HDR – Does it really require Multiple Exposure

I, as many of the folks, was under the impression that, to post process a HDR image , it would require multiple exposure or atleast a single RAW image (RAW images contains more information than JPEG, in that, it would be possible to extract shots with different exposure from a single RAW shot – I realized this from listening to Thomas Hawk @ ScobleShow)

But today when I was playing around with Artizen , was in for a pleasant surprise. I had just one jpeg image open and while going through the Menu (Modify -> Tone Mapping) saw the option ‘Tone Mapping’. It even automatically converts to 32 bit mode before applying ‘Tone Mapping’. I even tried converting a sample single exposure image to see the results (I tried some of the presets in the ‘pull down menu – TM Operator’ and settled for ‘Fattal’).

In the below you can see that one half was created using multiple exposure (three -2,0 and 2 xp to be precise) and the other was created with a single exposure (0) shot with Artizen. mmm quiet interesting results. Though the image from the single exposure seems to be washed out , I think it could be fixed with little post processing.

P.S : The only concern with Artizen is that it took nearly 10-15 for mins applying the Tone mapping on this below sample. Is it just this image or my PC that needs to be looked into :)

Artizen Photomatix

These are the multiple exposure shots used for the above post processing

So does it mean that we really do not need multiple exposure for creating a HDR. IMO (In my opinion) I would prefer multiple exposure. Before plunging into it lets gather some technical stuff here.

HDR – High Dynamic Range – as the name suggests is capable of storing high values of dynamic range. But most of the medium (lcd, crt or even print & paper) are not capable of displaying such high dynamic ranges. So to make these images compatible with the current mediums , a process called ‘Tone Mapping’ is generally used.

Tone Mapping – as read from wikipedia – Tone mapping is a computer graphics technique used to approximate the appearance of high dynamic range images in media with a more limited dynamic range. Print-outs, CRT or LCD monitors, and projectors all have a very limited dynamic range.

Hence, to me, the single shot stuff does not really enhance the Dynamic Range of the image and hence does not produce desirable results always. So as I said , I would still prefer multiple exposure for creating the HDRs, but again it would be on a case-by-case basis.

The Pros would be

1. Could be used with shots that contain action. Generally when taking multiple exposure, there tend to be some blur with the moving objects like the boy in this .

2. Could be used to take Panaromas. I found it extremely handy while trying out a HDR Panaroma. More on this later, for the time being u can refer to this shot .

3. U might not realize that a shot would be great for that HDR effect while composing the shot. Later if ur decide so u could always try with the single exposure u have (of course results not guaranteed ;-) )

The Cons would be

1. One does not create a HDR image, that could be later used to be displayed in an HDR Compatible devices (yes we do have some in the market like BrightSide)

2. Was not able to get ‘actual Range values’ [File -> Image Properties -> Dynamic Range] for the image created from a single exposure, since this is not actual HDR. But in many cases realized that the Range is not high enough, when created from a single exposure.

Note : If you do not have Artizen, the same can be achieved from Photoshop or other tools too. First use the single exposure shot. Play with the exposure setting to create two additional shots one with under exposure and one with over exposure. Then follow the same procedure to get the HDR effect.

Advertisements

4 Responses to “HDR – Does it really require Multiple Exposure”

  1. Excellent information. I learned something today!

    Like

  2. Tx Suresh. Keep Visiting for more !!! :)
    Tx for leaving a comment , not just for the comment , but by the way of leaving a comment, u invited me to ur web, it is impressive & inspiring. Now I have to spend time there. Good work.

    Like

  3. I noticed that this is not the first time at all that you mention this topic. Why have you decided to write about it again?

    Like

Trackbacks

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: