Metering for Manual Exposure

[Sriharsha Ganjam]

I have a simple metering question. If I am metering for the incident light by using my light meter, and setting the exposure in Manual mode, would the different metering modes (spot, partial, matrix, etc) be still valid?
In other words, if my understanding is correct, the different metering modes (spot, partial, etc) in our cameras are TTL meterings and based on reflected light. Now I understand how it works in AV and TV modes. But if I decided to meter for the incident light using my light meter and set the exposure on the M mode, how would a "Spot metered" image be different from say a "Evaluative metered" image? Would the TTL metering work in such a case at all? If it does not then why have the metering mode enabled in Manual Mode?
I hope I have got my point through, with out much confusion.
Please excuse me if the question seems trivial, but I would love to understand the science behind image making.
Thanks
Harsh

[Ganesh H Shankar]

Sriharsha, metering mode (evaluative/matrix, spot, center weighthed) and shooting mode (A,P,M,S..) not related! When you are in the manual mode you decide shutter and aperture, meter still reads light and camera still shows for the set aperture and shutter how much *it* thinks you are off. When you use incident light meter you simply ignore what that over/under exposure scale that camera shows based on the metering mode that you selected. Please note that if you use polarizer, extension tube etc (anything which cuts the light) then you need to compensate accordingly if you use incident light meter. Hope this clarifies science part of it

[Sriharsha Ganjam]

It did clarify the TTL part of the question Ganesh. But one part of the question still remains. Would a spot metered, manually exposed image differ from a matrix metered and manually exposed image, assuming I have retained the same aperture and shutter speed and just changed the metering mode from spot to matrix.

Thanks
Harsh

[Ganesh H Shankar]

It did clarify the TTL part of the question Ganesh. But one part of the question still remains. Would a spot metered, manually exposed image differ from a matrix metered and manually exposed image, assuming I have retained the same aperture and shutter speed and just changed the metering mode from spot to matrix.

Thanks
Harsh

I think I have not made it clear then! With incident light meter in your hand you have 4 different ways of metering for an image - incident, matrix/evaluative, center weighted and spot. While three modes are built in to the camera the fourth one is in your hand. For metering you will use only one of them. If you use incident meter don't look at what camera's meter shows. Whatever the reading camera shows (center weighthed/spot) does not affect your image because what affects your image is only shutter speed and aperture that you manually dial in based on what your incident light meter says. Is it clear now ? Let me know if it is not Sriharsha !

[Sriharsha Ganjam]

I got it now Ganesh Thanks I had tried out a few test shots using manual exposure ob a glowing bulb, with different metering options (spot, matrix etc) and all the images looked the same. But when I did the same exercise on Av mode there was a clear difference, which was achieved by a change in the shutter speed by the camera, for different metering modes. So your explanation ties in with my observations. Thanks so much for clearing my doubt.

Harsh