If you have a tablet, you could use it to carry a portfolio with samples of your work. A smartphone would work as well, but the screen is a bit too tiny... (and a tablet looks more professional ;) ).

A printed portfolio works as well, of course, and allows a larger size, but is bulkier.

I'm going to throw lots of ideas at a wall and make them stick. But changing cameras because it doesn't look the part is wrong. Use what is right for you.

Start with an introduction, and offer to show previous work. Whenever I make first contact with a model (granted it's online), I always introduce myself and provide examples. My business cards; each one has a different image from my portfolio on it; it's really useful as I always keep a few on me, and it allows people to see my previous work without the rigmarole of getting a phone out etc.

Make joke of the fact you have a tiny camera! So, mixed with what I said above, say something like, 'Hi, I'm Belle-Sophie; don't let the camera fool you, but I'm a photographer - can I take your picture please? If you're not sure, I'll happily show you some of my previous work!'

Wear a camera backpack, even if it's empty. You could be hiding a massive camera in there.

Make your camera look bigger? Could work. When I had my first SLR I used to fool people by chucking a battery grip on it and attaching a flash (even though most of the time it was off).

That said, use a flash! Learn about off camera flash/external flash, have that with you and obvious!

A side note, if they don't want to pose because your camera's tiny, these could be people you may not want to work with.

If you have problems with getting the full attention of your model: Try to get in a small conversation and also show them your portfolio, if you convince them with your work, than they will not think about the size of your cam.

At the sort of geeky/cosplay events you describe a good solution might be to wear a T-Shirt which addresses the issue. Here's an example I found with a quick search.

This should do a few things. To attendees it helps you look like "one of us". It indicates you are relatively serious about your photography, not just a random person with a point and shoot. It humorously addresses the issue you are actually concerned with, that people think you aren't serious/good just because you have a smaller camera.

I think this could help in combination with other people's suggestions. "I like your T-Shirt" is a good entry point for you to engage someone in conversation and explain why you think the camera you use is good for the type of shots you are taking.

Other than adding a battery grip or flash, you can't really make the camera larger, so it seems to me that your best options are to either prevent your subjects from judging the camera, or challenge their judgement:

• hide the camera: When you approach someone to ask them to pose, keep the camera out of sight. If you wear the camera on a strap, slide it around so that it's behind you; if you keep a camera bag with you, stick the camera in the bag. It like the expression out of sight, out of mind — even if they've seen you and your camera around, they'll be less likely to judge you for the camera's size if they're not looking at it as you talk to them.

• own it: Exactly the opposite of hiding the camera — make the camera the thing that starts the conversation. If you see someone looking at your camera, look them in the eye and say: "Aren't these mirrorless cameras amazing? All the resolution and features of a full size DSLR in a much smaller package! You should see the photos I get with this... here, let me show you." And then take a few shots, maybe asking them to pose however you want them. Then connect your phone or tablet to the camera so you can show them the photo on a larger display as you give them some patter about the built-in wifi and other great features of the camera. Give them your card and invite them to check out the photos on your web site later.

The models are obviously seeking maximum exposure.

They'll assume the people with several thousands worth of camera gear on them will be selling/providing the shots to magazines, big blogs, etc. Meanwhile, you with your little point and shoot look like you're adding to your own personal photo album/portfolio.

If you are providing these shots to somewhere with a large audience, make it known in your quick intro "Hi, I'm shooting for CosPlay Magazine".

If you are just adding to your own portfolio, you can't expect them to spare their time for you, as they're getting little from it. In that case, you'd have to "look the part" in order to get them to play ball, by playing on the same assumptions they're making which are currently stopping them posing for you.

I don't think it's about how people view your camera, it's about how people view you. If you're using an X-T2 and a 55/1.2 lens, it's quite enough for portraiture and the camera is capable of excellent results. However...

You describe yourself as "I'm this petite girl with a 'tiny' camera." Think of yourself as a confident woman with a first class camera and don't be scared to get in close for portraits. The ideal distance for this lens is when the subject's head about half-fills the field of view. Concentrate on getting the subjects eyes in crisp focus, don't overdo the bokeh (it's a tool not an end in itself) and watch what's going on in the background.

I'm 6'4" and choose to use my Fuji X-Pro2 .. in preference to my Canon 1D's and 5D's. Trust me on this, a small camera is wonderful.

I would suggest you print a few of your best images and show your portfolio to the middle and ask them if they can pose that well?

let them see what you can do. I get the same attitude holding a "little " Sony A7r2 with a 55 mm Zeiss lens till they look at my port on my phone or iPad

Consider using an off-camera flash, with a portable flash modifier.

I was helping my Dad take portraits of my mom at a Christmas lights show at night. I put a radio trigger on his, and acted as a voice-activate light stand with a fstopper flash disk on the flash. You'll be amazed how may people think that we're pros, and we got some nicely lit photos to boot. I felt that the bystanders were more patient and clearly avoid walking into the shots.

I would presume you're taking pictures of cosplay models in convention centres, where the indoor daylight lighting is actually fairly dark. You can use the flash to light and emphasize your subject away from the background, and make your pictures stand out more.

That's how marketing works: if you want customers, you have to show them what they want to see. If your models care about is how big your camera is, then getting a bigger camera is the easiest way to get their attention. Sure, it may be unnecessarily bulky and expensive but if this is what's working, just get one.

Do you think real estate brokers wear suits because these are comfortable and cheap?

If you want the ultimate in recognition (whether rightly or wrongly) of being the baddest pro at the geekfest, get a couple of friends to be "assistants" and be your "voice activated light stands." Give one a monopod with a speedlight and small modifier on the end and the other a 30-40" reflector set to carry while following you around. And since you'll have all of that with you, actually use it! You can get third party flash transmitters and cheap (but useful) flashes for the Fuji X system from Godox. And hey, the flash transmitter on your hot shoe screams "Pro!"

If you are indoors in bland convention centers, using flashes with modifiers can allow you to overcome the "blah" lighting by killing the ambient (or at least diminishing its influence on your subject) and will set your images apart from the herd. Outdoors it is just the opposite, a little fill goes a long way to reveal details of faces and costumes that would otherwise be lost in harsh shadows.

You all should dress like working professionals would be dressed when on the job. Business casual or better. Matching logoed Polo shirts would be a plus. No tank tops, SpongeBob SquarePants T-shirts, cut-off shorts, or flip-flops! Wearing a "weak" costume yourself will just add to the perception that you're one of the countless competitors of the other models who also happens to be an amateur fangirl, rather than a serious photographer there to do 'business'.

Make matching large, media style photo ID badges for all three of you. The kind that fit in an "oversize" holder that hangs around your neck via a lanyard. From inside such a holder, it's hard to tell the difference between something printed on heavy card stock and a plastic ID card. Yours should clearly identify you as "Chief Photographer" for whatever you choose to name your organization and theirs should be labeled as "Photographic Assistant." Select a unique but catchy and official sounding name to use to later market your Cosplay work, or use the name of your existing photography page, etc. Bonus points if the lanyard ribbon is from a high end photographic company such as PhaseOne, ElinChrom, or Prophoto. They're often freebees given out at such companies photographic trade show booths.

Don't forge an actual credential for an organization you don't actually represent! That will cost you in the long run, if not in the short run. Imagine running into a legit shooter for the entity you're claiming to be with! Even if that does not happen, word will get around in the Cosplay world very quickly that you don't really shoot for 'Wired' (are they even still in publication?) or 'Rolling Stone'.

You could also address the portfolio delima by having a few letter size flyers with several examples of your work along with your contact info (a sort of oversized business card) on a clipboard carried by one of your "assistants."

One offbeat way to expand the perceived size of your camera/lens without adding much weight is to use a blimp - an enclosure intended to minimize the sounds made by your camera when shooting with it in a noise-sensitive environment - if such exists that will fit your camera. As even DSLRs, not to mention mirrorless cameras, get quieter and quieter, though, blimps are fast disappearing other than those made for cinema film cameras.

Another suggestion, included in a now-deleted comment to the question, is to use a speedbooster with a larger and longer focal length lens.

Get a vest made of net (for coolness, both sensens) with lots of pockets. Call up some camera repair people & tell them you are looking for a cheap but impressive looking telephoto lens & that it doesn't have to actually work. Maybe they come across lens that can't be repaired practically. Put a lens cap on it & fix it so it sticks out of a pocket.

Get a fake, cheap, big but light plastic camera and carry it around in addition to your actual camera.
You'll make a better impression and get more chances to shoot. By the time they realize the bigger camera is fake, you'll be shooting already and they'll be too embarrassed to stop you.

Get a lanyard and put some kind of identifying card in it.
Make it look kind of professional but also outstanding, with fancy colors and text and a pic of your face, of course. You can also include your blog's URL, Instagram account, whatever flies your boat. Most people won't even read the card, but part of their attention would now shift from your tiny camera to your lanyard. They'll just assume it's some kind of credential or press pass and naturally let you shoot.

Those ideas are in the same spirit of your wearing a staff t-shirt or some other kind of professional-looking apparel. It all comes down to looking more professional. If your tiny camera (mine is an EPL-7) is making you look less professional, use props to work against that.

Cosplay as a "professional photographer"

Yeah this is going to sound silly, but buy a photography vest, wear a camera backpack. Use a double-sling with a couple of ancient —but huge— DSLRs on. Attach a reflector and monopod to your pack.

You'll look like a ridiculous caricature of a photographer, but you'll be unmistakeable as a photographer. Your models might even appreciate the effort you've gone to.

This isn't to say that how you act and what you say aren't as important, but we're a very visual species. If somebody decides you aren't going to take a good photo of them from across the room, they're probably not going to engage with you.

What could work: Get some outmoded and/or defective, but impressive looking gear cheaply, and carry it prominently on yourself - but USE the small camera giving some handwave-ish technical reason why you are using it instead (eg that you ONLY brought the big gear for longer-distance telephoto shots and that you do not want to get unnecessary dust in the lens mount by constantly changing lenses on-site - or that the big camera is out of battery and you are using your emergency kit).

I was going to write this as a comment but, answers should be answers. It's not your camera. It's your attitude.

You need to change your verbiage and be a bit mean. It will make you feel like an ass but it's what's needed.

In stead of "Hey can you stand over here so I can get your picture." Just come out the gate with "Stand over there! Big Smile! Thanks!"

Direct the subject where you want them. Don't ask, demand. Get pushy. If you watch the people getting the shots you will notice there not asking there just demanding. Make sure your not asking to much. Try not to be too aggressive and stay away from demeaning terms. If you recognize their costume call them by that name. For example "Hey Captain, look this way, smile big!" is great. "Hey sugar tits, look sexy for me!" Not ok. Depending on the conference and what not the line of too aggressive may move, but there are always things that are just off limits. It can take a while to get the hang of being aggressive without being rude, but at an even like a comic-con you have about 4 seconds to make an impression.

A good analogy is the annoying park photographers when you go to a theme park or zoo. They say stuff that you would otherwise find rude, snap a picture, throw a ticket at you and move on. "Hey Pa Pa, over here! snap You can pickup your pictures over at that counter." and off they go. You need that same level of pushy. Like you said your not the only photographer. Why should they take time from their fun for you? Instead of trying to make that argument, just do it. Some people will still say "No thanks", some will call you pushy, but at the end of the day, more people will respond positively then negatively.

petite girl with a 'tiny' camera

This could be your differentiator/gimmick - you may even be able to get angles not possible for the dinosaurs. Problems are benefits.

It seems you need to look professional, not just some one taking a pic, but not as any value statement on you, but because of publicity (as @i-CONICA said); and, secondarily portrait quality.

There are many aspects to communicating "professional!" in the answers: equipment, attitude, manner, a press badge(!), a portpolio, naming your publication, assistants. I think the easiest one is dressing formally - also helps you feel more professional, which comes across in your attitude.

[Another approach is to notice other photographers: apart from their equipment, what makes them instantly seem professional? Though I have to admit, bulky equipment is such a huge signal, probably overshadows any other.]

How can I get models (attendees) to take me more seriously as a photographer with a small camera?

There's a famous phrase: "clipboard mentality". In the 1990s, projectors started to become more common in colleges. Thieves would walk into a room, holding a clipboard, and steal the expensive projection equipment. While class was in session. Until this problem became notably widespread and security was forced to crack down on the issue, people just trusted professionally dressed people who looked like they had equipment and seemed to be doing good things.

"I have a clipboard. Therefore I'm a professional and expert, and know what I'm talking about."

How this applies to you is: equipment matters. Even if you're more skilled and can come up with higher quality results in smaller equipment, people's perceptions may not take all that into account, so the equipment you use can matter. So, let's not pretend like it doesn't.

A bunch of what I'm about to say may involve some trade-offs between usability and practicality (including ease of transporting things), and feasibility may vary based on just where you are. Naturally, use creativity to customize (slightly, or extremely massively) based on what you think will effectively work and what you desire. Just don't think that you should limit yourself to only your small camera, and you may be able to come up with something.

Often they carry tripods and reflector screens as well.

So you've offered your own solution. If successful people are getting the results you desire, and they are using that technique, then you using that same technique may help. That is one approach that doesn't involve you needing to change camera equipment.

Even if they have giant tripods that you don't want, consider some sort of small thing which at least shows that you're able to stabilize your equipment. Even if you don't use that equipment, just having it available may lead to them taking you more seriously.

Note that the equipment doesn't need to be professional photographic gear. You mentioned using a T-Shirt.

If you can corner off a section of land, make that area yours. Take some rope and make a "tunnel" for people to walk through, and shoot them at the end. Maybe have a prop, even if that isn't anything more than a bar stool people could sit (or stand!) on. Then people may pose for you because using the prop just looks fun.

Having a portfolio may also be helpful. (Ensure the participants look happy. Then your potential participants will be more inclined to want to do the happy-making thing.) remco's answer suggested a tablet. That may be one approach. Another approach may be to have a bunch of print-outs in a strip which you can hang on a wall (or toss half over a fence). Or somehow incorporate that into your costume. The back side of your shirt/jacket/whatever can be advertising space (whether you write something fun, witty, or just show a photo), possibly helping to serve you with your next customers while you're active with the first one.

A bit of music may also perform wonders. (Probably preferably wordless, so that you don't feel any need to talk over lyrics.)

I went to the one in Dallas a couple years ago, with a Sony alpha 6000 that’s as small as most micro four thirds. I didn't have any trouble getting people to stop for pictures, and often got, “yea, and can I take yours?”.

I had removed the branding from the tiny camera bag and integrated the pouch into my costume.

How can I get models (attendees) to take me more seriously as a photographer with a small camera?

If by "models" you've meant "people who don't know me" the answer sadly is:

You can't.

Try to see it from the model's perspective: Imagine several persons are being presented to you. Now you have one second to tell who is "pro" photographer with the potential to make you some great shots and who's just "a guy with a camera" wasting your time.

If one of them is Ansel Adams you can't tell that. If one of them publishes in word's best magazines, you can't tell that. If one of them had won multiple Pulitzers, you can't tell that. Vivian Maier photographed most of her life and noone ever noticed her (that was her strength, as it turns out).

Sadly, the only way of judging a photographer in few seconds is by looking at the size of their gear. If you're in the business, you can do even better: judge price of their gear.

To ask strangers for sessions, you already know the solution: 5D, L-series lens, tripod, flash, reflector screen. Add a bouncer-framed guy to carry that all for you : )

You ask them to take you seriously. You need to clearly demonstrate that you're taking photography seriously - investing few k$ in gear is as serious as you can show.

Bringing heavy gear to tote around is straightforward and proven to be effective. You can try workarounds, but they're likely require more work and be less effective. Which is sad, because nothing takes people shots like Fuji. With X-series being as good as they are in compact package, there is no reason for S5 successor.

A couple of people have commented that carrying something that resembles a press pass might help. But, why not get an actual press pass? In the UK press passes tend to be taken seriously, and, as all press passes pretty much look the same regardless of who issues them, they tend to be immediately recognisable. A real press pass may just give you the edge that you need.

Issuing bodies realise that professionals starting out need credentials too, so if you are working professionally and having your photographs published, even if only irregularly, I'd recommend joining a journalist's union and applying for an actual press pass.

Consider a flash mounted on a flash bracket (say screwing onto the camera's tripod mount) so the flash is located to one side of (and often somewhat above) the camera's centre line.

The flash mount can be useful as a grip point, and having the flash further away from the centre line improves flash results generally. (No red-eye, reduces flash spurious reflections even more than closer to centreline hotshoe mounted flashes.
Actually using Using the flash is optional :-) - and depends on situation.

Looking into a lens with a large lens hood increases the apparent size of lens and thus system. That it improves results is a bonus :-).

Showing people the results is often a "gateway" to more opportunities. I occasionally zoom in after a shot and position the image on eg a face. When they 1st look they expect a wider image and see a cropped face. Before they get time to react appreciably zoom out so the larger picture progressively appears. When photographing a group I find that sizing to show individuals and panning along the line as they view is much appreciated.

You've gotten a lot of good answers but one particular thing nobody has mentioned already:

Offer to pay for their time. "Excuse me, I'd love to get a few quick shots and would be happy to pay you for your time."

This is beneficial because you immediately establish you're serious and willing to pay. If they take you up on it you also no longer have to worry about delivering any copies to them high res or low res! On the other hand some may hear you and respond with "Oh you don't need to pay." Or show them (in camera) and if they like it can then try to swing it to a TPP. Just be prepared to pay if that is the outcome.