1/1000 shutter, 1Ds, Alien Bees - Error

[bradley]

Recently, using a 1Ds and a set of Bee 1600's, I noticed something

odd.

 

I can't seem to shoot any faster than 1/250 without getting a

fraction of the bottom of the shot cut off - at 250, the bottom

third is black.. at 1/1000 only a sliver of the top is visible.

 

Is it the Bee's, or user error?

[maxz]

This is something you will see with all cameras using focal plane shutters. Above (below?) a certain shutter speed the whole frame is not exposed at once, but rather one piece at the time using a small "moving window".

 

Read the manual to find out what the maximum sync speed of your camera is. My guess is 1/250.

[maxz]

See <A HREF="http://www.mir.com.my/rb/photography/fototech/focalplane/">http://www.mir.com.my/rb/photography/fototech/focalplane/</A> for an explanation on how focal plane shutters work. So, the answer to your question is "user error".<P>

Note that some DSLRs (the Nikon D70 for example) have hybrid shutters that can sync at any speed. Then the mechanical shutter is always open so that the whole frame is exposed at any one time. At exposure times faster than the fastest sync speed, the electronic shutter kicks in and "turns on and off" the sensor. Not all sensors have this capability though.

[bradley]

Well I'm a moron.<br/><br/>

 

I don't have the manual with me, but I could have used the interweb:

<a href="http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=GGLD,GGLD:2005-06,GGLD:en&q=1DS+sync%2Dspeed" target="_pNet">google's first 3 hits</a>. 1/250 indeed.

[edward_h]

> Note that some DSLRs (the Nikon D70 for example) have hybrid shutters that can sync at any speed.

 

No they don't. It's the high speed-mode on the on-camera flash that allows extreme shutter speeds.

[jim c]

I have a D2h that doesn't have an onboard flash and fires my studio strobes with high speed sync.

[maxz]

<I><BLOCKQUOTE STYLE="border-left: 1px solid blue; margin-left: 0.5em; padding-left: 0.5em;"><BLOCKQUOTE STYLE="border-left: 1px solid blue; margin-left: 0.5em; padding-left: 0.5em;"><B>Edward H wrote:</B><BR>Note that some DSLRs (the Nikon D70 for example) have hybrid shutters that can sync at any speed.</BLOCKQUOTE>

 

No they don't. It's the high speed-mode on the on-camera flash that allows extreme shutter speeds.</BLOCKQUOTE></I>

Well, actually they do! This is two separate matters. What you are mentioning is <I>Auto FP High-Speed Sync</I>, something which the D70 used as example are <I>not</I> able to do. It is only available on the more advanced DSLR models from Nikon at the time of writing.<P>

 

What I mention, with hybrid shutters and fast sync speeds, is something that is neither documented nor supported by Nikon, but many people have done it. When attaching a <I>dedicated</I> flash to a D70 the camera locks the range of available shutter speeds, prohibiting the use of any speed faster than 1/500s. But you can easily <A HREF="http://www.kenrockwell.com/nikon/d70flash.htm#flash">fool</A> the camera into believing that you don't have attached a flash (see the second "TRICK" on <A HREF="http://www.kenrockwell.com/nikon/d70flash.htm#flash">Rockwells page</A>). It will fire, but you won't get any automatic metering. This trick has been documented by several parties on the Internet. When using my studio strobes I use a simple hot-shoe-to-PC adapter which doesn't make the camera "see" the strobes and thus can achieve this effect. Personally I have never had a use for this feature myself though, since I shoot with my studio strobes in the studio and there I don't need these shutter speeds.<P>

One should also consider the fact that some flash pulses are <I>longer</I> than the fastest shutter speed on the D70 (1/8000s) so this <I>might</I> lead to uneven/random exposure if using and metering for strobes at full power with extremely short shutter speeds.

<I><BLOCKQUOTE STYLE="border-left: 1px solid blue; margin-left: 0.5em; padding-left: 0.5em;"><B>Bradley Walker wrote:</B><BR>Well I'm a moron.</BLOCKQUOTE></I>

Bradley, don't be so hard on yourself. Sometimes one make "stupid" mistakes with simple things and the most obvious reasons are <I>impossibly</I> hard to see without someone pointing them out for oneself. I know what I am talking about and have done this myself at a number of times. But, even knowing this, you still feel silly each time. :-)<P>

(Ahem... If you want faster shutter speeds with your AB's, you and I <I>could</I> trade cameras. My D70 for your 1Ds ;-D Cheers.)

[maxz]

Sorry. When editing the quotes in my posting above I made a mistake and it looks like Edward H wrote the innermost quote. That was mine quoted by him, and the one immediately following is his. Sorry for the confusion. One shouldn't post before having breakfast...