Please help me fine tune my new rig

After agonizing and reading I am the

proud owner of a D70 in a Subal housing. (With a Nikon 10.5mmFE and a 105mm

for macro.) After getting a surprisingly quick response and advice from Dr.

Mustard I saved myself over $1000 and stuck with my Ikelite Substrobe 100A left over from my Nikonos

days, and even bought another on ebay for $100. Now I have 2 100A’s on

8†Ultralight arms with the intention of using them with the camera set on

manual. I’m thinking that I would only need/use one when shooting macro.

Yes?

My question is, since they only have full and half power on MANUAL, will

these be too bright and if so, how do I calm them

down? Do my test shots topside have any relevance to what’s going to

happen under water, meaning that if I can dial them in on the surface I have a decent chance of getting good results below? Are the eight inch arms long enough to spread them out

enough? I don’t really want to have to wrestle with any more arm

segments.

Andy

hi Andy.

I think you will find that if you have the choice, 2 are better than 1 for macro. You will get less shadows and you can always turn one off if you want to create some shadows for composition.

The way to control your strobe output is with the fstop.

A good place to start would be this, its called strobe to subject distance. In other words how far you are from your subject will mean what fstop you use.

1/2 power on both strobes, no diffusers

less than 1 foot f16-f22

1 foot f11-16

2 feet f8-f11

3 feet f5.6-8

4 feet of more f4-5.6

as you can see there are 2 fstops for each distance, you need to bracket your stops and use the screen as well as the histogram on the camera to fine tune your exposures.

Have fun

You may find that using diffusers on the strobes can modify light output by a stop or so.

Take care,

John

Thanks Mike.

I guess I've been reading a lot about the ability of newer strobes to have a multitude of settings. Just trying to do my homework before I get in the water, although I guess I'm thinking like a film guy and forgetting that I can instantly see results and make corrections. TOO COOL for an old guy! My real concern was that the inability to be able to adjust the power of the strobe would force me into a very narrow range of fstop vs shutter speed, thus giving me limited options as far as composition and control of things like DOF . So if you're saying that both of those 100A's on half power will work for macro without overexposing everything are you also saying that I should keep them on half power for wide angle shots too? And the 8" arms are enough spread for using two strobes? Ah! I keep fogetting. I just have to look at the screen/histo.

Andy

I am worried about locking up your camera after taking a picture with those antiques from before digital era began. Make sure Subal provides center and ground contacts only from the camera hot shoe so you don't need special sync cords or need to cover camera shoe as described in following URL:

http://www.ikelite.com/web_pages/sync_cord_d1x.html

Thanks! I'm using a Nikonos to two Ike chord #4104.62 purchased from Reef Photo. I used my original Nikonos chord a few nights ago and all seemed fine. I'm going to load the whole thing up later tonight and see what happens. And, Oh yeah! I get to see the results. (still can't get over that)

Are you saying that even with this chord I could still have a problem? I read the link and it seemed to indicate that the Ike chord would take care of it.