DOF preview - metering?

[ryunin]

I noticed with my nikon FE that once I press the DOF preview button, the metering needle goes down if the aperture is small and doesn't move, if the aperture is fully open. That's quite confusing / does it mean that what I am normally metering is wrong as it is metering just what I see through the viewfinder with no aperture effect?

 

[Overread]

No - when you press the DOF preview button it just closes the aperture blades to the selected aperture (unless you have it at the max aperture open then nothing happens). It is only taking into account the aperture of the shot - and thus the depth of field. It is not considerin the shutter speed nor the ASA?(ISO) of the film you are using.

Thus the needle is not giving you an exposure reading - it goes down because suddenly the aperture blades are blocking out a lot of light which throws is metering off.

 

[ryunin]

I see, thanks.

 

[TylerF]

not to hijack the thread, but does that mean that if i were to look at the needle, i am not getting a proper reading? how do i know what adjustments to make?

 

[Big Mike]

Don't take a reading (look at the needle) when you have the DOF button pressed.
Make all your exposure adjustments without pressing the DOF preview.

 

[TylerF]

hmm im lost. then what is the point of the needle? sorry, i just got my first film camera a few days ago. my needle is down until i press the button and then it goes up until i let go

 

[Big Mike]

The 'needle' is the representation of the camera's light meter. In the auto modes, it's going to be on the ---0---. That will give you an average exposure for an average scene. You can adjust it away from the ---0--- by using EC (exposure compensation) or by using Manual mode. In manual mode, you have to adjust the settings yourself...normally you'd start by adjusting them until the needle gets to ---0--- (with the camera pointed at the scene). You can then make adjustments that will take the needle away from ---0---.

 

[TylerF]

oh, i dont have auto modes on my camera haha. i understand setting exposure on my d40 pretty well, but film is giving me a tid bit of trouble haha sorry for side tracking the thread

 

[Josh66]

Don't you have to stop down for metering with some cameras?

Is this one of those cameras?

The needle on my 350D doesn't move at all when I press the DOF preview button. Even stopped way down - f/22.

 

[bhop]

Ignore the meter when you're checking your DOF.

I have an FE myself. I don't understand the confusion to be honest..

For the benefit of others not familiar with the the FE, the meter isn't quite like modern cameras ---0--- where you "center" it. It's a match needle. Basically shutter speed numbers on the side with two needles. One needle tells you what the suggested shutter speed is. You then use the shutter speed dial or change the aperture to line it up with the other needle. Of course, this has nothing to do with the dof preview.

see here
Nikon FE - Basic Operations Part VII