5 replies to this topic

[Gazpacho]

Hi folks and happy new year to everybody.

I´d appreciate your advice on my following problem:
Sometimes, but not always, the lower part of my images is too dark when using strobes (lower part of image not being lit by flash lights). I post an example of my problem, taken at a night dive. Sorry, it´s not a good picture, but illustrates my problem.
I´m shooting a Nikon D 90 in a Hugyfot housing without TTL converter. I´ve got 2 INON Z 240 stobes, connected electrically. Usually I shoot completely on manual settings (camera and strobes) and use diffusers on the strobes. My guess would be that this a a sync problem with the shutter, but I have not yet been able to find out systematically.
Any experts out there who can help? Would be very much appreciated.

Greetings from Switzerland,
Gazpacho

[johnjvv]

Hi folks and happy new year to everybody.

I´d appreciate your advice on my following problem:
Sometimes, but not always, the lower part of my images is too dark when using strobes (lower part of image not being lit by flash lights). I post an example of my problem, taken at a night dive. Sorry, it´s not a good picture, but illustrates my problem.
I´m shooting a Nikon D 90 in a Hugyfot housing without TTL converter. I´ve got 2 INON Z 240 stobes, connected electrically. Usually I shoot completely on manual settings (camera and strobes) and use diffusers on the strobes. My guess would be that this a a sync problem with the shutter, but I have not yet been able to find out systematically.
Any experts out there who can help? Would be very much appreciated.

Greetings from Switzerland,
Gazpacho

What shutter speed are you using? It could be the curtain closing at the same time as the strobe firing. I think the max shutter speed you can use with strobes on a D90 is 1/200.

[Gazpacho]

What shutter speed are you using? It could be the curtain closing at the same time as the strobe firing. I think the max shutter speed you can use with strobes on a D90 is 1/200.

Hi Johnjvv,

I just reviewed the parameters of the pictures and think you are right. The shutter speed of the posted image was 1/400. On other images I had 1/320, and the dark part was smaller (curtain not that much closed, makes sense to me). On images with shutter speeds 1/200 or longer, the problem does not seem to exist.
I´m impressed by your profound knowledge and speed of response. I had not been aware of this problem. Thanks a lot!
Where did you get the technical information (1/200 for a D90) from?

Unfortunately, in the menu of my camera you can only define a LONGEST shutter opening when using a strobe. According to this problem, you should also be able to define a SHORTEST opening, and the problem would not occur. But as I shoot on manual settings anyway, now that I am aware of this, problem should be avoidable.

Pictures (without technical problems) of my latest trip to Cocos Island can be seen here: http://www.flickr.co...57628567090599/

Thanks again.

[johnjvv]

No worries...I knew it as I previously discussed fastest shutter speeds using a D90 with a friend when he mentioned that he found it easier to get a black background out of the camera with a D70 as the shutter speed could be set higher. So I tested what the maximum shutter speed was and the outcome looked similar to your picture when higher than 1/200.

I would not describe my knowledge as profound yet glad to be able to help in this instance!!

Cheers

[DiverPam]

I have D90 as well. Look in the technical specifications section at the end of the manual that came with the camera and you will find it. Also - when I got my D90 a couple of years ago - I bought the book Nikon D90 for Dummies - don't laugh - the lady who wrote it really has some great tips / short cuts / and other stuff that is hard to find in the manual.

Good luck with everything - DiverPam

Edited by DiverPam, 01 January 2012 - 02:26 PM.

[divengolf]

There was a real good article on front/rear curtains and flash synch speed for UW photogs a couple years ago. I cannot find it right now, but it may have been on WP or on the dive photo guide. I've got both a D70 and a D90. The synch speed of the D70 is faster at 1/500. The D90 is around 1/200 as previously stated.

If someone knows where the article is, it was very well written and informative on this topic.