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Mike Fuhr
02-28-2008, 02:43 PM
Here's a picture I took about a year ago one early morning on The Nature Conservancy's Four Canyon Nature Preserve in western Oklahoma. I've cropped because I like the panorama look much better for this shot. I also made minor adjustments to the color levels. I'd love to go back and take multiple photos in order to stitch them together but I do not know how to do that. Any advice there would also be appreciated.

Nikon D50
18mm
ISO 200
1/320 F/11
Hand held

Robert Amoruso
02-28-2008, 09:54 PM
Mike,

Having been to OK, I know that it can look pretty monotone and flat. The pano works well here as you have concentrated on the more important details in the image. I like the composition with the winding river on the rive balancing the FG rim and BG hills on the right. I might have walked forward some to include less of the rim and non of the grass at the lower right.

It also looks like you have a strong color cast. I donwloaded the image and did some corrections below. They include a Levels Adjustment to set a black point, white point and gray point. I then did a Selective Color Adjustment and removed magenta fromthe red and magenta channels. I did a curves adjustment with a moderate s-curve and then did a local contrast enhancement using unsharp mask at 32 radius and 42 amount. I then went back the the levels adjustment and did clicked the Options > Find Light & Dark Colors to get rid of any remaining cast. Sky is still a little funky looking but this is the JPG.

I have a procedure to find the gray point that I listed below. When using levels to set white and black points you can use a threshold adjustment similarly and set markers at the white pixels and the black pixels. For gray point I like to find the pixels that are around 128 RGB, this procedure allows you to do that vs. searching the image with the gray point dropper trying to find 128,128,128 or other combination where the RGB are all the same.



To Gray Point Balance, do the following.

1. Creates a layer, Layer>New>Layer or Shift+Crtl+N
2. Fill it with 50% gray, Edit>Fill or Shift + F5
3. Change the blending mode to “difference”
4. Create a Threshold Adjustment Layer, Layer>New Adjustment Layer,Threshold

This allows you to find a neutral point in the image for a Levels Adjustment Layer using the Gray Point Eyedropper, and set the gray point to remove color casts.

1. Double click on the Threshold Layer.
2. Move the slider all the way to the right - if not already there - until the image is white then move the slider to the right until the first pixels appear.
3. STOP moving the slider.
4. You want to hone in on those pixels that just start to appear as you move the slider.

May times these pixels will be visible when the Threshold Level is 1, 2 of other low number.
This is what you want as you’re locating those pixels at a 50% middle gray) and the 50% gray
layer your created is used to filter the Threshold Layer (with blending mode equal to Difference)
to expose those pixels.

Abode definition for Difference Blending Mode is:

Difference Looks at the color information in each channel and subtracts either the blend
color from the base color or the base color from the blend color, depending on which has
the greater brightness value. Blending with white inverts the base color values; blending
with black produces no change.

The neutral gray RGB values of 128 are subtracted from those values that are 128 or greater in the original image when that layer’s blending mode is changed to Difference. Then using the Threshold Adjustment, we can exposure those values that are 0, 1, 2, etc. and close/same as a 50% neutral Gray.

1. Close the Threshold Layer when you find them.
2. Next pick the Color Sampler Tool from the palette.
3. Using the Color Sampler, select one or more of the points you revealed and click on them to place a marker point.
4. Next delete the Threshold and Gray Point layers.
5. You will see the image again with the marker point(s) you selected.
6. Create a Levels Adjustment Layer.
7. Click on the Gray Point Eyedropper (middle eye dropper).
8. Hit the caps lock to make the cursor a bull’s-eye like the marker points you set.
9. Next mouse the dropper over the control point and click. This will set the mid-tones to middle gray and remove most all color casts.
10. Close the Levels Adjustment box.
11. To remove the control points, move the cursor over them with the Color Sampler Tool and when the tool changes to an arrow, grab and drag them off of the image.

Mike Fuhr
02-29-2008, 11:16 AM
Robert:

This is great information -- I really appreciate the advice. That next "penninsula" along the bluff would be great place for the next shot to avoid so much foreground distraction. Perhaps a sunrise.

I'll follow the procudures you listed -- they will devinately help get a better handle on Photoshop and all it can do! Thanks again,

Mike

Brian Wong
02-29-2008, 08:55 PM
.... I'd love to go back and take multiple photos in order to stitch them together but I do not know how to do that. Any advice there would also be appreciated.



Hi Mike!

There are many applications that can help you nice stitch panoramas. If you have Photoshop, you can go there now and try PS's module.

Here's a few tips to get started with a simple panorama:

1) Try learning initially with only 2 or 3 frames at a time.
2) Set your white balance manually, and set your exposure manually. This will help with blending your seams (especially clear blue sky).
3) Initially, select scenes that do not have any nearby foreground objects. (This will help you avoid parallax problems ... they are handled with more advanced techniques)
4) Initially, try selecting static scenes ... progressing later to moving people, cars, water waves, etc. These will probably "entice" you to learn how to mask.
5) Experiment with the amount of overlap in your frames.
6) Initially, try keeping the camera level. It is always a good habit, but once you get the hang of it, this concept will make sense as you learn when and how to exploit this.

Hope that helps!

Robert Amoruso
02-29-2008, 09:31 PM
Thanks Brian for the follow-up on the stitching instructions. Greatly appreciated. Once I finished up the workflow I forgot to do that.

David Kennedy
03-01-2008, 01:27 AM
...2) Set your white balance manually, and set your exposure manually. This will help with blending your seams (especially clear blue sky).
3) Initially, select scenes that do not have any nearby foreground objects. (This will help you avoid parallax problems ... they are handled with more advanced techniques)...

There are only a couple of things Brian mentioned that I would amend. On the question of white balance: there's no question, everything has to be the same, but white balance is the one setting you can ignore in the field. White balance can be set for all RAW captures in the conversion process. As a result, I leave my camera in auto white balance almost all of the time.

Along that line: everything has to be the same from one capture to the next. Work in manual mode and expose for the highlights. Everything will fall into place.

What I would say about Brian's second point about parallax: you need to know what parallax is now so you can avoid it now. As you pan your camera with a normal lens (i.e. a lens without a tripod collar), an object in the foreground will shift in position with objects in the background. I don't mean to be an advertisement, but Really Right Stuff's MPR-CL II i (http://reallyrightstuff.com/pano/03.html)s a wise investment if you think you'll be doing a lot of panoramic photography. If allows you to cantilever the camera so that when you pan, the lens rotates over the optical center. I created a photo illustration of this about three years ago when I drafted a note on this on my web site. I really need to update it, but it will work for our purposes now (http://www.david-kennedy.com/technique.html).

So, how do you beat parallax without getting a rail like this? My experience has been that lenses with tripod collars generally are pretty close to the optical center so that panning does not introduce much in the way or parallax. You can shift it forwards or backwards to eliminate it, but when I'm using my 70-200 f/4 L, I don't bother to do any adjustments because with a 30% overlap between images, I don't encounter any serious problems that cannot simply be "masked away," and they are few and far between. 75% of the stitches I'm making at this point require no manual "corrections." And, for what it's worth, 70-200's are ideal for panoramic photography. The sweet spot for me is often around 90mm, which seems like overkill for a wide image, but it allows you to capture a high level of detail across 8 to 10 vertical images to make a wide image that can print very, very well.

Cheers,
David

Robert Amoruso
03-04-2008, 07:23 AM
David,

Great points. I use the 70-200mm f/4 all the time and 90mm is a favorite of mine. I also find of the three TS Canon lenses I have, the 90mm is the one I use most.

David Kennedy
03-04-2008, 01:43 PM
David,

Great points. I use the 70-200mm f/4 all the time and 90mm is a favorite of mine. I also find of the three TS Canon lenses I have, the 90mm is the one I use most.

That's good to know. I have the 24 TS-E but have been curious about the others. I had already planned to borrow the 90mm from CPS this summer for Dad--he wants to try it for macro work--but was also curious about it for landscape.

One trick that you probably know already is that the 1.4 teleconverter works with the tilt & shifts. It's not "recommended" but it does work!