Using red light for focusing

[Barmaglot]

Shooting macro, every now and then, I encounter a light-shy critter - saron shrimp, banded pipefish, some crabs, etc. I have a red mode on my focus light, but actually using it is near impossible - at least on my Sony a6300 + 90mm macro lens combo, I basically get a solid red screen with no distinguishing features. Pointing it here and there while mashing the focus-on button I get some darker blotches but nothing identifiable, so getting a shot is basically a matter of blind luck.

 

I'm currently transitioning to a new a6700, and playing with its features, I discovered that if I set the white balance to a custom value off the red light (it ended up reading something like 3600K), then - at least while playing with it dry, in a darkened room, under a red light - the on-screen picture is a lot clearer. The resulting shot is extremely green-tinted, but when shooting raw, it doesn't really matter. However, and this is even more frustrating, this only works when live shoot effect is set to ON - when using settings appropriate for macro (f/16, 1/160s, ISO 100) this produces a black screen, since it previews the exposure as it would be without a flash, and if I set live shoot effect to OFF, then the white balance value is ignored along with everything else for the purposes of framing display, and everything goes super red and indistinguishable again.

 

Are there any ways to make using red focus lights easier on modern Sony mirrorless?

[Chris Ross]

I've used a red focus light on land with both Olympus and Canon and it seems to work quite well, that however is shooting fairly distant subjects and there is contrast between subject matter and the black backgrounds.  Have you tried reducing the brightness either on the light or taking it further away - one possibility is it is saturating the chip and as it's all red light it can't find anything to focus on.

[Barmaglot]

1 hour ago, Chris Ross said:

Have you tried reducing the brightness either on the light or taking it further away - one possibility is it is saturating the chip and as it's all red light it can't find anything to focus on.

Interesting idea - no, I haven't tried that. The Weefine Smart Focus 1000 that I use does have full and half-power settings in its red mode, but I've only ever used the full. Weather permitting, I'm planning to do some macro dives this coming weekend, so I'll try that out.

[Guest]

I use my strobes focus light instead of a focus light in desperate situations and never had an issue 

it also shuts off when firing the strobes

never been a fan of those red focus lights 

[Chris Ross]

2 hours ago, Barmaglot said:

Interesting idea - no, I haven't tried that. The Weefine Smart Focus 1000 that I use does have full and half-power settings in its red mode, but I've only ever used the full. Weather permitting, I'm planning to do some macro dives this coming weekend, so I'll try that out.

Don't forget UW red light is scattered much faster, the light should be a little dimmer - try both settings.

[Lewis88]

I use a Sola 1200 with red light, and it's worked great for me. 

 

I noticed as well that critters are less skittish, and my a6100 locks on focus quickly. 

[Barmaglot]

10 hours ago, Interceptor121 said:

I use my strobes focus light instead of a focus light in desperate situations and never had an issue 

it also shuts off when firing the strobes

never been a fan of those red focus lights 

Strobe modeling light is useful on blackwater dives when you get a critter that is attracted to light - that way you can track it by spinning around, instead of losing it as it swims into your focus light. I'm talking about a different situation though, shooting stuff that will retreat into its hole if you shine a light on it, doesn't matter where the light comes from.

[Guest]

3 minutes ago, Barmaglot said:

Strobe modeling light is useful on blackwater dives when you get a critter that is attracted to light - that way you can track it by spinning around, instead of losing it as it swims into your focus light. I'm talking about a different situation though, shooting stuff that will retreat into its hole if you shine a light on it, doesn't matter where the light comes from.

Strobe modelling light is red in my strobes

[Architeuthis]

I have Weefine 3400 focuslight and the red light is very useful for nightdives (during the day I do not use any focus light in most cases). At the beginning of the nightdive, I use the normal white light and as soon as I see a critter, I switch to red for making the photo. Focus is more difficult with red light, but most critters do not see the red light...

 

Wolfgang

[Barmaglot]

Took my new a6700 out for the first time yesterday and checked focus with red light. Conditions weren't perfect - the dives were shallow with lots of sunlight, but very poor visibility (tons of particulate matter in the water, lost sight of other divers at 3-5m) but I found some dark crevices, and to my surprise, I was able to see perfectly well on the camera screen while using the red mode on the focus light. I don't know what is it that Sony had changed between a6300 and a6700 in this regard, but whatever it is, it appears to be working very well.