D7100 ocf issues. a little help?

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ewick

Senior Member
Just bought the d7100 and out the box the battery charger didnt work. Contact B&H and was told they will send me a new one.
Took the d7100 out for a test run (night life photography) and when I put the sb700 on it, it lit the flash for about 4 seconds making a short like sound (still fires the flash normal as well). Thought it might be the flash so I popped the sb900 and same thing.
I also found out that any time my fat middle finger bumps the PV button it causes the flash to light up like it was causing a short for about 4 seconds I take it thats not normal.
If any one has an idea of what is going on I would love to hear it or suggestions on what I should do.
I would be more than happy to share a video off my phone so any one can visually see what Im talking about just pm your number.

Thanks community
 
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mustang

Senior Member
your modeling light is turned on in the menu and it is set to the pv button ,
setting e5 on the custom menu .
turn it off or quit pressing the preview button
or reassign the preview button to something else
 
E

ewick

Senior Member
mustang said:
your modeling light is turned on in the menu and it is set to the pv button ,
setting e5 on the custom menu .
turn it off or quit pressing the preview button
or reassign the preview button to something else
Click to expand...

This forum is AWESOME! thanks a bunch. I just got the camera and getting to know it. So I just started reading Derrell Youngs mastering the 7100 so I can get to know the camera like the back of my hand. So whats the purpose of the modeling lamp?
 
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mustang

Senior Member
ewick said:
This forum is AWESOME! thanks a bunch. I just got the camera and getting to know it. So I just started reading Derrell Youngs mastering the 7100 so I can get to know the camera like the back of my hand. So whats the purpose of the modeling lamp?
Click to expand...
in therory it is to preview what your lighting will look like thus why it is default set for the preview button .
if you have sb800 , 700, 900, or 910 mounted it will give that long strobe flash .
if you only have the popup flash you will just get 1 flash .
 
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yauman

Senior Member
Modeling light was useful especially for off-camera strobe situations or extreme or weird bounce strobing, It gives you a preview of what the light and shadows will look like. It was very crucial in the film days but today with digital, most of us model photographers prefer to just chimp. The down side is modeling light really eats up the battery and in the case of the SB900 can heat up the head prematurely. You can turn off the model lighting on the D7100 - most people do - as it's really not that useful anymore.
 
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E

ewick

Senior Member
mustang said:
in therory it is to preview what your lighting will look like thus why it is default set for the preview button .
if you have sb800 , 700, 900, or 910 mounted it will give that long strobe flash .
if you only have the popup flash you will just get 1 flash .
Click to expand...

That makes perfect sense. So how do you get to enable the modeling light without triggering the long flsh on the strobe?

yauman said:
Modeling light was useful especially for off-camera strobe situations or extreme or weird bounce strobing, It give you a preview of what the light and shadows will look like. It was very crucial in the film days but today with digital, most of us model photographer prefer to just chimp. The down side is modeling light really eats up the battery and in the case of the SB900 can heat up the head prematurely. You can turn off the model lighting on the D7100 - most people do - as it's really not that useful anymore.
Click to expand...

Thank you for your response. I am really impressed with this community. I been on forums where all you get are snide/rude responses. Really looking forward to exploring this forum and my new camera.
 
Y

yauman

Senior Member
ewick said:
That makes perfect sense. So how do you get to enable the modeling light without triggering the long flsh on the strobe?
Click to expand...

You cannot - that how Nikon implements their modeling feature. Other speed light manufacturers may implement it differently. And actually it's worse - the "long" flash you see is actually many many pulses of short bursts, so close together that you see it as a long continuous light. If I remember right, i think the way SB700 implement it is to pulse at 1/16 (1/32?) power at maximum recycle speed, ie fire and quench as soon as 1/16 of max light power is reached, recharge and fire again. Since the charge capacitor bank is big enough to fire at 100% power and recharge in 2sec, at 1/16th power it will recharge fast enough to put out another light pulse without you seeing a "blank" so it looks like a long continuous flash.

FYI, these strobes are not capable of lighting up continuously. The light bulb (tube) is filled with Xenon which requires 5,000-10,000 volts to sustain a discharge to produce light - but no one wants to carry a 10KV power supply with them. So they build a charging circuit inside which steps up your 4x1.2volt battery to about 5KV-10KV to charge up a bank of tiny high voltage capacitors. When triggered, the capacitor makes connection to the xenon tube and the flash occurs. Another circuit then "quench" the capacitor when enough light power is put out for the particular setting. At full power the SB700 can sustain a light output of 1/1000 sec (full dump of a fully charged capacitor bank) and at lowest power 1/128th power, it puts out a light pulse of 1/40,000 sec's long. At 1/16th power the light pulse is 1/10000 sec long. The camera sensors can deal with that short time but our eyes cannot and our optic nerves and brain "stretch" out that 1/10000 sec pulse and when repeated, we think it's a continuous light! Now you can appreciate where the battery drain comes from when you use the modeling light feature and why the on-board flash's "modeling" light only give you just one full-power flash (the flash draws from the same battery your camera uses for other functions!)
 
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