Review of HDRapp for the Nokia 898 PureView
Real in-phone HDR merging
Real in-phone HDR merging
As written earlier (http://pureviewclub.com/2012/5623) one of the great features of the Nokia 808 PureView is bracketing. In bracketing mode the camera automatically takes 3 or 5 shots with different exposures. With these 3 or 5 consecutive shots you make your HDR picture by merging them. Up till now this merging had to be done with a dedicated HDR program on a computer. Or you had to use older apps that do not use all the features of the PureView camera. But now Jeff Shaw developed an app to do the merging internally in the Nokia 808 PureView itself. And that’s great, now you can shoot your bracket, make a real HDR picture “in the field” and share it immediately with the world; “Connected HDR”! It’s less than 6 weeks ago that Jeff (Forum name: vader) launched the idea of such an app on the PureViewClub Forum.
Already one week after Jeff posted this idea he shared on the forum his first beta widget which he himself described as “a very basic demo of HDR algorithm”. Indeed the interface was horrible and so was the workflow but it worked very well and you got beautiful HDR pictures when you had used a tripod for your shots. After 2 weeks Alexandro Lacadena (Forum name: petaqui) offered to help with the GUI and soon the appearance of the app improved. As an HDR photographer I had the pleasure to test the various versions and share ideas and opinions .
Now about 6 weeks later Jeff released Beta version 0.94 and this version is already so mature that a full review is appropriate.
The app opens like follows:
As written earlier (http://pureviewclub.com/2012/5623), usually 3 different exposed shots are enough for a good HDR result. Bracketing set in the Nokia 808 to zero -2.0 and + 2.0 will do the job in 80% of the situations. That’s why Jeff wrote his HDRapp for a 3 shots bracket. After opening the HDRapp you have to choose the first shot of your 3 shots bracket. Then the HDRapp automatically looks for the second end the third shot. Here a screenshot of the app with the first shot choosen.
The app fills in the other 2 shots within about 5 to 10 seconds (depending on file size 8, 5 or 3 MP).
When you then click “Preview” it again depends a little bit on the size of the shots; 8 MP, 5 MP or 3 MP but the HDRapp normally does not taken more than 10 to 20 seconds to merge to an HDR picture.
The image quality of the HDR picture showed next is very good. We have here a “classic” HDR picture; view from the inside out. Dynamic range, colors and sharpness of this 1551×956 picture are outstanding. This picture is deliberately tonemapped in PS to examine the image quality which shows to be very good.
The big point with all HDR software is to align the 3 shots. As we all know 3 shots taken with the phone on a tripod is the ideal situation. But we don’t live in an ideal world and in practice of daily photography less than 5 % of the pictures are taken with the camera on a tripod. In case of a smartphone like the Nokia 808 PureView this number will even be smaller. So Jeff had to build in an algorithm to align the 3 shots and he introduced that in Beta version 0.94 . He combined it with an option for the user to define where in the picture the start of the alignment should be. This is important because in practice the type of images differ very much.
I tested the HDRapp v Beta 0.94 with an held held bracket of 3 shots (zero, -+ 2 Stop) 400 ISO, PureView 5 MP, and after selecting the first shot the app shows up with the next screenshot.
After touching on “Preview” the app gives you the HDR picture very quickly, 5 to 10 seconds, and you see:
Now you have the choice to let the app automatically align the 3 images by pushing on the preview image. You choose a spot where you think it is most important to start the alignment. Normally you will select a central point in the image. But it can occur that you have to choose an off centre point.
As Jeff Shaw writes: “Just make sure the area you select has enough information to align (eg. horizontal and vertical differences). You can long press to zoom in/out and drag around in zoom.
I still haven’t added rotation, but this algorithm will enable it to be added later.”
In this situation I simply touch the centre and auto alignment started and already after 6 seconds the result was there.
First a screenshot of the the centre of the picture without alignment. Obviously this hand held bracket needs alignment because the 3 shots differ too much as can be seen.
And now the result in the centre of the picture after “asking” to align by touching.
The final aligned image can be saved and shared to the world immediately. Next image shows the result. It is really balanced in tonalities and on inspection in PhotoShop the image quality turns out to be very good.
I have not jet spoken about the 2 sliders “Dark” and “Light”. With these sliders you can edit the resulting HDR picture. This editing needs some training; you have to try and get a feeling for the results you want to achieve. It seems that the app weights in more or less of the lightest and the darkest shots of your bracket. So it is a sort of mixer. It works but personally I would favour an approach which edits the resulted HDR picture itself. But as you can see also the non-edited HDR is of good tonal value.
Many HDR pictures will be taken outside, in nature and of course I also tested the app there. Without many words I show you the consecutive screenshots and the end result. It was a smooth process to get a good result.
Saving is straight forward; you can navigate to any map on your phone. I advice you to save with the number of the first shot (of your 3 shots bracket) followed by hdr. So in this case it will be saved as: 4178hdr.jpg
You can see your saved HDR picture in your Gallery and get all the normal options build into your Nokia 808 PureView to share (I am on Flickr as you see) and edit.
I did some final editing to give my HDR picture a little more “punch”.
To end this review I show one HDR of a pillow on my couch. Hand held 3 shots bracket; zero -+2 stop.
Detail shots show the need for alignment and the HDRapp did that very well.
Hand held or tripod.
HDR software has to combine 3 (or even more) shots to get the result you want. Therefore all HDR software so also this HDRapp has to align those shots and that’s only possible if they don’t differ too much. You have to keep your smartphone steady while you shoot your bracket. Fortunately the Nokia 808 in the PureView 8 MP, 5 MP or 3 MP mode writes pictures to the phone’s mass memory rather fast. That speed enables you to keep your device steady. It helps to lean with your body against a wall, a tree or something. Or you can perhaps sit down which often also gives an interesting view for your pictures. Working this way normally the HDRapp will be able to correct the differences of the shots. And it does it remarkable fast. As with all new software you have to try it out. The speed of the HDRapp permits you to see the results within 1minute. When you are not satisfied you can take another bracket and try to keep your phone more steady. It is wise that Jeff has not tried to build in a so called deghosting feature (for moving objects in the scene like walking people, cars etc). That would cost too much processor power and even desktop dedicated HDR apps has big trouble to give good results in many situations.
The final word
It was a real pleasure to test the HDRapp of Jeff Shaw and Alexandro Lacadena.
It’s amazing that Jeff was able to write the code in such a short time while doing his normal work and things. And Alexandro made a nice looking interface.
It was a pleasure to test because the app is working so smoothly and the workflow is very straight forward. It’s really an app for in the field.
– The HDR app for the Nokia 808 PureView is a serious high quality piece of software
– The app is fast, straight forward and reliable
– Options to align or not and where to align are build into the app
– It can be used in the field to share your beautiful HDR pictures with the world
– The HDR pictures this app makes are of high image quality. But keep in mind “garbage in, garbage out”; the quality of your bracket shots determines the quality of the HDR you get
– Editing your HDR in the app is limited but that’s no problem. Most of the time the resulting HDR is already of good tonality and has dynamics in lights and shadows. And if the sliders of the app don’t give what you want, you can use the editing possibilities that are standard build into your Nokia 808 PureView
To see bigger sizes the HDR pictures that were made for this review go to: FLICKR
To read my earlier article for the PureViewClub about HDR with the Nokia 808 PureView go to: CLUB
This review was written December 2 2012 by Peter Meijs and published on December 6 2012 on the Blog of the PureViewClub. If you want to see this article in the context of the PureViewClub you can click: ClubBlog