[traer]

Well, as you may have guessed, my question is that of sport.
I have just started taking photo's (yesterday). Before that, i had my camcorder and things seemed alot easier.

The problem is this: I own a BMX clothing company (1120.co.uk) and last night i was taking the camera out for the first time, we had a few people out - i was trying to get to grips with the differences between still photography and action filming.

It was night time here (UK), around 4pm and i wanted to get some shots in quick, nothing came out...only the ones without action involved.

This morning and afternoon, i have been playing with a few settings; shutter speeds, aperture settings, manual focus...etc

now being new to this, i assume that because i am having to use i high shutter speed for capturing riders, this is why my pictures come out really dark, the flash i use is the one on the camera...the fish-eye lens is needed for close-up shots of my subject, but when i use the flash, the size of the lens gets in the way and leaves it's shadow on all the pictures.
should i use flash? also, with the camera that i have, is there a way of letting more light in? if i change the aperture settings, i can get more light, but at the risk of camera shake and i can't change the shutter speed...if i change the ISO settings to 800(max) then this will affect image quality.

maybe i am looking at this all wrong, and there is a setting i can use (i haven't figured out the 'Manual' setting)

Well, if anyone can decipher this babble, please help, thanks

[Dave]

Fish Eye lens will need a seperate flash gun , as you have experienced the side effects of onboard vsn with this lens.

To get more light into the camera you have the following options, with associated impact :-

- Open the aperture .....reduces depth of field
- Up the ISO .... introduces more noise to shot...more noticeable at 800 & above
- Provide artificial light...eg flash .

In the conditions you were talking about & shutter speeds required, a decent flash gun is the only option. In brighter conditions you could have upped the ISO & turned the extra noise to your advantage..make the shots grittier on purpose.

[traer]

thanks, i'm not entirely up to speed yet with some things, so is this normal: last night i was trying in a lit room with shutter speeds set to 1/125 f8 with flash off, the picture came out really dark and again with 1/125 and f2.8, i then tried with the flash on and the picture came out fine. the question i have to ask would be, if i were taking pictures in bright sunlight, would the picture still come out dark as it did in the lit room? if so i can't use a light to compensate in this situation.

here are some pictures to show you what's wrong

Shutter Problems

[abirkill]

Our eyes are incredibly good at adjusting to different levels of light. The difference between a averagely lit room at night and a bright sunny day might not seem much to you, but would at an absolute bare minimum be around 10 times darker, and could be as much as 50 times darker (i.e. 50 times fewer photons reaching your eye/camera).

As you can see in the 1/125th shot at f/2.8 without flash, you are getting more light into the camera (because the aperture is that much wider), as you can just about see the shape of the TV and the lights on the equipment below, which isn't visible on the f/8 shot. But obviously, the camera needs a lot more light (or a higher ISO setting) in those circumstances.

On the other hand, for example, beach photography on a bright sunny day in July may well require a shutter speed of around 1/4000th of a second at f/2.8 to be correctly exposed - that's how much more light is available.

You should be able to get a good action shot without needing a flash on a bright winter's day, especially at f/2.8, and if you're prepared to put the ISO up to 400 or so. I don't know the speed that a BMX goes at, but I'd have expected you to need a shutter speed more in the region of 1/250th-1/400th to get a sharp image - but you'll need to try it out. Personally I'd happily go up to ISO 800 given the excellent software that's around these days to process out the noise without losing detail in the image, which will allow you to speed up the shutter.

But also, don't underestimate the power of a decent flash - photographers do use a flash even on bright sunny days, to provide fill light and prevent the photograph from having harsh shadows. Obviously the built-in flash is nowhere near powerful enough for this, so you'll need a powerful external flash, and if you're using a fisheye lens you'll almost certainly need it on an off-shoe cable.

[Rob Barron]

Traer, the flash unit built into your camera will make adjustments to the amount of light it puts out so it will usually set its own shutter speed: we usually refer to this as the flash synch(ronisation) speed. On different cameras this ranges from 1/60th second to 1/250th second with specialist camera settings able to set faster speeds.

So the way it works is this: You choose the aperture so that you can get the right depth of field (for a room you want more than f2.8, I would suggest f8) and the camera will set the flash synch speed. It will read the light that is already there and then flash enough light to top it up to perfect exposure.

Now, you need to remember that the flash built in to even a good camera will only have relatively low power. On my Canon 20D it has a Guide Number (GN) of 13 which is fine for subjects just a few feet away and for adding fill-in flash. But if the room is a bit bigger, the flash unit can only put out its maximum amount of light and that might not be enough so the picture will look darker. That is where an external flashgun that sits in the hotshoe on top of the camera comes in.

I have a Canon 550EX which only works on Canon cameras but has a GN of 55. As you can see, that is a lot more power (a lot more light!) potential than the camera's own unit. With my Canon flash gun, I can put a lot more light into the room and therefore I can take photos from greater distance and still get good lighting.

With your flasgun turned on, if there is a lot of light already, the camera will simply not fire the flash unit at all unless you force it to (perhaps as fill-in flash to avoid a silhouette) so you can see the flashgun is communicating with the rest of the camera and working the light out for you.

I hope that helps you understand the relationship between the flashgun and the camera and how to use it.

Cheers,
Rob