Need some help with Flash photography

[mintydave]

This is a typical pic of what i want to capture but im have some trouble and dont fully understand flash photography.

My initial problem is that simular pictures are either too dark or blown with white so my first question is how does metering work, does distance from the subject or the ammount of reflected light come into the equation.

The above was taken on my 450D with apperture at 4.5, shutter 1/15 and iso 800 with internal flash, and is about the best i have managed so far.

this pic was taken on the same settings and the subject was quite close but its too dark and i dont know why

I have tinkred with all the settings and even with the iso down to 100, smaller apperture and a faster shutter, or the total opposite and im still getting poor results, . I assume the camera is automatically compensating and bumping up/reducing the flash power.
Obviously i cant do a longer exposure with no flash as that wouldnt work.

any advice would be great and i appreciate that a flash gun would be the ideal solution but i still need some help understanding whats going to get the best from my kit

cheers
Dave

 

[Slimbert]

I'd recommend looking through your instruction manual and reading about 2nd curtain/rear flash, and make sure you have your camera flash settings set to E-TTL which I think the 450D has, but I'll leave this to someone with a bit more flash knowledge as I very rarely use flashes!

 

[cherryrig]

What camera mode you got it on? Manual Tv Av?

On board flashes are such a pain as normally they are just going to fire right at the subject and give a very harsh and unflatting image. That's why it's best to use a flash on the hot shoe so then at least you can bounce the light rather than being fired right at the subject

 

[CT]

The above shot has worked because the slow shutter speed of 1/15th has recorded the background detail pretty well in the low ambient room lighting, while the flash has illuminated the foregound figures.

On - camera flash is very linear in the way it works - the flash bounces off the nearest subject and back through the lens where an on board flash sensor deems the exposure correct and quenches the flash. With a faster shutter speed you'd have had a dark bg which is typical of the auto flash shots you see from pont and shoot cameras in this sort of situation.

So meter for the room light which will mean a slow shutter speed to record the room detail while the flash will illuminate the foreground subjects. Just be aware that you can get some secondary ambient light image blur as the shutter is open long after the flash has died away, so any subject movement records as ghost images.

Pop up flashes are very limited in range and power compared to a full blown flashgun which also allows you to to bounce the light for a softer effect and better spread of light.

Edit - there's nothing much wrong with your 2nd shot at all btw.

 

[Blue Eagle]

I would look into an external flash if you can. Flash in the pan does some very reasonably priced non-canon ones and they will give you great flexibility. The addition power lets you use f/8 or similar so you will usually get pin sharp shots one after the other.

I've got this flash (although i got it at the bargin price of £39, i still thought it was decent value at the original £100) It has given me some great shots and the only noticable disadvantage is the slow recharge time meaning you have to allow a moment or two between shots.

 

[mintydave]

I'd recommend looking through your instruction manual and reading about 2nd curtain/rear flash, and make sure you have your camera flash settings set to E-TTL which I think the 450D has, but I'll leave this to someone with a bit more flash knowledge as I very rarely use flashes!

The canon does have the facility to tinker with E-TTL. evaluate or average and the manual is a bit vague after that other than saying its for advanced users, the same is with 2nd curtain - very little info

What camera mode you got it on? Manual Tv Av?

Was shooting in manual mode that night

The above shot has worked because the slow shutter speed of 1/15th has recorded the background detail pretty well in the low ambient room lighting, while the flash has illuminated the foregound figures.

On - camera flash is very linear in the way it works - the flash bounces off the nearest subject and back through the lens where an on board flash sensor deems the exposure correct and quenches the flash. With a faster shutter speed you'd have had a dark bg which is typical of the auto flash shots you see from pont and shoot cameras in this sort of situation.

So meter for the room light which will mean a slow shutter speed to record the room detail while the flash will illuminate the foreground subjects. Just be aware that you can get some secondary ambient light image blur as the shutter is open long after the flash has died away, so any subject movement records as ghost images.

Pop up flashes are very limited in range and power compared to a full blown flashgun which also allows you to to bounce the light for a softer effect and better spread of light.

Edit - there's nothing much wrong with your 2nd shot at all btw.

in an ideal world i would have liked a bit more subject light but i assume the green background light was a bit brighter than the red in pic 1 which made it different, also the guys shirt?

Thanks for the replies, understand a bit more now.

regards
Dave

 

[CT]

in an ideal world i would have liked a bit more subject light but i assume the green background light was a bit brighter than the red in pic 1 which made it different, also the guys shirt?

Bingo! It would have been the very light guy's shirt causing the flash to quench early. Darker clothes as in your first example, would have reflected less light and exposed better for the skin tones, but there 's nothing in your 2nd shot which couldn't be sorted with a levels tweak.

In that situation, I'd use AV, but meter for the room light which should give you a pretty slow shutter speed. Set the flash on ETTL and you should get pretty good results. Just watch out for that blur from the longer ambient light exposure.

 

[CT]

I wouldn't worry about 2nd curtain sync in that situation tbh - it all comes down to whether you want that ambient blurring before or after the flash fires which is isn't going to make a big diffence in those sort of shots.Many people use that blurring to great effect anyway.

There's an explanation of 2nd curtain sync which may help HERE.

 

[mintydave]

Bingo! It would have been the very light guy's shirt causing the flash to quench early. Darker clothes as in your first example, would have reflected less light and exposed better for the skin tones, but there 's nothing in your 2nd shot which couldn't be sorted with a levels tweak.

In that situation, I'd use AV, but meter for the room light which should give you a pretty slow shutter speed. Set the flash on ETTL and you should get pretty good results. Just watch out for that blur from the longer ambient light exposure.

Thanks for that. im happy to use a big apperture as backgroung blurr is not an issue for me, especially on shots like this, so i will hopefully get a decent shutter speed. as i said the ETTL is either Evaluate or Average and i assume its Average i want.

Im out again on friday so will try it again, any other things to try while im on site just in case?

cheers
Dave

Ps - please feel free to have a tweak so i can see the difference and if you do i would appreciate a quick rundown on what. i dont want to use the picture for anything its just about practice, evaluation and learning

Dave