Episode 037: The Two Minute Holiday Shot Edit
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I was in Berlin for four days last week. And I only took a point and shoot digital camera with me. So this episode covers quick editing of holiday pictures, done in two minutes.
In this short time one can only do the basic stuff. And so I give you some easy recipes for getting more out of your snapshots. If you take this small amount of time, your images will get a lot better.
- Rotate them, so that they are level
- Adjust the perspective to get these falling lines out
- Find a good crop
- Adjust the contrast with the curves tool, applying an S-curve helps in most cases
- Double the layer and use a layer mask to apply your edits only to a part of the image. Get more light into a dark corner or dim down a bright spot
- Double the layer and use overlay or screen mode to change the overall contrast in an image. Use the opacity slider to adjust the strength of this effect. Try other modes, sometimes they work really good.
Don’t forget the challenge! Make a monochrome image and post it in our meetthegimp.org photogroup at 23 and be sure to use the tag “mtg-monochrome”. The challenge ends March 31 1600GMT and I’ll draw a winner by random choice.
You can find the image used in this episode here on the Download Page
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Tags: beginner, contrast, curves, layers, perspective, rotate
March 19th, 2008 at 12:24 am
The lens distortion can be corrected using the “Lens Distortion” (under Filters->Distort) plugin
March 19th, 2008 at 12:29 am
Only after the show I became clear to me that the image above is a composite. At first I thought it was a sky scraper with large sheets of advertisement or so. Great image! I will keep this in mind when I shoot a high rise building myself.
The panotools are great. I use Hugin, the GUI to it. Even for simple perspective correction I use it. It takes some time to learn but it all pays back.
As usual, thanks for the show!
March 19th, 2008 at 1:31 am
something odd: The video is 39 MB but this post says it’s 12 mb. ??
March 19th, 2008 at 12:03 pm
@David: Thanks! Just fixed that.
@Rootie & Serge: Thanks for the tips. I’ll try both ways. Guess next weeks theme…..
March 19th, 2008 at 2:55 pm
Serge, can you give me a pointer how to do that in Hugin?
Edit: found this: http://www.linux.com/articles/55174
March 19th, 2008 at 6:52 pm
Great show, a lot of very handy tips. Thanks!
March 19th, 2008 at 8:22 pm
Enjoyed it very much. Right at the end there was a throw away mention of PTlens a piece of software that I only became aware of today. Easy to use, corrects CA, and runs in Ubuntu when installed with Cross Over. No access to the help file however.
March 20th, 2008 at 1:12 am
Thank you very much these magnificent tutorials.
I would like to reconstruction the GIMP logo,
and I don’t know how can i do that. Can you help me?
Thanks!
March 20th, 2008 at 6:59 pm
My comment is not related to show 37 but to first 3 or 4 … which I like very much.
- that’s usually the case for Photoshop tutorials.
I am just discovering your shows and enjoy them, so for the time being I have no suggestions to improve something. But I like you accent in English - I am not an native English speaker so it is much more easier to understand you than an American narrator
Thanks for helping me and many others to learn Gimp in an easy way.
Mihai.
March 20th, 2008 at 10:39 pm
Rolf,
I read the article at linux.com. Tomorrow I will give some tips and tricks.
Serge
March 21st, 2008 at 1:20 pm
I would like to assure Mihai that I am able to understand Rolf far easier than many American narrators and I am a native English speaker.
March 21st, 2008 at 1:36 pm
@Norman: Now my ears are glowing pink…..
March 21st, 2008 at 7:35 pm
Rolf,
The article you found gives a very good general introduction on how to deal with correction of barrel distortion and perspectiv distortion. The following one might also be useful.
http://hugin.sourceforge.net/tutorials/architectural/en.shtml
So I will not go into the workflow and GUI but instead give you some tips which might be useful. I will limit them to what is important for correcting only one picture, not a series of photos.
- The tab “Crop” can be skipped. The tab “Assistant” is optional; it guides you through the steps to be taken.
- Hugin will ask values for the HFoV (horizontal field of view) and focal length. Only the HFoV matters because Hugin uses this parameter in its calculations. The focal length is calculated automatically but is bogus for point-and-shoot cameras: Hugin presumes 35 mm film.
- An initial value of 40 degrees for HFoV is okay. It is not necessary to give an accurate value as Hugin will find it during its optimisation calculations. This is really the only value wich you have to supply. The others are not used or will be calculated by Hugin. (In fact, every value is a reasonable starting value of a parameter in mathematical formulae. Those parameter values are then varied within certain limits during the solution of the optimialization problem.)
- I add control points manually. Start with 4 or 5. I seldom use more than 10.
- Spread the control points and avoid the very border area of the photo if possible. Here lense imperfections are more severe and make the calculations for Hugin more difficult (I think here about the unsharpness and possible chromatic aberration, not the barrel distortion)
- Place control points at high contrast areas, like edges of houses or windows, sharp colour transitions, etc. Smooth areas make it more difficult for Hugin to optimize its result and can even cause nonsense results.
- If you use automatic generation of control points, check them. They are not necessarily correct!
- I normally start with optimization of only pitch and roll. This should already give a reasonable start. If not, then very probably something is wrong with the control points. It is not necessary to include yaw.
- After that I add view and optimize again. The calculated HFoV should stay in reasonable limits (I typically have 30-50 degrees) but is not necessarily the physical correct value. But that is not our goal; we want a nice picture. If the maximum deviation exceeds, say, 5 there is probably a problem with one or two control points.
- Then I add barrel. The resulting picture should now really look well and the barrel value should stay low (I typically have < 0.05)
- Distortion a and especially c are the fine tuning parameters and might even not be necessay. I always add one parameter at a time and check the result. Also these parameters should stay low (like < 0.05). At this point I sometime exclude view and/or barrel again. Especially when there are not many control points Hugin cannot always find a meaningful optimization with too many variables. If they are not excluded, the HFoV and barrel should only change slightly; if not, you should mistrust the result.
- x and y shift do not apply here.
- For “stitching” one picture, one should choose rectilinear projection (unless you are after some special effects)
- I use always the nona engine. It is way faster than PTStitcher and moreover, PTStitcher appeared to be not that stable on my system.
- Push always the button “Calculate Optimal Size” otherwise your image might get scaled.
- “Soft Blending” is useless for one picture. I do not use it anyway but do it manually in GIMP.
This is what comes into my mind now. I hope it helps and feel free to ask.
Serge
March 22nd, 2008 at 3:56 pm
This was a great show, with a great concept. Really cool how quickly you can go in with a layer mask and improve parts of the image - I never would’ve been able to do this prior to Meet the Gimp! Thanks a lot Rolf.
March 23rd, 2008 at 1:21 pm
I just discovered Meet The gimp some days ago and already have downloaded all your screencasts. This is really awesome. The best resource about The Gimp by far. I’ve learned a lot about photo correction viewing your tutorials. Thanks a lot, Rolf
March 23rd, 2008 at 4:06 pm
Just wanted to say thank you for all your effort, this really helps a lot!
March 23rd, 2008 at 5:37 pm
[...] Episode 037: The Two Minute Holiday Shot Edit [...]
March 24th, 2008 at 5:02 pm
Thank you for showing me how to fix the contrast in only part of the image using the layer mask. This was a very helpful and useful. I have subscribed in Miro and I look forward to future episodes. Thank!