How do I manually focus my macro in poor lighting conditions?

Question

I'm using my Canon 100mm f/2.8L macro handheld all the time together with a flash rig and it works wonders. Most of the time I have an Eg-S focusing screen installed as well which makes it even easier to get the focal plane where I want it. A couple of weeks ago I got the Kenko 1.4x teleconverter and started to use it together with my macro and with it I was able to take some even cooler shots.

As the results with the Kenko 1.4x were much better than I expected I decided to pick up their 3x teleconverter too as Mark Plonsky, one of my main sources of insipration, seems to be doing pretty well with it.

However, due to the three stop loss of light it is now considerably more difficult to manually focus using the viewfinder since unless lighting conditions are optimal it is very dark. Using liveview works really well but since many of my shots are handheld I usually steady the camera against, for instance, my shoulder and then liveview isn't really usable as it is too close to my eyes.

One thing I have considered to address this issue is to get a Brightscreen but reviewers seem to have mixed feelings about them. Do you have any suggestions on how I can manually focus with the three stop light loss without losing the flexibility of working handheld?

Answer 1

Do you have any suggestions on how I can manually focus with the three stop light loss without losing the flexibility of working handheld?

If you'll excuse the trivial level of the answer - which works well for me - I on occasion use an LED torch for night lighting for focusing purposes either when the flash focus assist light is ineffective or I'm not using flash.

To retain manual flexibility you'll possibly want to grow an extra arm or find some convenient way to hold a torch or, (something I'm considering), provide a camera mounted clip on light for this purpose. There are many small LED lights with clips available. Ideal would be either something you can turn on and off without moving your fingers far from their default positions, or a timed on period so you can push a button and have say 5 seconds of illumination.

Answer 2

due to the three stop loss of light it is now considerably more difficult to manually focus using the viewfinder since unless lighting conditions are optimal it is very dark

with that kind of teleconverter, you're losing another 3 stops to whatever you're lens is set to. Even @ f/2.8 that will reduce the relative aperture to f/8. With that type of optical system, you cannot do much about the aperture, ISO won't help improving focusing so only the amount of light coming in can be adjusted. Using extra source light only during the focusing phase will help you there.

Now, I'm just wondering if you can really acheive sharp results like that:

Using liveview works really well but since many of my shots are handheld I usually steady the camera against, for instance, my shoulder and then liveview isn't really usable as it is too close to my eyes.

Because shooting with a macro lens wide open + a 3x teleconverter will give you an extra shallow Depth of field, making your handlheld focusing pointless... unless you're not looking for sharp results.