Link AF point and AE

fontku · 03-15-2008, 11:26 AM

Hello,

I am really a newbie, but I don't understand this setting and the difference from using the AE-Lock. Can someone explain it?

Thanks

Joan.

elnero · 03-16-2008, 10:41 AM

I'm pretty sure, thought no positive, that it means that metering will adjust its 'focus' to the focus point you have selected. Meaning, if you have the center AF point selected, your meter will use that point to center on if you have matrix metering, or use that point for the spot meter. Or if you selected the left AF point, the meter will shift to the left to properly expose the infocus area of the frame.
this is what my old nikon film body does at least.

Sideway · 03-17-2008, 05:43 AM

I believe turning Link AF point and AE on does what elnero said, except only in matrix metering mode. I like to think of it as a AF point weighted meter mode.

The camera still only uses the center point for metering in spot meter mode.

Workingdog · 03-17-2008, 06:50 PM

I've played with it and you guys pretty much have it right.
1. Works only in Matrix metering mode
2. Sets exposure to properly expose the section of the matrix where focus is locked (when the green focus indicator in the viewfinder is illuminated)

It essentially works like a spot meter only the spot, instead of being in the center, is whatever focus point you or the camera (in green focus mode) has chosen.

Note if you've disconnected the half-press focus, this only kicks in if you press and hold the focus button down thus keeping the focus indicator illuminated. If you press and release the focus button the exposure will revert to normal matrix metering because even though the focus isn't going anywhere it is not technically locked as far as the camera is concerned.

mattdm · 03-18-2008, 06:26 AM

Originally Posted by Workingdog

It essentially works like a spot meter only the spot, instead of being in the center, is whatever focus point you or the camera (in green focus mode) has chosen.

Is it like a spot meter, which ignores the rest, or weighted metering which slants things towards the selected point but still takes the rest into consideration?

Workingdog · 03-18-2008, 08:49 AM

Matt,
As I recall during my very unscientific testing under not very well controlled conditions, the exposure the camera chose for the selected focus point was virtually the same when I switched to spot meter and pointed the center area to the same place (a lamp shade with the light on). So, in my opinion it acts like a spot meter.

*Canada_Rockies* · 03-18-2008, 10:53 AM

Originally Posted by Workingdog

Matt,
As I recall during my very unscientific testing under not very well controlled conditions, the exposure the camera chose for the selected focus point was virtually the same when I switched to spot meter and pointed the center area to the same place (a lamp shade with the light on). So, in my opinion it acts like a spot meter.

I think it works like an averaging meter using the meter area in which the focus spot appears. Have a look at the metering pattern in matrix metering, and you can see what I think it is doing. I can see uses for this, and plan on trying it out along with everything else I have to do with the camera. So many images, so little time.

Workingdog · 03-18-2008, 12:15 PM

Albert,
You're probably more technically correct in your description but the result is more like a spot meter than center weighted as I did actually compare both. Seems like it looks ONLY at the meter area where the focus lock occurs and ignores the rest.

*Canada_Rockies* · 03-18-2008, 12:18 PM

Originally Posted by Workingdog

Albert,
You're probably more technically correct in your description but the result is more like a spot meter than center weighted as I did actually compare both. Seems like it looks ONLY at the meter area where the focus lock occurs and ignores the rest.

I think our difference of opinion is basically that I consider the spot meter in my K10D not to be a spot meter, because it is 2.5% of the field. To me, (check age) a spot meter is 1%. So I think we are both correct, and anyone reading both our posts will get the idea of what the camera is doing. Thanks.

mattdm · 03-18-2008, 07:28 PM

Originally Posted by Workingdog

Matt,
As I recall during my very unscientific testing under not very well controlled conditions, the exposure the camera chose for the selected focus point was virtually the same when I switched to spot meter and pointed the center area to the same place (a lamp shade with the light on). So, in my opinion it acts like a spot meter.

Hmmm. In that case, I'd find it about a million times more useful if this setting affected the spot metering dial setting and left matrix metering as actual matrix metering — then you could simply put the focus spot to the center when you want center-spot metering. As it is, you have to decide if you want matrix metering or movable spot metering.

fontku · 03-19-2008, 01:57 AM

Thanks all for your information and knowledge.

mattdm · 04-02-2008, 09:48 AM

Originally Posted by mattdm

Hmmm. In that case, I'd find it about a million times more useful if this setting affected the spot metering dial setting and left matrix metering as actual matrix metering — then you could simply put the focus spot to the center when you want center-spot metering. As it is, you have to decide if you want matrix metering or movable spot metering.

So, I got e-mail back from Pentax USA on this. They confirmed that it works as spot metering, and also agreed with me that it'd make more sense if the setting replaced the Spot Metering dial option rather than the Multi-Segment Matrix one.

(Heh. Thanks for agreeing, but maybe please do something about it, too? Firmware upgrade, or change to the way it works in the next model? Please!)