flash pics dark at the edges: 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...

billozz Loc: Birmingham, England

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

CaptainC Loc: Colorado, south of Denver

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

Hard to know without an image to view, but if you are using a wide-angle lens, it is possible the flash does not the ability to spread the light wide enough. Does your flash have the automatic ability to spread the beam to equal the lens in use?

Weddingguy Loc: British Columbia - Canada

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

You can solve the problem for $30.00 with one of these, and by the way, not all reflector/diffusers are the same. I.ve tried them all and this is definitely the best!
http://www.amazon.com/Lite-Genius-Lite-scoop-Reflector-diffuser/dp/B007PKCZV0/ref=sr_1_1?ie=UTF8&qid=1381685537&sr=8-1&keywords=lite+genius

billozz Loc: Birmingham, England

hi captain thanks for the reply, it does have the ability to change the spread of light i think, it has a butoon on the back which cycles through various focal lengths from 24mm to 100mm but it doesnt do this automatically, even when in ttl mode you can still change this, maybe this is the problem, i thought when in ttl mode it would do thid automatically so didnt give it any though. does this mean that if i am using a zoom lens i have to keep changing that setting on the flash too. would a canon flash do this automatically do you know.
thanks again foor the reply
Bill

Wabbit Loc: Arizona Desert

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

Pics Doc .....

jeep_daddy Loc: Prescott AZ

billozz wrote:

hi captain thanks for the reply, it does have the ... (show quote)

If it isn't a Canon flash then it's probably not E-TTL compatible with your body. In this case, you'd have to use the zoom feature manually on the flash or use a light modifier to spread the light.

If you are using a wide angle lens then all bets are off since it could also be a host of other problems such as having a thick screw on filter, ill fitting hood or hood attached wrong etc.

CaptainC Loc: Colorado, south of Denver

billozz wrote:

hi captain thanks for the reply, it does have the ... (show quote)

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.

Weddingguy Loc: British Columbia - 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.

Canon does it also Captain. Actually if it is a Yongnuo or similar Nikon compatable flash it should also be automatic. It also depends on the flash being in the "normal" straight ahead position, not tilted up OR down.

CaptainC Loc: Colorado, south of Denver

Weddingguy wrote:

Canon does it also Captain. Actually if it is a Yongnuo or similar Nikon compatable flash it should also be automatic. It also depends on the flash being in the "normal" straight ahead position, not tilted up OR down.

Yes - I would assume as much. And yes, the auto-zoom only works in the straight-ahead posit - [auto]zooming in any other orientation makes no sense.

LoneRangeFinder Loc: Left field

Weddingguy wrote:

Canon does it also Captain. Actually if it is a Yongnuo or similar Nikon compatable flash it should also be automatic. It also depends on the flash being in the "normal" straight ahead position, not tilted up OR down.

Many Yongnuos are manually. Not enough information here. As already noted, the angle of the lens could be wider than the flash. My Yongnuo goes to 24mm (all manual-- I have to adjust it); I have two lenses wider than that.

speters Loc: Grangeville/Idaho

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

Sounds like regular light fall-off, it has to do with the inverse square law.

cthahn

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

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.

donnieb55 Loc: Greensboro, NC

Check your camera's flash sync speed. My Nikon d3100 1/200 second or under. It makes the flash go off late or early if not set correctly causing the dark edges. I learned this from experience.

Pablo8 Loc: Nottingham UK.

speters wrote:

Sounds like regular light fall-off, it has to do with the inverse square law.

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.

anotherview Loc: California

Some flash units have a plastic flap that pulls out and lies over the flash unit face, to spread the flash lighting output.

If yours does, then you may wish to experiment with its use to see how much it spreads the light. Shoot against a dark flat surface, and examine the spread of the flash lighting.

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