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I have a Nikon d7200 camera and managed to get my hands on Tamron 90mm f2.8 macro lens. While trying to take some shots at 1:1, I found lighting a big issue if I am stopping my lens down. I was suggested to buy a ring flash.

My question is, how do I select a ring flash? What parameters should I be looking at? I am not a professional, just a beginner trying it out as a hobby. Only flash I have at present is the pop up flash that is built into the body. Thanks.

My first concern would be...

Do I need a ring flash?

Yes, having your big lens in front of a bug will cast shadows, and yes, a ring flash solve most cases, but it has a very particular look.

Here are some macro photos where you can see the light source is not a ring flash.
They are using lateral diffused light.

https://blazepress.com/2015/01/magical-macro-photography-bugs-vadim-trunov/

This one has the light above the bug (Cenital-ish)

https://guttikar.com/photography-news/macro-photography-tip-using-normal-lens-turned-around/

So, a normal radio trigger and an external Speedlight (probably with a softbox, even a small one) could be what you need.

But answering your question

1. Will it fit my lens?

2. Does it have enough power if I need to lower the aperture to have better Depth of field?

3. Can you change the power output?

4. Real flash or Continuous light.




5. Bulkiness.




6. Do you want to use it later, for portrait photography?

For macro photography, you do not need much power. So any led based light will do at a basic level.

Point 1 is pretty obvious.

Point 2 and 3 are the ones that will give you flexibility.

The rest is ok to consider.

If you want a true ring flash, depending on your kind of macrophotography:

• Still objects, plenty of time: you can work in manual, do test short... about any flash will do. No need for much power at close range.


• Shooting outdoors, handheld, moving objects (bugs, etc...): something that is compatible with the camera TTL exposure will allow you to shoot using the camera auto modes.

If you do very close shots, there are also circular LED lights that aren't technically flashes but are much less expensive and can do the job (Canon has a macro lens where such LED are built-in).

Being able to use only one half of the device for side lighting is a useful feature (full ring flash tends to produce flat, shadow-less images).

Especially in case you are considering a legacy device, especially if non-TTL, check how low in power it can go.

One example of a device hard to use nowadays is the Soligor AR-20 not infrequently found on the used market - this is a computer (external photocell) ring flash which is only specified for 20cm and more subject distance, and is designed to serve at either f/8 or f/16 at ISO 100.

Some DSLRs/DSLMs do not even have ISO 100 anymore, and f/8 leaves you terribly little maneuvering space if you need to get closer or need to tone down a stop or two - you easily end up with your iso cranked all the way down, your aperture at f/22 (great DoF but you are in deep in diffraction territory here ... and when have you last cleaned your sensor? :) ), and still overexposing....

There are some cheap and cheerful ring flash adaptors if you've got an external flash. They work surprisingly well for close range considering they're basically just light guides, thought the one I have doesn't deliver as much light at the bottom as at the top/sides and needed a little modification to fit nicely. This isn't much of an issue if you're shooting landscape.

Because they're dumb light guides, the TTL in your flash functions as it normally would.

The only shot I've got to hand taken with it has blown highlights and was taken at annoyingly high ISO, which I forgot to change after shooting at dusk with a long lens. It was also cropped from a resized image I was using as a desktop background. But here it is anyway: