snubbr.com

External flash question
Hi,.

I noticed that when I used my external flash on my camera, that the shutter spead is always on 1/60. Is this the way it should be? If so, why?.

Kind regards,Mil...

Comments (11)

Milbogo wrote:.

Hi,I noticed that when I used my external flash on my camera, that theshutter spead is always on 1/60. Is this the way it should be? Ifso, why?.

Kind regards,Mil..

To the first question. You probably should get a choice. Though you may not.I can tell you that it is typical of most cameras..

As to why. The shutter in a camera has two curtains. The first starts across the sensor and opens it to light. The second starts across the sensor and closes it to light. The speed of the curtains determines the sync speed of the flash. The flash has to go off when the first curtain is fully open and the second has not yet started to close, otherwise you will have an underexposed portion of the picture that was partially covered by one of the curtains..

Even in the very best of cameras sync speeds don't typically exceed 1/250th of a second. Above those speeds the second curtain is following the first curtain so closely that the sensor is always partially covered by one curtain or the other. In other words there is a narrow slit between the two curtains that is traversing the sensor. Thus if the flash goes off when the shutter is set to say 1/500th you get just a half picture..

You may be able to test the upper limits of the sync speed of your camera if you have access to manual mode and flash. Just keep dialing up the shutter speed untill you get a partial picture and you've found the upper limit of the sync speed..

There are other technical issues here and the upper limit that you've just found may not be reliably used......depends.A member of the rabble in good standing...

Comment #1

You seem to have a Canon 350D. I have a 400D, but I assume the basics to be the same..

The shutter speed depends on the modus you are in.I have no idea about the scene modes..

In the P mode, the speed is set to 1/60th..

In the Av and Tv Modes the Camera meters normally and completly ignores the flash.In M mode you have to set everything manually..

F you have a eTTL flash, I would advise using manual mode. Just set the Aperture and shutter speed so that the background is exposed the way you want. The Flash will fire and adjust automagically to produce a correctly exposed foreground. You can dial in Exposure Compensation for the flash using FEC in the menus..

If you want to have a correvtly exposed background and just light up something, use Av or Tv mode..

Try not to use a shutter speed higher than 1/200th, for the reasons mentioned before..

If you have a Canon Ex Flash, you can set it into Highspeed mode, this way the flash fires a longer bursts and allows faster shutter speeds. I suspect this features is available on other flashes as well....

Bye,Philip..

Comment #2

Thank you for your replies,.

Doesn't 1/60 mean I will get camera shake and blur?What I cant understand is why P mode and my 580ex work it out automatically?..

Comment #3

As the other responders have mentioned, it depends on the mode. On Canon EOS cameras, the best flash mode is M on the Camera and ETTL on the flash. With a flash mounted in ETTL mode, and M on the camera, it is not fully manual, but instead a semi-automatic mode. You can set whatever aperture you want for DOF, and any shutter speed up to the cameras sync speed of 1/200 s, and the flash system will try to automatically output enough light to cover your settings. Only with the flash in M and the camera in M do you have full manual with a flash mounted..

Av and Tv are flash fill modes on Canon cameras. The camera meters and exposes for ambient light, and the flash fires to fill in the shadows. On the 350D in Av mode, the shutter speed is variable but defaults to 1/60 s; you can set it to a fixed 1/200 s using custom function 03 (CFn 03) in the menus..

Brian A...

Comment #4

Milbogo wrote:.

Thank you for your replies,.

Doesn't 1/60 mean I will get camera shake and blur?.

Not necessarily. You might get Blur or camera shake on the background, but the main subject should be fine, as long as it is primarily illuminated by the flash..

The flash is a very short burst of light, short enough to avoid motion blur and shake. However if there is enough light to illuminate the subject further, you might get shake and/or blur from that..

What I cant understand is why P mode and my 580ex work it outautomatically?.

The problem is, that they can sort out so much automatically. The flash can automatically adjust it's power so that any given settings (within a reasonable range) will produce a perfectly exposed main subject. The problem is how much of the background should be exposed.The Tv and Av modes try to expose the background perfectly.But to me the real way to shoot Flash is to use the M mode..

You can select any aperture to get the desired Depth of Field, Select a shutter speed fast enough to capture the main subject, and set the ISO to 200. If you want to get some of the background into the shot, adjust the parameters until you are satisfied..

If I know i'm going to use flash for the next couple of shots, I just drop to M mode and select some settings and stick with them..

Bye,Philip..

Comment #5

Milbogo wrote:.

Doesn't 1/60 mean I will get camera shake and blur?.

Not necessarily. The duration of the flash is about 1/500 s, even at full power. When the flash outputs at lower levels, the duration is even less. The flash itself will stop motion, providing there isnt too much ambient light in the exposure..

What I cant understand is why P mode and my 580ex work it outautomatically?.

The flash outputs a preflash and the system uses this to calculate how much power to output. Shutter speeds, providing they are not faster than the sync speed, make no difference to the flash exposure because the flash duration is always less than the length of time the shutter is open..

Brian A...

Comment #6

Nabx wrote:.

Why no text?.

Because the question in the subject line was sufficient. There was no need for any text in the message body; hence the (nt) suffix with the post. The (nt) tells the reader that he or she doesnt need to open the post, all the information is in the subject line. NT posts are used frequently on message boards and internet forums..

To what does your Its OKpost refer to?.

Brian A...

Comment #7

Wow - thanks guys. What an important thing to know - I had no idea. Yes, most of my blurred shots have alot of ambient light. But I just dont have the confidence to shoot in M. What looks good on screen, may not be so good on computer..

Are there any safe M settings for chickens like me? (I am a chicken ause I don't want to miss the shot, and want to play it safe).

Kind regards,Mil...

Comment #8

Milbogo wrote:.

Are there any safe M settings for chickens like me? (I am a chickenause I don't want to miss the shot, and want to play it safe).

You can shoot with the lens stopped down to say f/11 and the shutter speed at 1/200 s and get virtually no ambient light in the exposure, unless you are outdoors. Or you could shoot with the aperture fully open and at a relatively slow shutter speed of say 1/60s, and this would give you a shot at letting in more ambient light into the exposure. Raising or lowering the ISO setting will also allow you to adjust the amount of ambient light in the exposure..

Flash shots tend to be better, look more natural, with some ambient light in the exposure to light the background. With no ambient light in the exposure you can end up with very dark backgrounds. For some shots this may be what you want, but for most probably not..

As long as you dont exceed the flash sync speed, and dont exceed the flashes range, there are a wide range of settings that will work. The ETTL system will try to output enough light for a correct exposure. It can fail for the same reasons that ambient light exposures fail: bright subjects tend to get underexposed and dark subjects tend to get over exposed. That is why there is FEC (flash exposure compensation), which you would use in the same way as you use regular exposure compensation in Av mode when shooting without a flash..

If you want a good starting point, then I would suggest 1/160 s @ f/8 and ISO 200..

As far as exceeding the power of the flash is concerned, there is a table in the 580exs manual that gives the maximum range at various apertures and focal lengths. The 580ex has a guide number (GN) of 58 metres at ISO 100 with a focal length of 105 mm and at a theoretical f/1. You can calculate the maximum range using a simple formula:.

GN = distance times f-stop.

Or.

Max distance = GN / f-stop.

So at ISO 100 and f/8 you have:.

Max distance = 58 / 8 = 7.25 meters..

If you wanted to shoot something further than 7.25 metres at f/8, then you would have to use a higher ISO. Same goes if you are shooting at a wider angle than 105 mm, the flash beam would be spread more, so you would have to get closer or raise the ISO..

Brian A...

Comment #9

Another point, which I hope doesnt cloud the main issue..

Doubling the ISO sensitivity doesnt double the range of the flash, increases it by 1.4 times. To double the range, you would have to go from ISO 100 to ISO 400..

Brian A..

Hugowolf wrote:.

Milbogo wrote:.

Are there any safe M settings for chickens like me? (I am a chickenause I don't want to miss the shot, and want to play it safe).

You can shoot with the lens stopped down to say f/11 and the shutterspeed at 1/200 s and get virtually no ambient light in the exposure,unless you are outdoors. Or you could shoot with the aperture fullyopen and at a relatively slow shutter speed of say 1/60s, and thiswould give you a shot at letting in more ambient light into theexposure. Raising or lowering the ISO setting will also allow you toadjust the amount of ambient light in the exposure..

Flash shots tend to be better, look more natural, with some ambientlight in the exposure to light the background. With no ambient lightin the exposure you can end up with very dark backgrounds. For someshots this may be what you want, but for most probably not..

As long as you dont exceed the flash sync speed, and dont exceedthe flashes range, there are a wide range of settings that willwork. The ETTL system will try to output enough light for a correctexposure. It can fail for the same reasons that ambient lightexposures fail: bright subjects tend to get underexposed and darksubjects tend to get over exposed. That is why there is FEC (flashexposure compensation), which you would use in the same way as youuse regular exposure compensation in Av mode when shooting without aflash..

If you want a good starting point, then I would suggest 1/160 s @ f/8and ISO 200..

As far as exceeding the power of the flash is concerned, there is atable in the 580exs manual that gives the maximum range at variousapertures and focal lengths. The 580ex has a guide number (GN) of 58metres at ISO 100 with a focal length of 105 mm and at a theoreticalf/1. You can calculate the maximum range using a simple formula:.

GN = distance times f-stop.

Or.

Max distance = GN / f-stop.

So at ISO 100 and f/8 you have:.

Max distance = 58 / 8 = 7.25 meters..

If you wanted to shoot something further than 7.25 metres at f/8,then you would have to use a higher ISO. Same goes if you areshooting at a wider angle than 105 mm, the flash beam would be spreadmore, so you would have to get closer or raise the ISO..

Brian A...

Comment #10

What really confused me was the 580ex manual that says to set it to P - for fully automatic operation. This is misleading - fully automatic suggests that the camera will work it out - but if there is too much ambient light, the P mode does not automatically compensate for it...and you get blur.

Man - this thread has saved a major problem. I just could not work out why pics were blurry..

Using a flash set to P when there is ambient light is a No NO..

Thanks again guys - you've made me a happy chap - now I just need to take you suggestions on board and try to use the darn thing - so much to learn........

Mil..

Comment #11

Click Here to View All...

Sponsored Amazon Deals:

1. Get big savings on Amazon warehouse deals.
2. Save up to 70% on Amazon Products.


This question was taken from a support group/message board and re-posted here so others can learn from it.

 

Categories: Home | Diet & Weight Management | Vitamins & Supplements | Herbs & Cleansing |

Sexual Health | Medifast Support | Nutrisystem Support | Medifast Questions |

Web Hosting | Web Hosts | Website Hosting | Hosting |

Web Hosting | GoDaddy | Digital Cameras | Best WebHosts |

Web Hosting FAQ | Web Hosts FAQ | Hosting FAQ | Hosting Group |

Hosting Questions | Camera Tips | Best Cameras To Buy | Best Cameras This Year |

Camera Q-A | Digital Cameras Q-A | Camera Forum | Nov 2010 - Cameras |

Oct 2010 - Cameras | Oct 2010 - DSLRs | Oct 2010 - Camera Tips | Sep 2010 - Cameras |

Sep 2010 - DSLRS | Sep 2010 - Camera Tips | Aug 2010 - Cameras | Aug 2010 - DSLR Tips |

Aug 2010 - Camera Tips | July 2010 - Cameras | July 2010 - Nikon Cameras | July 2010 - Canon Cameras |

July 2010 - Pentax Cameras | Medifast Recipes | Medifast Recipes Tips | Medifast Recipes Strategies |

Medifast Recipes Experiences | Medifast Recipes Group | Medifast Recipes Forum | Medifast Support Strategies |

Medifast Support Experiences |

 

(C) Copyright 2010 All rights reserved.