Strobe Problem with Wide Angle

[Pacifichiflyer 0]

I have a Sea & Sea 5000G with 0.6X Wide Conversion lense and YS-90 Strobe. On many of my pictures I am getting what looks like a reflection of light in the upper left at about the 10 o'clock position. Sometimes it is a single curved stroke of white but can also be two or three curved strokes changing from white to magenta. Sometimes will get in both the 10 o'clock position and 4 o'clock position, usually when I get two or three stokes. Have attached two examples of problem. Pictures taken with same f stop, speed and ISO. It does not happen all the time. When I am in very close it seems not to be a problem. After looking at the exif data/properties I at first thought this problem was associated with large lens openings ie f 8.1 more often than f 4.7 or f 2.5. But after really looking at number of pics taken with each f stop there really was not a correlation. I also supected something on the lense, port etc. but found nothing and problem continued to occur after a though cleaning and checking with magnifying lense. This problem only occurs when using the wide angle lense and strobe. HELP!!

 

Ron

[DuikKees 1]

It seems to me your problem has to do with stobeplacement. When you put your strobes further away from the lens and/or aim slightly outwards, your problem should be fine.

 

P.S. do a search here on strobeplacement and a lot of interesting aticles will pop up.

[james 0]

Yes, this is called lens flare and can be caused by the flash shining on the lens, or the sun shining onto the lens.

 

Cheers

James

[Pacifichiflyer 0]

Thanks for the replys. I have tried moving the strobe to different positions and that did not seem to do any good. I have a fisheye tray with two handles which are about 4" high. The strobe is mounted on the top of the left handle using two 6" ULCS arms and clamps. On the right handle I have a fisheye focus light on an 8" flexible arm. I have moved the strobe and focus light and even took shots with the focus light off and still sometimes get these reflections. I checked out http://www.kelpfish.net/strobe.swf, when I first built my setup. It shows putting the strobe out front of the lense and other postions so not sure this is a strobe placement problem.

 

Ron

[Steve Jones 0]

Ron,

 

Mounting the strobes forward of the camera works fine with longer focal lengths, but for wide angle you really need to pull them back. Judging from the nature of the backscatter in your second shot, your strobe is too far forward, and that's why you are getting flare in the port. Pull your strobe back - even to the point where it is behind the camera.

 

Finally be careful not to angle the strobe in too much.

 

Good luck

 

Steve

[Kelpfish 15]

The natural reaction for UW photographers is to aim their strobes at the subject and that more is better. When you position your strobes away from the subject the natural tendency is that no light will hit the subject. You just have to accept the fact that a good beam angle can solve a whole bunch of issues....backscatter, hotspots, flare, soothing light, etc. In the case of light, less is preferable in wide angle. Next time you dive, shoot a few pictures but dont look thru your viewfinder.....watch the background and see what your light does...see how it illuminates other areas besides the subject in front of your camera. It is quite amazing.

 

Joe

[Pacifichiflyer 0]

Thanks for the pointers. Did not pick up on the difference in strobe placement for wide angle vs longer focul lengths. Will give it a try. Also still working on strobe aim. I have some pics where I intentionally pointed the strobe away from the subject and got some neat shadows. Will try that more.

 

Ron