17 replies to this topic

[caolino]

Hi,
I moved from my Olympus tg2 to Sony rx100 iv with single strobe sea and sea d2 and I get very controversial results.
At shallow depth it looks good but I can basically even avoid strobe but after 10m the situation change drammatically, the awb in the screen looks very blueish and after the flash the image is sometime overexposed or the opposite.
I shot in S with 1/100 iso80 and flas in ds ttl. Strobe in center position above the camera, diffuser 100 degree.
Thanks for your comments






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[Atobit]

Hello
I’m not specialist of this camera but when I look at your pictures it’s seems your strobe is oriented at the front of your target.
The lower part of the images are overexposed, while the above doesn’t receive any light from your strobe.
Depending of the distance between your camera and target you have to align you strobe adequately.

Next, 1/100 shutter speed seems to low, you have a lot of motion blur. 1/250 would be better.


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Edited by Atobit, 27 April 2018 - 09:16 PM.

[kdgonzalez]

I have to agree with Atobit. Both pictures are overexposed at the bottom which leads me to believe your strobe is actually pointed down rather than straight or ideally a little bit up from your subject.  Try putting the strobe in the 10-11 or 1-2 o'clock position, this way you get both the benefit of color and contrast as compared to top or side lighting. 

[caolino]

I have to agree with Atobit. Both pictures are overexposed at the bottom which leads me to believe your strobe is actually pointed down rather than straight or ideally a little bit up from your subject.  Try putting the strobe in the 10-11 or 1-2 o'clock position, this way you get both the benefit of color and contrast as compared to top or side lighting. 

Thanks both for the quick feedback
I changed the setting and the position of the strobe, find new position below



What do you think?
Thanks
Giovanni


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[TimG]

One other thought Giovanni, when the strobe fires the light does not travel very far because of the effect of water. I'd suggest you get much closer to your subject, ideally 30-60 cms away. This reduces the amount of water between you and the subject and should give you better lighting and a clearer image.

[kdgonzalez]

Heres a good intro article to strobe position.  I wouldnt position the strobe directly on top of the camera but a little more to the side.  Top position gives you better color, side position better contrast, diagonal should be a good compromise.  Since you have one strobe try to be aware of the sun and you can use it a second light source (usually also diagonal). Good luck

 

http://www.uwphotogr...obe-positioning

TimG is also right get as close as your subject will allow you.  I have dual YSD2 and even when shooting wide angle I am within 1-3 ft of my foreground.

[MikeVeitch]

Your strobe positioning is fine.  One of the main problems is that you are using S instead of M.  If you have a look at your photos I think you will find that most of them have an fstop of f2.8 or similar open fstop.  You are getting far too much natural light in the photos and the colour doesn't pop because of that.

 

Try using M with 1/125 or 1/200 on nicer day and f5.6 - f8 with ISO 200 and the strobe on TTL.

[Undertow]

Mike is right. This is the second time recently I've seen the same question asked and people keep talking about the strobe.

 

(Yes you may find strobe positioning when over a bright bottom is something to work on but that's completely secondary to the main issue here.)

 

Your ambient (non-strobe) exposure is way too bright. 

[caolino]

Mike is right. This is the second time recently I've seen the same question asked and people keep talking about the strobe.
 
(Yes you may find strobe positioning when over a bright bottom is something to work on but that's completely secondary to the main issue here.)
 
Your ambient (non-strobe) exposure is way too bright. 

Thanks for all the feedback and I’m sorry for the stupid question. I’ve read a lot of articles for strobe positioning and general setting but never realised that the problem can be the overall exposure. I need to be honest and even on land I never use M so maybe I need to start from there. I have a friend with an Olympus tg4 with single strobe and he always use Auto and in general he takes better photo than me, the blue is definitely better (find picture below). I can’t match yet that blue
Thanks to all


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[kdgonzalez]

Have to disagree with Mike and undertow.  Your shutter speed is slow enough for the strobe to fill the scene. I would tend to agree if you had a shutter speed that was faster than your strobe (ie 1/250 or faster) but slow is not usually a problem.  See my photo below with same shutter speed both upclose and wide angle (shutter speed 1/100-1/160).  I do agree that you should shoot in M mode. 

 

fiji-20 by Karyll Gonzalez, on Flickr

 

fiji-25 by Karyll Gonzalez, on Flickr

 

fiji-22 by Karyll Gonzalez, on Flickr

 

fiji-24 by Karyll Gonzalez, on Flickr

Edited by kdgonzalez, 03 May 2018 - 08:54 PM.

[Undertow]

Have to disagree with Mike and undertow.  Your shutter speed is slow enough for the strobe to fill the scene. I would tend to agree if you had a shutter speed that was faster than your strobe (ie 1/250 or faster) but slow is not usually a problem.  See my photo below with same shutter speed both upclose and wide angle (shutter speed 1/100-1/160).  I do agree that you should shoot in M mode. 

 

I think you've misunderstood Mike and I. What we said has nothing to do with the strobe syncing with the camera (i.e. having too fast a shutter speed).

 

This is basic exposure stuff. When using strobes, you're mixing 2 forms of light:

 

1. Strobe Light

- strobe exposure determined by combination of strobe power and aperture

 

2. Ambient light from the sun

- ambient exposure determined by combination of shutter speed and aperture

 

In your excellent images, kdgonzalez, if you erased the strobe light (if your strobe didn't fire), they would be very dark, very underexposed. The eel image would likely be black. That means you have a dark ambient exposure. The issue with the original poster's images was that the ambient exposure was way too bright to begin with. 

 

There's no room for disagreement here, this is 100% true. 

[Uwshoot46]

Maybe the problem is easy to fix with new batteries in your strobe. I've had the same problem with old rechargeable batteries. Bought some fresh ones... problem solved.

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[caolino]

Maybe the problem is easy to fix with new batteries in your strobe. I've had the same problem with old rechargeable batteries. Bought some fresh ones... problem solved.
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Since I make few dives per year I always use not rechargeable batteries...anyway thanks for helping

[caolino]

Your strobe positioning is fine.  One of the main problems is that you are using S instead of M.  If you have a look at your photos I think you will find that most of them have an fstop of f2.8 or similar open fstop.  You are getting far too much natural light in the photos and the colour doesn't pop because of that.
 
Try using M with 1/125 or 1/200 on nicer day and f5.6 - f8 with ISO 200 and the strobe on TTL.

You are right most of the pictures are around 2.8 and I should learn to use M but why my friends with the Olympus tg4, Inon S2000 stone and automode is always able to capture good pictures? In theory Sony RX100 should be a better set up...

[caolino]

[quote name="kdgonzalez" post="395049" timestamp="1525409459"]Have to disagree with Mike and undertow.  Your shutter speed is slow enough for the strobe to fill the scene. I would tend to agree if you had a shutter speed that was faster than your strobe (ie 1/250 or faster) but slow is not usually a problem.  See my photo below with same shutter speed both upclose and wide angle (shutter speed 1/100-1/160).  I do agree that you should shoot in M mode. 
 
Fantastic pictures!
Can you please share your gear setup and the shooting info?

[String]

To me it looks like standard TTL failing.

 

As the ambient is quite bright its not firing the strobe enough to put any sort of light or colour back in.

Its a fairly common failing of TTL - it just tries to get a good exposure.  It has no idea the purpose of underwater is to block out a lot of ambient and overpower it with strobe.

 

You really need to shoot manual where you can set these things for yourself.  Automatic TTL modes from my experience always underfire the strobe and create washed out images on wide angle like this.

[ChrisRoss]

I would agree, TTL will often dial the exposure from the flash back below what is needed.  TTL is highly variable between cameras and just because another camera works well in TTL doesn't mean yours will. 

 

Looking at your images there seems to be way too much contrast, things that are in sunlight appear blown out so your ambient exposure is too high and everything else is dull and flat- meaning some light from the flash has gotten there but not much and it's mostly an ambient light shot in shadow.  The only way to reliably avoid this is switching to manual and also getting closer.  I would look at starting with 1/250 @ f4 ISO100 on the RX100  and get closer to your subejct.  Have your flash on manual and dial up the flash exposure until the exposure on your subject looks right.  Use Auto WB as that generally works with flash exposures.  The deep blues come from keeping the ambient exposure down AND have the white balance set for the daylight exposure from the strobe.  This means the blues in open water become very deep.

 

You can get the approximate exposure on land by shooting in  a darkened room, shoot a subject about 500-700mm away and adjust your strobe output till exposure is correct.  That is then you starting point underwater for subjects at about that distance.

[jonm]

The key thing you're running into is that the natural light is overpowering your strobe. You can tell this because the red colors are really undersaturated, and there's a lot of blue. Underwater, natural light loses most of the red spectrum, whereas your strobe has the full spectrum of light. So what you need to do is use the controls of the camera to limit how much natural light gets in, and create more opportunity for your strobe light to be recorded. 

 

When you set your camera to do the metering for you, it's going to make its calculations based on the light it can see, and guess how much flash needs to be added to make a properly exposed picture. The problem is that there's plenty of light coming in, it's just all natural light, which is strongly blue.

 

If you don't want to mess around with manual settings, you can use your camera's exposure compensation to try to tell it to ignore some of the natural light. I'd try dialing the exposure compensation down to -1 or even -2, and see if that helps make less natural light come in. You might then need to dial the flash strength on your strobe higher. And, as other people said, get closer: the less water between your camera and the subject, the less light gets filtered out by the water.

 

However, in the long term you're going to get the best results by going manual, as other people say. It's not that hard to get used to, it just takes some experimentation. You can do this on land, too. Go into a darker room with a window. Put something on the table in front of the window. Experiment with shutter, aperture, ISO and strobe speed until the subject and the stuff outside the window are equally exposed. I like to start by picking an ISO (such as 400), picking a shutter speed (1/100 is a good starting point), setting the strobe at midpoint, and then using the aperture to get the subject properly exposed. Then you adjust the shutter speed to get the background properly exposed. A slower shutter speed will increase the exposure of the background, and a faster shutter speed will make the background darker. Try this a few times and a few situations in the air before you try it under water.

 

-Jon