The best AE metering pattern for the most dashcams.

[TonyM]

Compared to the B1W (first image), it is both brighter and a faster shutter speed:
View attachment 37648
View attachment 37649

• The A129 image in the 2nd post is the same image as in the first post, but with the brightness turned down in a photo editor!

If you are posting comparison frames (e.g. B1W vs A129) I think it is potentially misleading when you adjust the brightness of one image in a photo editor.

 

[Nigel]

If you are posting comparison frames (e.g. B1W vs A129) I think it is potentially misleading when you adjust the brightness of one image in a photo editor.

There is a lot that is potentially misleading, such as using a CPL on only one, and one being a prototype with significant work left to do on it, and the other not being from the current production run. The adjusted image may be more representative of the final product, or maybe not.

The image was chosen to show the field of view of the camera relative to the field of illumination of my headlights, not for comparison purposes.

 

[nutsey]

Okay, let's move on. Any AE metering tables do make sense only if we are sure about the horizon level set for a certain device, right?

 

[vvs49]

only if we are sure about the horizon level set for a certain device, right?

Of course, otherwise the tables do not work correctly.
Here is an example, the tables are the same, the DVR is the same!

 

[Nigel]

Okay, let's move on. Any AE metering tables do make sense only if we are sure about the horizon level set for a certain device, right?

You can make it less sensitive to positioning and vehicle, for example if you put zeros across the bottom then you remove the effect of having a dark coloured car hood brightening the image or bright coloured car hood darkening the image, and it doesn't really matter if like me you don't have the car hood in the image at all... until someone fills half the image with their dark black car hood and then drives in snowy conditions which overexposes all the snow, which does happen!

What is needed is localised exposure so that the car hood gets exposed differently to the road and sky.

 

[c4rc4m]

I think the real issue with dashcams is a lack of matrix metering. The trouble with simple metering is it's easy to set parameters for a particular lighting situation, but very difficult to set parameters that work well in a variety of conditions as shown by the above metering selections / tunnel scenario.

 

[vvs49]

for example if you put zeros across the bottom then you remove the effect of having a dark coloured car hood brightening the image or bright coloured car

This is not true.
Zeros - are not taken into account in determining the frame exposure.
That is, how was black / white and stayed.

 

[nutsey]

I see it like this:

0 0 0 0
3 2 2 3
3 2 2 3
1 0 0 1

During night there is too much light at low-central 2 2 zone because of car headlights.

enjoy,
Mtz

I like this idea.

What about improving it to such 8x8 (assuming the sky/ground level as 30/70)?

0 1 1 0 0 1 1 0
1 1 1 1 1 1 1 1
2 2 2 1 1 2 2 2
2 2 1 1 1 1 2 2
2 1 1 1 1 1 1 2
1 1 1 0 0 1 1 1
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0