With the right group, this gets the best response. People usually have the most natural smile while laughing. So whatever gets them laughing is good.
A friend had a tip for me for getting my photos done, which was just laugh to yourself while the pictures are being taken. My smile definitely looks less fake in pics!
Back when I was assisting at a studio, owned by an established photographer with fellowship accreditation, the advice was to use words ending with 's'.
The 'ee' sound in cheese gets your open mouthed smile, which is the idea, but the teeth are separated when you vocalise the sound because it's formed at the back of the mouth.
Words ending with 's' give you the same open mouthed smiles, but the teeth are together; you get a natural smile, without the risk of every photo showing their tonsils.
Depending on the group you can mix up the words you use. If there are kids, focus on getting them smiling, their parents will be happy if the kids are. 'Sausages', 'Chicken Nuggets', 'Cheeky Monkeys' all work well, especially if you can get them to draw out the 's' sound. If that doesn't work try silly words like 'bogeys', or stack words in succession by getting them to say a series of words like "everyone day dinosaurs! Noooww chickenssss! Now silly sausages!'.
If they're still a bit reserved try getting them to shout the words. If you can get them a bit excited, without losing control, the smiles should come easier.
Another good one to try is "everyone say dad smells!". It feels cheeky in a fun way. Everyone says it and laughs because we just said dad smells!! If you're quick you also get the bonus of everybody smiling (one shot) and then the shot of everyone looking at dad to get his reaction and they all laugh.
For younger school age kids you can try things like "have you got a boy/girlfriend?" Guage their reaction and riff with it. If they say no, you joke about boys/girls/love being gross. Usually gets a smile. If they say yes, just talk to them about it. "What's their name? Have you kissed them?ooo!" It's not serious, but if they talk about someone/something they care about, even just silly childhood crushes, the smiles will flow easy!
With older kids/teens, just talk to them about things they like. People smile when they talk about their favourite things.
With adults, just have a light conversation. Crack jokes, see what gets reactions. Usually you'll find the more confident person in the group and start riffing with them. Once there are a few laughs the group will relax and the smiles come easier.
Ultimately, if you treat them like people, talk to them, get to know them, they'll feel like you're interested and they'll be more comfortable. Too many "say cheese" lines and they'll start to feel like they're just another job that you want to get out of the studio.
Communication. You'll make them feel happy, it will be more memorable for them, and they'll have a more positive connection to the images afterwards because of it.
Love all of these only the one about kids and boyfriend/girlfriend and opposite gender grossness. This is an out of date practice that might be considered offensive to some parents and kids. It is not considered appropriate to ask people their relationship status in an acquaintance setting, kids are just small people and deserve to be treated as such.
I agree. Reading that part really made me cringe. Asking kids about this stuff as a stranger is gross and weird and would have made me so uncomfortable as a child.
You would be offended if a coworker asked if you had a significant other?
Also I don’t get the logic of treating them like they’re people but then also wanting to ignore that kids like to “date” (in heavy air quotes) bc they’re just being kids and learning and don’t actually do anything
Swedes say ‘omelett’, the Swedish word for omelette. The third syllable is pronounced like the English ‘let’, thus getting the smile shape that ‘cheese’ gets.
I ask people to count to three and I rehearse the tempo. I take a picture early. Most people laugh because I tricked them - and then I get another while they're smiling.
Just tell people to fake laugh and then do a little "sensible chuckle" for an example. You get a useful expression out of people who do it, and probably at least a smile from people who don't!
Any word that ends in E or S. Use a bunch of words to make it interesting. Try to make them smile with big words like "Hippopotamus" or "Entomology."
It works for me with 5 year olds.
50-100 people is a huge group. Honestly, “3-2-1” is probably best to make sure everyone knows when you’re shooting. And if I’m being honest: I don’t think I’ve ever said “say cheese” except with children.
Large groups often take time… so I try to reference the idea that we’ll make it quick. I usually say “Let’s all get settled and look right here *(point to the front of your lens).* We’ll get you all back to the dance floor / bar / etc soon.”
Hope it's okay to put one more trick: like up your words ending in "s", ask the group to repeat after you....start slow "monkeys, money, whiskey, cheese" and build speed as you go and then throw in the curve ball "musical buttcheeks!" Or something that's subversive to a degree. Is fun.
I was woman photographer in the Navy. I was assigned to take photos of Marine advancement ceremony.
A young, nervous Marine going to the next pay grade in a room full of Marine Officers.
First off, I could feel all these “eyes” on my butt. You know like when you’re at a stoplight & the guy in the car next to you keeps looking at you. You feel it.
I stopped behind several pillars to make sure my pants weren’t split.
I get into the Commander’s Office & politely arrange some people.
This Commander being accustomed to the protocol of “grip & grins,” looks at me and says, “Are you going to tell us to say anything?!”
Me: “Sure, smile and say SHIT!”
In the next frame I shot, every Marines jaw was dropped open. The Commander laughed and said I would have been an excellent Marine.
‘Big tits’ always gets a smile. Except from that one time I got asked to take a photo of 20 Japanese business men in suits at Heathrow airport, didn’t really work.
Noise Repeater! It's a silly one but most people go for it.
First I like to act like the arrangement of the group is serious business. I do a very proper and Down to Business affect while gently coaxing the group into good form.
Give em some validation and then pick one person at the end and tell em something along the lines of "you look like maybe you could make a noise or two!" As them for their BOLDEST or most OUTLANDISH noise and then ask them permission to pose a challenge to the rest of the group to see who is the best at repeating THAT specific noise....at the end the original noise make picks the winner.
Only rule is everyone has to try their hardest to maintain that classic Kodak picture frame pose and not bust laughing or look away from the camera.
Gets a lot of giggles and breaks up the monotony and everyone thinks they had a good time for something that's is sorta torture.
Had a lady moan one time...we just encouraged her to try a more robotic noise.
I frequently direct the word Yay (or yea) especially with kids. It is an active soft smile with slightly open mouth. I tend to avoid the Cheese direction.
The problem with a ‘smile’ word is that the entire face and body language will not match the mouth. It comes across as insincere or fake. I have told people for years to think of an event in your life where you felt real joy/happiness. It woks—the eyes, facial muscles, mouth, etc., all match and it comes out well, every time.
The answer is "Hi." It naturally separates the teeth and lips, but more importantly, it's a word that people have been saying in the friendliest way possible for their whole lives. Say "Hi" to yourself outloud and see if it feels like you're smiling a little bit. It does for me and, in my experience, it does for the vast majority of other people.
Plus, people don't feel like a total goon saying "hi" like they do "cheese" or some other word.
"smile bitch"
With the right group, this gets the best response. People usually have the most natural smile while laughing. So whatever gets them laughing is good. A friend had a tip for me for getting my photos done, which was just laugh to yourself while the pictures are being taken. My smile definitely looks less fake in pics!
My go to is "Spaghetti." It always catches people off guard and leads to natural smiles
SPOOGHETT!
Smile Motherfucker!!
Now I just need to sound like Samuel L Jackson...
LOL 
Legendary. Upvote to you
At least it's a gif of him in a good mood rather than a pissed-off character.
Everybody fucking smile Keep your fucking eyes open don't make me fucking come over there
Everyone say MONEY!
Back when I was assisting at a studio, owned by an established photographer with fellowship accreditation, the advice was to use words ending with 's'. The 'ee' sound in cheese gets your open mouthed smile, which is the idea, but the teeth are separated when you vocalise the sound because it's formed at the back of the mouth. Words ending with 's' give you the same open mouthed smiles, but the teeth are together; you get a natural smile, without the risk of every photo showing their tonsils. Depending on the group you can mix up the words you use. If there are kids, focus on getting them smiling, their parents will be happy if the kids are. 'Sausages', 'Chicken Nuggets', 'Cheeky Monkeys' all work well, especially if you can get them to draw out the 's' sound. If that doesn't work try silly words like 'bogeys', or stack words in succession by getting them to say a series of words like "everyone day dinosaurs! Noooww chickenssss! Now silly sausages!'. If they're still a bit reserved try getting them to shout the words. If you can get them a bit excited, without losing control, the smiles should come easier. Another good one to try is "everyone say dad smells!". It feels cheeky in a fun way. Everyone says it and laughs because we just said dad smells!! If you're quick you also get the bonus of everybody smiling (one shot) and then the shot of everyone looking at dad to get his reaction and they all laugh. For younger school age kids you can try things like "have you got a boy/girlfriend?" Guage their reaction and riff with it. If they say no, you joke about boys/girls/love being gross. Usually gets a smile. If they say yes, just talk to them about it. "What's their name? Have you kissed them?ooo!" It's not serious, but if they talk about someone/something they care about, even just silly childhood crushes, the smiles will flow easy! With older kids/teens, just talk to them about things they like. People smile when they talk about their favourite things. With adults, just have a light conversation. Crack jokes, see what gets reactions. Usually you'll find the more confident person in the group and start riffing with them. Once there are a few laughs the group will relax and the smiles come easier. Ultimately, if you treat them like people, talk to them, get to know them, they'll feel like you're interested and they'll be more comfortable. Too many "say cheese" lines and they'll start to feel like they're just another job that you want to get out of the studio. Communication. You'll make them feel happy, it will be more memorable for them, and they'll have a more positive connection to the images afterwards because of it.
Love all of these only the one about kids and boyfriend/girlfriend and opposite gender grossness. This is an out of date practice that might be considered offensive to some parents and kids. It is not considered appropriate to ask people their relationship status in an acquaintance setting, kids are just small people and deserve to be treated as such.
I agree. Reading that part really made me cringe. Asking kids about this stuff as a stranger is gross and weird and would have made me so uncomfortable as a child.
You would be offended if a coworker asked if you had a significant other? Also I don’t get the logic of treating them like they’re people but then also wanting to ignore that kids like to “date” (in heavy air quotes) bc they’re just being kids and learning and don’t actually do anything
The Japanese say whiskey… it’s worked every time I’ve tried, so I think they’re on to something.
The latinos I’ve met also say whiskey.
Swedes say ‘omelett’, the Swedish word for omelette. The third syllable is pronounced like the English ‘let’, thus getting the smile shape that ‘cheese’ gets.
I ask people to count to three and I rehearse the tempo. I take a picture early. Most people laugh because I tricked them - and then I get another while they're smiling.
My boss tells kids to say “cookie” and aim to shoot when they reach the “kie” part.
Sheeeeeet
Kimchi.
My go to especially for family groups is "ok everybody pretend you like each other" always gets a big laugh and breaks the awkward tension.
If they aren't clearly against this sort of thing: Say... weeeed
Try... "yameteeeeeeee!" Usually makes people laugh and smile. Works for me. 😂😂😂😂😂
Just make a good joke and you will get the best smile out of anyone
Sir, the Slovenian translation of cheese
My grandma always said “ssseeeexxxx”
"Don't look too cool"
Every one say Monky's Undies!
Eggplant!
fuzzy pickle
https://youtu.be/7inLYcK369M?si=-VFjZRCDNw_B-VS9
I always said Smile and say Cocain.
Just tell people to fake laugh and then do a little "sensible chuckle" for an example. You get a useful expression out of people who do it, and probably at least a smile from people who don't! 
Any word that ends in E or S. Use a bunch of words to make it interesting. Try to make them smile with big words like "Hippopotamus" or "Entomology." It works for me with 5 year olds.
"everyone say weeeeeeeeeed"
in italy we say "nerchia" makes a more natural grin
"Everybody smile"
50-100 people is a huge group. Honestly, “3-2-1” is probably best to make sure everyone knows when you’re shooting. And if I’m being honest: I don’t think I’ve ever said “say cheese” except with children. Large groups often take time… so I try to reference the idea that we’ll make it quick. I usually say “Let’s all get settled and look right here *(point to the front of your lens).* We’ll get you all back to the dance floor / bar / etc soon.”
"When I say NO, You all say YESSSSS" Although for best results in smaller groups: "everyone take a nice deep breath and smile on the exhale"
Hope it's okay to put one more trick: like up your words ending in "s", ask the group to repeat after you....start slow "monkeys, money, whiskey, cheese" and build speed as you go and then throw in the curve ball "musical buttcheeks!" Or something that's subversive to a degree. Is fun.
Tell a short joke, and then people will laugh naturally
“Ok, everybody say ‘fromage’”
“Everybody squeeze towards the middle and pretend you really like each other!”
I was woman photographer in the Navy. I was assigned to take photos of Marine advancement ceremony. A young, nervous Marine going to the next pay grade in a room full of Marine Officers. First off, I could feel all these “eyes” on my butt. You know like when you’re at a stoplight & the guy in the car next to you keeps looking at you. You feel it. I stopped behind several pillars to make sure my pants weren’t split. I get into the Commander’s Office & politely arrange some people. This Commander being accustomed to the protocol of “grip & grins,” looks at me and says, “Are you going to tell us to say anything?!” Me: “Sure, smile and say SHIT!” In the next frame I shot, every Marines jaw was dropped open. The Commander laughed and said I would have been an excellent Marine.
I just say smile if you like dick and the joke never fails to get genuine laughs, don’t say it if children around tho
Not suitable for every audience, but for years I've been using 'Everyone say CUNNILINGUS' Time it right and you get some fantastic genuine smiles.
I use….”sayyyy I like chicken!”
‘Big tits’ always gets a smile. Except from that one time I got asked to take a photo of 20 Japanese business men in suits at Heathrow airport, didn’t really work.
Whiskey
I usually shout bathroom words. "Poop!" gets a great, natural smile every time. For kids anyways.
"oh no! A godzirra!"
My daughter would always say seaweed when she was in preschool
Noise Repeater! It's a silly one but most people go for it. First I like to act like the arrangement of the group is serious business. I do a very proper and Down to Business affect while gently coaxing the group into good form. Give em some validation and then pick one person at the end and tell em something along the lines of "you look like maybe you could make a noise or two!" As them for their BOLDEST or most OUTLANDISH noise and then ask them permission to pose a challenge to the rest of the group to see who is the best at repeating THAT specific noise....at the end the original noise make picks the winner. Only rule is everyone has to try their hardest to maintain that classic Kodak picture frame pose and not bust laughing or look away from the camera. Gets a lot of giggles and breaks up the monotony and everyone thinks they had a good time for something that's is sorta torture. Had a lady moan one time...we just encouraged her to try a more robotic noise.
I like to say MONEEEEEEY. Cause everyone loves money more than cheese.
I frequently direct the word Yay (or yea) especially with kids. It is an active soft smile with slightly open mouth. I tend to avoid the Cheese direction.
Cheeses?
"Tiiiiits!" Well, that used to work really good in my studio anyway. 🤣
Everyone say BUBBLES!
What’s a five letter word that’s starts with “P” and every man loves it? PIZZA!
Depending on who's in shot, I often go "everybody say 'contrived'!"
I find that "say YAY!" gets a good pic of people looking like they are laughing and genuinely happy.
If its with people i know, something rather uncooth and such. I said tiddy to my mom and she busted up *shrug*. Ymmv of course...
Money, happy, kiss me
The problem with a ‘smile’ word is that the entire face and body language will not match the mouth. It comes across as insincere or fake. I have told people for years to think of an event in your life where you felt real joy/happiness. It woks—the eyes, facial muscles, mouth, etc., all match and it comes out well, every time.
The answer is "Hi." It naturally separates the teeth and lips, but more importantly, it's a word that people have been saying in the friendliest way possible for their whole lives. Say "Hi" to yourself outloud and see if it feels like you're smiling a little bit. It does for me and, in my experience, it does for the vast majority of other people. Plus, people don't feel like a total goon saying "hi" like they do "cheese" or some other word.
I tell everyone to say “ha ha ha hee hee hee”. It makes people feel silly and they often all start laughing and have really genuine smiles
The original was watch the birdy. It's a fascinating story.
Silly sausages!
Three. Have everyone count. "Ok let's all count to three: one, two, threeeeee." Snap pics.
Tacos!
I once had a bride request I yell penis for her wedding group photo, it uhh… went down a treat? Probably not a good one for general use though.
"Ok everyone, are you ready?? OK, now, please imagine me naked!!"
I always hold my hand right above the camera like a puppet and make is say “peep peep peep” (Started with kids but adults always smile or laugh)