Macro Photography with Two SB-28s

[jeff_plomley1]

Experienced SB28 Users,

 

I am currently shooting a single SB-28 with a Lumiquest softbox and

with the flash off-camera connected to an F4S via the SC-17 cord. I

wish to move to a two flash system and am considering a second SB-28.

Apparently, full TTL control can be maintained for both units if the

slave unit is connected by either the Nikon SU-4 (infrared TTL slave

unit) or the SC-18/19 connecting cord (i.e. the SC-18/19 cord

connects the two units either from the SC-17 hotshoe to the slave

directly or via an AS-10 hotshoe). My question is whether or not the

slave unit (i.e. fill flash)exposure compensation is accessible when

configured in the described fashion above. For example, can the

second unit be set to -1 while the main flash has no exposure

compensation. I have searched the archives of this forum and this

question has never been asked, nor mentioned in similiar discussions

concerning dual flash setups.

 

Thanks in advance for all replies.

[danny_weber]

Simple answer--No!

 

The master flash sets the comp. Control of ratios is by distance, diffuser (or ND) or by using a weaker flash (such as the SB-23) for the slave.

[brian_small]

Jeff--Danny is correct...........the simple answer to your question is no. However, you should also understand that the "slave" flash connected via the SC 18/19 will do exactly the same thing as the "master" flash. In other words, whatever you program the "master" to do, the "slave" will follow along.

[jim_simon]

For some really good info on this, check out George Lepp's book, "Beyond the Basics" (the first one). It's available through his website, www.leppphoto.com. There's alot of info on macrophotography using dual flash setups. Basically what Lepp does is cover one of the flashes with a gel-type ND filter to decrease the light output on one side and give some modeling effect to the subject. Jim

[jeff_plomley1]

Gentlemen,

 

Thank-you all for the responses. I must admit that I am quit surprised by the answers. Given the cost of such a set-up one would expect at least the basic functionality of an offset exposure between flashes. I hope Nikon recognizes this as a shortcoming of their product offering and plans on rectifying the situation. From what I understand, Canon has introduced a flash unit that when used with a slave unit allows the user to specify a lighting ratio (e.g. 2:1). Given the trend of Nikon taking several years to introduce competitive products (e.g. Vibration reduction lenses, tilt-shift lenses etc...) I guess I won't hold my breath for anything soon on improving the sophistication of their flash units when used in tandem....

[ron_goodman]

What you can do with the SB-28 is to change the zoom setting on one to vary the GN, which will do what you want. For example, the GN at the 24mm setting is 98 while the GN at 50mm is 138(from the Magic Lantern Guide for the SB-26). That's a 1 stop difference in power.

[piotr_mikolajczyk]

Indeed, you can get quite sophisticated wireless Evaluative-TTL flash control with many Canon Speedlite 550EX units (in up to 3 groups) working in tandem with an EOS-3 (and 1v, I assume). One of the functions is to set the master/slave flash ratio from 8:1 to 1:8. Works great providing the flash-to-subject distance is more or less the same for the strobes in question.

 

I think that setting both flashes at different distances or putting an ND filter on one of them should work well. With macro applications the camera and strobes are usually quite close to the subject. Consequently:

 

a) even not-so-big changes in flash-to-subject distance will produce noticeable differences in illumination, and

 

b) I am afraid that zooming the head to the wideangle setting (and hence reducing the GN) may not quite cut it as at close distances even the smallest GN may be enough to cover the range. Maybe you can play with the aperture to precisely adjust the max flash range at a given GN but it would be probably very cumbersome and unpredictable in the field (e.g. available light messing up your calculations).

 

Piotr