The other one got locked and I wanted to bump it since the con is getting close so I am just going to make a new one and try to get it stickied. So this thread is going to be advice for how to pose for pictures and how to take pictures. Please feel free to add more if I forgot something.
As a cosplayer:There are essentially two types of pictures: ones for others and ones for yourself and there are do's and don't for both.
For Others:These are the pictures that will be the most common. When someone comes up to you and asks if they can take your picture. To me getting my picture taken is a huge complement, it tells me that my costume is good enough for someone to want to document and that is how most people should view it.
For these pictures you may want to practice some poses before hand. I would recommend about three or more poses. A well known costume will have a lot of pictures taken and you don't want to see the same things over and over do you? So do a little research on your character and find a few poses that they would do. This may involve you being a little creative. It is a good idea to practice these poses in front of a mirror and while a friend takes a picture. It is easy to do a good pose in a mirror but it may be harder to duplicate the same one when you can't see yourself so have a parent or a friend take some shots and review them.
As for some good slimming poses it is a good idea to do a 3/4 stance, or your feet pointed to the side and your torso turned to the camera. This will show the narrowest part of your stomach. Also pull your shoulders back and be aware of your chin. I used to let mine drape down and it would give me multiple chins. If your character does more of a downward look it is still easy to fix, lower your shoulders as much as possible without looking awkward and then pull them back. Also stick your neck out just slightly to give your neck a more elongated illusion.
Also, if you have props make sure you use them. If they are a defining characteristic of the character make sure they are visible in the picture. Props make it much much easier to pose yourself as well. There is so much to do with a simple prop. If your character doesn't have one maybe you could find something that would work. Here are some examples of using a prop to pose.
For yourself:These are the pictures that you are going to want to look back and remember. Most of the time these will be the best picture of your costume and will involve a professional photographer or someone who is good at taking pictures. These are the pictures where you can break character or do some things that you may not know how they will look. When you are posing for a picture for someone else you typically want to give them something that looks nice, but here you will have the opportunity to do something that may turn out to be really really cool or horrible and never want to see again.
For these pictures you will need to be a lot more creative then taking pictures for others. Sometimes photographers will pose you but it is also be your responsibility to do some of the work as well. If you head to cosplay.com they have a bunch of pictures that are showcase pictures. These are the best of the best.
Also inspiration can strike at anytime for these pictures. The picture below was actually taken when my photographer was taking a picture from above me and I was reaching up for the camera to view the picture she just took and she stopped me and told me to use the other hand.
Action shots are also very nice. Shots while moving or battling may turn out really well, if the photographer has a camera that is able to capture it. This is a picture that was taken while I was spinning and it turned out great.
Again use your props. Here are some pictures that use the props but you wouldn't want to give as a quick snap shoot during a con
As a photographer:This is mainly going to be for the amateur photographers not the professionals because they don't need help. But as I stated earlier these pictures are for you. You should take a look at the picture after you take it and make sure it is what you want, if it isn't good enough then ask for another. Also, it is a good idea to show them the picture as well. They may be able to do something so much better.
The cosplayers may pose themselves but you may also have a pose you would like them to do. If they are already in a pose take the picture and then politely ask them to do the one you want. I have done this before myself. A friend had a great costume and I saw him pose for someone else by flipping off the camera and when I asked he did a different pose. Latter I found out my friend knew him and then I asked him to do that same pose. I was happy I did because it was a great picture.
If there is a lot of people in the background and you would like to not have them there you can wait for them to pass, politely ask them to move or change the angle of the shot. You can get lower to the ground and shoot up to get the sky or the ceiling in the picture. This would help cut out people in the background and create an interesting angle and photo to look at. One piece of advice is to not have the model look at the lens to avoid getting multiple chins. Or you can shoot down. If you do this you will want them to either look at the lense, or around that area. You don't want them to look down or you might miss some great details....like their face.
Finally, and this is very important,
please respect the cosplayer. Sometimes a cosplayer has been so busy and had their picture taken a lot and all they want to do is sit down and relax. If you ask for a picture and they say no do not call them names or bash them after you leave. Ask them again later and you can probably get it. Also so people do not feel comfortable having their picture taken and possible posted on the internet so they may say no and they have the right to. Please respect their choices. We are all doing this for fun. Also if you see a cosplayer is eating you can go up and ask to take their picture AFTER THEY ARE DONE EATING. Do not ask them right then because you will probably get a no. I remember in 08 we were sitting outside in the park eating and my Gaara and Kankuro took off their props and this girl came up and asked us for a picture when we were done eating. We said sure and after we were done we started to put the props back on and she came over and waited patiently (it is a long process x.x ) and got the picture she wanted. So please please please be respectful and you will probably get what you want.
For both parties:
Remember your please and thank yous. You are borrowing time from someone so always thank them for their time. Also, be sure when you take a picture to move out of the way of other people. Please for the love of God do not block the hallways. Those halls are small and narrow so respect others.
I hope this helps some of you a little.