Is there actually anything Wrong - 7D?

[zcf]

from what I think the flash is indeed compensating, as you see all three photo about similar exposure instead of getting darker. The things that go wrong is the metering, is you spot meter on the bright white wall, sure it will try to assume the exposure is good enough, that why end up the flash ou put is lower. Try multisegment metering and see, or use spot metering but use AEL lock on some not too bright, not to dark area.

 

[TuTu_CaR]

hmmmm okok i get your point.... but i already using spot metering mode on the curtain... i guess something wrong with my metering system?... :think:

 

[UY79]

from what I think the flash is indeed compensating, as you see all three photo about similar exposure instead of getting darker. The things that go wrong is the metering, is you spot meter on the bright white wall, sure it will try to assume the exposure is good enough, that why end up the flash ou put is lower. Try multisegment metering and see, or use spot metering but use AEL lock on some not too bright, not to dark area.

Your concept of flash exposure is wrong. The flash did not compensate.

Like I said earlier, flash exposure is independant of shutter speed.

Unlike ambient exposure where the duration of the shutter speed and aperture determines the exposure, in flash exposure, the burst of flash, usually lasting 1/500 of a second or faster, and aperture will determine the flash exposure.

The role the shutter speed plays in flash photography is just to sync. You will have to understand why there's a maximum x-sync speed and why HSS or FP flash mode is invented so to use the flash at higher shutter speeds above x-sync.

Here are 2 useful links to flash sync and HSS.
http://www.photozone.de/3Technology/flashtec4.htm
http://www.photozone.de/3Technology/flashtec5.htm

You can set the flash in manual ratio mode, take a few shots with at different shutter speeds below 1/125 or 1/160 if AS is off, keeping aperture constant, and you find that all the shots will have the similar exposures.

 

[l_n_h]

Your concept of flash exposure is wrong. The flash did not compensate.

Like I said earlier, flash exposure is independant of shutter speed.

Unlike ambient exposure where the duration of the shutter speed and aperture determines the exposure, in flash exposure, the burst of flash, usually lasting 1/500 of a second or faster, and aperture will determine the flash exposure.

The role the shutter speed plays in flash photography is just to sync. You will have to understand why there's a maximum x-sync speed and why HSS or FP flash mode is invented so to use the flash at higher shutter speeds above x-sync.

Here are 2 useful links to flash sync and HSS.
http://www.photozone.de/3Technology/flashtec4.htm
http://www.photozone.de/3Technology/flashtec5.htm

You can set the flash in manual ratio mode, take a few shots with at different shutter speeds below 1/125 or 1/160 if AS is off, keeping aperture constant, and you find that all the shots will have the similar exposures.

since shutter speed do not affect flash exposure, does that means that when using flash, we should just use s mode? i am confused...

 

[Agetan]

Hiee Pals...

Juz got off a conversation and some casual trials with the 7D with a contact....and then rviwed again on weather there is actualy anything wrong with the Dynax 7D metering in Manual Mode "M" with flash.

It really look like there is actually nothing wrong. Why? Lets see...here are some pointers...to consider...

In Manual Mode (M):

Case 1a: Without Flash - Assuming Without Flash in a Dimly Lit Room
User will play/tweak the Aperture and Shutter to make the indicator move to center for a "properly exposed shot". Let say the Settings were as follows: Tv:10" Av: f4.5

Case 1b: Without Flash again - Now in the same room, with a light on the ceiling turned on.
Now based on the Photographer's choice of keeping the Shutter Speed same - Tv: 10"
now the new aperture that corresponds to the same exposure with the light is now at Av: f13.

**The above examples do not have flash as main source of illumination.

Case 2a: Now With Flash (either pop up or 3600/5600) in the same Dimly Lit Room
Now, the metering indicator shows fixed center point on the metering scale. Why? Probably because now the camera (Come on after paying $2500 for a body you would expect some level of automation wonders here....) will "DIE-DIE!" take the shot ...in the dim room...with flash.... And get a properly exposed shot. Hence this equates to the metering indicator to be always in the center. As long as the subject is within the power coverage of the flash, then it will take the shot properly exposed. Therefore.....the camera is now telling you that...
- Okay Leave it to me...I'll do the job....!!!!
With the flash on board or mounted e.g 3600... If the photographer decides to choose the max shutter speed....i.e...the shutter will go to its max at Tv: 1/125sec. Now If the user tweaks the aperture....As long as the flash power is sufficient based on the distance + Aperture combo at specific ISO, the image should be correctly exposed.
However, If the shutter speeds chosen is really slow....say 15sec....and the subject distance is within power range, the subject e.g 1.5metres will be lit with the first blast of flash at exposure time.....and the rest of the 14++ sec or so will then be ambient lighting (maybe from TV or street light etc).....

So if let say i wanna play with DOF then with the specific Shutter speed like flash sync (Tv:1/125sec) i just need to play with aperture ......

From the above cases, it can then be seen that it make sense that the metering indicator in the viewfinder stays in the middle if flash is used in M Mode.... It will move unless the photographer dials in EV compensation +/- which will move the needel left or right respectively. Power of the flash is adjusted during exposure time to ensure the metered scene is properly exposed.

Do feel free to talk more about this....if you think otherwise...

NOTE: Seems like Most of the Under Exposures experienced may be due to using lower guide numbered flash....(using pop up flash) with a combo of small apertures....

rgds,
sulhan

I agree with what you said Sulhan... That was my thought all along..

Hart

 

[sulhan]

Your concept of flash exposure is wrong. The flash did not compensate.

...........

You can set the flash in manual ratio mode, take a few shots with at different shutter speeds below 1/125 or 1/160 if AS is off, keeping aperture constant, and you find that all the shots will have the similar exposures.

I think.....Provided the subject is within the power range...then this is true.
If your subject is far away.....(estimation by guide number with aperture setting) and flash as the main source of light.... this may not be true.

Some times, if shutter speeds get slower illumination due to other external sources of light may need to consider as one may think that its lighting from the flash that exposes the distant subject...

rgds,
sulhan

 

[TME]

I think you made an error here. Manual mode doesn't follow any rules as it let you have complete control over the camera, unless I've mistaken your remarks for something else.

My mistake... what I am trying to say is that your shutter speeds are limited to those for a correct exposure and coverage cos the flash cannot sync faster than that without HSS available.

 

[UY79]

since shutter speed do not affect flash exposure, does that means that when using flash, we should just use s mode? i am confused...

No, S mode should only be used when you need to control exposure time like long exposure night photography. The best mode to use with flash is M mode when lighting is constant and A mode when lighting changes.

The choice of shutter speed in flash photography has to be high enough so that the effects of handshake of the ambient exposure does not affect your photo. But that's something different all together from what we are discussing here.

 

[UY79]

I think.....Provided the subject is within the power range...then this is true.
If your subject is far away.....(estimation by guide number with aperture setting) and flash as the main source of light.... this may not be true.

It will always be true. Whether it underexposes or over, that's dependant on the power and aperture used. Exposure in that experiment will alway produce similar results in flash exposure regardless of shutter speed. You just have to try it.

Some times, if shutter speeds get slower illumination due to other external sources of light may need to consider as one may think that its lighting from the flash that exposes the distant subject...

This is correct. But for his case that we are discussing, it's obvious the ambient exposure has no effect even at 1/30s. If the ambient lighting is stronger, we will see a difference in ambient exposure as the shutter speed is varied, but the flash exposure will remain the same.

 

[UY79]

This post responds to the first post by sulhan.

Take for example, the ambient lighting is much more than what I've set in M mode, say by two stops, and for some reason I'm already using flash.

Isn't it flawed in this case if my exposure meter is fixed at the 0EV mark, in which I've no warning that the shot is going to be overexposed?

If the meter tells me that shot will be overexposed, I could adjust accordingly to take the shot.

The other arguement would be if the meter is working, I could adjust balance the ambient exposure with the flash exposure so that I do not kill the background lighting as with most cases of letting the camera handle the flash exposure.

 

[TuTu_CaR]

This is correct. But for his case that we are discussing, it's obvious the ambient exposure has no effect even at 1/30s. If the ambient lighting is stronger, we will see a difference in ambient exposure as the shutter speed is varied, but the flash exposure will remain the same.

Finally i understand.... :bsmilie: :thumbsup:

 

[TME]

Glad u did Tutu_Car.... it's not very obvious unless u have been shooting in M mode on the Dynax 7 or other similar cameras... the moment I got my hands on the 7D and shot in M mode, I was like... what's going on... how come I dun get ambient exposure feedback at all... at least my copy is now ok and that at least indicates that that's how KM wanted the exposure metering scale on the camera to work... for some reason, it does not on most bodies but then again... it's KM's first body and there are bound to be bugs... in any case the lack of another firmware upgrade indicates a few possible things: 1) the problem cannot be solved by a software upgrade 2) they cannot identify what causes the problem, 3) there is going to be a 7D MkII so too bad... I think it's more of 1) and 3)...

Edit: I know this has been discussed to death in other earlier threads but for the benefit of newbies to the KM system...