3 for C&C

GeorgieGirl · Nov 22, 2011

markv20 said:
bazooka said:

Im not to familar with either of the following:

-chromatic abberation, What causes that and how is it fixed in the raw editing?
-perspective distortion, What causes that and how is it fixed in the raw editing?

Click to expand...

Its your lens, what are you using? Also in LR you can get some lens issues resoved quickly on the right panel in the Develop mode toward the bottom with the feature to correct Lens Distortions....your lens should pop up in the dialog box when you check the feature and you can see the differnce when you check the box.

Nice job with the sunset in the windows!

markv20 · Nov 22, 2011

GeorgieGirl said:
markv20 said:

bazooka said:

Im not to familar with either of the following:

-chromatic abberation, What causes that and how is it fixed in the raw editing?
-perspective distortion, What causes that and how is it fixed in the raw editing?

Click to expand...

Its your lens, what are you using? Also in LR you can get some lens issues resoved quickly on the right panel in the Develop mode toward the bottom with the feature to correct Lens Distortions....your lens should pop up in the dialog box when you check the feature and you can see the differnce when you check the box.

Nice job with the sunset in the windows!

Click to expand...

Im using the 18-55mm f/3.5-5.6G VR Lens that came with my d5000. Ahh, ok Ill have to check that out. Thank you!

bazooka · Nov 22, 2011

I'm no optical guru or anything, but I think chromatic abberation occurs because different wavelengths travel through some parts of the lenses at different speeds, much like when white light is separated in a prizm. Someone please correct me if I'm wrong. Anyway, that part doesn't really matter.

What matters is taking steps to avoid it, and correcting it when you see it.

Zoom in on the lighthouse in your #3 (not my edit, but the original). You can see that the left side has a fringe color to it, and the right side has the *opposite* fringe color. Green/Magenta and Blue/Yellow are the two varieties you will see. I can't remember which you have and can't see the image at the moment, but I'm sure you'll see it quite easily. It usually is only noticeable in areas of high brightness contrast.

To avoid it, avoid shooting your lenses wide open. However, CA is so easily fixed in RAW that it's not something you should be too concerned with when shooting unless you just want to cut down on a step in post.

I'm not familiar with LR, but it will be under lens corrections.

Perspective distortion on vertical structures occurs when the camera is not level with the horizon. The most obvious example is imagine shooting a wide angle pointed up at sky scrapers. The edges would appear to meet in the middle at some imaginary point. Edges that we know are parallel, appear to converge, like train tracks.

There are 3 ways to avoid this (if you want to, sometimes it's desireable, but generally I would say it's not).

#1 Use a perspective control lens, also known as tilt-shift, at least the Canon versions are. I do not know what Nikon offers for PC lenses. However, it's basically a specialist lens and quite expensive.

#2 Shoot wider than normal so you can get the desired angle of view while still keeping the camera parallel to the horizon, and then crop in post. If the vertical structure is quite tall or you want to get a lot of sky, this may require you to crop out most of the image! Not ideal.

#3 LR probably has a perspective distortion adjustment tool. Using it will also cause you to lose pixels, and moreover, the quality of the image will be higher at the top or bottom because it's effectively stretching either the bottom or the top of the image while shrinking the other half. However, you will lose fewer pixels with this method than #2, and it's much much cheaper than #1. This is how I fixed the perspective in the edit that I posted.

markv20 · Nov 23, 2011

bazooka said:
I'm no optical guru or anything, but I think chromatic abberation occurs because different wavelengths travel through some parts of the lenses at different speeds, much like when white light is separated in a prizm. Someone please correct me if I'm wrong. Anyway, that part doesn't really matter.

What matters is taking steps to avoid it, and correcting it when you see it.

Zoom in on the lighthouse in your #3 (not my edit, but the original). You can see that the left side has a fringe color to it, and the right side has the *opposite* fringe color. Green/Magenta and Blue/Yellow are the two varieties you will see. I can't remember which you have and can't see the image at the moment, but I'm sure you'll see it quite easily. It usually is only noticeable in areas of high brightness contrast.

To avoid it, avoid shooting your lenses wide open. However, CA is so easily fixed in RAW that it's not something you should be too concerned with when shooting unless you just want to cut down on a step in post.

I'm not familiar with LR, but it will be under lens corrections.

Perspective distortion on vertical structures occurs when the camera is not level with the horizon. The most obvious example is imagine shooting a wide angle pointed up at sky scrapers. The edges would appear to meet in the middle at some imaginary point. Edges that we know are parallel, appear to converge, like train tracks.

There are 3 ways to avoid this (if you want to, sometimes it's desireable, but generally I would say it's not).

#1 Use a perspective control lens, also known as tilt-shift, at least the Canon versions are. I do not know what Nikon offers for PC lenses. However, it's basically a specialist lens and quite expensive.

#2 Shoot wider than normal so you can get the desired angle of view while still keeping the camera parallel to the horizon, and then crop in post. If the vertical structure is quite tall or you want to get a lot of sky, this may require you to crop out most of the image! Not ideal.

#3 LR probably has a perspective distortion adjustment tool. Using it will also cause you to lose pixels, and moreover, the quality of the image will be higher at the top or bottom because it's effectively stretching either the bottom or the top of the image while shrinking the other half. However, you will lose fewer pixels with this method than #2, and it's much much cheaper than #1. This is how I fixed the perspective in the edit that I posted.