Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Canon EOS dSLR

Reply
 
Thread Tools Search this Thread
Old Apr 20, 2009, 6:37 PM   #1
Senior Member
 
Join Date: Jun 2004
Posts: 627
Default

I have a book with great photos in it and the exif information is included. So I'm attempting to recreate those shots using the same exif info.

I set my camera to full manual mode.

I set the ISO to 400, F 2.8, TV to 1/320 of a second, external flash connected and working. I also tried several higher F stops, I gave up after 7.0

I'm using a tripod and remote shutter release. As soon as I do all this, my CAMERA changes the 1/320 to 1/200!!!

Why would or how could it over-ride my instructions?

This is just about as frustrating as MS Word set in columns mode






FaithfulPastor is offline   Reply With Quote
Sponsored Links
Old Apr 20, 2009, 7:55 PM   #2
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Your camera has a fastest x-sync speed of 1/200 second.

If you want to use faster shutter speeds than the x-sync speed with flash, you'll need a dedicated flash that has FP mode (high speed sync) available. Canon models like the 430EX and 580EX support High Speed Sync. It's probably a mode choice on the flash if you're using one of these models.

When you try to use shutter speeds that are faster than your camera's x-sync speed , the sensor (or film) is never exposed to the entire image at the same time. So, a single short flash burst wouldn't work.

Instead, flash systems that support faster shutter speeds use a special High Speed Sync mode (a.k.a., FP mode) in order to "pulse" the light to expose the image as a traveling slit of light from the shutter curtains is traveling across your film or sensor. Note that using High Speed sync reduces flash range. See this article about how High Speed Sync works:

http://www.photozone.de/hi-speed-flash-sync

JimC is offline   Reply With Quote
Old Apr 21, 2009, 7:30 AM   #3
Senior Member
 
Join Date: Jun 2004
Posts: 627
Default

I got out my manual, found the FP button (High Speed Sync). Read it. Don't understand it. Could have read it 100 times and never thought that was the answer to the problem.

So I pushed the button on the flash, and took the photo at 1/320th.

That's why you're the pro and I the schmoe.

You guys are really good.

Faithfully Yours,

FP (That stands for FaithfulPastor, not High Spped Sync)

Does FP for the flash stand for "Fill Flash Portrait"?




FaithfulPastor is offline   Reply With Quote
Old Apr 21, 2009, 7:33 AM   #4
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

FP is short for Focal Plane (the type of shutter mechanism used by modern SLR type cameras).


JimC is offline   Reply With Quote
Old Apr 21, 2009, 7:43 AM   #5
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

P.S.

This shutter type allows the use of faster shutter speeds. But, because one curtain begins to close before the other curtain is fully open at faster shutter speeds, you end up with a slit of light moving across the film or sensor.

So, you need a longer burning flash bulb, or a flash that can pulse the flash over a longer duration, in order to expose an image using fast shutter speeds. Without this kind of setup, a flash is going to use a single short flash burst (usually anywhere from 1/10000 second to 1/1000 second duration, depending on the flash and distance to subject, etc.). That would cause an image with darker areas, (i.e., a dark band across part of the image) with less and less of the entire frame exposed as shutter speeds get faster. So, many modern flash systems can pulse the light over a longer duration in order to expose the film or sensor as the shutter curtains are traveling. This "High Speed Sync" mode is often referred to as FP mode.
JimC is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 11:19 PM.