*Stitched panorama Help? Exposure problems*

[rammy]

Help for a newbie please:

I'm sad that this image came out soo badly and I don't know why! :-(

Can anyone please help explain why the left edges of the images (blended to make a panoramic) are dark and then light on the right side of the next image? I used Canon's PhotoStitch which I thought would blend the darkness/lightness between shots. Or am I doing something fundamentally wrong that is causing this to happen.

I have a 300D using the standard 18-55 lens kit and focused exposure to the middle of the scene (on the London Eye). Should I have focused on the brightest part of the scene (the sky) to get exposure setting or the darkest (water)? Image was taken quickly so the light did not change too much between each shot. I also bracketed 1 stop which all came out the same as this one.

Anyone know how I could "fix" the image in PhotoShop so it blends? Should I replace the sky (which in my opinion is the best bit) and the water? I have tried using colour match in PhotoShop CS, on each image prior to blending but that just makes it worse. Or should I just give up and try taking the shot again?

Anyone have a suggestion of a technique or steps they use that are "newbie proof"?

Thanks for any help you can offer.

http://www.crystalsymphony.plus.com/Temp/LondonEye_Orig.jpg

[tommykjensen]

This is because with each photo You shot Your camera measured lighting every time giving different shutter and/or aperture.

To ensure good results You need to go full manual. First simulate (half-press shutter) each shot noting the settings the camera choose, You can do this in P. Then figure out which setting would be best for the entire image and use those in manual mode.

To "save" this panorama You would need to process each image sperately and adjusting levels and such until all 3 images look as close os possible then merge them again.

But the person You really should wait for input from is Scottes. I think he is the master of panorama photos :lol:

[Scottes]

But the person You really should wait for input from is Scottes. I think he is the master of panorama photos :lol:

Yeah, after having shot 3 of them I'm a master. :lol:

Tommy is right on though about manual mode. I switch to Av mode and I'll do several half-shutter-presses across the scene. Since Av is set this gives me the longest and shortest shutter speeds. I then flip to manual mode and set the same aperture and the shortest shutter speed found during the scan. I then take a single frame of the brightest/whitest part of the scene and check the histogram. If possible I'll increase the shutter by 1/3 or 1/2 if I can.

Then I take the pictures across the scene quickly, overlapping about 30% on each. I then go back and review the histograms to make sure that I didn't blow anything out, and also to make sure that I "exposed to the right" as much as possible. If I messed up I'll do it again.

Note that I set the camera to RAW + Large Fine JPG for this. Developing the RAWs can be tricky so I'll have a set of JPGs which should most definitely match. I won't blame anyone if they just stick to JPG for a pano. :D And if you do shot JPG I think (but I'm not positive) that it's best to set the JPG parameters to Set 2 (I think - anyway it's the set that doesn't do any processing to the JPGs).

If using RAW you need to make sure that each one matches perfectly while still processing them all to the fullest. Easier said than done. I'll open both the brightest and darkest images in the RAW editor and play with the settings until I'm satisfied that the same settings will produce the best possible processing for both images. When the settings are done I process each of the images, processing each with identical setting. (Batch processing is the good/fast way to do this.)

Easier said than done, and again, I won't blame anyone if they just stick to JPG for a pano. :D

Now that you've got a set of images you should be ready to stitch. Being somewhat of a crazy person I stitch by hand. Crazy or not, this gives me the most control.

The first thing I'll do is lay out 2 of the images into a single image, each on their own layer. I start with the middle or middle two images in case there's tilt (see next paragraph). I then line them up, always zooming to 100%. I use the Move tool but then just use the arrow keys to move 1 pixel at a time. Also I reduce the opactity of the "upper" layer so I can clearly line things up.

At this point I'll check the horizon line if there is one, or just get an idea if I've tilted the camera too much. It's pretty difficult - even with bubble levels - to get within 0.5 degrees. Across a pano, a half degree is quite detectable to the eye. When lining things up make sure that you check a detail at the top and a detail at the bottom. Sometimes only one lines up because of tilt.

If it's tilted it's easy to fix. Grab the Measure Tool under the Eyedropper. On one frame draw a line from the top detail to the bottom detail. Write down the angle. Do the same thing on the other frame. Subtract the angles to get the necessary rotation of one frame. Chose Edit... Transform... Rotate and enter the angle in the appropriate box at the top of the screen. Now both details, top and bottom, should line up.

When lined up I turn the opacity back to 100%. On the upper layer I'll then click the "eye" in the layer toolbox to turn it off, and then on again. This will let me compare one edge of the lower layer to the edge of the upper layer. Sometimes one is obviously better quality. The right side of my 70-200 is much better than the left side, for some reason.

Now that I know which layer looks better I'll reduce opacity of the upper layer and then I'll scope the scene for the correct placement for a seam. I never use a straight seam since it's too easy for the eye to catch it. Instead I plan on a zig-zag seam using the Polygonal Lasso tool. When this zig-zag gets blended it will be much harder to detect. Also, never have the seam go through the middle of something, like a house or tree. Make the edge of the house the seam in that area, or Lasso closely around the tree so the edge of the tree becomes the scene. Again, it helps hide the seam.

Always draw the seam on the upper layer since it will be what you throw away. The upper layer will cover the unused portion of the lower layer so you only need to delete the unused portion of the upper layer.

Once seamed and the unused stuff is thrown away I'll zoom to 100% along the seam and use the Stamp/Clone tool to hide the seam better.

Now that I have 2 images stitched (finally!) I'll save the image (pano-01 since I'll be saving a new file for every added frame), then flatten the layers and do a Purge All to free up memory. I'll then increase the canvas size and add the next image and do this all over again.

I like to start in the middle and work right, left, right, left until I'm done. That is, if I have 6 images (1 2 3 4 5 6) I'll first stitch 3 & 4, then add 5, then 2, then 6, then 1. If things get tilted or don't line up you'll only lose half of what you would if you started at one end.

And if you have tilt remember that it's easier to rotate 0.5 degrees on each frame individually rather than trying to rotate 0.5 degrees on an image that's 21,000 pixels wide. (Don't ask me how I know this.) You'll also lose less of the top and bottom by rotating individually.

I think that's it... :D

[MilesG]

i think the difference in lighting adds to the picture i really like it! my compliments!

[chris.bailey]

It can also be good to do them with the camera in portrait as you then end up with a bit more 'height'.

[KO_300D]

top notch info Scottes!

I've worked with panoramics a bit myself (not brave enough to use RAW yet tho :wink: ) and I couldn't have said it better myself.

[rammy]

Thanks very much guys! Especially Scottes and Tommy! Thanks Miles for comments, it's not the result I was hoping for though :?

Thanks Tommy about using Levels in PS, I'll give that a go but will try and get it right first.

Scottes, some follow up questions please:

1) You talk about using Av and finding the longest and shortest shutter speed, what aperature do you use for this? f8, f11? Does it matter?

2) Setting camera after the "scan" you say that you take a single frame and increase shutter. Does this mean that you increase the shutter speed because the brightest part may over expose? Are you looking for the blinking white bits when you look at histogram and making sure the histogram is mostly to the right?

3) How many shots would you take on lets say a 135 degree shot? I took three panning shots, is this ok? More if I was doing it portrait as Chris.Bailey suggests?

4) Last one: What is the best or typical focal length to use on panoramics? Wide, normal or zoom? Wide gives that curve at the edges, is close to 50mm better?

Thanks to all, help is very much appreciated. When it's not raining in London I'll go out and give this another go and post the results.

[ohenry]

Why take your meter readings in P or Av or Tv? Just go to M, select the shutter speed or aperture you want, then adjust the other until the meter indicates proper exposure (or amount of compensation desired).

[Scottes]

1) You talk about using Av and finding the longest and shortest shutter speed, what aperature do you use for this? f8, f11? Does it matter?

Use the smallest aperture that will get everything in focus. Google for "hyperfocal distance" - in very short summary you set the focus point to a particular distance, and everything from half that distance to infinity will be in focus. It's very dependent on focal length and aperture.


2) Setting camera after the "scan" you say that you take a single frame and increase shutter. Does this mean that you increase the shutter speed because the brightest part may over expose? Are you looking for the blinking white bits when you look at histogram and making sure the histogram is mostly to the right?

Yes on the bolded part.


3) How many shots would you take on lets say a 135 degree shot? I took three panning shots, is this ok? More if I was doing it portrait as Chris.Bailey suggests?

Depends on the lens. A 10mm lens may get 135-degrees in one shot. A 400mm will need a LOT more. But you will need more in portrait mode because the angle of view is shorter. Just be sure to overlap about 30% and just take however many frames are necessary.


4) Last one: What is the best or typical focal length to use on panoramics? Wide, normal or zoom? Wide gives that curve at the edges, is close to 50mm better?


Again, it depends on the lens and what you wish to shoot. Again in short summary - a wide angle lens will let you get more foreground in focus compared to a longer lens. But a wide angle lens "curves the edges" and is much more prone to parallax error, which is when an object in the scene "shifts" when you rotate the camera. This is because you're not rotating the camera around the lens's nodal point.


Hmmm... "hyperfocal distance" and "parallax error" and "nodal point" are all very important when taking panoramics. BUT only when you're using a wide angle lens and trying to get foreground in the picture. If you shoot distant objects with a longer lens (70mm+) then you don't have to worry about any of those things. (That's kinda loose, so add "within reason" to that sentence.)

It is a LOT easier to do panos with longer lenses shooting distant objects.

Heck, even at 55mm f/22 you're safe shooting stuff that's at least 50 feet away from you. Any closer any you may have to worry about parallax error. If you go with a wider angle you'll have to worry about parallax error AND hyperfocal.


However, you're in it deep because you asked. You may not have even known about those things yet your picture came out great in those regards because it didn't involve any of them. All you needed to know concerned setting the camera to manual mode, and if you do everything else exactly the same you will have a great shot.

So don't worry about those things, or your head will spin and your brain may explode. :D

[rammy]

Thanks VERY MUCH Scottes! You are a star!

I didn't realise there was soo much to know; Hyperforcal thingy, parallax jobby and nodal points!!?!?!? :? :oops:

Erm, I think I'll buy a book. If you think I don't need to worry about that confusing stuff and just do the manual aperature technique then I'll give that a go first.

Thanks again to all! Will post next version soon so you can see my learning in progress :wink:

[CyberDyneSystems]

The Big guns have already arrived on the scene here.. nothing to add excep that it looks like we have another excellent Tutorial/info thread on our hands! :mrgreen:

Thanks Scottes.

Rammy,. hope you don't mind I altered the title of your post to make it more descriptive.

[Scottes]

I didn't realise there was soo much to know; Hyperforcal thingy, parallax jobby and nodal points!!?!?!? :? :oops:

Erm, I think I'll buy a book.

Rammy you weren't listening! I told you not to worry about all that stuff because you've done fine so far!

:D

I actually don't know of a book out there that covers this topic, but let us know if you find one. Googles for the above phrases and even "panoramic tutorial" should give you sufficient info.

Whatever you do, don't look up "panoramic heads" for tripods.
<whoops>

[Scottes]

...it looks like we have another excellent Tutorial/info thread on our hands!

If I can grab some time I'll find some of the good tutorials and explanations out there and add the links. THEN it will be a good tutorial, and we can make it sticky somewhere. It really is an often lot to cover in one thread so external links will be ncessary.


Of course, if anyone knows of some good links please post them here.

[rammy]

Ok Scottes, I'll carry on with what I know so far. Thanks.

With this one, I followed tommykjensen's advice and had a go at using the Levels in PS to get them to match better. Being ok with PS, this gives me a lot of confidence.

As you can see, I've lost the nice deep blueish saturation from the original but atleast it looks a better blend :) Will have another go at taking the picture to get back the blue saturation.

I also used the "Overlay-neutral colour" layer trick in PS to highlight the dark parts.

http://www.crystalsymphony.plus.com/Temp/LondonEye10.jpg

[Andy_T]

Rammy,

that panorama looks awesome! 8)

Do you have a link to a larger version, as well?

Best regards,
Andy

[Scottes]

That looks great Rammy!

[CyberDyneSystems]

I believe we have a FAST LEARNER in our midst! 8)

That is an AWESOME job! 8) :shock:

[tommykjensen]

Great job.

[Bruce Watson]

There are some inexpensive to free software fixes available.

Check out http://www.tawbaware.com/forum2/ for some good advice and a place to get answers/comments on images.

Max's software is very good, especially when combined with the free Autopano and Enblend.

As suggested, always use manual everything for this type of project, the above mentioned software will automate good results with minimal effort.

Cheers,

Bruce

[Nabil-A]

PTassembler is shareware.., does one need to register it when using it in conjunction with enblend and autopano?

[Jesper]

PTassembler is shareware.., does one need to register it when using it in conjunction with enblend and autopano?PTAssembler is just one GUI for Panorama Tools. There are some alternatives, which look suspiciously like eachother...

Hugin (http://hugin.sourceforge.net/) for example is free.
Or this one: http://www.nic.fi/~juhe/ptbcbgui/

Try searching for "panorama tools gui" with Google, you'll find more alternatives.

[Huckaback Photo]

Find the down load for Autostitch
it works behind the scenes, so to speak , you take a load of images of a scene put them in one folder , open in autostitch and just run it. now it dont work on all but is darn clever.
This software was developed at the university of British Columbia, and was available free down load for evaluation purposes, get it while you still can.
try it
Let me know
Cheers
Martin (Huckaback Photo)

[rammy]

Hi,

I've been trying out the suggestions and practicing my "panoramic skills" further. ;-)

Here is a composition done after reading a large part of this forum and understanding the difficulties of taking many shots of the same scene.

This one did not actually need any post-processing! Yippee! At last, I am getting better at actually taking the pictures.

BTW: I used Photoshop CS ONLY (I have many years of experience with this software) to do the manual stitching. I realise now that most, if not all, panoramic stitchers are pretty bad at making seamless joins. I did the joins myself.

Thanks to all who provide great feedback!

http://www.crystalsymphony.plus.com/Temp/CabotPlaceFalls.jpg

[jerseycowboy]

I've read through these posts and am still confused on how I can even out my exposure. I'm still a real rookie with my Digital Rebel and am still learning what settings work for what situations, while trying to get off those auto-settings.

Here's my latest attempt at the stitching. I used Photoshop Elements Photomerge for this. Canon's PhotoStitch didn't yield a much better result.

Any help would be appreciated.
http://www.jerseycowboy.com/attempt.jpg

[rammy]

Hi jerseycowboy,

You are getting the same problems that I initially did - Exposures not consistent across the shots. Have a good read through Scottes replies to this strand as they helped me out greatly. I'll try and add my 5pence worth!

Here is what I have learnt so far:

On my original, I actually used the LEVELS trick in PhotoShop to fix it. Try this:
FIX FOR EXPOSURES - AFTER TAKING SHOTS:
Open up both images in PS. Create a new document that is wide enough for your images. Drag each of your images INTO the new document. You will have "x" number of layers now, one for each image. Align the images (move them on each layer) so they match up best you can. Change opacity to see layers beneath you.

Here is the trick: Highlight your second layer (you are going to match the exposures of all other layers to your bottom layer, or previous layer). If you want to change the LEVELS and CURVES on your first layer then do so now. Make sure you have second layer active. Go to the channels pallette. Highlight the red channel. Bring up LEVELS. Now move the sliders (the middle gamma one) until the image on layer 2 is the same shade/exposure etc as the image on layer 1. Do this for the other channels (Green and Blue) as well.

Now go back to the Layers palette and highlight layer 3. Go back to channels, and highlight red channel. You are now going to use LEVELS to match layer 3 to layer 2. Keep doing this for all your layers.

Once done, move the images BACK to their original files. Save and merge using your software. I personally do not do this step. Once I have adjusted the levels on the channels pallette, I use Layer Masks to show/hide portions of the layers so I can manually stitch them.

BTW - This technique requires you have a good eye for spotting blending shades. Also, Photomerge is rubbish. I do all my panoramic stitching BY HAND now. I use to use PhotoStitch. I do not anymore.

FIX FOR PANORAMICS - AS YOU ARE TAKING THE SHOTS:
Simply put, what I did to rectify this issue;

ALWAYS HAVE CAMERA ON MANUAL!

Hook your camera up to your tripod and make sure it is level (I have a hot shoe level) and also make sure you have the shutter release plugged in.

Make a decision now: How much of the sky vs. the ground are you going to capture and is there eqi-distance between the ground and the sky, when you pan. If there is then continue to next paragraph. If the horizon is not level then capturing an "average setting" may be difficult. I purchased some LEE ND Filters to get round this issue :-)

Keep the shutter half pressed and take a scan of the view you will capture. Look at the metering system. Watch by how much the indicator shifts as you pan your camera. You now need to decide on an average setting. If the meter moves -1 to +1 stop as you pan, then an average is 0 F-Stops. So now set your shutter speed and aperature to capture the DOF you want. Set your aperture first, by using a hyperfocal chart, then set the shutter speed to get the right esposure you are looking for.

If, for example, the meter moves -1 and back to 0 then average is -0.5 stops down.

Once you are happy with shutter speed and aperture, PAN AND TAKE YOUR SHOTS QUICKLY. You'll be surprised what a few seconds can do to your shots!

Good luck and I hope this helps.

[jerseycowboy]

Thanks Rammy - I saw your posts and how quickly you learned how to fix the exposure differences. I appreciate you taking the time to share your experiences.

I'm currently using Photoshop Elements. I know it's not the best, but it's what came with the camera and I can't really afford a full blown copy of Photoshop now. That said, can I use Elements for the adjustments you described? Would it basically be the same steps?

[rammy]

Hi jerseyCowboy, yeah, you should be able to use levels on the channel palette in Elements.

I have many years experience with PS so found it easy to fix the problem, once I know how to do it ;-) Using the camera, I have about 1 years experience so still learning a lot there! This forum is SUPER GREAT for info!

Don't forget to digest Scottes thread. If you do not understand a terminology used then search the Net. That is how I learned, thanks again Scottes! My saviour :-)

Another way is to use colour match option on the sky, although this won't give you much control on foreground. You could though use levels on your main images instead of the channels palette and use the eyedroppers on the bottom right to pick the shadow, midtones etc across all your images.

Good luck, post your "fixed" image. If you find you are struggling then put a URL to your source images in a thread and I'll try and have a go and explain better if I can ;-)

[Scottes]

Rammy, you learned fast. And taught yourself some stuff. And shared that info back to the forum.

"Thank You" for that. It makes this place a great place.

[rammy]

Thanks scottes! Couldn't have got better without the help and willing to post more to this forum as I learn. Still have a way to go, trying night shots at the moment.

Here is another image I took recently that I did not post-process, I used your advice, to the letter! Then stitched together manually in PS using Transform and layer masks.

http://www.crystalsymphony.plus.com/Temp/Parliament_atNight.jpg

What I have not got the hang of is taking the panoramic shots with the camera tilted to portrait. I can't seem to align them well. Do you use a Hot Shoe Level or do you watch the horizon through the viewfinder and align with AF points to make sure it is "level"? Because of the mis-alignment, I have to crop the top and bottom of the panoramic, making it shorter.

Also, do you have any advice on taking vertical panoramics? Any different to landscape shooting? Should I keep with your method with regards to verticals as well?

[Scottes]

That's a nice shot Rammy. I love night shots - even though I've yet to take one. (Probably because I get up at 3:00 AM to catch the sunrise...) Do you have a bigger version?

Yes, I do have a hotshoe "double bubble" level. That whole process drive me crazy - level the tripod, then level the base of the head, then level the camera. It's a pain with a ball head I tell ya! So I got a few doohickeys which I have yet to try out. I got a Bogen Leveling Base (http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=146230&is=REG) for the tripod which should help a lot. And a new pan/tilt head, as well as a Nodal Ninja pano bracket (http://www.tawbaware.com/forum2/viewtopic.php?t=1473).

I hope that the leveling base will cut down leveling time to a minute or two. One of these days I'll get a chance to try all this gear....


As to advice... I've just found that leveling is a bit more critical, since it's not so easy to see in the viewfinder. The last one I did wasn't very level so I opened and levels each pic and then proceeded to layer and merge them.

I've also got to try PanoTools and PTAssembler next time, too.

[Scottes]

This one thanks to Radtech:

Also use Custom White Balance to set the same temperature for each shot, especially if you shoot JPG. Shooting RAW can be a serious pain, but would allow you to set all the images to the same White Balance and tint when developing.

This can be crucial to getting all the colors perfect together. And it explains the issue I had with one pano when the light kept changing slightly. You'll never notice it by eye, but when you stitch the images it can be quite apparent.

Thanks Rad!

[Nabil-A]

http://www.crystalsymphony.plus.com/Temp/Parliament_atNight.jpg



Nice shot, but i can still see the seams in the sky. Perhaps if you used clone tool?

[Nabil-A]

Shooting RAW can be a serious pain

I dont understand all the fuss with shooting raw? with my last attempt, i set all my images to the same whitebalance setting and then converted to tiff. Worked on tiff all the way through.

[thomas1122]

Depends on the lens. A 10mm lens may get 135-degrees in one shot. A 400mm will need a LOT more. But you will need more in portrait mode because the angle of view is shorter. Just be sure to overlap about 30% and just take however many frames are necessary.

Hi There,

I have to say I'm complete newbe to panoramas and all I have read here makes perfect sense for me apart from one small thing. I just recently got myself GigaPan Pro and have a problem shots not overlapping. For instance when I shoot at 50mm everything will be ok but when I go to say 200mm then GigaPan still divides whole Panorama in the same amount of shots and there is no way they will overlap. Any ideas on that stupid problem please?

Thx a mil
Thomas