Focusing problem with Canon G11 & FIX Fisheye lens

I have just returned from a dive trip, cage diving with great white sharks, at Guadalupe off the Baja. I was using my new Canon G11 in an FIX housing with an FIX Fisheye wide lens. Photos of my cage buddy ( about 4 to 5 feet away ) came out in focus and great color. However, every time a great white shark came near the cage the G11 would not autofocus and the shutter would not open. If the sharks were more distant the camera focused, the shutter open and the photos were taken. Yes, the camera was set to macro mode. Another diver/photographer onboard suggested that the failure to focus may have been due to the lack of contrast between shark and the blue water. Two other divers using a G10 and Ikelite housing and a G11 in a Canon housing with standard ports were getting excellent results. Can anyone suggest what I might have been doing wrong or what I should have done to get some exciting close up photos of large sharks within 4 to 5 feet of my lens?

Why did you have the camera set to Macro mode when you're filming large animals 4-5ft away?

It's possible that the lack of contrast caused the camera to hunt more, but as you say, why were the others getting their shots off. And why did it work further away?

Can you post the EXIF data on one of the shots that came out?

J.Daniel,

I got curious and so i took some time to verify your issue with my G11 (but here on my desk and no housing or wetlens)

There is a difference in macro mode between AUTO and Av/Tv/M mode as follows:

1. G11 set to AUTO mode

Wide Angle: focus distance is 1cm-infinite/0.39inch to infinite

Full Zoom: focus distance is 30-50cm/11.8inch to infinite

- camera focuses from minimum focusing distance to to infinite

(automatic switch from macro to normal mode) - You can't activate macro mode manually

2. G11 set to Av/Tv/M mode

Wide Angle: focus distance is 1-50cm/0.39 to 19.6inch

Full Zoom: focus distance is 30-50cm/11.8 to 19.6 inch

- You HAVE to (dis)activate macro mode manually

- Camera will focus ONLY in the range she is set to!

General considerations:

- minimum focusing distance depending on your zoom factor

- while zooming the camera displays minimum focusing distance on uper left corner

- putting the camera in macro mode works only with static stuff or very slow animals

- usual lens - flat/dome port combinations don't need to be set to macro to focus non-macro

- I belive that on my G11 - INON D-2000 combination, Av/Tv mode give better results than using AUTO mode.

- Use Av to control FoV and Tv to control the color and brightnes of the background.

Next time set the G11 to AUTO and she will focus from minimum to infinite or use Av/Tv/M and shoot non macro.

I belive that on my G11 - INON D-2000 combination, Av/Tv mode give better results than using AUTO mode.

Use Av to control FoV and Tv to control the color and brightnes of the background.

Chris

Why did you have the camera set to Macro mode when you're filming large animals 4-5ft away?

 

 

It's possible that the lack of contrast caused the camera to hunt more, but as you say, why were the others getting their shots off. And why did it work further away?

 

Can you post the EXIF data on one of the shots that came out?

The G11 is set to macro mode because the manufacture of the FIX housing and fisheye lens and the retailer (Backscatter in Monterey Ca) state that this is what you do. I also use Aperture Priority more often than Manual. Interestingly, I tested the set up on land the other day using my adult daughter (5' 7"), standing 3' from the lens and took three photos with three different settings-- macro, normal and manual focus. They came out identical and can only tell the difference by checking Exif 'focus mode' that shows "0" for manual and a "1" for macro and normal.

Here is a the Exif data for a photo of a shark in focus and at about 15-20 distance. Dan (Incidentally do you have a reference that provides a detailed data sheet for the tags and fields for the G11 Exif data?)

Aperture Value: 4.34375

Color Space: sRGB

Compressed Bits Per Pixel: 3

Custom Rendered: Normal process

Date Time Digitized: 2010:11:04 06:36:12

Date Time Original: 2010:11:04 06:36:12

Digital Zoom Ratio: 1

Exif Version: 2.2.1

Exposure Bias Value: 0

Exposure Mode: Auto exposure

Exposure Time: 1 / 60

Flash: Flash fired, compulsory flash mode, red-eye reduction mode

FlashPix Version: 1.0

FNumber: 4.5

Focal Length: 6.1

Focal Plane Resolution Unit: inches

Focal Plane X Resolution: 12493.15

Focal Plane Y Resolution: 12493.15

ISO Speed Ratings: 200

Max Aperture Value: 2.96875

Metering Mode: CenterWeightedAverage

Pixel X Dimension: 3648

Pixel Y Dimension: 2736

Scene Capture Type: Standard

Sensing Method: One-chip color area sensor

Shutter Speed Value: 5.90625

White Balance: Auto white balance

_ImageStabilization: 3

AFInfo: 0.45, 0.45, 0.1, 0.1, f

Firmware: Firmware Version 1.00

Flash Compensation: -2

Focus Mode: 1

Lens ID: 65535

Lens Info: 6.1, 30.5, 0, 0

Lens Model: 6.1-30.5 mm