Author Topic: Correcting for under exposure (Read 4795 times)

rjmiz · « **on:** March 19, 2007, 04:02 »

Recently someone asked be how to prevent blown out highlights. Especially if your shooting INTO Sunlight. I really don't have a right or wrong answer, but I told him what I do: I expose for the Sun.

The reason being I don't want blown highlights. Once the highlights are blown out, all information is lost and CAN NOT be recovered. I can however, recover information in an image that is UNDER EXPOSED.

So here is a RAW image taken with my camera. The image below that is processed in photoshop to recover the underexposed information in the lighthouse. I will not go into details, but my method involves the extensive use of masking, and blending.

Now, I realize that I have just about added an entirely new sky, however I also have a third version with the original sky that is not blown out because I exposed for the sky, rather than the building.

In this age of digital imaging, some of the film techniques for handling this situation, are unnecessary when you use photoshop.

Any questions?

CJPhoto · « **Reply #1 on:** March 19, 2007, 06:18 »

Quote from: rjmiz on March 19, 2007, 04:02

Now, I realize that I have just about added an entirely new sky, however I also have a third version with the original sky that is not blown out because I exposed for the sky, rather than the building.

that third version would be a better one to show. If you are going to replace the sky, their is no point exposing for the sky(sun). Of course you dont always know this at the time (therefore good recover of the building).

Greg Boiarsky · « **Reply #2 on:** March 19, 2007, 08:52 »

How do your handle the increased shadow noise that comes from underexposing the shadows?

rjmiz · « **Reply #3 on:** March 20, 2007, 01:26 »

Although the sky was replaced, the luminance remains the same for the entire picture. Meaning
had I not exposed for the Sun, the building would had been so over exposed, that the entire
shot would have had to have been trashed.

Here is another example where the sky was NOT modified
Notice there is not one blown highlight in the entire image?

leaf · « **Reply #4 on:** March 20, 2007, 03:25 »

if you had exposed for the building which is what you kept - then the building would not be overexposed.

Grizzlybear · « **Reply #5 on:** March 20, 2007, 03:37 »

Why not use Dynamic Range Increase, in the first place?

1. With camera mounted on tripod-meter sky-take shot

2. meter land/water-take shot

3. Add lighter image to darker image as a new layer

4. Select "color range"-"highlights", check "invert" box,click "ok"

5. Add layer mask

6. Filter>Blur>Gaussian Blur 250 pixels radius

7. Flatten and save

CJPhoto · « **Reply #6 on:** March 20, 2007, 04:31 »

Quote from: Grizzlybear on March 20, 2007, 03:37

4. Select "color range"-"highlights", check "invert" box,click "ok"

5. Add layer mask

I dont think I can do this in elements. Is there an option for us poor elements users?

Note to self - buy CS3.

rjmiz · « **Reply #7 on:** March 20, 2007, 09:10 »

Quote from: leaf on March 20, 2007, 03:25

if you had exposed for the building which is what you kept - then the building would not be overexposed.

But the sky, the ice, and the Sun would have been.
Once blown out, information is lost, and can NEVER be recovered....(total white).
Under exposed information is still there, and CAN be processed.

Grizzlybear's suggestion is what I usually would do if I had a tripod.
I always USE HDR. However
steps:
4. Select "color range"-"highlights", check "invert" box,click "ok"

5. Add layer mask

6. Filter>Blur>Gaussian Blur 250 pixels radius

7. Flatten and save

are NOT necessary

Grizzlybear · « **Reply #8 on:** April 10, 2007, 06:18 »

Those steps are necessary if you do not have CS2(which has HDR) I have CS which doesn't have HDR, so I use my version of Dynamic range Increase, as shown. To boost color I would use the unsharp mask at a large radius (30-100pixels) with a small amount (5-20%) as Local Contrast Increase-this can also decrease atmospheric hazing. regards, Grizzlybear.

litifeta · « **Reply #9 on:** April 10, 2007, 06:27 »

Grizzly ... I have PS7. How do you use the Dynamic range?

Grizzlybear · « **Reply #10 on:** April 10, 2007, 18:31 »

Hi, read my previous post, regards, Grizzlybear

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Author Topic: Correcting for under exposure (Read 4795 times)

rjmiz

CJPhoto

Greg Boiarsky

rjmiz

leaf

Grizzlybear

CJPhoto

rjmiz

Grizzlybear

litifeta

Grizzlybear

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