Category Archives: Photo Techniques

Moving water

Long exposure is a good way to reveal water movement.

2 to 6 seconds depending on water flow speed is a good average and, of course, you will need a tripod !

If you want to make sure you have all key success elements on your side, then think about using a remote shutter release system. This will prevent any camera movement during your shots…

This is only for the technical piece of course, the creative one is still on your side !

Flowing

Photo Stitching – Quick tutorial

Previous article was introducing this technique and main benefits coming out of it. The main one is the capability to produce very high resolution images.

You want to check by yourself ? Click on this image. It is the result of 81 stitched pictures. There is a full resolution preview functionality allowing you to zoom within this image.

Horseshoe Bend

Now, let’s see the main parameters you need to consider when shooting.

Tripod or not tripod ? That is the question…
The good news is… that you don’t always need a tripod. So you can start testing this technique with your DSLR camera only… It also works with compact cameras ! Of course there are (a lot) of scenarios for which having a tripod and a specific pano head will be mandatory !

Horizontal or vertical shooting ?
When shooting one raw, I would recommend shooting in vertical mode. Using horizontal mode, the result can quickly generate outstanding ratio images, 4:1 or 5:1 (or more) which is not really… my cup of tea ! However, if you plan to go for a vertical pano, then, you can think about horizontal shooting ! As I’m very kind, I leave this choice to you ! (it may be the only one !)

Overlapping :
If you want to facilitate stitching process done by the software, you will have to think about 20-30% overlap between each picture. The smaller your focal length is, the higher the overlap ratio should be… and the easier it will be for stitching software avoiding/reducing deformation issues.

Focal length… which one ?
It’s up to you ! The higher focal length is, the higher number of shots you’ll need in order to capture the scene… and the higher the result image resolution will be ! 80% of my panos are done between 35 and 70mm focal length (using a 24-70mm f/2.8 ). If you’re new with this technique, you can start shooting 3 to 5 images in order to get the favour of it.

Nodal Point… what’s that ?
This is also called NPP (no-point parallax) or entrance pupil.
To keep it simple, let’s see that as the ideal point around which the camera shoot rotate in order to avoid parallax issue between pictures. This parallax may quickly become a big issue if you have a very close foreground. This is the kind of situation where you will need a tripod and a pano head… If you don’t have a close foreground, then you may skip the tripod as parallax issue will become less important. I won’t go more in details here but this NPP has nothing to do with the tripod mount located under your camera…

Having said that, I think I gave you good chance to get a pretty good results… Let’s go deeper…

Ideally speaking, here are additional recommendations you should follow :

– Do the focus once. Don’t change focus between each shot
– Don’t change focal length. Keep the same for all shots
– Automatic white balance is fine. This could be changed and fixed only for very complex scenes
– Shoot in RAW mode when possible

Top of the top… shoot in manual mode !
That’s probably the most difficult piece as you may capture a very large scene having large dynamic constraints from dark to bright areas… You need to determine the best exposure for the entire scene, then manually fix aperture and speed values.
You’ll understand pretty quickly why I’m also combining photo stitching technique with HDR one !

Back to your computer…
There are a lot of stitching software, I let you Google search. One of the well-known one is Kolor Autopano Giga that I’ve being using for couple of years now.

 

Photo stitching – Introduction

Photo stitching

Just to get started… what is photo stitching technique about ?

This technique consists of taking several pictures which are overlapping each over in order to capture a scene.  This can be 2 or 3 pictures… but it can be thousands ! It can be one row… or dozens of rows, each of them containing dozens of images… it’s up to you !
Stitching software will then build a single and large image based on those shots.

I know you may have some questions :
– Why wasting time taking 20 or 30 pictures of a scene I can capture in only one shot ?
– What’s the real benefit ?
– Is it still photographic art or just photographic technique ?

Let me try to answer :

Yes… in some cases, we can capture a scene in one shot instead of 20… even 5 pics. But in some cases you won’t have enough space to step back and capture the entire scene, even with very wide lenses. This is the case in this image built from 74 stitched pictures. It could have been done from probably 4 or 6 images but impossible with only one.

Canyon de la Faucille

This technique will allow you to :
– capture very wide landscapes you cannot capture in one shot
– avoid/reduce deformation coming from very wide lenses,
– build a final image with a very high resolution. Think about the image resolution coming from 10 stitched pictures. Even if you take in consideration 20% overlap between each view, you can easily and quickly get a 80-100 megapixel image. And now you can think about a very nice… and very big print !

Last year, I organized one of my biggest exhibition in a French old fortress : 30 images located in 3 very large rooms. Each image was 1.5 meters long and the biggest one was a 5 meters long canvas print ! This one was the result of more than 100 stitched pictures (more than 1 gigapixel image…).
The nice thing with very high resolution and very large prints is that you don’t need to step back in order to enjoy a 2 meters long print. You can stand up pretty close to the prints and feel the immersion coming from all the details you can see thanks to the resolution. Honestly, that’s a real cool feeling !
OK, you probably don’t need or want so large prints but I’m sure you have couple new ideas coming…

Is it still Art ? I hope so ! Mastering the technique is just one piece of the game, finding the right spot, revealing a special atmosphere is still on the artist side, right !

The image associated to that post is the result of 74 stitched pictures. Because of the very large range between very dark and very bright areas, I also combined photo stitching technique with another special technique… HDR one (High Dynamic Range). So in reality, I shouldn’t speak about 74 pictures but 74*3=222 because of the bracketing being used for each single view !
In that case, post-processing consists (most of the time) of building HDR shots first and then stitching HDR views. I’m using photomatix pro for HDR as it can run HDR tasks in batch mode… Autopano giga is then taking care of stitching step and PS6 for final adjustments.

Let’s take a break !

In the next article, we’ll see the main parameters you need to consider when shooting.