flash pics dark at the edges (Page 2): You have to deal with light loss in all directions (the light travels), you'll have the same light loss in spread towards the edges.

speters Loc: Grangeville/Idaho

Pablo8 wrote:

Sorry the Inverse Square Law does not relate to this problem. The posters problem is about light spread coverage in relation to the coverage of the lens in use..The Inverse Square Law is to do with light intensity and the distance the light is from the subject. How moving the light back to twice the distance, the exposure needs to be increased by 2 stops. (2 squared = 4) Four times the amount of extra exposure needed.

You have to deal with light loss in all directions (the light travels), you'll have the same light loss in spread towards the edges.

Randolph Loc: Medway, UK

billozz wrote:

hi all,
can anyone suggest a reason why some of my pics of a group of people are coming out darker at the edges of the pic than in the middle when using flash, is it because i dont have a diffuser fitted to the flash?, the flash i am using isnt a canon flash ( i have a 450d ) its one i bought from jessops.
thanks
Bill

The obvious solution is to take it back to Jessops with your camera, let them fix it or change the flash unit if faulty.

anotherview Loc: California

The flash lighting from the flash head likely does not spread enough to cover beyond the default focal length of the flash unit.

Some flash units come with a wide panel that that spreads the flashing lighting more.

The Canon 580EX II, for example, has a built-in wide panel. When pulled out and placed over the flash head, "[t]he flash coverage will then be extended for 14mm." (Manual, Page 20)

You did not specify which Jessop's flash unit you own, so I cannot evaluate it for suggestions.

billozz wrote:

hi all,
can anyone suggest a reason why some of my pics of a group of people are coming out darker at the edges of the pic than in the middle when using flash, is it because i dont have a diffuser fitted to the flash?, the flash i am using isnt a canon flash ( i have a 450d ) its one i bought from jessops.
thanks
Bill

Chevy Truck Grillwork

Wellhiem Loc: Sunny England.

cthahn wrote:

If your photography knowledge is anything like the way you write, no wonder you are having problems. The slop English you use is disgusting. You do not mention what flash you are using so how do you expect any help.

I'm sure that helped, Mr Perfect.

If you have the ability to zoom manualy, then I'd be very suprised if it will do it automatically in any setting. I may be wrong. Unlike cthahn, I'm not perfect.

billozz Loc: Birmingham, England

cthahn wrote:

If your photography knowledge is anything like the way you write, no wonder you are having problems. The slop English you use is disgusting. You do not mention what flash you are using so how do you expect any help.

good job u r in hiding as id pop round and teach you a few manners.

billozz Loc: Birmingham, England

can i just say a big thank you to most people that answered and make one suggestion, clean the contacts on your flash and hotshoe, looks like it may have been a communication problem between camera and flash, the flash had no idea i was using the wider end of the 18-55 lens so defaulted to 50mm hence the light fall off at either end, having cleaned both a little ( although no discernable dirt on either) seems to have sorted the problem.
thanks again to those who tried to help, and go take a running jump to those who chose not to but still commented
Bill

billozz Loc: Birmingham, England

Randolph wrote:

The obvious solution is to take it back to Jessops with your camera, let them fix it or change the flash unit if faulty.

jessops have closed down haven't they?

billozz Loc: Birmingham, England

cthahn wrote:

If your photography knowledge is anything like the way you write, no wonder you are having problems. The slop English you use is disgusting. You do not mention what flash you are using so how do you expect any help.

ive read a few more of your posts and your just not a very nice person at all, you dont give constructive criticism you just criticise, why do you bother to come on here nobody wants to hear what you have to say go away and get back under your rock

napabob Loc: Napa CA

cthahn wrote:

If your photography knowledge is anything like the way you write, no wonder you are having problems. The slop English you use is disgusting. You do not mention what flash you are using so how do you expect any help.

maybe your mother should have let you in on the secret of, if you don't have anything nice to say SHUT UP, of course I'm assuming you had one...............

anotherview Loc: California

Meanwhile, a little civility on the part of all will go a long way.

Keeping in mind we here have an interest in photography may point us in the right direction.

billozz wrote:

ive read a few more of your posts and your just not a very nice person at all, you dont give constructive criticism you just criticise, why do you bother to come on here nobody wants to hear what you have to say go away and get back under your rock

Girl with Puppy

wiselee Loc: Henderson,NV.

cthahn wrote:

If your photography knowledge is anything like the way you write, no wonder you are having problems. The slop English you use is disgusting. You do not mention what flash you are using so how do you expect any help.

Are you a very unhappy person? Such sarachasim isn't really necessary! :thumbdown:

Randolph Loc: Medway, UK

billozz wrote:

jessops have closed down haven't they?

Peter Jones bought Jessop's when they were in administration and closed many stores. If you go to their website you will see which stores are near you.

raysass Loc: Brooklin, On, Canada.

CaptainC wrote:

I do not know for sure, but I would bet the Canon flashes will automatically adjust flash spread to match the lens angle of view. The Nikon flash does, so I can assume the Canon flash will do as well.

Captain, sorry for butting in but what if the camera and flash is Canon but the lens is Sigma, will the flash still adjust automatically?

anotherview Loc: California

For my part, I have the Sigma 17-50mm lens mounted on a Canon T4i with the Canon 580EX II flash unit in the hotshoe. I use this combination to shoot family gatherings and similar events. The gear works well together.

raysass wrote:

Captain, sorry for butting in but what if the camera and flash is Canon but the lens is Sigma, will the flash still adjust automatically?

Mesa Near Cayonlands NP

lightchime Loc: Somewhere Over The Rainbow

Pablo8 wrote:

Sorry the Inverse Square Law does not relate to this problem. The posters problem is about light spread coverage in relation to the coverage of the lens in use..The Inverse Square Law is to do with light intensity and the distance the light is from the subject. How moving the light back to twice the distance, the exposure needs to be increased by 2 stops. (2 squared = 4) Four times the amount of extra exposure needed.

Yes, but:

As the light spreads outward from the flash, the intensity of the light diminishes. If you draw a plane through the sensor and one at an arbitrary 15 feet away, the light will be greater in front of the camera than it is at the ends of the distant plane. The distance is greater at the ends and the inverse square does apply. This is exactly what you are saying, but not realizing that there is a greater distance at the spread of the light.

The point is that light is greatest directly in front of the source, but as it spreads, it diminishes.