tyrophagus
Member
I thought I'd share a few screen grabs of a program I use for post processing. These were test shots taken to try find the best position for my camera - there are horrible reflections so please ignore them. This is not about the photos but about the techniques available to correct distortion.
I have never had a needed to correct geometric distortions until I started taking photos of my tank. I'm still trying to decide what works best. I use Adobe Lightroom, Adobe Photoshop CS5 and DXO Optics 5.
Photoshop can be used to correct distortion but you need a degree in graphic design....
I recommend DXO Optics, a stand alone piece of software that can be very useful in correcting both lens and geometric distortion in images. It takes a few minutes to develop an image.
I always take photographs in raw format so that I'm working with a digital negative rather than trusting the camera's computer to adjust the raw data and produce a jpeg. The camera applies all sorts of corrections like contrast, saturation, sharpening and brightness to the raw data and then produces a jpeg which is a compressed image format. This means that the jpeg file is very limited in its ability to survive any form of post processing. You end up trying to adjust a fraction of the original data the camera recorded. Why save a jpeg image if you can save the original raw format with all its information intact?
All the above programs adjust raw images but will adjust (to a lesser extent) tiffs and jpegs. DXO will adjust jpegs if you have no choice but to use them and correct distortion and geometric distortion.
The above screen grab is DXO working as a plugin to lightroom (it works on its own as well). The image on the left side is the original raw file and the image on the right is the corrected image. The image on the left has some green dots at each corner of the tank which is the tool telling the program where the corners are that need to be arrange in a rectangle.
I think you can see from the original that I even took the photo from off center so the right of the tank is distorted to be higher than the left.
In the screen grab below I adjusted the white balance as the camera did not meter this correctly and the wall behind the tank has a green tinge. I've also applied a crop to the tank which is why the space around the tank is slightly greyed out.
The following image shows what happens when you take a picture from above. Using post processing can introduce artifacts and as you can see it does not quite work in this image as it creates and artificial depth and the back edges of the tank have not been corrected.
So here is a before and after. The first image is a raw file with no adjustments
The 2nd image is with geometric and lens corrections applied as well as white balance correction.
Another before and after shot from above the tank
I've also used a new tool in the PS CS5 to automatically fill the reflection with what the program thinks should be there - pretty amazing as it took no effort, I just drew around the highlight and asked it to replace it.
I have never had a needed to correct geometric distortions until I started taking photos of my tank. I'm still trying to decide what works best. I use Adobe Lightroom, Adobe Photoshop CS5 and DXO Optics 5.
Photoshop can be used to correct distortion but you need a degree in graphic design....
I recommend DXO Optics, a stand alone piece of software that can be very useful in correcting both lens and geometric distortion in images. It takes a few minutes to develop an image.
I always take photographs in raw format so that I'm working with a digital negative rather than trusting the camera's computer to adjust the raw data and produce a jpeg. The camera applies all sorts of corrections like contrast, saturation, sharpening and brightness to the raw data and then produces a jpeg which is a compressed image format. This means that the jpeg file is very limited in its ability to survive any form of post processing. You end up trying to adjust a fraction of the original data the camera recorded. Why save a jpeg image if you can save the original raw format with all its information intact?
All the above programs adjust raw images but will adjust (to a lesser extent) tiffs and jpegs. DXO will adjust jpegs if you have no choice but to use them and correct distortion and geometric distortion.
The above screen grab is DXO working as a plugin to lightroom (it works on its own as well). The image on the left side is the original raw file and the image on the right is the corrected image. The image on the left has some green dots at each corner of the tank which is the tool telling the program where the corners are that need to be arrange in a rectangle.
I think you can see from the original that I even took the photo from off center so the right of the tank is distorted to be higher than the left.
In the screen grab below I adjusted the white balance as the camera did not meter this correctly and the wall behind the tank has a green tinge. I've also applied a crop to the tank which is why the space around the tank is slightly greyed out.
The following image shows what happens when you take a picture from above. Using post processing can introduce artifacts and as you can see it does not quite work in this image as it creates and artificial depth and the back edges of the tank have not been corrected.
So here is a before and after. The first image is a raw file with no adjustments
The 2nd image is with geometric and lens corrections applied as well as white balance correction.
Another before and after shot from above the tank
I've also used a new tool in the PS CS5 to automatically fill the reflection with what the program thinks should be there - pretty amazing as it took no effort, I just drew around the highlight and asked it to replace it.