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peterbkk

Member Since 25 May 2005
Offline Last Active Apr 25 2015 06:50 AM
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#360426 How important is underwater tripod?

Posted by peterbkk on 23 April 2015 - 02:32 PM

Hi all,
 
Would like to get an opinion in regards of underwater tripod. I'm thinking to purchase one for video both for WA shoot and macro.
 
I do have gorilla pod that can be used underwater but adjusting them is such a pain!
 
Considering the price - the proper one is expensive! - I do want to be sure it will help in getting a stable clip.
 
Thanks in advance!
 
Bona

Like most things in life, the answer is "it depends". :)

It depends on what you want to use it for.

For most WA shooting underwater, you don't need a tripod. For some scenes it might help but for others it will be a hindrance.

For most macro, a tripod is very important. If you are shooting bottom-dwelling creatures, a large Gorillapod is great. I think that the "Focus" model is the biggest. If you soak them well after diving, they will last a while. Easy to position. More difficult to keep still.

A tripod wth hard legs is necessary when you want to do macro above the bottom, like on a wall. But, here you will often have a challenge finding the best position to place the legs. The "hard leg" tripods are also a bit more fiddly to adjust the camera angle and position. But very stable.

In summary, there is no perfect answer. You need to work out what works best for you and then become familiar its use.

Regards
Peter


#360022 Potential solution to shaky video footage?

Posted by peterbkk on 14 April 2015 - 01:36 AM

 

Even though I have my GH4 as neutral as possible (and thanks to your tips on this) it still suffers from some jittering underwater if I pan etc.

 

 

Is the housing well-balanced?  Jittering can come from muscles countering balance issues. 

 

The other tip for panning is to point your body towards the end point of the pan and then swing your arms / camera towards the start point.  Start the shot still for a few seconds then pan so that your arms are moving into their natural alignment with your body rather than away from it.  Your muscles relax during the pan rather than tighten up.

 

Regards

Peter




#360010 Potential solution to shaky video footage?

Posted by peterbkk on 13 April 2015 - 04:52 PM

 

I've sent a message to them, asking why the need for Mic input and Video output (I presume for time syncing, can't understand why the mic input thou). 

 

 

Maybe they are writing some inaudible (to humans) sync sounds onto the audio track that their NLE plug-in can read.




#359685 Tracking focus with a GH4 in the NA-GH4

Posted by peterbkk on 06 April 2015 - 03:38 AM

I agree. The main missing points for me are similar

1. AutoISO in 'M' Movie Mode
2. Upper limit of AutoISO

And having access to exposure compensation also, so we can ETTR a little bit.


Sent from my iPhone using Tapatalk

 

And, regardless of whether shooting M, P, S or A mode, display both shutter speed and aperture in the monitor, regardless of whether it is selected by the user or the camera.




#359651 Tracking focus with a GH4 in the NA-GH4

Posted by peterbkk on 05 April 2015 - 06:13 AM

What peaking colour and level do you use for this type of work?

 

I have the level set to "low" and the colour set to "white".

 

It might be overkill.   This setting makes the in-focus subject look like it's covered in sparkling snow.  Very pretty!  :)

 

If I was using it all the time, I'd definitely tone it down.  But, I am only using this technique for close-up subjects that will move.  Keeping them in focus is the most critical success factor for the shot so I am happy to have bright sparkling snow covering the subject and on the ground around the subject.

 

I found that, with an octopus or cuttlefish on the dark Lembeh sand, not only could I see that the subject's eyes were in the middle of the focus-peaking "snow" zone, but I could see a path of snow along which the animal could move and stay in focus.

 

Regards

Peter




#359649 Tracking focus with a GH4 in the NA-GH4

Posted by peterbkk on 05 April 2015 - 05:59 AM

By the way I've also had little success shooting with auto-focus. Even if it looks like it's working well underwater, get the footage on the computer and you can see the nasty little shifts in focus while it hunts. I badly wish we could lock off focus during a shot.

 

Hi Nick,

 

Yes, both the auto-focus and auto-exposure show the GH4's still photo heritage.  

 

I recently panned upwards with the camera set for AE.  Looked OK at the time.  But, on the computer, I could see small step changes in the exposure as the scene panned from dark to light.  Not smooth.  Had to do a little keyframing in FCPX to hide the steps.

 

Now I always use AFL and AEL before starting to shoot.

 

Regards

Peter




#359636 Tracking focus with a GH4 in the NA-GH4

Posted by peterbkk on 04 April 2015 - 06:19 PM

Caveat: Maybe you all know about this technique and find this thread a bit "ho hum".  In which case, please ignore.  But, for me, it was an exciting breakthrough that improved my success rate shooting moving subjects.

 

Situation:

 

Panasonic GH4 in a Nauticam NA-GH4 housing with either the 7-14mm, 12-35mm (dome) or the PZ 14-42mm (flat port) shooting video of octopus, cuttlefish and squid in Lembeh.  I wanted to be able to shoot these critters "up close" and "on the move" but still keep them in sharp focus.

 

Problem:

 

I don't trust any auto-focus tracking system and have not had reliable success using it with the GH4 underwater, especially in murky conditions.  I prefer to use AFL/AEL to lock in focus and exposure for the whole clip.  With the camera set to AFS and a small centre focus point, I lock in the focus on the eye of the critter at the start of the clip.  But, then the critter starts to move.  How do I ensure that the critter's eye stays firmly in the narrow depth of field?  Obviously I need to move the camera with the subject, keeping the distance between the critter's eye and the lens at the same distance.  But that's quite difficult, especially checking the focus with the small monitor on the back of the GH4.

 

Solution 1 (attach a better monitor):

 

Use a large monitor that has built-in focus peaking like the Shogun.  But, Nauticam have not yet released the Shogun housing.  And I need to get the footage now.

 

Solution 2 (flip on the GH4's focus peaking): 

 

Unfortunately, the GH4's focus peaking only works when the camera is set to manual focus (Panasonic: could this be fixed in a firmware update, please).  The lens / port combinations that I'm using don't have manual focus.

 

But (and here is my big breakthrough), the NA-GH4 housing has a MF-AFC-AFS switch in a convenient location.  

 

Here's what worked: Before diving, turn on focus peaking in the camera's menu and save it to your favourite UW custom setting.  Underwater, set the MF-AFC-AFS switch to AFS and use the rear lever to set AFL to get a sharp lock on the subject's eye.  Flip the MF-AFC-AFS switch to MF.  The lens stays at the same focus distance as locked in.  But now the subject is also covered with focus peaking dots.  As the subject moves, move the camera with the subject, ensuring that the focus peaking dots continue to flicker all around the subject's eyes.  

 

If it's not moving too fast (e.g. an octopus walking), I was able to keep the subject firmly in the plane of focus (9 times out of 10)...

 

Regards

Peter




#359534 How would you shoot this scene?

Posted by peterbkk on 02 April 2015 - 06:21 AM

I don't think a video light would make any different.

 

So, if you're in my situation, what would you do differently?

 

 

If you want more depth of field you need either a wider lens or a smaller aperture (larger f-stop number).

 

To get a smaller aperture for video (don't mess with the shutter speed) you need more light.  Turning up the ISO leads to graininess.  So, your best bet is a powerful video light system that covers all the subject and is somewhat balanced to the same colour temp as the ambient light.

 

Regards

Peter




#358916 GH4 - Nauticam Macro Lens/Port Thoughts

Posted by peterbkk on 17 March 2015 - 04:16 AM

Yes. The result being an IL stabilized 14-42 lens, with full zoom control. With the flip diopter you should have a slightly better setup as the Oly 12-50 is not stabilized and no other mid-zoom lenses allow for manual focus (behind a flat port).


I accidentally ended up in Raja Ampat with all my camera gear except the Nauticam lens gears for the 7-14mm and the 14-42PZ lenses. Focus was not a problem as I use the AFL lever for most shots anyway. For the 7-14mm, I just left it set at 8mm and that was fine for most WA shots. For the 14-42PZ lens in the flat port, I remembered this thread and set the Fn1 button to zoom control. Worked just fine for all the macro shots. Thanks guys!

Regards
Peter


#358713 Chariot of Fire - Fire Urchins with Coleman Shrimps, Zebra Crabs & Urchin...

Posted by peterbkk on 10 March 2015 - 12:11 AM

Could you do the acting for me Peter? ;)
 


Yes, but I bumped one of those beasties with my knee once so I know what to expect - it'll be expensive:

- Lead actor fee (I'd want top billing ahead of the shrimp and the prickly ball)
- Stunt man fee
- Speaking role fee (I get to yell "F%$k!" at least once)
- Danger money
- On site medical response team (in case I have an allergic reaction or a heart attack)
- Medical Fees
Total: $1M

So, if you can stump up the money, I'll shove my hand onto the fire urchin.

Rgeards
Peter


#358099 Panasonic GH4 might get a V-log profile?

Posted by peterbkk on 20 February 2015 - 02:33 AM

As always it is a personal and creative choice but I never use red filters underwater.

Red filter only have any benefit in certain situations and they add a bunch of complications to an already complex process. Too shallow and they make the footage too red. Too deep and they remove too much light (remember that the filter removes blue and green but does not add red). If you leave it on in the wrong light situation, you will have some difficult footage to grade. Even if you do get the on-off timing right, the footage either side of the transition is difficult to color match. If you pan up, all the highlights will have a red tinge.

And why bother with that complication when the GH4 has a more viable solution: the 4 WB presets. Fill these up BEFORE you go diving and flip between them, depending on the ambient light color. I wrote an earlier post on how to do this. Just take a WB setting off four pieces of coloured paper in sunlight, save them in the presets and remember which preset is for which lighting condition. Save that with your other favorite settings in a Custom Setting so you can get back to them quickly if you ever decided to play with MWB while diving. I keep it simple: 1. shallow to mid tropical blue water, 2. mid to deep tropical blue water, 3. shallow to mid greenish water and 4. mid to deep greenish water. These get you very close to a good WB that can be tweaked in the edit. And it doesn't rob you of an f-stop or two.

Regards
Peter


#357929 Panasonic GH4 might get a V-log profile?

Posted by peterbkk on 16 February 2015 - 09:49 PM

If your white balance is a bit off, do you still use it as it, or you would attempt to color grade it?

 

I use a fairly flat profile in the GH4.

 

In FCPX, I've set up and saved a few colour grading presets:

- Increase contrast

- Reduce Green a little

- Reduce Green a lot

- Increase Blue a little

- Increase Blue a lot

- Warm up slightly

 

These seem to work on 95% of all footage.

 

Regards

Peter




#356680 GH4 with 14-42mm lens or LX100?

Posted by peterbkk on 16 January 2015 - 10:25 PM

Agreed, and I'm pretty good with the slow panning when required, but there are always those scenarios where a shark or codfish will dart across the frame. 

 

If the difference between the two isn't significant then no big deal, but if it's pronounced then it will tip the scales.

 

I think that you are worrying about an immaterial thing.  Rolling shutter is only obvious when panning across straight, distinct verticals.  Underwater, about the only place you'll find straight, distinct verticals are on ship-wrecks.  And then only obvious with a fast pan - which is likely to make your audience so dizzy that they won't notice the "rolling shutter" anyway.

 

Any shark darting across the scene might look slightly distorted if compared to a still photo but the audience will be oblivious.

 

Regards

Peter




#356011 Upcoming Panasonic GH-4K

Posted by peterbkk on 30 December 2014 - 01:59 AM

Or you could mount a rear-view mirror so you could watch for sharks sneaking up behind you.


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#355901 GH4 - Nauticam Macro Lens/Port Thoughts

Posted by peterbkk on 27 December 2014 - 05:54 PM

 

Hi Peter,

Do you meant Panasonic PZ 14-42mm?

I might try that lens.

Cheers,

 

Hi EunJae,

 

Yes, you are right. I did mean the PZ 14-42mm.  (http://www.bhphotovi...arch=yes&sts=pi)

 

It works fine as a macro lens with video lights providing enough light to shoot in the middle of its f-stop range.

 

And, if a larger critter comes along, you do have some options for catching some footage - although it is definitely not a substitute for a good WA lens and a dome port.

 

The only downside is that the PZ does not have manual focus underwater.  So, you have to do an AFL and nudge the housing to fine tune the focus.    (hopefully, with the Shogun and its big screen / focus tools, small focus adjustments are going to become much easier for people like me with ageing eyes)

 

 

Regards

Peter

 

PS.  Love your "Christmas eve in East Sea of Korea" video.  I was driving down the east coast of Korea around Gyeongju last year and saw some people going out in a dive boat.  If I had have known that the diving was that good, I'd have brought my dive gear and camera.  The visibility looks great and the water is such a rich, deep blue.