Even though we ARE Nikon lovers,we are NOT affiliated with Nikon Corp. in any way.

English German French

Sign up Login
Home Forums Articles Galleries Recent Photos Contest Help Search News Workshops Shop Upgrade Membership Recommended
members
All members Wiki Contests Vouchers Apps Newsletter THE NIKONIAN™ Magazines Podcasts Fundraising

SB800 Preflash Sequence: Again.

HBB

Phoenix, US
8783 posts

Click to send email to this author Click to send private message to this author
HBB Moderator Hal is an expert in several areas, including CLS Awarded for his excellent article contributions to the Resources. Donor Ribbon awarded for his very generous support to the Fundraising Campaign 2015 Charter Member
Wed 16-Jan-08 01:19 PM

Colleagues:

I posted this image some months ago for those interested in looking at the SB800 preflash sequence in a bit more detail. Since then, I have reversed the image so it "reads" from left to right, which is a bit less confusing.

This shot includes an on-camera master SB800 (M) and one SB800 in each of the three remote groups A, B and C.

Beneath each of the letters A, B and C is the preflash sequence which appears to involve an exchange of at least two pulses each from the master and each of the remotes. This sequence occurs in milliseconds prior to shutter opening. For those trying to synch other non-CLS strobes with the SB800 in the TTL mode, the complexity of this sequence is probably beyond the ability of Wein or other triggering units to deal with.

Following all of the exposure compensation calculations and exchanges, the shutter opens and a final triggering pulse can be seen from the master and then all units; master and groups A, B and C, fire for image capture.

Alson and others with multichannel recording oscilloscopes have provided detailed views of the pulse modulation occurring in the preflash sequence.

While not shown in this image, placing the remote SB800s in manual mode will not work either, as the on-camera master will fire a single, one-way pulse to the remotes prior to shutter opening to convey the manual power setting M1/1 to M1/128. If there are three groups of remotes, three pulses will be sent, one for each group. Any non-CLS units with optical triggers will likely fire prior to shutter opening.

Hope this helps shed some light on the CLS signaling technology.

Regards,

HBB in Phoenix, Arizona

Click on image to view larger version


Attachment#1 (jpg file)

HBB in Phoenix, Arizona
Nikonian Team Member

Photography is a journey with no conceivable destination.

Subject
ID
Reply message RE: SB800 Preflash Sequence: Again.
1
Reply message RE: SB800 Preflash Sequence: Again.
2
     Reply message RE: SB800 Preflash Sequence: Again.
3
          Reply message RE: SB800 Preflash Sequence: Again.
4
               Reply message RE: SB800 Preflash Sequence: Again.
5
                    Reply message RE: SB800 Preflash Sequence: Again.
6
                    Reply message RE: SB800 Preflash Sequence: Again.
7
                         Reply message RE: SB800 Preflash Sequence: Again.
8
                    Reply message RE: SB800 Preflash Sequence: Again.
9
                         Reply message RE: SB800 Preflash Sequence: Again.
10
                         Reply message RE: SB800 Preflash Sequence: Again.
11

G