Focus and the TG4/5

The Olympus Tough TG4 and TG5 are two camera models that you’ll see a lot of around the macro dive sites.  They’re relatively cheap and have an awesome macro mode.

Like most compact cameras, the TGs have a single large focus point in the center of the frame.  It makes focusing a bit of a challenge sometimes.  Here are some techniques to help you out.

Focus, Hold, and Reframe.

This is a typical way that people work around the fixed focus point with a compact camera.  It works like this:

  • Select a focus target.
  • Half-press the shutter button to get an initial focus.  You’ll see the focus square in the LCD change to the color green and the camera will beep.  The beep is hard to hear when the camera is in a housing and underwater.
  • Keep holding the shutter button at half-press to keep the focus locked.  Don’t let go and don’t push it all the way to take the shot.
  • Reframe the picture.
  • Check to make sure that the right part of the picture is in focus.  Move the camera back and forth to move the focus.
  • Push the shutter button all the way down to take the shot.

So for something like a nudibranch’s rhinophores (their “horns” or “eyes” or “sensor stalks” or whatever you what to call them), you will always have problems getting them in focus with a compact camera because the area between the rhinophores is empty space.  So focus on one rhinophore, hold the focus, reframe to put both rhinophores in focus and the subject in the frame, and snap the shot.

One problem with this technique is that when you change the framing you might move the camera in or out a little bit which changes your focus.  So right before after I reframe, I do one split-second check that my focus didn’t move.

Focus Lock

Both models of TG camera have a highly undocumented focus lock feature.  The way you set it:

  • Select a focus target.
  • Half-press the shutter button to get an initial focus AND HOLD IT THAT WAY.  You’ll see the focus square in the LCD change to the color green and the camera will beep.  The beep is hard to hear when the camera is in a housing and underwater.
  • Push the “OK” button on the back of the camera to lock the focus.  Now the camera works the same as with Back Button Focus.  If you didn’t hold the shutter button at halfway, pressing “OK” will take you to the quick settings menu.
  • Take pictures using the locked focus.  Move the camera back and forth to change the focus point to put it exactly where you want it.  Pivot around the subject to change the angle of the focal plane.
  • Continue to take pictures with the locked focus.  You can now take pictures a lot faster than with the focus, hold, and reframe technique.
  • To unlock the focus, hit the “OK” button again.

Going back to our nudibranch example.  Focus on the flat spot between their rhinophores, lock focus, then usually you back off a tiny bit to put the rhinophores into focus.

Manual Focus Adjustment

Most compact cameras do not have manual focus.  But the TG4/5 supports it, although strangely.  You lock the focus just like described before.  Then you can use the up and down arrows on the keypad to move the focus point forward and back.  A shrewd reader will discover that they can use focus lock and the down arrow to move the focus as close to the front of the lens as possible and this lets you to take shots where tiny subjects fill the frame.  You’re welcome.

See you underwater!!

–Mike

Behind the Shot: White Rose

Teeny tiny tubeworm. TG4 with 2 handheld torches.

A post shared by Michael Smith (@ryzhe.kuznetsov) on

Location: Tulamben, Bali, Indonesia

Dive Site: Kwanji (awesome place to get grilled tuna or jack during surface interval)

Depth: 18 Meters

Story:

I was a student in a workshop run by Irwin Ang and it was a pretty rough day. Being at the end of the dive season in late December, the waves at Tulamben were fairly high and made shore entries hard. We aborted at a dive site the next day.  The surge was killing my stability to take focused shots without motion blur.  I was overweighted by 3kg just to keep from getting pushed around as much by the surge.  That also made water entry even more worse with the big waves: it’s hard to keep your head above the surface when you’re packing 8kg of ballast and no exposure suit.

When the start of the dive is hard, it’s almost impossible to get into the right mindset to go hunting.  Sometimes you can’t find anything because all the creatures are on strike or asleep.  Or it could be that you forgot how to see and you need to just take pictures of anything so your eyes work again.  So I started looking for abstracts to take pictures of.

If you’ve never been to Tulamben, it’s the land of black sand… all volcanic rock.  After every dive, you dig it out of your dive clothes.  It’s awesome for low-key (black background) images.  And it’s easy to see white things on.

I found this tiny white tubeworm, a white thing on the black sand.  It was at the most 3mm across.  This takes a supermacro setup and even with the macro mode on the TG4 I barely had enough magnification to see the subject.  So I zoomed in and used focus lock and manual focus to as close to the lens as I could get.

Lighting was hard–at anything below 12m or so there isn’t enough ambient light.  I had been hand-holding a torch with my left hand alongside the camera.  But the more you zoom (ie, the closer you get to supermacro), the more light you need.  A single torch just wasn’t bright enough.

I almost always carry an extra torch in my right thigh pocket.  So I pulled it out, turned it on, and set it on the ground about 1.5cm to the right of and slightly in front of the tubeworm.  Then I put my other torch similarly on the left side.  This made a “miniature portable underwater macro portrait lighting studio”.  Just like your glamor shots only different.  =)

I did bump the ground once and the tubeworm disappeared for a couple of minutes when it felt the vibration.  Working close with tubeworms, you sometimes have to back off a bit, let it relax and come back out.  They can feel vibration and they can feel moving water.  The trick with a tubeworm on the bottom is to remember where they are because otherwise you’re back to searching on the sandy bottom.

Lessons Learned:

Lighting.  Carry extra.  In the tropics, I usually wear neoprene tech diving shorts with thigh pockets and have one or two more torches clipped off in my right pocket.  This allows me to mark good subjects for friends and add more light when I need it.

The ground can sometimes give you a third, fourth, and fifth hand. Feel free to set a torch down to provide side lighting or even backlighting.  Add colored lights if you feel like it.

When you can’t find a normal subject like nudies or shrimp, look around at coral, tubeworms, etc. Find patterns and abstracts. Sometimes it’s that your brain isn’t in the right mood to look for tiny things and taking pictures gets it working right.

Take a minute to watch the subject and go slow when you set up for a shot.  Some subjects don’t like shadows, the wake of a diver, white light, or vibrations.  Almost always go slow and then 150% slower than that.

Behind the Shot: Baby Boxfish

This is the first of a new feature I’m adding called “Behind the Shot” to explain how and where I took the photo.

Have a look at this baby boxfish. They’re the cutest thing you’ll ever see underwater.

Location: Yap, Federated States of Micronesia

Dive Site: Slow and Easy

Depth: 14 meters

Story:

Even though Yap is known for its larger animals like mantas and sharks, it does have excellent macro in a couple of places. The folks at Manta Bay Resort can show you where.

On this dive, the outer reefs were beaten up by the waves in the afternoon wind. So we rigged from wide-angle photography gear to macro. After a very short boat ride from the dive center, we dropped into Slow and Easy.

Slow and Easy has a moderate sandy slope from 8 meters down to 25+ (I haven’t been that deep there). There are large boulders up top in the 5-8 meter depths and they have a lot of interesting life there like pipefish, blennies, and lizardfish.

On this dive, I was with Elaine, as usual. As soon as we finished our decent, she started working a hermit crab and I started to swim slowly and scan for things to shoot. You know, the basic beginning of a macro dive.

There was a 70-cm round depression. You’ll see this a lot on the sandy bottom, usually uphill from a rock and off to one side. I’ll scan these quite a bit because they collect floating materials like grass, seaweed, etc. This was no exception, and the name of the game that day was “eel grass”. There was quite a bit of it lining the depression.

I took out my pointer stick and started to look around under the eel grass, gently lifting up individual pieces. Some movement caught my eye. What really caught my eye was how everything was drifting away slowly with the current except for a 2mm pea which was holding its position and even going up-current.

With things this small, you don’t really know what it looks like, even with good light. But you can see it using your camera and a supermacro diopter: they turn your camera into a microscope. I got a focus lock on a nearby piece of sand and then held up the camera to view the green ball in it. All I could see was 2 big eyes staring back at me. So I turned on my strobes and followed the pea for a bit, taking photos as it moved around.

I moved the camera in and out until it looked like the eyes were in focus and then pushed the shutter. This was harder than you might think. The boxfish was moving. I was moving to chase it. The camera was moving because I had to hold it in mid-water.

I got maybe a total of 10 shots. Then when I looked down to refocus closer to the end of the lens, I couldn’t find the boxfish again.

After the dive I had to research on Google to find out what it was that I found.

Lessons Learned:

Take a test photo underwater as soon as you descend and adjust your exposure so that it’s good.  This will reduce the amount of time that it takes to start taking pictures when you find a subject.

Go slow when you dive and learn how to hunt.  Nothing beats time underwater for building skills and intuition at hunting.

If you know that a subject is rare, small, and moving, it’s best to take a handful of photos with your existing camera settings then make major adjustments like adding another diopter.

See You Underwater

–Mike

Some Words on Focus Lights

To follow up on my camera setup, you will see that I have a focus light set up.  I don’t use it constantly for reasons that I’ll explain in a minute.  However, I think it’s a very important accessory to have and use and it will save your dive several times over.

Why use a Focus Light

In order to understand focus lights, you have to understand autofocus.  The camera has a focus zone that depends on the camera make, model, and configuration.  On compact cameras like an Olympus TG5, it’s a fairly large square in the middle of the picture.  On my Olympus OMD EM10MkII, it’s a square that can be configured for size, location, and how much of the surrounding area is included as secondary focus.  On high-end DSLRs like the D850, it’s a set of squares inside a larger zone that can be configured in several ways.

The way that autofocus works is that the camera zooms the lens in and out.  This is called “hunting” in photography slang.  As it zooms in and out, the computer in the camera looks at the lines, patterns, and individual pixels inside the focus zone.  It tries to find the zoom setting where the largest piece of the focus zone is sharp.  Even with a slow autofocus, it will zoom in and out once or twice and then set the focus.

However, when you’re in low-light situations such as underwater, there is not enough contrast between light and dark for the camera to see how sharp or unsharp the photo is when it zooms the lens.  As a result, the camera keeps hunting.  If you see the camera hunt over 2 times, then you need to add light to help it.  I think this is worse with supermacro where the focal plane is very thin, so as a side-note, you can use higher aperture settings and maybe get better focus.

Extreme Low Light

I’ll turn on my focus light when the light is so bad that I can’t tell–even with back-button focus–if the subject is in focus.  Just a little bit of light helps me see in the viewfinder.  I will also use the focus light on my strobes during times like this.

Shrimps and Crabs and Focus Lights

Shrimps and crabs hate white light.  I think it hurts their eyes.  They will always turn away from you if you use a white focus light.  However, there is a way!  If you use a red focus light and strobes, they can’t see it.  They’ll gladly sit there all day while you take your photos.

Protip: you can drop a white-light torch around the back of the shrimp and they will turn around and face you or come to your side of the coral whip.  Just a little bit of light–if you overdo it, it’s rather abusive to the creature and is animal manipulation.

Nudies and Flatworms and Focus Lights

Nudies and flatworms can feel the heat from torches, including your focus light.  That’s why when they get within focus range, they turn to the side and “ruin” your face-on shot that you set up so meticulously.  After a couple of times, it begins to feel like they can sense right before you push the shutter button.  After a couple of days of doing this, you’ll think that the nudies are psychic and are reading your mind.

To fix this, use the minimum amount of focus light to reduce the heat or lock your focus and turn the light off.

Strobes and Focus Light

Some strobes have a button on the back that turns on a small onboard focus light.  In some cases, this is preferred to the main focus light because it doesn’t shine down the port.  On some strobe diffusers, like the ones that come with the YS-D2s that I have, they have a piece of plastic that you pop into the diffuser to make a red focus light.  To be honest, I don’t use this much except for super low light conditions.

Colors!

Some focus lights can add other colors into the picture.  Most of them can add red.  Because shrimp.  Some of them also can add blue or ultraviolet.  A tiny amount of blue or UV will make the white in the subject glow slightly, like a white t-shirt under a black light at your favorite nightclub.  It’s a very nice effect to put into your photos.  Just try not to disco dance.

 

Focus Lights and Backscatter

It’s an inconvenient truth for an underwater macro photographer: your focus light causes backscatter.  It’s probably ruining most of the photos that you’re taking today.  Because the focus light is shining down the side of your lens port, it lights up sand and dirt between the end of the lens and the subject.  Or sometimes behind the subject, but your strobes were going to hit that anyway.  That dirt and sand shows up in your pictures as backscatter.

All this ugly sand in my photos blocking my rhinophores, what’s a macro photographer to do?

Well, there are 3 ways to reduce backscatter with a focus light.

  1. Reduce the brightness of your focus light.  That minimizes backscatter because there isn’t as much light to be reflected.  It took me a long time to get into the habit, but always use the minimum amount of focus light that you need to get a focus and if you don’t need a focus light, don’t use it.
  2. Turn on the focus light, use focus lock, and then turn the focus light off.  You would be amazed how infrequently I refocus on a dive: mostly I focus once and then take many photos with that same focus.  Having a zoom gear on the camera helps, too: you can manually focus if you need to refocus.
  3. Add an arm to the focus light to move it up so that it shines down on the subject instead of shining down the side of the lens port.  That moves the light away from the end of the lens.

 

 

See you underwater!!

–Mike

The Whys of Back-Button Focus and Focus Lock

Back-button focus is a technique where you change the focus button to on of the programmable function buttons (F1, F2, F3, etc) on the camera so that it makes the camera focus instead of the usual half-press on the shutter button.  This will let you lock the focus at the same distance from the end of the lens until you use the function button to refocus.

You then:

  • Choose a subject.
  • Push the focus button to get a focus lock.
  • Move the camera back and forth until the subject is focused the way you want it.
  • Push the shutter button for an instant picture.
  • Keep taking pictures with the same focus.

“That sounds complicated just to take a picture.  Why would you do this?”

For starters, autofocus is slow.  You half-press on the shutter button, the camera picks a piece of the picture, moves the lens in and out until the blur disappears or is the smallest that it will get, then signals that it has focus.  You then push the shutter button the rest of the way.  If you lock the focus, then for the cost of a little bit of time setting up the shot, you can take all of your pictures after that very quickly.

You get more control.  You can think of focal plane as a sheet of glass perpendicular to the lens and at a fixed distance away from the end of the lens.  As long as something is inside that sheet of glass, it’s in focus.  Now you can do like I did with the skeleton shrimp below and put eyes and “hands” in focus by angling the camera so that the those pieces of the picture are inside the focal plane.

You can focus on something that’s not the subject and then reframe.  I do this a lot with subjects that are hard to focus on.  Moving things.  Things inside holes.  Things not in the center.  Point your camera at something the same distance away from the camera lens as the subject and then focus lock on it.  You can then move your camera back to the subject and move it towards and away from the subject to get it in focus.

Macro photography is almost impossible without focus lock.  You have too many variables to consider to make a shot.  Simplify your shooting by reducing the effort of using autofocus by locking your focus.

Shooting in low-light situations is hard, even if you’re using strobes.  You can’t always use a focus light.  Crabs and shrimps look the other way when you shine white light in their eyes.  Nudibranchs feel the heat and change direction.  When you turn off the focus light, you’ll see the camera “hunt” when you try to focus: the lens moves in and out trying to find the right focus but because it’s too dark it can’t see the difference in focus distances.  So turn on the focus light, focus on the sand or coral, turn the focus light off, reframe on the subject, and keep shooting.

Most compact cameras don’t have a moveable focus point.  On most DSLRs and mirrorless, you can use the direction arrows or joystick to move the focus point around inside of the frame.  With compact cameras, you can get focus in the center of the frame, lock the focus, then reframe the subject.

“Wow, Mike, that sounds like an awesome idea that I’m really sold on, how do you set it up?”

It depends on the camera, they all do it differently across brands.  For a howto specific to your camera, try google for “<model> back button focus”.  I’ll post later on how to do this for the Olympus OMD mirrorless.

On compact cameras, programmable buttons are fairly rare.  However, they sometimes have a “focus lock” feature where you can focus on an object and then lock the focus point.  I’ll post later on how to do this for the Olympus TG4 and TG5.

Sample times when I’ve used back-button focus:

  • Fast Little Blue Fish.  They move in and around the coral too fast for you to get a good focus.  So lock your focus and take a picture when they appear in the gap between coral.  I talked about this in Little Fast Blue Fish.
  • Skeleton Shrimp.  They live usually on hydroids: cousins to coral that look like little white-brown shrubberies.  These hydroids sway gently in the current.  Back and forth, back and forth.  Too fast for your auto focus.  Next time they swing by, focus on them and lock your focus then snap each time they swing by after that.
  • “Fast-Moving” Nudibranchs.  Focus on a spot in front of their direction of movement where they crest a micro-hill and lock your focus.  When they move up on top of the terrain, get a picture when they’re more silhouetted. I describe this in this post about Bornella.
  • Critters in Tunicates. You’re taking a picture where the subject is inside a tube.  The autofocus on the camera sometimes will lock on the top of the tube.  Lock focus then move the camera forward to move the focus into the middle of the tube.
  • Hairy Shrimp and Other Teeny-Tiny Things.  When using supermacro gear and taking pictures of things smaller than 3mm across, your focal plane is extremely small.  Use focus lock to lock your focus then move the camera slightly to give you the focus that you want.

 

 

See you underwater!!

–Mike