Wednesday, 27 May 2009

Just practising

In the odd spare moment I've been trying to learn a little more about high dynamic range photography (HDR). Ant has been really helpful in this and I've also recently bought "High Dynamic Range Digital Photography" by Ferrell McCollough which is definitely an interesting read. Unfortunately neither the weather nor work commitments have allowed me to take the time to experiment until today.

This evening I tried a quick test of HDR vs. a regular photograph. The results are interesting. Firstly, HDR really does help bring things out that you don't see in one single photo. On the other hand, at least in the brief test tonight, image quality suffers. I suspect taking pictures of flowers really isn't the right way to do this though. Although it wasn't windy I did find a gentle breeze would really screw things up!

In any case, the picture above shows the regular photo on the left and the HDR photo on the right. The latter used 5 images from -2 stops to +2. I had a +3 image but the wind made that too blurry.

These aren't great pictures by any means, but I thought it would be interesting to show the difference between the two techniques. Next time I'll try this on something that doesn't move in a gentle wind - a building for instance.

Oh, back up the mountain late this weekend. Maybe I can experiment up there, circadian rhythm be damned.

Just thought I'd add a picture of the curly wurly plant in the yard. Next time I'll get the whole thing in focus but I can tell you now that a flower like this is a great way to confuse a point-and-shoot camera...


Protege said...

The top picture to the right is so much better; the colours are more saturated and vivid and the contrast is better.
I love the curly wurly flower; it looks like it is knitted.;))
And of course, please just pop over for a beer anytime!;))

parv said...

Tom, how did the colours turn up (in a "regular" image) when underexposed (wrt the left one) by 0.5 to 1 stop?

In the HDR image, green blur is distracting as it steals attention away from the blossoms. (At least you are fiddling with HDR unlike me, who has taken images for the purpose only to be deleted|ignored.:)

mirmilant said...


Let me just say first of all that this is a really nice image of the flower (and curly is cool!). Now let me say that I don't think that this really counts as HDR as there isn't much of a contrast range in the original image. But the colours are a lot better. So what I think is happening is that when you do the HDR processing, the more saturated colours come through from your underexposed images (and did you tweak that saturation slider?!).

So I'm thinking that you could probably have obtained that look to your image with just a single image with a slightly lower exposure value, and you must have that image already (as I think Parv is intimating in his comment above).

To get "real HDR" try something with a broader range of contrast in the field. Take a test shot at what the camera thinks is a normal exposure - are there regions which are significantly clipped either in the highlights or darks? If so, then you can do something with that. But most importantly, keep doing what you're doing - taking pictures!!

Glad to see that you are taking more than just 3 shots! ;-)

Lou Minatti said...

Pete comments:

Your blog is infinitely more interesting than mine.

- Lou

Tom said...

Guys, I'm just practicing for god's sake! (That reminds me I need to correct the spelling in the header).

Seriously, one thing I noticed about using the camera on my tripod is that it vibrates for quite a few seconds after hitting the shutter and manually changing the expoure time really adds to this vibration. I was trying to work out a technique that lessened the problem!

I know it wasn't the best example I could pick but it was the best thing I could pick out at the time.

Lou - don't agree, I love reading your stuff. Not being a financial wizard and definitely not growing up as a true American I find your posts fascinating. I might not always agree with your politics but you write stuff about things I have no experience of but am really interested in. Please keep it up!

PS. Is Pete still with us?

Tom said...

PS. I take that back - I think "practising" is the British spelling, so I'll live with it!

Tom said...

PPS. Parv - will get back to you on your question about exposure.

Keera Ann Fox said...

Funny how different our tastes are. I don't care for the HDR version because the sharpness in it reminds me of water color paintings where you can see the pencil outlines underneath. :-)

But I love that you experiment (it is teaching me something, too) and the silly string flower is delightfully silly string-looking. :-)

Maren aka hilobeads aka Palms, Etc. said...

FYI: the curly wurly flower is a monkeypod tree (samanea saman, if I remember correctly).