|
| Author | Thread |
|
|
04/13/2006 12:14:34 PM · #26 |
Originally posted by sir_bazz:
Originally posted by Prof_Fate:
Did you miss what i posted, or perhaps i was not clear.
...snip...
|
Ahhhh...you read this rule in a book.
I suspect that once you've had your monos for more than a few weeks you'll realise that these rules, although nice to know, are also made to be broken.
cheers,
bazz. |
Umm...people that do this for a living, for 40 years (quite a bit more than a few weeks) that run multiple studios.
Canon and Nikon - but i suppose their technical people just make this stuff up.
The companies that make the strobes themselves. No reason for them to want the user to get eh best results I suppose.
The people that make light meters say this too (sekonic).
I have used 1/160 and had no issues. Since like 95% of what I've rad on this subject says 1/125, I'll go with that. I am not an engineer or a physicist, but many that recomend this as the ideal shuitter speed are.
Slower shutter speeds (1/60 for exapmple) can begin to let in ambient light and that will throw off the color of the image as you're now mixing light types.
You can be creative and use whatever shutter speed you like, but 1/125 is what is considered standard these days. One reason for slower speeds years ago was the reciprocity failure of film under short exposures. Exceeding the X-sync or your camera will certainly cause problems.
|
|
|
|
04/13/2006 12:20:30 PM · #27 |
To understand the right sync speed, you need to understand the flash duration of whatever equipment you are using. Most manufacturers can easily give you this data, or, in some instances, it will be in your manual. The following is taken from the Speedotron Brown line manual:
Flash Duration
Flash duration of a Speedotron Brown Line system will vary with the type of flash tube, the amount of power outputted and the number of light units connected to the power supply. For example, a D402 system with two M90 light units and two MW3R light units will have four MW3-1 flash tubes and a 400Ws power supply. When set to full power each flash tube will output 100 Ws with a flash duration of 1/1500 second.
Ws MW3-1 MW3Q MW9H MW9Q
per tube
100Ws 1/1500 1/1500 1/3000 1/3000
200Ws 1/1200 1/1200 1/2200 1/2200
400Ws 1/750 1/750 1/1400 1/1400
600Ws ------- 1/580 1/1000 1/1000
800Ws ------- 1/450 1/700 1/700
1200Ws ------- 1/330 1/500 1/500
1600Ws ------- ------- ------- 1/400
Flash duration is measured from 1/2 peak light output to 1/2 light peak output. Light will continue to be produced for about five times the flash duration but will add little to the exposure. This will not affect action stopping abilities for most normal contrast subjects.
If you are using less than full power, you can have a much faster light pulse and can get away with a higher sync speed (within the capabilites of your camera). Based on the table above, I'd hesitate to use a 1/250 sync speed if I was using a setup that gave me a flash duration longer than 1/500.
As long as your ambient lights are not too bright, having a slower sync speed (1/60 or 1/30) is not an issue. The only time sync speed really becomes an issue is when you start mixing strobe with continuous lighting.
FWIW, the Canon 550EX has a Full Power flash duration of 1.2 milliseconds or 1/833 seconds. As power is reduced, that pulse will get faster, but the relationship is not necessarily linear. So you can't assume that a 1/128th power pulse from a 550EX would be 1/106624th of a second.
Message edited by author 2006-04-13 12:25:48.
|
|
|
|
04/13/2006 04:27:06 PM · #28 |
Originally posted by Prof_Fate:
too fast a shutter speed means you may not capture all the light the strobes put out |
Chris,
Are you under the impression that if you shoot a current Canon or Nikon camera (say a 5D, 20D or a D200) that you can actually get the camera to operate within its x-sync (1/200th, 1/200th and 1/500th if I remember correctly) and yet still not capture all of the flash from whatever strobes you are using?
Spazmo's comments are straight from the mfr and any other light mfr should provide similar tables. For AlienBees the slowest they have is the B1600 which has a duration of 1/1600th second. This is only a fraction of the whole time that the shutter is open. Even with lights being triggered optically I've never failed to get light from one of the strobes because I was using the x-sync shutter speed. Light travels at 186,282 miles per second and my lights are never more than about 20 feet apart at the most. Even adding the resistence of the signal that travels from the light trigger to the triggering mechanism within the strobe housing I find it difficult to believe that all 4 lights won't fire and be completely finished with the flash pulse before the shutter on the camera closes.
Everything I've read suggests that the whole range of shutter speeds up to and including the x-sync on a camera is viable with any modern strobe.
I looked through the Norman Flash Guide (written in 1968) and the Lighting Fundamentals link you provided. The mention of shutter speed that I found was in the Lighting Fundamentals where an example was given
This doesn't say to use 1/160th but it just uses 1/160th as the example. There may be great reasons to use a slower than x-sync shutter speed but I think sir_bazz's comment is valid that 1/160th isn't necessarily any better than the camera x-sync or any other shutter speed.
Do you have any other sources where this speed is supposed to be better than any other viable speed?
Kev
|
|
|
|
04/13/2006 08:33:34 PM · #29 |
Originally posted by Prof_Fate:
I have used 1/160 and had no issues. Since like 95% of what I've rad on this subject says 1/125, I'll go with that. I am not an engineer or a physicist, but many that recomend this as the ideal shuitter speed are.
|
So now you've gone from saying ALWAYS use 1/125 to saying that 1/125 is recommended. Thats a big difference just there isn't it Chris ?
Funny that nowhere in the manuals for my Sekonic L358, or my dslr or my Bowens strobes does it say I should ALWAYS use 1/125.
Even your quote from Ken Rockwell mentions using a shutter speed of 1/250.
Sheesh...just give it up and admit you were wrong and there's no reason to ALWAYS use a certain shutter speed.
cheers,
bazz.
|
|
|
|
04/15/2006 04:28:25 PM · #30 |
Thanks Chris, it was good starting point.
2nd attempt
Message edited by author 2006-04-15 16:29:03. |
|
|
|
Current Server Time: 09/24/2025 09:56:18 AM  |
Home -
Challenges -
Community -
League -
Photos -
Cameras -
Lenses -
Learn -
Help -
Terms of Use -
Privacy -
Top ^
DPChallenge, and website content and design, Copyright © 2001-2025 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 09/24/2025 09:56:18 AM EDT.
|
