Thursday, July 14, 2011

HOW TO: HDR photography

HDR mergedLet me talk about my experiences with HDR photography! PIC INTENSIVE =O!!

I’m a photography NOOB. But I do like to try a thing or two when I see stuff online or when I read articles in magazines. Let me share what I’ve learnt =)

As far as I know, HDR stands for High Dynamic Range (imaging). Don’t know the specific science behind it, but it seems that all you do is take a few pics of varying exposure (preferably, some under, some over and some “correct ones”), then superimpose them to create one image. This ultimately produces an image with a good RANGE of exposure, light and contrast =)

HDR on mobile phones

I found out about HDR through my phone. There were camera apps which had “HDR effect” in them, thing is, many of these apps were just post-processing them to make it look that way. It wasn’t actually taking different pics and merging them. So recently, I found an android app that actually does it properly creatively called “HDR camera” (more info in the next blog post!). I’m pretty sure IOS has similar apps (in fact I think the Iphone4 has this feature built in) too.

1. Operation is pretty easy: Just hold the phone still, touch to focus and it will take the pictures.

2. Keep your hand as still as possible! I’ve noticed the software seems to handle shakes pretty well, but its still best to avoid sudden movements!

3. Give it some time and it will merge and create a nice HDR pic for you!

Some results and comparisons:

Dark Indoors, normal camera

IMG_20110712_140354

Dark indoors, HDR camera

2011-07-12 14.03.28

This was taken at the cinemas. If you look closely, the stone (or stone look alike) wall in the HDR has much more defined details. The bumps are more visible and its less washed out than the normal camera. Also, you can see the ceiling a bit better in the HDR pic.

Backlit indoors, normal camera

IMG_20110713_112747

Backlit indoor, HDR camera

2011-07-13 11.28.19

I tried to keep the image as similar as possible, but still the results are distinguishable. Again, the darker areas are more defined and bright areas don’t wash out all over the place. The HDR pic seems more like what we see in real life.

Outdoors, normal camera

IMG_20110714_121909IMG_20110712_164403

Outdoors, HDR camera

2011-07-14 12.19.532011-07-12 16.44.33

Same results really, more defined dark and light areas. I do notice that the HDR has a bit more noise. Please notice that ugly antennae my neighbour put up. It was strategically placed right in the middle of my sunset >=(

With a proper DSLR camera

But when it comes to photography, we know we shouldn’t be doing things like this on phones ^^. There are just too much limitations on a camera phone. So lets try this again with a proper DSLR camera:

Take an overexposed pic

Manually adjust the shutter to be a longer than normal time. I guess you could always change the f-number too, but I wanted to keep that the same to keep the depth of field the same for all the pics.

 _IGP6025

I found halving the normal shutter speed to work pretty well here,

Take a normal pic

Keeping an eye on the camera’s settings, take a “normal” pic. You can also use auto here (though your cam should be telling you if your settings are right in manual):

_IGP6026

Take an underexposed pic

Make the shutter speed faster, try to keep the f-number the same:

_IGP6027

Doubling the shutter speed seemed to work for me.

HDR merged

Info on how to merge in last section! I’ve tried to keep modifying things to a minimum, but you can freely adjust things to make it look more realistic.

HDR merged

Having said that, you can see that the colour you can reach through HDR to be pretty good. I didn’t purposely saturate this or anything, this was almost all automatically done (only slider I changed is one, because the picture was too bright. No changes to individual settings like exposure and saturation were made)

With a normal Point and shoot

I’m not too sure if its possible, but I guess you can fiddle with built in modes to take under and over exposed pics. Here’s my attempt at HDR with a point and shoot:

Take an overexposed pic

Most cameras will have a “night” mode, used for taking night scenery and pics at night. I’ve found my P&S to have a much longer shutter time, which allows more light in… So in normal situations, I hope it does the same, keep an eye out on the focus type, my P&S seemed to only have “infinite” focus for these slow settings and made my subject blurry:

CIMG3243

Again, keep your hand still as any movements will be easily picked up by the camera! ^^ Overexposed as predicted!

Take a normal pic

Put your cam into normal mode again and snap the same picture:

CIMG3247

Take an underexposed pic

This seemed a bit harder to achieve, but the “sport” mode seemed to be the closest thing I could find. It does have quicker shutter speed, so I’d assume it will be slightly darker by comparison:

CIMG3246

My P&S didn’t have a sport mode (though the Ricoh does)… Closest thing I could find was “Pets” which had higher sensitivity. The shutter speed was only a nick faster

HDR merged

Ha-ha here’s a good example of what happens when you don’t hold your camera still or have the same angle the whole time (This is not good =P):

HDR merged 2

Guess more practice, or a tripod will make these better! I think the results and procedure are best carried out on a proper DSLR though =)

Merging the pictures

First off credit to this site. I’m just trying this out and found this set of instructions to be pretty good. So making it more simple:

1. Open up Photoshop

2. Go to “File > Automate> Merge to HDR”

3. Browse and select all your pics and click OK.

4. The merging should finish pretty quickly. I got a message saying my pics weren’t from the same camera (weird), but you should see something like this:

window

5. As you can see, the merging result was NO WHERE near any of my original pics. You can change the overall picture by drawing that slider around, I found dragging it to the right to make it darker and more realistic. Once you’re happy click OK

6. Doing just this, your file cannot be saved (the source site said something about 32bit channel and being unsaveable in this state etc.… read that for an explanation =p). Navigate to “Image > 8bits/channel” and you should see this:

window2

7. You can play around with the sliders and options, but I decided to leave those untouched (Why would you want to change so much?!). Once done click OK.

8. You can save it like any normal picture now by “Save As”.

Interesting isn’t it?! I’m just obsessed by the difference! I’ve also read that in HDR, the image is closer to what we see in real life. So for my next post, I’ll be covering the apps I found. Keep an eye out! I don’t think these posts should have a drawing in them… you? Let me know =) I can add it if you like.

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