because that feature is superflous in digital cameras.
Think the same effect can be achieved in pp, without relying on a digital camera for exposure bracketing, (no need for multiple photos, or the processing and memory involved with that, or a tripod to take these HDR shots) if the same logic as film is followed. Need confirmation of this line of thought.

Yes, with PP you can get lot better final image than in camera processing. If you want you can go for deeper exposure bracketing like 10 or 20 exposure to make one HDR.
Even though you can do HDR processing with just one photograph, it's better to have multiple photos. If you opt for multiple photos, it's better to have tripod or at least make shift arrangements for the camera to stay steady for the entire bracketing shots.

ok. then what is the benefit of the photos other than the one with the lowest exposure.

yeah, I donno all about HDR, and tripod is good anyway, but I cannot understand why to rely on camera for the +exposure. So to take HDR shots, all you need to do is go around with -max exposure of your bracketing and then do the rest in pp?

G

Anorion said:
Im not able to understand what cameras exactly change with exposure bracketing. Like ISO, shutter speed, aperture all have direct physical things that change, don't understand how cameras change exposure, and if the exact process is different in each camera. Is it changing aperture, or shutter speed, or ISO and how to control this or find out.

Just checked, Aperture was constant, ISO and shutter speed changed for the 3 shots.

ooh ok. Guess aperture does not change then. I found out mine from exif (feel stupid for not bothering to check there). It changes only shutter speed.

Anorion said:
ok. then what is the benefit of the photos other than the one with the lowest exposure.

yeah, I donno all about HDR, and tripod is good anyway, but I cannot understand why to rely on camera for the +exposure. So to take HDR shots, all you need to do is go around with -max exposure of your bracketing and then do the rest in pp?

You mean lowest = slowest?
If you want to do the HDR in PP with just one shot, you have to push the image a lot and the end result won't be as good as multiple photos.
With multiple photos, you have clean image to start with and your final image will be clean and have lot more clarity/iq/colour and all...

For eg: I highly doubt SX130's image will be this clean with just one shot processing

*i102.photobucket.com/albums/m108/tkphotos1/IMG_6831%20bw_zps6kdqzyej.jpg

^meant lowest exposure or fastest shutter speed in my case

ok so the shutter speed of my exposure bracketed shots are like
1/1000 sec, 1/500 sec, 1/250 sec
1/1500, 1/1000, 1/500
1/750, 1/250, 1/125 sec
1/500, 1/250, 1/125 sec

Guess it is better to manually set shutter speed in 1/1500 sec for most detail

Anorion said:
Guess it is better to manually set shutter speed in 1/1500 sec for most detail

Why this assumption? Isn't the shutter speed depends on light availability?
Why not 1/60th of a sec wouldn't give you most detail?

images

This is the fastest shutter speed shot
*i.imgur.com/ssINwGL.jpg

This is the slowest shutter speed shot
*i.imgur.com/VRZzI2c.jpg

You can get the second image from the first by changing the levels, did in pixlr
*i.imgur.com/a1sbn2D.jpg

but you cannot get the first image from the second, the information is gone in the overexposed shot

Anorion said:
You can get the second image from the first by changing the levels, did in pixlr
but you cannot get the first image from the second, the information is gone in the overexposed shot

Come on Ano, you deliberately clipped it and expecting to pull details from it. What would be the case if you used 1/1500th of sec on a new moon night with no use of artificial lighting? You would see no details in the image, but you would see if you used long exposure.

ah yes. I see what you mean. It depends on the situation. No I didn't deliberately clip it. I just thought the other two shots are unnecessary in this situation.
in any case, it is better to control the shutter speed and get what you want instead of depending on cam for exposure bracketing

Anorion said:
I just thought the other two shots are unnecessary in this situation.
in any case, it is better to control the shutter speed and get what you want instead of depending on cam for exposure bracketing

It could be useful, if you want to make HDR. You don't necessarily need to make a dramatic kinda HDR with the bracketing shot.
That's your priority. If you find the Tv is better, stick with it.

I am gonna try yours with photomatix. Will see what I get...

- - - Updated - - -

*i102.photobucket.com/albums/m108/tkphotos1/Untitled_HDR2_zpsbkumlu85.jpg

It gives fade effect in video

Anorion said:
It gives fade effect in video

Is the background taken from Varanasi ? such a beautiful city...

^yeah? Must be nice. I wanna go there. This is Nashik.

R

Lifting shadows from images that have been exposed for the highlights is likely to result in a lot of noise. Even without that, multiple exposures can be used to reduce noise without sacrificing detail as most noise is random.

^yes. Noticed that. Lot of noise. The bracketed shots option produces better quality photos.

bracketed shots
*i.imgur.com/Jbs8TPy.jpg

from one
*i.imgur.com/UhJMxkQ.jpg