Gifcam, will do a swell job if you are just capturing video if you want to sex everything up use photoshop.
Reposting my own post from several eons ago:
There are many ways that lead to Gifs. One of the easiest and with the most options is using Photoshop.
And since I'm in a good mood, I made a tutorial:
1) Get Ps if you haven't torrented it already you internet scum.
2) Find a moment to gif, I didn't but since I have to show something I just randomly picked a moment from Christian Frei's Excellent documentary about James Nachtwey known as "War Photographer".
3) Trim video to gif length (or as close to) so you don't have to work with an unnecessarily large file, use your preferred video editing program for this, or Quick Time if you are on a Mac, which I presume you are.(Which is actually quite good for snipping out small gif size bits out of videos.)
4) Import video in Ps: File > Import > Video to layers. If you can't find it, here's a screenshot:
Then you will get this dialog box in which you can further trim the video to your every desire:
5) Now check all them layers brah!
This is the phase where you want to edit stuff and add meaningful phrases for Tumblr, if you want to get rid of some black bars the fast way is: Command + Option + A (To select all layers) and crop.
If you want to add that soggy meaningful text: just make a text layer, and alt paste that between every frame and then Command + Option + G to create clipping masks out of those layers, for items the same thing applies.
If you want make text flash, remove a frame every so often, if you want the typing effect, just add a new letter ever few frames.
You should end up with something like this:
6) Now cool people living on the edge show of their finger dexterity and press Command + Option + Shift + S, not so cool people click File > Save for Web.
We got a lovely dialog box with plenty of options:
Put file container to GIF
Colours at highest setting (256), dither at 100% and lossy at 0%.
Make sure the file size doesn't get to large.
Be sure to preview to make sure everything is right then save.
7) Upload to the interwebs using your preferred service, copy paste that url and put it in.
Narcissistic sociopath, wine critic, style guru, design aficionado, Swiss watch cognoscente and authority on architecture who shoots tri-X and draws monochrome studies of models @ http://www.omnidata.fr/