Exposure bracketing

2010-04-27

I have an old Canon 20D. I’m pretty happy with it, the large pixels behave well in low light conditions and it’s got reasonably comfortable handling. There’s just one thing that’s been really bothering me, and as far as I know, all the other cameras suck just as much as mine.

Exposure bracketing was implemented by someone who hates HDR, photographers, and humanity altogether.

I use continuous shooting mode (hold the button down and the camera keeps shooting as fast as it can until it chokes). First, I have to press the button and hold it for exactly the right amount of time to get three pictures. In the beginning, it used to give me a headache, but after some time I got used to it. It’s stil an inconvenience, but a rather minor issue.

There’s something I don’t get at all: Why do I even have to shoot more pictures to get more dynamic range?

If the wonderful RAW format had for example 32bit depth instead of 12 or 14, we wouldn’t need bracketing at all! You would just take the longest of the exposures, and the camera could record all the data without overblowing the highlights. Or, if that is too much hassle, it could make 3 “virtual” RAW files – by simply taking a snapshot of the sensor’s state at three different times during the single exposure.

Given the amazing feedback I’ve been getting here lately, I don’t expect an answer. But I do wonder – is there anything in the way? Or are camera manufacturers incompetent?

PS: Yes, HDR is an instrument of the devil. If you look at my recent pictures, you might see that I realized that aready. But sometimes, sometimes I like to go to the dark side…

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9 thoughts on “Exposure bracketing”

nessumo 2010-05-06

I’m not sure if the idea with three virtual photos is technically feasable. You want to make three snapshots while single exposure, so you need three dumps of image to memory. This takes time ;) But whole idea is good and I’m sure someone is already working on it. And one thing: even if there is such camera, it won’t be revealed to public till companies get all the money they can from “normal” stuff :)

Marek 2010-05-14

Hi there!

The problem with extending dynamic range is you need 3 different apertures set in your lenses for 3 shots. So in theory, you could have one press = 3 to 5 shots with different apertures, but there is no way you will get more dynamic range from single shot. Problem is not in RAW, it is in dynamic range of you sensor. And even if they would increase that range by 3 times, you would still benefit when doing HRD multiple shots (cause you could expand dynamic range even more).

Not sure what is the problem through? In my Nikon D5000 I need to press the shutter 3 times to get 3 images. And honestly I do not find it bad or anything. It does what I want it to do and that is it.

PS. bracketing was not designed for HDR (at least not in the past). It was designed for people that need to take shots quickly (sport for example) and are not sure of the settings they need to use.

PS. Nice blog btw :)

tasuki 2010-05-16

@nessumo: right, it might take some time to take snapshot of the sensor.

@Marek: Or you can have one aperture and different exposure time (different aperture gives you different DoF, which is usually a bad thing). As for the dynamic range of the sensor… that is indeed the problem – but do you think it’s a hardware or software problem? Expanding the dynamic range 2 times would probably be enough for all my hdr needs.

As for pressing the shutter 3 times to get 3 images – if you have the time (and tripod), it’s not a problem. However, if you are taking pictures of anything that moves…

I realise that bracketing wasn’t initially meant for hdr, but that’s what it’s mostly used for nowadays (if you are just unsure about exposure settings, raw will usually give you enough room for error). And people who create present cameras should try to take that into account.

Marek 2010-05-17

tasuki wrote:

You're right about aperture. My mistake. About sensor – it is purely hardware thing. Although now that I said it… I am not entirely sure. Cause these days you've got wide range of ISO settings as well. If software would be asked to do an 'HRD setting shot' it could potentially hijack the whole camera, do three shots with 3 different ISOs/times. Of course it would take 3 times longer to take full 'HDR shot', but it could work. By the way I think there are cameras these days that will combine HDR images in their body for you.

Marek 2010-05-17

I’ve messed up my XHTML sorry. Should be:

Or you can have one aperture and different exposure time (different aperture gives you different DoF, which is usually a bad thing). As for the dynamic range of the sensor… that is indeed the problem – but do you think it’s a hardware or software problem? Expanding the dynamic range 2 times would probably be enough for all my hdr needs. You’re right about aperture. My mistake. About sensor – it is purely hardware thing. Although now that I said it… I am not entirely sure. Cause these days you’ve got wide range of ISO settings as well. If software would be asked to do an ‘HRD setting shot’ it could potentially hijack the whole camera, do three shots with 3 different ISOs/times. Of course it would take 3 times longer to take full ‘HDR shot’, but it could work. By the way I think there are cameras these days that will combine HDR images in their body for you.

Marek 2010-05-17

Argh! How do I close blockquote cite?? Without XTML:

tasuki wrote:

“Or you can have one aperture and different exposure time (different aperture gives you different DoF, which is usually a bad thing). As for the dynamic range of the sensor… that is indeed the problem – but do you think it’s a hardware or software problem? Expanding the dynamic range 2 times would probably be enough for all my hdr needs.”

You’re right about aperture. My mistake. About sensor – it is purely hardware thing. Although now that I said it… I am not entirely sure. Cause these days you’ve got wide range of ISO settings as well. If software would be asked to do an ‘HRD setting shot’ it could potentially hijack the whole camera, do three shots with 3 different ISOs/times. Of course it would take 3 times longer to take full ‘HDR shot’, but it could work.

By the way I think there are cameras these days that will combine HDR images in their body for you.

Havuz 2010-07-22

thanks very nice article.

Fotoğrafçı 2010-07-22

yes it is good.

Peruk 2010-07-22

ı didnt understand.

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