Out of season

First for April

Out of Season

HDRi comparison…Photomatix Pro vs Picturenaut…a first look

HDRi software has been getting a bad press recently, perhaps due to some of the very extreme “surrealistic” images that are readily found on the web and in particular on Flickr. But it doesn’t have to be that way. The more subtle combinations of multiple exposures of a scene can produce a beautiful and more realistic result. In my quest for the best in HDRi software, I’ve been taking a look at Picturenaut.

Picturenaut is open source software being developed by HDRlabs. See their latest news. When you download the software, which is completely free (though a donation is welcome), there is a pdf file that you can download to show how to install it and basics of use. This proved to be very well written and easy to follow.

Using the same tree, photographed in 5 shots with 1 exposure between each, I made a comparison between PhotomatixPro and Picturenaut conversions. Picturenaut aligned and combined the images a little faster than Photomatix, though on just one testing I think it would be unfair to say that this would always be the case. The Picturenaut controls were easy to use and the large preview enabled accurate control of the tone mapping. There are two global tone mapping interfaces, Photoreceptor Physiology, which is said to protect underlying colours beneath highlights, and Adaptive Logarithmic, which creates a smooth logathithmic compression. These are to be combined in a future version, but at the moment you have to choose one or the other. I used Photoreceptor Physiology. Once you have adjusted any of the sliders, the main image is quickly updated with the changes and I found it (on this image) much easier to achieve the result I was looking for than with Photomatix.

Reading around the subject tells me that the global tone mapping in Picturenaut does not carry with it the risk of severe haloes and surrealistic blends, which you can get with local tone mappers like Photomatix. So, the resulting blended image is more realistic. For those people who like the surrealistic blends of Photomatix, I would suggest that you won’t find those in Picturenaut. However, it is rumoured that, for those individuals wanting a more extreme blend of images, Picturenaut will, in fact be introducing a local tone mapping feature in a forthcoming version.

I imported the resulting tiff file into PhotoShop, where I carried out the same “finishing” to the image as I had with the Photomatix image, except for the sheep on the horizon, which I left in the Picturenaut version. The results are very close, see below.

Tree with PhotomatixPro

Tree with Picturenaut

The Photomatix sky is very slightly darker and more saturated. Cloud detail and contrast is also very slightly better in the Photomatix version. Fine detail of the branches and tree trunk is very slightly better in the Picturenaut image. Both exhibit a good crisp blend of the images (which were taken on a tripod but in strong wind).

In addition to HDRi production, Picturenaut also features “automatic image alignment, exposure correction, colour balancing, noise level compensation, automatic computation of the camera curve from the source images.” Additionally it offers 7 different interpolation options for resizing HDRs. There are a number of plugins available for Picturenaut, which I have not yet tried, including HDRShop plugins and a collection by Francesco Banterle.

This is a very first impression and I cannot say, with fairness, which software is better. I need to make some comparisons with more extreme variation of lighting.

However, I did find the Picturenaut experience more enjoyable – there is a real feel to what you are doing with the sliders and the preview gives a realistic view of the final image. I will certainly be looking more at Picturenaut and for those not wanting to buy Photomatix Pro, Picturenaut is a very real and very free alternative.

Dovestone Mist

Taken from the Holmfirth road above the Dovestones Valley.

HDR Panorama

Each of my HDR panos is 5 images deep, that is, 5 bracketed shots -2, -1, 0, +1, +2 stops each and usually 3-5 frames across.

I merge each 5 exposure frame into a single HDR image in Photomatics. I tone map that frame and leave it on screen whilst I prepare the next 5 exposure frame, which I then tone map alongside the first, so that I can balance the two frames together. I continue like this until all the frames of my panorama are now merged into single tone-mapped files which match as closely as possible in colour and tone. Once I am satisfied with the resulting tone-mapping, I then export the files as 32 bit tiffs and merge them to a single panorama. I will then tweak the panorama in PhotoShop until I am happy with the result.

Dovestones and Ashway Gap from Alderman

Knowle Top Farm, Greenfield

What can I say? It works for me.

Google Earth and HDRi

The tree was found by looking in fields on Google Earth (saves a lot of fuel driving round!). The mist was a gift on the way back home!

HDRi

Here’s a few more examples of HDRi – which I am really starting to enjoy. Having been put off by seeing a lot of very flat looking HDR photos elsewhere, I am finding that HDR doesn’t have to be like that…with only a little practice, it’s possible to process images to have good colour and contrast whilst retaining the benefits of HDR merging and tone-mapping.

For the benefit of those new to digital photography, HDRi stands for “High Dynamic Range image”. High Dynamic Range Imaging is a method to digitally capture and edit all light in a scene, from the brightest highlights to the deepest shadows and comes into its own when the contrast range in a scene is too high to capture in a single exposure without burning highlights or blocking up shadows. It represents a major leap in digital imaging technology. The good thing is you can do it with any camera that allows you to bracket or exercise manual control or compensation of exposure. That means yours!

If you are serious about photography, particularly landscape and low light photography, you will find that HDRi is the final step that places digital way ahead of analogue. You’ll never want to go back to film and wet processing again. The old problem of over/underexposure in analogue photography is a now thing of the past. A huge variety of subjects can now be photographed for the first time ever in fantastic detail, from high contrast stitched panoramas to church interiors…just think, you can now capture all the detail in the stained glass windows as well as the dimly lit interior. Wow!

How does it work?

Several bracketed shots are taken of the scene (preferably on a tripod, though I didn’t!!!). The underexposed shots will give full detail in the highlights and the overexposed shots full detail in the shadows. The middle exposure will be “average metering”.  Using the special “merge to HDR” feature in PhotoShop or other HDR software, a 32 bit image is created, containing the full range of tones, maybe up to 10 stops of information. Then comes the tricky bit….the 10 stops of information have to be constricted back down to about 5 stops, whilst retaining all that lovely highlight and shadow detail. An added spin-off is that noise in shadows becomes much less obvious and skies are shown in their fullest splendour.

A fairly simple explanation is given at http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm – that saves me going into fine detail here.

A New Year

New year thoughts “Judge your success by what you had to give up in order to get it and remember that not getting what you want is sometimes the blessing.”

New year images…we were blessed with snow again this week…and I’ve been playing with HDR….some results below.

Variations….

Click image to enlarge.

A little about the HDR shots. Three photographs bracketed by 1 stop were blended as a high dynamic range file in Photoshop or Photomatix. Since I didn’t use a tripod to take the shots and the alignment in PhotoShop is better than the alignment done in Photomatix, it produced a higher quality result in PhotoShop, with no indication of ghosting resulting from the blend of three not quite lined up images. The resulting tone mapping in PhotoShop was very disappointing and Photomatix does a much better job of that, so that was used for the tone mapping. When the images line up perfectly, I think that Photomatixs also does a better job of the HDR file too, but it’s early days yet and I am certainly no expert in this technique!

Venice

A little shot from Venice, with just a touch of softness and texture added.

Sea pictures

From Dorset…

Weathered

Threatening weather – Holy Island

Isle St Louis

More Paris…Isle St Louis, where many wealthy Parisians have their home. We had arrived in Paris on a rather dull and overcast afternoon. By the time we checked into our hotel, though, the clouds were starting to clear, so we dashed down to the River Seine to catch the last light of the day.

This image is a panoramic stitch of three separate exposures.

Tunnel

One of my favourite places for urban photography – La Defense in Paris. This is actually a bridge over the main road, linking buildings on either side, but it gives a tunel effect to me. It can look a bit shabby and drab until the sunlight catches it in the right place. I tried it in both colour and mono.

I find the colours very attractive, but there’s more of a feeling of being taken into the picture in the mono version.