wd-20 wide angle lens on a panasonic lx-7 help

[sablefish]

Hello, I am shooting video with a panasonic LX-7 through a wd-20 lens, and i am in green water. it is really silty and dark, and i have a sartek 1500lm lighting system, but am still shooting wide open at f/1.4.

i am having trouble with obtaining sharpness through the wd-20, especially on the edges. i find with i have to zoom the LX-7 in a bit to avoid vignetting or a completely circular image.

1. what would be the optimal settings to obtain the most sharpness through the wd-20 with the lx7 in an ikelite 6171 housing?

2. is zooming in unavoidable, and is there some type of (in-housing) diopter i can add to the lx-7 to regain the widest setting?

3. would a wd-4 attached to the the ikelite 6171 housing allow me to shoot at the widest zoom setting? would the wd-4 offer better edge-to-edge sharpness than the wd-20 when the aperture is wide open?

4. would a wd-30 work better with this camera and housing in terms of edge-to-edge sharpness?

any help would be welcome. thanks!

 

[Ikelite Staff]

Hello, I am shooting video with a panasonic LX-7 through a wd-20 lens, and i am in green water. it is really silty and dark, and i have a sartek 1500lm lighting system, but am still shooting wide open at f/1.4.

i am having trouble with obtaining sharpness through the wd-20, especially on the edges. i find with i have to zoom the LX-7 in a bit to avoid vignetting or a completely circular image.

1. what would be the optimal settings to obtain the most sharpness through the wd-20 with the lx7 in an ikelite 6171 housing?

2. is zooming in unavoidable, and is there some type of (in-housing) diopter i can add to the lx-7 to regain the widest setting?

3. would a wd-4 attached to the the ikelite 6171 housing allow me to shoot at the widest zoom setting? would the wd-4 offer better edge-to-edge sharpness than the wd-20 when the aperture is wide open?

4. would a wd-30 work better with this camera and housing in terms of edge-to-edge sharpness?

any help would be welcome. thanks!

sablefish,

1. We only recommend initial camera settings for "still" photography in the instruction manual. Normally when shooting stills or video you do not want to zoom in and open the aperture any wider than necessary because you lose depth-of-field, which can result in soft corners. Since vignetting is significant with this housing and lens combination, you would get better results removing the W-20 lens and shooting at widest angle setting. Your shooting conditions are far from ideal, so you may want to get a 2nd video light if you haven't already.

2. No

3. Unknown, since the WD-4 is not offered as an accessory for this housing. This is due to the diameter differential between the housing port and WD-4.

4. You would get approximately an additional 10% coverage angle, so you would not need to zoom as far and therefore be able to gain perhaps an f-stop, however, I am not sure the small amount of improvement could justify the lens cost or the improvement in image quality.

Regards,

Brett Foster - Ikelite

 

[sablefish]

i'll add a second matching light, and stop down. i find the wide angle effect useful for cinematography and framing shots over the regular flat port; i'll keep plugging away until i can get better results.

thanks for the advice!