Too much contrast?

[Nigel]

Hi,

These are some frames from my 0803, all taken yesterday mid afternoon in good lighting with the road etc easily visible to my human eye.

In all of them the sky is perfect, but in most the road is too dark and even in the last one where the road is fine and you can easily read the registration plate of the car, it is not so easy to tell what model of car because the side is too dark.

I want to turn the contrast down, but there is no setting. I've turned EV up to +2. I tried spot but couldn't see any difference to centre, these are all set to centre. I tried WDR but it turned the vegetation mushy, these are WDR off. It was better before I added a polarizing filter but I think that is just making an existing problem worse rather than causing the problem.

I haven't worked out what the EV setting actually does? I had expected the sky to become over exposed and the road to become brighter but the sky stays perfect!

So they are nice snapshots but as an accident cam you really want to be able to see the road!

Any ideas?
Should a contrast adjustment be added to the wish list?

Silhouette of a phoenix!

Road in shadow = can't see it. No problem at all to the human eye.

Nice bright picture, but can't see where the registration plate is so no chance of reading it.

Beautiful Sky

With the sun behind and thus a darker sky, I can see the road and read the registration plate, but what model of car?...

 

[jokiin]

Can't see any of your pics but make sure you don't have too much sky in frame, about 40% above the horizon is plenty, if too much sky it messes with the exposure

 

[Nigel]

There is not a lot of sky in the second image but it does get close to the centre. Pointing the camera down any further is pointless since it just shows the front of my car when it could be showing far more interesting flying things, trees etc.! It would be good to have an option to expose for 2/3rds of the way down the image instead of in the centre so that it is always exposed for the road/cars instead of exposing for the sky half the time...

Are the images visible now? Somebody has changed the way things work since I last shared an image folder!

This one has almost no sky:

 

[jokiin]

can see the pics now, looks terrible, you still need to aim it down though, too much sky

if you have a polariser on there can you take it off, return all settings to their defaults, aim the camera down and then do some screenshots?

 

[Nigel]

can see the pics now, looks terrible, you still need to aim it down though, too much sky

if you have a polariser on there can you take it off, return all settings to their defaults, aim the camera down and then do some screenshots?

OK, I went into the menu, chose "Default Settings/Yes", removed the polariser, forgot to point it down and collected some more frames.

Obviously these are not selected because they are the best, I've selected them to show the problem.

This one is typical, still too much contrast for my liking and using the default settings has turned WDR on which gives a mushy effect in the vegetation, plus the sky was much nicer with the polariser.

Next, I went under some trees, lots of reflections without the polariser and far too much contrast:

Final image, I'm stopped waiting for them to cross the road, it's had plenty of time to adjust and the lighting is not particularly difficult.

If I waited for some clouds to block out the sun so there is less contrast then it would be fine, but with the current weather it is fairly awful. Much better with WDR off instead of the default of on, and most of the time it is better with the polariser but that does increase the contrast even more and things disappear into darkness.

I'm suspecting that the camera was designed and tested indoors followed by a bit of testing under polluted city sky which diffuses the sun and doesn't create the high contrast views I have at the moment, in the first set of images you can see the clouds on the horizon are just as clear as things a few meters away, no pollution, high contrast....

 

[jokiin]

frequency set to 50Hz or 60Hz?

 

[Nigel]

frequency set to 50Hz or 60Hz?

Flicker is set to the default of "Auto", or do you mean something else?

 

[jokiin]

Flicker is set to "Auto", or do you mean something else?

does it have manual settings or just Auto?

if it has a 60Hz option can you give it a try, I've seen a few reports that this improves the picture a lot, may be firmware version dependant but worth a try given how it looks now

 

[Nigel]

does it have manual settings or just Auto?

if it has a 60Hz option can you give it a try, I've seen a few reports that this improves the picture a lot, may be firmware version dependant but worth a try given how it looks now

It has "Auto" as default, plus "50" and "60". I will give it a go later.

What does the setting do? I guessed it was to avoid flicker when it is viewing streetlights, or our LED traffic lights, which it either shows as flickering or turned off when they are actually on! I can't think what it would have to do with daylight contrast?

 

[jokiin]

It has "Auto" as default, plus "50" and "60". I will give it a go later.

What does the setting do? I guessed it was to avoid flicker when it is viewing streetlights, or our LED traffic lights, which it either shows as flickering or turned off when they are actually on! I can't think what it would have to do with daylight contrast?

nothing to do with contrast but I think there's a bug in some of these firmwares that is messing with the picture, a few users reported much better results when changing from 50Hz to 60Hz, it is to reduce flicker in AC powered lighting, LED lighting will still give some flicker regardless so you won't likely see too much negative effect

if you do give it a go let us know how you get on as it may be useful info for others

 

[Nigel]

nothing to do with contrast but I think there's a bug in some of these firmwares that is messing with the picture, a few users reported much better results when changing from 50Hz to 60Hz, it is to reduce flicker in AC powered lighting, LED lighting will still give some flicker regardless so you won't likely see too much negative effect

if you do give it a go let us know how you get on as it may be useful info for others

The weather has changed and the sky is a lot less clear so I can't compare todays video with yesterdays and be sure of what the settings change has done.

Testing it in the garden instead of the on the road because it is much quicker, I can't see any difference between 50Hz, 60Hz and Auto, although I did notice that I do not get the mushy effect from the WDR unless there is a lot of movement, maybe it is the same with the Hz setting. It would make sense that 60Hz is best as that is exactly 2x the frame rate so if it is doing some filtering to smooth high speed changes then it might use a much simpler algorithm. Maybe the ghost images we sometimes see trailing fast moving things are part of this?

I could not see an effect from WDR in the garden at all, dark things did not get brighter as they would with my Olympus stills camera. I'm not sure what WDR is trying to do but for some reason it appears to be affected by movement, things go mushy if it is on and there is movement. Has anybody seen a useful effect from turning WDR on?

EV did make things brighter and burned out the sky as I expect when I increased it which wasn't what I thought I saw before. I found it odd today that pressing the up button decreased EV when I was expecting it to increase, seemed to work correctly yesterday! At 0 there is a lot of the image that is too dark, at +1 I still have shaded things too dark, at +2.0 I actually had things too bright at times today. I do wonder if I had increased it one step too far in my original images on this thread - When you get to +2.0 and increase it one more step you get -2.0, hard to see the change on the screen.

When we get some more clear weather I will investigate again and report back...

I still think a menu to adjust contrast would allow a lot more detail to be captured and stop things disappearing into darkness. The images might then seem a bit dull but if I'm using it as an accident camera then it doesn't need to produce nice bright high contrast holiday snaps, although I do want that as an option.

It would also be nice to have the third of the normal video controls added too - saturation adjustment.

 

[chris-s]

Next, I went under some trees, lots of reflections without the polariser and far too much contrast:

Final image, I'm stopped waiting for them to cross the road, it's had plenty of time to adjust and the lighting is not particularly difficult.

.

Still too much sky in those pictures.
The amount of "road" should be greater than the amount of "sky".
You need to point the camera one or two clicks down.
Then, for better results, you can set EV to +1.0

You'll have to know that the camera is mesuring the light at the center of the picture.
So, if the center of the picture is in the bright sky, it will adjust the brightness to the sky, not to the road.

 

[chris-s]

Look how I have set my 0803.

1/3 sky, 2/3 road , EV +1.0

 

[Nigel]

You'll have to know that the camera is mesuring the light at the center of the picture.
So, if the center of the picture is in the bright sky, it will adjust the brightness to the sky, not to the road.

Seems that is probably only true in Spot mode, in Centre mode it takes it from a triangle with corners bottom left, centre, bottom right with highest effect on the line from bottom centre to the centre, the centre itself has fairly minor effect on the exposure since it's a small area compared to the total size of the triangle. See http://dc.p-mc.eu/metering.php That map doesn't appear to be from an 0803 though and I find it hard to tell if it matches what I experience...

My issue with contrast seems to have disappeared with the weather, we had a several days of very bright and clear skies so contrast was higher than normal. Since the weather changed and it has just been sunny with a few clouds but a lot more water vapour in the atmosphere the images have been much better and when cloudy they are fine.

I'm still playing with the settings though, I'll post a conclusion at some point.

Thanks for the suggestion.

 

[chris-s]

See http://dc.p-mc.eu/metering.php That map doesn't appear to be from an 0803 though and I find it hard to tell if it matches what I experience....

Very interesting link ! Thanks.
unfortunately, 0803 doesn't seem to react that way

But in your case, what is sure is that you have too much sky compared to road.

 

[Nigel]

Very interesting link ! Thanks.
unfortunately, 0803 doesn't seem to react that way

But in your case, what is sure is that you have too much sky compared to road.

Note that spot has the sky filled with zero values while centre has it filled with '1' which might explain why I see that if there is any sky in the image then the sky is exposed within range. I would change the table for centre to have zeros in the sky and move the top of the triangle down a bit but Tobi@s's A7 Tool meter table editor appears to only work for the 0801 at present and I'm not sure that I want to try and hack it...

 

[Nigel]

Update: Having installed firmware 0812 (http://dashcamtalk.com/forum/threads/mini0803-firmware-update-to-0812-version-megtech.6859/) the image contrast in difficult situations is very different.

This is fairly typical of the original firmware when under trees:

This is typical of the new firmware:

And even when conditions get really difficult with the sun full in the frame and the road in full shadow, you can now still see the road and traffic:

At dusk there is a lack of detail and the image is a lot more "painted" than it was, but you can see what is happening a lot easier than with the first firmware. You can see from the lights that this was actually quite dark:

 

[reverend]

Have you tried @Falsicator's custom Procam firmware as that had modifications to the contrast etc? Is definitely give it a go as he does some great firmware mods!

http://dashcamtalk.com/forum/threads/custom-firmware-from-procam-cx4-revision-3-0.6715/

 

[Nigel]

Have you tried @Falsicator's custom Procam firmware as that had modifications to the contrast etc? Is definitely give it a go as he does some great firmware mods!

http://dashcamtalk.com/forum/threads/custom-firmware-from-procam-cx4-revision-3-0.6715/

No I haven't. I assumed that he was adjusting the contrast and sharpness settings that are available in the menu of the new firmware, but they turn out to be useless, it works best on default settings. So maybe his modifications are something different?

I'm fairly happy with this new firmware, the images sometimes look very painted but that tends to be in conditions where my far more expensive stills camera would really struggle to do as well at showing what was happening on the road. The only disadvantage is that in some conditions the plates are not as readable as they were with the previous version but I don't think other cameras do significantly better...

 

[reverend]

I would recommend giving it a go as he does change internal settings you don't have access too - plus the exposure table is brought over from another camera - there's a huge thread in Russian where they go through all of this.

I'd recommend giving it a go - like I say with his firmware on my 3H2F it was the best quality I ever saw on that device