Ok, I kind of overread that the OP want´s to go in ultra-macro … different story
I wish plants didn’t move. Many of my pictures are fingers with flower, as there is always a breeze. Just. In the moment when I click the shutter.
I use an Olympus Stylus TG-4 camera. It has “microscope” settings for close ups and an LED ring that clips over the lens. It is a small point and shoot type camera a fair digital telephoto. Also it has built in GPS. It is my go-to camera for i-Naturalist.
It’s an Amaran Halo and this particular model seems to have been discontinued for years which renders it kind of moot to share that info now. I use it with my Canon PowerShot SX40 HS (also apparently discontinued) with a Raynox DCR-250 snap on macro lens. They work well together, but it might not work as well for larger lenses on dSLRs. I seem to remember reading it causes vignetting with some larger lenses and was incompatible with some Nikon cameras. I think your best bet is to do a search for ring flash or LED ring light in combo with whatever camera brand you’re using.
I deal with migraine headaches from time to time which I understand is not at all the same thing but I occasionally deal with some similar issues. One simple solution is I wear sunglasses and close my eyes right before I hit the shutter. I agree that at 2x, you will never be happy with a contestant light source. One thing I did in the past was use a super bright led headlamp that I could set directly on the lens. This worked, but never produced high quality results as you can’t really freeze time. You can choose to accept noise and shake and just deal with it, but I was never happy with this. One option could be to settle for in studio work. This way, you can set up a studio where the flash is never visible. I believe Sam Droege has a YouTube video showing his Styrofoam cooler bounce flash set up. The flash is completely enclosed our at least could easily be modified to be completely enclosed. Diy diffusers can help with field photography. Making a snoot with a diffuser at the end can limit the area the flash hits. After market eye cups can also help reduce the outside light bleeding into the viewfinder. Another thing that may help is to set your shutter to single frame rather than a continuous mode to eliminate a strobe effect. Most flash heads will perform better this way too unless you get something real high end.
A flash shouldn’t be a problem, at least with a real camera. And anything beyond 1:1 magnification pretty much requires a real camera.
The reason the flash shouldn’t be a problem is that you shouldn’t ever actually see the flash. You have one eye closed, and the other against the viewfinder. The closed eye won’t see the flash since it’s closed. You can’t see the flash in the viewfinder because the mirror is up during the time of the flash. At most you’ll see a weak flash coming thru your eyelid, or the momentary increase in ambient light around the viewfinder. Both those are heavily attenuated.
I don’t know much about how sensitive some epileptics can be to a single flash, but all the above is worth considering. The few epileptics I’m familiar with are sensitive to repeated flashes, usually around 5-10 Hz being the worst. A single flash wouldn’t bother them.
To answer your other question, yes, you really need a flash for serious macro photography like you describe, with greater than 1:1 magnification. Yes, I know cell phones can take recognizable pictures on “macro” with sufficient ambient light. However, that macro rarely goes to 1:1 (equivalent for 35mm frame), and shutter speed will be slow and the depth of field poor.
The basic physics of how lenses work means you need a lot of light for macros. We think of f-stops being normalized measures of how much light the lens lets thru. If a picture of your house looks good at 1/200 second and f/8, then it will look good with any other lens also set to f/8 in otherwise the same conditions.
This simple view of f-stops only works because the magnification is much less than 1. In reality, the light indicated by an f-stop setting is actually attenuated by the square of (1 + M), where M is the magnification from the subject to the image plane. With a picture of your house, the magnification is much much less than 1, so (1 + M) squared is still basically 1.
However, at a magnification of 1, (1 + M) squared is 4, so you’re already getting 2 f-stops less light than what the lens setting would otherwise indicate. At 1:2, you loose a factor of 9, or about 3 f-stops.
Depth of field is another problem magnification. To get higher depth of field, you need a higher f-stop to get a smaller diameter lens. That robs you of more light.
Then there is camera shake. Small movements that you normally wouldn’t notice are magnified just like the subject. Holding the camera still can be a real challenge for macro photography. Unless you have a still subject and can mount the camera, you need to use a faster shutter speed to compensate for wobbles. That takes even more light.
Put all these together, and a flash is pretty much the only viable option. It gives you a lot of extra light, and works like a fast shutter at the same time.
A steady light the same brightness of a flash would be very bright. It would take a lot of power, and quite possibly would blind and/or cook whatever you are trying to take a picture of.
If you’re serious about macro photography, try a xenon flash ring light. That puts the light right where you need it, and also acts as a baffle to reduce the amount of flash bouncing back in your direction.
This seems obvious, but it’s not always true. I often look through the viewfinder with my dominant eye and leave the other one open most of the time, because if I keep it closed for too long I have trouble getting the two eyes to coordinate for a few seconds, and I don’t like that. We humans are often a bit weird.
Plus if you ever worked with microscope you know you need to have both eyes opened and it helps with macro too, as object can suddenly move and you’ll loose it if you won’t see it with another eye, so it’s a nice skill to have!
Agree whole heartedly with Olin.
Using a flash camera is much different than facing one. When using DSLR through the viewfinder you just won’t see the flash pop.
Have you ran this past your doctor/specialist? Is a single bounced flash a defined trigger for you?
For me, especially in the field, a diffused flash is the simplest most flexible way to go. Further to keeping it simple I use the compact clip on diffuser that came with the flash. Works great for my needs, 1:1 and super macro.
I admire those that do stacked imaging but in the field it would be highly restrictive. Subjects that pose still on a static platform are rare to find.