SB 600 as off camera flash for D90

[lightwave]

@lightwave: Hope you get the point by amits reply here.. .. Even if you use the pop up flash in manual mode and put the slave on ttl in commander mode, the pop up fires while exposure takes place. Hence, a black card helps a lot in preventing the pop up flash effecting the picture but this certainly increases the range of the CLS cause I believe that the pre flash also would be of a more intense pulse. Shall do a test as scheduled this weekend and update here..

This is the craziest reasoning I ever saw. You can just disable the popup flash to fire during exposure. Perhaps Nikon's system is totally non-intuitive or perhaps all that is being done here is in a round about way. For me it is simple and logical:
Pop flash can be used as commander to trigger remote off camera flash. This can be done with either the popup flash ALSO firing during capture, or ONLY remote firing during exposure (The equivalent of your black card). Essentially I don't EVER need a black card. I can just disable the popup flash to fire during exposure. The preflashes fired do not matter and will never affect exposure. All this confusion is coming due to terminology of using popup in manual mode while acting as master.

[lightwave]

Here is the test from Canon cam. It let's me set from one of three options when using the popup flash as Master. 1st image is ONLY slave flash fires (a 580EX in this case) and 2nd and 3rd options are BOTH the popup and off camera slave firing. I have purposely selected a shining surface as Vikram wanted to see some test results with a shiny surface.
It is clearly seen in image 1 that ONLY the off camera flash has contributed to the exposure in spite of NO BLACK CARD being used.

In fact if your camera needs a black card to block out the popup flash from contributing to the exposure and there is no other way to do it, it is time to switch to Canon.

PS: There is a difference between 2nd and third images as well with BOTH flashes firing but the manual does not tell me what the difference is. The settings are (using text in place of icons):
1st image: REMOTE ONLY
2nd image: POPUP:REMOTE
3rd Image: POPUP+Remote.

Don't know the difference between the colon sign and the plus sign here. but I am guessing witht he + sign EACH flash exposes as if the other did not exist? As the 3rd image seems to be slightly more exposed than the 2nd image.

[RBP Photography]

@ Lightwave: Yes, you are right. Did the test, wanted to get done with this TTL doom.. .  There is no way to increase the PULSE of the pre flash. The damn thing fires at the same pulse whether in manual/TTL/-- mode. It doesent bother to fire an intense pulse no matter what. I was trying if this is possible since the intensity of the preflash pulse is what limits the range...

And dont even get me started about canon, I am happy shooting with what I have.. .. Good day

[amit_hazari]

@ Lightwave: Yes, you are right. Did the test, wanted to get done with this TTL doom.. .  There is no way to increase the PULSE of the pre flash. The damn thing fires at the same pulse whether in manual/TTL/-- mode. It doesent bother to fire an intense pulse no matter what. I was trying if this is possible since the intensity of the preflash pulse is what limits the range...

And dont even get me started about canon, I am happy shooting with what I have.. .. Good day

Raj,
   With this experiment, can we conclude that Nikon SG-3IR IR Panel (that black plastic) is not required?. Since the intensity of the pre-flash pulse does not depend on the flash mode, there is no reason why someone would keep the popup flash to manual or ttl mode but still want to prevent it from contributing to exposure.

Thanks.

Edit: Nikon IR Panel may still be useful. Please see the post below.

[amit_hazari]

In Nikon D90 there are three options for the flash units (for both master and slave) in commander mode: TTL, M, and -- (there is one additional for slave).
In the double dash mode, the master flash fires only for triggering the slave unit and it does NOT contribute towards exposure. However, if you set the master flash to TTL mode or manual mode then it will contribute towards exposure.

See the attached pictures for comparison. The slave flash was kept on the right side of the box. In the first pic, the master flash (the popup one) was set to TTL and it did fire. In the second pic, it was set to -- and it did fire only for triggering the slave but as you can see that it did not contribute towards exposure.

Could I ask you to repeat that experiment with a reflective surface?

So fire using "--" at an item that is placed infront of a shiny surface such as plexi-glass/acrylic/mirror/glass ... I think you'll see slightly different results. My experience has been that in almost all conditions when set to "--" the pop-flash doesn't show up (effect exposure), but when shooting glass against plexiglass/acrylic, you do tend to end up with reflections of the on-camera flash.

I did the experiment suggested by Vikram. The most reflective surface I could find was my iMac's screen. The slave flash unit was kept on the right side of the screen. Here are the results:
Pic 1: Popup flash set to off (--): You can see in the first pic that the popup flash did fire and contributed to exposure.
Pic 2: Popup flash set to off (--) and blocked by a black sheet: You can see that the only flash contributing to the exposure is the slave one.
Pic 3: Popup flash set to TTL: Both popup and slave are contributing to the exposure.
Pic 4: Flash off. Just to show you guys that my mac isn't as ugly and dirty as it appeared because of flash in first 3 pics

Vikram, you were correct, reflection of the popup flash is clearly visible in pic 1.

Thank you all for contributing to the discussion.

[lightwave]

You mean with Nikon there is NO WAY except black sheet to stop Popup flash from contributing to exposure? Either you are doing something wrong or Nikon's system is not quite correct?

[amit_hazari]

You mean with Nikon there is NO WAY except black sheet to stop Popup flash from contributing to exposure? Either you are doing something wrong or Nikon's system is not quite correct?

I couldn't figure out a way to stop the popup flash from contributing. Although the intensity of the popup flash remains very low, this can have impact on the photographs in some scenarios. The difference was not much apparent from the previous pics I had attached, however, the difference should be very clear in the pics that I have attached in this post. The name of the book is visible in the pic for which black sheet was not used. You can also notice the reflection of the flash in the monitor.

Thanks,
Amit

[Rebel]

You mean with Nikon there is NO WAY except black sheet to stop Popup flash from contributing to exposure? Either you are doing something wrong or Nikon's system is not quite correct?

@Lightwave, I second what Amit has done here, Its absolutely true that even when the Popup is set to (--) in commander mode the popup contributes to the exposure. irrespective of the fact weather the remote flash is in Wireless TTL or just a plain Manual Slave flash.

I always thought that popup wasnt leading to any exposure!!

Now Is this quite right or Is Nikon's CLS flawed??

I am really hoping to find an answer to this Popup Flash drama!!

Regards

[amit_hazari]

Rebel,
   There is a workaround (I haven't tested it yet). See the last post by 'rycee' in this thread:
http://forums.dpreview.com/forums/read.asp?forum=1034&message=30147539

Dr. Rajesh,
   Could you please let us know the shutter speed value in your first pic of glass in which only the remote flash was fired?

[Rebel]

Rebel,
   There is a workaround (I haven't tested it yet). See the last post by 'rycee' in this thread:
http://forums.dpreview.com/forums/read.asp?forum=1034&message=30147539

Dr. Rajesh,
   Could you please let us know the shutter speed value in your first pic of glass in which only the remote flash was fired?

Amit,

Thanks for the link.

Well certainly i cant because there is no Auto-FP in Nissin, But neither can u because the Sync speed doesn't allow us to go above 1/200 in our cameras, right? or i might have missed out on something.

[amit_hazari]

Rebel,
   There is a workaround (I haven't tested it yet). See the last post by 'rycee' in this thread:
http://forums.dpreview.com/forums/read.asp?forum=1034&message=30147539

Dr. Rajesh,
   Could you please let us know the shutter speed value in your first pic of glass in which only the remote flash was fired?

Amit,

Thanks for the link.

Well certainly i cant because there is no Auto-FP in Nissin, But neither can u because the Sync speed doesn't allow us to go above 1/200 in our cameras, right? or i might have missed out on something.

You need to turn on Auto FP from camera body. In D90, you can go to settings and turn on the following:
Custom Settings Menu-> Bracketing/flash -> Auto FP (e5)

I verified the workaround. It works! As soon as I set the shutter speed to 1/250, the popup flash (which was set to --) stopped contributing to the exposure.
Please be aware that if you use shutter speed faster than the flash sync speed (1/200 for D90) then you will get substantially less power as compared to the normal flash mode.

[Rebel]

Oh nice.

Bad luck with my Nissin!!

[amit_hazari]

Oh nice.

Bad luck with my Nissin!!

I don't understand Rebel.
Can you try to turn on Auto FP in the D90 body and see if the popup flash get triggered when set on -- mode at 1/250?

[Rebel]

Yep I tried and 1/250, the flash isnt in sync....at 1/200 i can see the flsah but at 1/250 no flash at all!!
I think since there is no option of AutoFP in nissin, Hence i am not able to get the flash to sync.

[amit_hazari]

Yep I tried and 1/250, the flash isnt in sync....at 1/200 i can see the flsah but at 1/250 no flash at all!!
I think since there is no option of AutoFP in nissin, Hence i am not able to get the flash to sync.

I see the problem now, however, I don't think that this a major problem. The black card workaround will still work for you, which IMHO is a better workaround because with this you can get full power of flash.

In most of the situations, even the black card workaround isn't needed because the contribution of the popup flash in overall exposure is small if it is set on -- mode.

[Rebel]

Yep I tried and 1/250, the flash isnt in sync....at 1/200 i can see the flsah but at 1/250 no flash at all!!
I think since there is no option of AutoFP in nissin, Hence i am not able to get the flash to sync.

I see the problem now, however, I don't think that this a major problem. The black card workaround will still work for you, which IMHO is a better workaround because with this you can get full power of flash.

In most of the situations, even the black card workaround isn't needed because the contribution of the popup flash in overall exposure is small if it is set on -- mode.

Maybe, I really dont know, I just got the flash may be after playing around with the flash, i might discover a way around it or for an extreme approach would buy an RF trigger