Ok, after the recent announcement from apple on HDR photography, alien subspecies in small planets near Betelgeuse have an awareness of HDR and are probably shooting exclusively in HDR. Probably there is a revolt somewhere that the professional camera makers are not including it along with the kitchen sink in their cameras.

Well, I am pretty excited to be able to expand the Dynamic range of the iPhone by cool software tricks and to me HDR it is a welcome feature. It is really impressive that the iphone is able to capture multiple frames in a really short burst and process them in mere seconds. This is really mind boggling. But the trick with photography has always been the ability to understand and use the camera as a tool and HDR is not an exclusion. One needs to understand there is a time and place for using it and it should be used with care (and understanding). Here is a sample image I shot, hoping HDR will help me get some details in the shadows, Here are the results.

You can click through to see reasonable sized images in  new window.

First off, the HDR version (full image) has indeed ‘brightened’ the shadow areas. Look particularly at the front wall of the church and the flowers in the foreground. But I do not particularly like the ‘processing’ the camera has captured very little details to begin with and the HDR algorithm seems to have eaten a lot more of the details. It should be noted that the processing of HDR is kind of arty-farty right now and it requires a quite a bit of judgement to merge the images to make them look natural. It is no wonder that decent HDR packages cost upwards of 100$. I am sure there will be a lot of research on improving the standard algo and in time the merging will get a lot better, but I do not like what I see now

In the second row, I picked a crop of the clouds along with a church steeple. You can see there is a little more discernable details in the clouds in the HDR. That is nice and the blues in the sky were a bit darker too. but it seems that there is  a bit of visible noise introduced in the image. You might also notice a bit of ghosting in the steeple in the HDR. This is because to capture HDR, they shoot 3 images in sequence with different exposures and merge them. Now the 3 images are shot sequentially and quickly but they are different exposures. This means that a bit of hand shake, moving objects etc will confuse the algorithm and the merging will have to guess what to keep or to average (or dodge or multiply or whatever else) the local perturbation. The result is ghosting. I found this pretty bad with people moving around. Now it is not a deficiency of the algo, I am just saying that one has to take care of this issue.

You will notice the issue pretty pronounced in the clock crop. The strong contrast seems to have messed up the internals of the HDR algo. *Geek* I am guessing there is a global translation / rotation transform that is applied at the point of merging. I can think of a slightly more process intensive solution, by applying a sequence of local corrections.. But it would take more processing time and one has to balance time with quality *Geek*. As you can see the Standard version actually preserved a lot more of the details. I am also guessing that the lens is of a standard aperture and the camera captures 3 images at the same shutter speed but different ISO which might explain the pronounced noise in the HDR image…

Lastly, the centre crop is what I shot the HDR for: A bit more details of the inside of the church. As you can see the exposure adjustment is probably not very pronounced, there is very little details brought out in the shadow. The Mid-tones have been pretty strongly influenced but the shadows are not touched at all. It is a bummer, but an understandable tradeoff, pulling a lot out of the shadows will make things more difficult for the algo to work with and the results will be very unnatural too. But when I look at the loss of details in the flowers, I regret shooting this in HDR. ugh…

I guess my point is this. HDR is a cool idea but it is not a cure all for thinking about the scene before shooting. I will use the feature but am going to switch on the ‘settings’ for keeping the standard image. Now that iPhone has implemented this, I expect every phone camera to update their software and some geeky app will allow you to tweak a lot of parameters too. The algorithm will improve a lot over time, thats for sure. But it is going to be just another tool in a decent photographers kit.

This made me smile.

Now, I wonder what my stable of bikes are up to when I am at work… I am fine as long as they are back before dark

via copenhagenize

I like being alone. But that does not mean that everyone else does too. The social interaction scene is pretty bustling right now (actually has been for a few years now) and I figured at the least, I can be civil. Thence, I decided to make it easy for everyone to share articles from here to wherever they want to share to.

It is probably easy for one to just copy the URL from top and paste it to where they want, but making the process a single button click is just good karma.

So if you find the need to quickly share articles from here, click away at the buttons.

Note: It seems like a clever marketing ploy to alleviate my Analytic Depression. But the truth is that my brother has been pounding my head with his experiments in social networking and I finally found a nice plugin to add these buttons painlessly.