Wide angle close focus with TTL question

[danhngo9594]

If I’m shooting wide angle with 2 Ds160 in TTL , what is the exact technique?
Focus on foreground object
Recompose (rule of third)
Meter the background to correct exposure?
Do I meter the exposure for the object or background? I’m not really sure about this
If I meter the background would their be a case that I overexposed my foreground?
Thank you

 

[chris kippax]

Meter the back ground once you hit the depth or change depth/directions.
Ditch the TTL and move your focus point to the image subject.

 

[Nemrod]

I have been using my Inon D-2000 strobes in either eAuto or Manual for this. I meter for the background and then set my strobes (in strobe Manual mode) for the camera aperture. If it is too over exposed I back the strobe power down or vice versa. If My D-2000 are at full dump then I have no choice but to open the aperture, move closer or up the shutter speed to compensate. My new camera has maximum sync of 1/160. I will see how that works out. I have been using 1/125 and f8 (In clear tropical water could be typical) with my S90, my new A6400, beats me?

The D-2000 (and Z240) have eAuto mode. The strobe has it's own exposure system built in. But to use the strobes this way I have to point them toward the CF subject. I am trying to understand why Inon has dumped the eAuto on the new Z330 and D-200? If they are going to do that why not give me HSS in place? Jeeeezzz.

I will use back button focus on my new camera. I typically shoot Manual mode on the camera. If I am in Aperture Priority A mode then I would use the half press for exposure so I can recompose, not needed if you are in Manual. I have also been known to use my Sekonic Marine II meter for general metering of the scene.

Not the best example of CFWA, I was about four feet away, full dump on the D-2000 strobes pretty sure, working in eAuto and camera in Aperture priority mode at f5.6.

Poor D-2000s again at full dump, f11 I think it was to combat the sun:

Hey, I cannot help it if my models are goofy but the exposure is good:

James

 

[JackConnick]

I think our free Handbook "Shooting Close Focus Wide Angle" will answer your questions.
You should meter the blue water, TTL won't always be that successful either, nor give you the control you need.

 

[danhngo9594]

Sorry I know how camera work but I have not worked with strobe before
So correct me if I understand this wrong.
When shooting, My camera sync speed is 1/180
-What shutter speed range should I use?
So If I have my setting aperture F11, ISO 200, Shutter speed (range above), then the meter will read some where -2 or -1. (Do I always need to have my meter at 0 for exposure?)
-And the strobe will fire that much amount of light to compensate that 1-2 stop?
Also if I add a diffuser, the strobe power reduce 1/2 stop, then my pic will lightly underexposed?

 

[Nemrod]

Meter the blue water or general scene. Adjust exposure via shutter speed, aperture and ISO to get +/-0. If you cannnot get a +/- 0 meter reading then you will either need to adjust ISO, SS or aperture. Take a test shot, adjust until you have the desired exposure. Set strobe to expose the subject per your aperture. You may have to adjust the power of your strobes up or down to your liking or move closer or further away.

Some cameras have auto ISO setting in Manual mode. The camera will then choose the ISO for your shot based on your set shutter speed and aperture. You can bias the exposure up or down in automatic ISO with your camera usually under the Function button to darken or lighten the back ground.

N

 

[danhngo9594]

Meter the blue water or general scene. Adjust exposure via shutter speed, aperture and ISO to get +/-0. If you cannnot get a +/- 0 meter reading then you will either need to adjust ISO, SS or aperture. Take a test shot, adjust until you have the desired exposure. Set strobe to expose the subject per your aperture. You may have to adjust the power of your strobes up or down to your liking or move closer or further away.

Some cameras have auto ISO setting in Manual mode. The camera will then choose the ISO for your shot based on your set shutter speed and aperture. You can bias the exposure up or down in automatic ISO with your camera usually under the Function button to darken or lighten the back ground.

N

So you mean that, we need to meter the background or any fishes that we trying to capture to correct exposure +/-0. Then my question is, when then meter read +/-0 when I’m metering the fish, then the fish will be correctly exposed, and what is the strobe for? Bringing back the color only, also can it be overexposed? If I’m shooting in TTL?
Because the object is already well exposed, the strobe light will make it too bright?
Sorry for my stupid question , but I’m really confusing, will set up a test it tomorrow when the strobe come.

 

[Chris Ross]

You need enough strobe light to bring up your colours and it will also act as fill in crevices and under overhangs etc. It needs to be the dominant light source on your subject - too little flash and the subject will be blue -green. TTL may or may not work well for UW shots - it is largely down to the camera whether it deals properly with the blue water background in your shots and adds enough light to be dominant over the ambient light, your strobes just flash as the camera instructs them to. Some cameras do this better than others in UW shooting - this is why many UW shooters use manual strobe exposure.

Your background exposure is set by the combination of your shutter speed and ISO if you meter at zero the water column will be rendered at the tonality of 18% grey - which may be a little brighter than what is normally used in UW shots and you may find you prefer to underexpose a little. The choice of shutter speed is generally in the range maybe 1/125 up to your maximum sync speed and you adjust your ISO to get within this range. You are generally trying to shoot upwards and often this exposure is not enough to light your subject fully as ambient light coming in from the front is not as bright as looking up into the water column. This is particularly so if you have a sunball in the frame, in which case you may need to stop down more than you otherwise would to get the shutter speed less than your camera's sync speed.

The strobe exposure will also try to render the subject 18% grey in TTL. the ikelite housings need the TTL converter which takes the signals from the camera and transfers them to the flash. You adjust flash exposure by dialing flash exposure compensation up and down from the camera. Whether it is exposed correctly depends on whether the camera reads the scene properly.

 

[ReadyDiverOne]

I think our free Handbook "Shooting Close Focus Wide Angle" will answer your questions.
You should meter the blue water, TTL won't always be that successful either, nor give you the control you need.

Very nice, thanks much. I usually seek to underexpose the background to get more blue therein. Two questions for you:

First, when taking a test shot of the background only, does firing the strobes effect that at all? Should I take a shot without them on to get the truest background exposure? Second, I heard recently from a pro photographer that one should take one test photo at depth into the sun and one away from the sun to get the right settings, are you familiar with this technique? Again, should this be done with or without firing the strobes?

Let me add that I always shoot RAW and manual for both camera and strobes.

Thanks again for Handbook, very well done and helpful.

Everyone stay safe!

 

[Nemrod]

You can fire the strobes, the light produced by the strobes will not have anything to reflect from. The 1/125 up to maximum sync speed is the shutter speed target range. The aperture will need to be whatever it takes to further control the background exposure. I usually shoot at ISO 100 and that is minimum ISO for my camera so I cannot drop ISO to darken the background (more blue). That leaves me with only aperture. So if shooting into the sun, often for effect (sun balls) and I am stopped way down and at ISO 100 I am going to be punching my strobes way up to provide enough light to expose my subject in the foreground with that small aperture opening and ISO. If my strobes are at maximum power and the subject is still under exposed I have choices. I can move closer, open the aperture, change shot angle, go to maximum sync speed (to compensate for the larger aperture needed) if not already there or purchase more powerful strobes and a camera with more dynamic range. If you increase ISO you are going to have to stop down the aperture even further.

Some shots are not possible with the current existing cameras. I suspect, DR aside, that my old S90 can do some sun ball shots that my new A6400 cannot despite having a tiny sensor in comparison and less DR. Why, because it will sync at any shutter speed. What the UW photography world really needs is an UNDERWATER camera based on a hybrid range finder that would have a leaf or iris shutter. Then any sync speed is near possible. Well, there is HSS but it compromises strobe total light output. HSS does allow the full range of shutter speeds with the camera but the strobe would need to be very strong (and HSS capable).

James