spot metering - does canon do it differently?

[janetg]

just an observation - so NO EQUIPMENT WARS OR I WILL ASK THE MOD TO CLOSE THIS DOWN. i just want a friendly discussion.

i had some time to play in my sister in law's backyard today - she has the most wonderful wonderful yard... there's a post about her on the people forum..but on to the question..

using canon's spot metering, i really notice a biggg drop off in light almost like a natural vignette - i really like this look. i don't think i got the same results with spot metering on my nikon.

is this just my imagination? or do canon and nikon do this quite differently - and has anyone else noticed it?

i've attached a pic for an example

[venchka]

I'd say it has more to do with the subject and the reflectance and contrast range of this scene.

Extra style points for not mentioning a brand name.

[janetg]

you can notice it though on some of the people shots as well, and yes, there is a lot of contrast in this particular photo - but it was perhaps the most striking example of the day.

i just recently switched brands of camera - like within the past 2 weeks, so i apologize for mentioning names, i just believe there really is a difference the way these two mfg's have their spot metering programmed. it's the only metering mode i notice a distinct difference. the others are pretty much the same on both cameras - as far as i can tell up to this point.

[MRCPix]

I don't know Janet I use spot metering all the time and like you just switched, but have not noticed this affect.

[jeffkohn]

Spot metering cannot possibly be the cause of any light falloff or vignetting; all the spot meter does is determine what exposure you're going to shoot at based on what you point it at. The entire frame then gets the same exposure. The only difference in Canon/Nikon spot metering is that on at least some of the Canon models (not sure if it's all of them), the spot meter is always in the center of the frame (as opposed to following the active focus sensor on Nikons).

That said, some of Canon's wideangle lenses are known for light falloff, especially on full-frame. Has nothing to do with metering though.

[Pascal]

Don't the two big players (Canon & Nikon) use different spot metering circles - could that make a difference.
I think canon's spot metering circle is slightly bigger than Nikon's and hence not as precise. For my use, either one, including a 3rd brand I use (olympus - which I think is variable as they have 2-3 options for spot metering) works differently.

Also, just guessing - maybe it also depends on what algorith each OEM uses to process the image, the sensor type 9CCD or CMOS or NMOS, etc.), etc. I am sure that must have some input on the final result.

Then again, the drop off in light could just be a result of the spot that is metered. If metered right, only the spot/certain are should be what the camera sees and compensates for as far as metering is concerend. The rest of the frame is whatever light is available (highlight or shadow) for the camera to capture. Some photographers use spot metering readings of several points in the frame before choosing shutter speed/aperture/ISO manually and setting each to match what they want the output to be.

[janetg]

thank you for the reply - this is starting to make sense to me now. i didn't think about the size of the spot metering circle, or the differences in sensors.