Over expossure

Hi,

so I finally was able to dive with the D7100 and experienced some issues with over exposure. Searching the net shows some have the same problem (no solutions), others saying the D7100 would under expose instead.

I tried a variety of changes in settings and there was a big improvement when changing the ISO setting from dynamic to 100, but there are still problems even in easy conditions. The below is an example with a green turtle on the sandy bottom at a depth of 10 meters.

The equipment: D7100, Ikelite housing and a DS125 flash.

Scaled picture attached. Location: Red Sea near El Quseir.

EXIF / information from original file in case the scaled picture has different:

General:

 

Color Model: RGB
Depth: 8
DPI Height: 300
DPI Width: 300
Orientation: 1 (Normal)
Pixel Height: 4 000
Pixel Width: 6 000
Profile Name: sRGB IEC61966-2.1

EXIF:

 

Color Space: sRGB
Components Configuration: 1, 2, 3, 0
Compressed Bits Per Pixel: 4
Contrast: Normal
Custom Rendered: Normal process
Date Time Digitized: 25 apr 2014 10:32:44
Date Time Original: 25 apr 2014 10:32:44
Digital Zoom Ratio: 1
Exif Version: 2.3
Exposure Bias Value: 0
Exposure Mode: Auto exposure
Exposure Program: Not defined
Exposure Time: 1/125
File Source: DSC
Flash: On, return light detected
FlashPix Version: 1.0
FNumber: 5,6
Focal Length: 60
Focal Length In 35mm Film: 60
Gain Control: None
Photographic Sensitivity (ISO): 100
Light Source: unknown
Max Aperture Value: 3
Metering Mode: Pattern
Pixel X Dimension: 6 000
Pixel Y Dimension: 4 000
Saturation: Normal
Scene Capture Type: Standard
Scene Type: A directly photographed image
Sensing Method: One-chip color area sensor
SensitivityType: Recommended exposure index (REI)
Sharpness: Normal
Subject Distance Range: unknown
Sub-second Time: 60
Sub-second Time Digitized: 60
Sub-second Time Original: 60
User Comment: El Quseir
White Balance: Auto white balance
AFInfo: 0.1947482, 0.64801, 0.04191517, 0.05323383, n, 0.2593605, 0.64801, 0.04191517, 0.05323383, n, 0.3239728, 0.64801, 0.04191517, 0.05323383, n, 0.398277, 0.6752487, 0.04837641, 0.06044776, f, 0.4758118, 0.6752487, 0.04837641, 0.06044776, f, 0.5533466, 0.6752487, 0.04837641, 0.06044776, n, 0.634112, 0.64801, 0.04191517, 0.05323383, n, 0.6987243, 0.64801, 0.04191517, 0.05323383, n, 0.7633367, 0.64801, 0.04191517, 0.05323383, n, 0.1301359, 0.5606965, 0.04191517, 0.05323383, n, 0.1947482, 0.5606965, 0.04191517, 0.05323383, n, 0.2593605, 0.5606965, 0.04191517, 0.05323383, n, 0.3239728, 0.5606965, 0.04191517, 0.05323383, n, 0.398277, 0.5725124, 0.04837641, 0.06044776, f, 0.4758118, 0.5725124, 0.04837641, 0.06044776, f, 0.5533466, 0.5725124, 0.04837641, 0.06044776, F, 0.634112, 0.5606965, 0.04191517, 0.05323383, n, 0.6987243, 0.5606965, 0.04191517, 0.05323383, n, 0.7633367, 0.5606965, 0.04191517, 0.05323383, n, 0.8279489, 0.5606965, 0.04191517, 0.05323383, n, 0.1301359, 0.4733831, 0.04191517, 0.05323383, n, 0.1947482, 0.4733831, 0.04191517, 0.05323383, n, 0.2593605, 0.4733831, 0.04191517, 0.05323383, n, 0.3239728, 0.4733831, 0.04191517, 0.05323383, n, 0.398277, 0.4697761, 0.04837641, 0.06044776, n, 0.4758118, 0.4697761, 0.04837641, 0.06044776, f, 0.5533466, 0.4697761, 0.04837641, 0.06044776, n, 0.634112, 0.4733831, 0.04191517, 0.05323383, n, 0.6987243, 0.4733831, 0.04191517, 0.05323383, n, 0.7633367, 0.4733831, 0.04191517, 0.05323383, n, 0.8279489, 0.4733831, 0.04191517, 0.05323383, n, 0.1301359, 0.3860697, 0.04191517, 0.05323383, n, 0.1947482, 0.3860697, 0.04191517, 0.05323383, n, 0.2593605, 0.3860697, 0.04191517, 0.05323383, n, 0.3239728, 0.3860697, 0.04191517, 0.05323383, n, 0.398277, 0.3670398, 0.04837641, 0.06044776, n, 0.4758118, 0.3670398, 0.04837641, 0.06044776, n, 0.5533466, 0.3670398, 0.04837641, 0.06044776, n, 0.634112, 0.3860697, 0.04191517, 0.05323383, n, 0.6987243, 0.3860697, 0.04191517, 0.05323383, n, 0.7633367, 0.3860697, 0.04191517, 0.05323383, n, 0.8279489, 0.3860697, 0.04191517, 0.05323383, n, 0.1947482, 0.2987562, 0.04191517, 0.05323383, n, 0.2593605, 0.2987562, 0.04191517, 0.05323383, n, 0.3239728, 0.2987562, 0.04191517, 0.05323383, n, 0.398277, 0.2643035, 0.04837641, 0.06044776, n, 0.4758118, 0.2643035, 0.04837641, 0.06044776, n, 0.5533466, 0.2643035, 0.04837641, 0.06044776, n, 0.634112, 0.2987562, 0.04191517, 0.05323383, n, 0.6987243, 0.2987562, 0.04191517, 0.05323383, n, 0.7633367, 0.2987562, 0.04191517, 0.05323383, n
Flash Compensation: 0
Focus Distance: 1,995
Focus Mode: 1
Image Number: 1 006
Image Stabilization: 0
Lens Info: 60, 60, 2.8, 2.8
Lens Model: AF Micro-Nikkor 60mm f/2.8D

Nikon info

 

Flash Setting: NORMAL
Focus Mode: AF-A
ISO Setting: 0, 100
Lens Type: 2
Quality: FINE
Shooting Mode: 0
Shutter Count: 1 006
White Balance Mode: AUTO1

Picture style:

 

Brightness Value: 0, 0, 0
Filter Effect: N/A, 255, 255
Hue Adjustment: 0, 0, 0
Monochrome: 0, 0, 0
Pict Style Color Space: sRGB, 1, 1
Picture Control Adjust: 0, 0, 0
Picture Style: Standard, 3, 3
Sharpness: -128, -128, -128
Toning Effect: N/A, 255, 255

Any clues would be appreciated! Next trip comming up in a month.

Also it seems that it is not possible to use a single center focus point in auto more, correct?

Many thanks,

Lars

Hi Lars,

There are number of potential issues!

Firstly, I would suggest that you do not shoot in Auto mode. The camera is doing its best to cope with the light underwater, but cannot deal with it. In addition, you are adding external light with a strobe, which further complicates the issue. For best results underwater, you should probably try to shoot in manual mode.

I note that you flash mode is normal-I'm not sure that Auto mode will give you the option, but it needs to be working in TTL mode in order to expose correctly with a DS125. In truth, for wide angle shooting, most people would be using their strobes in manual mode too.

Most underwater shooters prefer to use RAW rather than jpg, as this gives better results when editing. I would also avoid sRGB, and shoot in Adobe RGB-it has a wider gamut.

There is a wealth of info on here about shooting with your SLR underwater. I would suggest a thorough browse of the forum too...

Adam

Hi Adam,

thanks! I've spent some time looking around and will try it out the next two weeks. Guess my error was thinking that since I got ok pictures in auto mode with my old one, I would get it too with this (better) camera. Practice time!

best regards,

Lars

The image does not look too blown and would have been workable from raw. You will need to do a lot of post processing shooting a turtle from a distance (> 1 m). At these distances the strobe will be contributing relatively little light and at 10m depth the light is already rather blue.

Have you tried working with the jpg? Some basic jpg image editors (such as Preview on a Mac - it is under "adjust colors") have white balance control and contrast control.

Auto exposure almost always seems to over-expose, at least with of my Nikons, over the years. The EXIF data says "pattern" metering, which has probably completely misinterpreted the scene: spot metering can be better underwater. TTL strobe settings can help, but in the end almost everyone comes to manual exposure and manual strobes for wide-angle images.

I'm pretty sure that you can select the focus point and keep Auto metering: there should be a combination of Menu and camera settings to do that on such a sophisticated camera. I've certainly done that with a D200 and all my subsequent cameras.

Lars,

I agree with tdpriest- Nikon's Matrix metering for both wide angle and macro can lead to an exposure misinterpretation underwater. I also shoot with a d7100 and would say I'm set on center weighted metering about 70% of the time and spot meeting the other 30% (talking about wide angle now.). I will shoot on manual (both camera and strobes) while using the viewfinder exposure meter as a base line guide for camera and strobe settings and make my choice of aperture and shutter speed depend on what I want to express (shallow depth of field, blue water backgrounds, etc.) I prefer the manual settings because it gives the diver total control over the artistic outcome of the composition, rather than allowing the camera's exposure models to decide for you. You just need to experiment with different combinations of settings.

You're right, though... It is no doubt more labor intensive - initially, but as you gain experience it will soon become more intuitive and a larger advantage for you with a much greater range of tools in your box. With practice, you will start to anticipate your favorite settings for a range of scenes, just remember to enjoy every moment! I am just a newbie in this world of UW photography and it sometimes seems very frustrating when the outcomes are no way near my intentions but that just gives me more reason to dive again... more practice! Lol...

If you have the chance, try to shoot in RAW and not JPEG. This will give you a whole lot more options for tweaks with programs like Lightroom just in case the settings didn't yield what you were looking for. Again, the final product will be more in your hands than what the camera chooses.

james