Image merging

[Alison]

Does anyone know how this really works?
I have heard that you can merge images together to create better quality pictures.
Do you need a special programme for photo merging?

[mjs1973]

How are you merging them? I have merged separate photos to make a panorama image, as well as to combine photos to increase the dynamic range of the scene. Say one photo for the FG and one for the BG.

To merge them for a Pano, I use the Photo Merge function of Photoshop. File > Automate >Photo Merge.

To increase they dynamic range, I just use layers in PS. Take one image, and paste it over the other. Then use a layer mask to paint in what I want, and to hide what I don't want.

[readingr]

Alison,

There are many ways of doing this and depends what you are wotking with.

You can create three images from a RAW file, highlights, midtones, shadows and then merge the appropriate using layers and the eraser or as I prefer the black and whitre paint brush to create masks.

You can use the same principle and use layer properties to multiply, screen, etc. to get a similar effect, and combined with masks it makes it a powerful tool.

You can also use the PS HDR facility in CS2/CS3 to create a similar effect.

It really depends on what you want to do,

I sometimes bracket photos on a tripod and then merge them to get the effect I want from pics which need a large dynamic range, e.g. bright skies and deep shadows to cope with.

You can also use the same techniques to swap skies for instance. If you lived closer I could give you a demo.

Roger

[Alison]

Ahh yes I understand all of that and do it all the time. What I am after is more megapixels.
Something like this
http://itnews.com.au/News/76243,boff...ry-camera.aspx
I swear someone posted on the forums here once, that they could merge photo's, to create a higher resolution photograph.
Is this the same kind of thing as I have been doing all along?

[AgingEyes]

Ahh yes I understand all of that and do it all the time. What I am after is more megapixels.
Something like this
http://itnews.com.au/News/76243,boff...ry-camera.aspx
I swear someone posted on the forums here once, that they could merge photo's, to create a higher resolution photograph.
Is this the same kind of thing as I have been doing all along?

I believe what they did essentially is what many do to create a pano. It's been done by many already to make photos of different kinds, pano or not.

[Medley]

Ah, you're talking about photo-stitching. Yes, there is software out there that can do this, but the ones I've seen have been tailored to panorama shots. That is, they're very good at stitching the photos horizontally, but not vertically.

I've attempted this manually, and found it to be a frustrating and time-consuming process. One of the best pieces of advice I can give is that if you try this, use your 50mm lens to minimize lens distortion. It'll make the stitching process MUCH easier. Also, use a manual setting, and keep the setting consistent throughout all the shots. This provides consistent lighting throughout the stitched image. Meter for what will be the brightest area of the stitched image to best determine the setting to use.

It almost goes without saying that this kind of work is best accomplished with a tripod. I use Photoshop to stitch the images. Overlap them, and set the blend mode of the top layer to Difference. Look at the overlapped area. Black indicates where the two layers are identical, white indicating where the edges don't line up. Transform the layers as necessary to make them match (such a simple statement, but that's where the frustration begins...). Start by using 4 photos (2x2) then proceed from there.

One last piece of advice- use a computer with LOTS of RAM. These images are memory hogs, and you can run out of RAM fairly quickly.

- Joe U.

[freygr]

Ahh yes I understand all of that and do it all the time. What I am after is more megapixels.
Something like this
http://itnews.com.au/News/76243,boff...ry-camera.aspx
I swear someone posted on the forums here once, that they could merge photo's, to create a higher resolution photograph.
Is this the same kind of thing as I have been doing all along?

This is done with a standard camera with a long lens. Take a butch of photos in a grid pattern and then use a stitching program to merger it all together.

I've done it using Panorama Factory, link: http://www.panoramafactory.com/ and it you go to: http://www.panoguide.com/products/ there are reviews of most current available programs.

[fx101]

Oh wow people are making this so much harder than it actually is! It's actually quite simple provided you have the software and the equipment:

Equipment:
--DSLR of some sort
--Good Tripod (preferrably that lets you switch the head) absolutely nescessary for good panoramas
--Panoramic Head (not nescessary but it will remove weird parallax distortions and give you stitched panoramas suitable enough for exhibition quality large printing).

--Lens: Something that zooms to around 50mm or more with the crop factor.

Software:
--Distortion correction software (you don't need DXO...ptlens is really cheap and is incredibly effective).
--Ptgui (it's a graphic version of panorama tools...but you really don't want to bother with the text version). It lets you stitch multi-row panoramas very effectively.

Method:
I think you're using a Canon right? A good lens for panoramas is the 50mm (f/1. whatever). Mount your camera on your tripod. If you are using a panoramic head (which almost guarantees a good panorama without weird perspective errors) then mount your camera on that and use its instructions for finding the nodal point. A good (and cheap) panoramic head is called "Nodal Ninja" and lets you make these multi-row panoramas you are talking about. Basically, go to the site you want to take the picture of. It needs to be pretty still because things moving in different parts of the image will give you a messed up final image. Buildings and/or stationary objects/landscapes are preferred. Find the lowest left part of the image you want to shoot and frame it. Set your camera to MANUAL exposure, set it to f/8 and meter for your exposure, put it in manual focus (focus and then leave it for the entire duration of the shoot) and DO NOT change the exposure in between shots. Then take images and keep panning (perfectly horizontally) in between shots until you reach the lower right part of the image. MAKE SURE TO OVERLAP!!! Also make sure to leave a good deal of extra room on each side because the image mapping will require a slight crop. When you reach the lower right corner, pan vertically until you leave a slight overlap with the previous image and then pan horizontally to form a total of two rows of overlapping images. Keep on doing this until you capture the complete scene.

The preparation:
You will have to import all your images into your computer. Then use ptlens (or DXO if you have it) to perform distortion correction on every image you took. This is important if you want a perfect stitch. Then, import your images into ptgui and have the software mess with them. You will then have to select control points, it's self explanatory, read the manual. The software automatically organizes the images, so once you pick control points click "optimize" and it will roughly generate your panorama. To finalize it, make sure you select "max image size" in the export/render menu. The final image will take about an hour to render (a 120 megapixel landscape took that long on my computer) and then save it and you're done! Then import that into photoshop using large file processing and edit away!

Hope this helps!

[readingr]

Alison,

You have PhotoStitch which came with your Canon Camera. I use this to create panorama's both vertical and horizontal stitching. easy to use

Roger