Multi-camera setup project.

mphx

210

Re: Multi-camera setup project.

« Reply #220 on: 07 / October / 2014, 17:57:45 »

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Quote from: srsa_4c on 07 / October / 2014, 16:17:18

Are you saying that you still get distorted JPEGs at the tele end of zoom? Here's a user that claims otherwise. The changes mentioned in the linked post are now part of the CHDK 1.3 release for the a2500.
Can you compare JPEGs made
- after zooming with set_zoom
- after zooming manually
?

I am saying that 2 people (me and my friend ) see distorted jpeg and cameras running the latest up-to-date chdk version (meaning the "fix" is applied).

We tested jpeg and dng formats.Dng format shows less distortion than jpeg BUT dng photos are like ~ 20mb in size.
Every dng file needs like around 10secs to get downloaded. 64cameras = 64 photos = 640secs to download ONE set of photos. That's around 10mins.

So we forget dng.

Let's talk about jpeg now.If i throw little numbers in set_zoom , and by little numbers i mean up to 10-15 , distortion is handled.If we throw numbers from 20 and up , distortion is NOT handled.
3d modelling program is confused and cant produce correct model.

We did several tests today.The golden number for us is zoom = 20 . At that point distortion can't be handled unfortunately.

And since we have 64 cameras to handle(=zoom in/out) i seriously don't care what is the behavior with manually zooming

Only light in the tunnel is a setting we found in 3d modelling program about "calibrating" cameras by using some pattern and distortion correction algorithms..a bit complicating procedure and a bit cheap way to solve the problem.

I will check the thing you mentioned about iso and cameras menu as soon as i am back at studio.
About "setting custom white balance"..how do you mean it?How can been done?

Thanks for your input.

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reyalp

14114

Re: Multi-camera setup project.

« Reply #221 on: 07 / October / 2014, 23:34:17 »

Quote from: mphx on 07 / October / 2014, 15:25:05

Canon A2500 suck.

It is a bottom of the line P&S, so this shouldn't be a huge surprise.

Quote

Big time.Noise in the photos is pathetic.We did a test.3 cameras shooting the same thing in daylight conditions.
A canon dslr camera , a canon A2500 compact camera and galaxy s4 , my phone.

Dslr result was nearly perfect..minimum to none noise, expected.galaxy s4 , second place , minimum noise and last position belongs to A2500...pa-the-tic.

I'm not surprised the A2500 sucks, but I am somewhat surprised it is much worse than the S4. Can you upload the sample shots somewhere?

Quote

That's why we got into the thing of updating chdk in the cameras in order to "fix" the zoom thing.
But it got fixed partially..if you zoom a little bit , distortion is little...if you zoom more , distortion is more.
More distortion = more screwed up models produced = no go.

Can you verify whether or not the same distortion appears if you zoom using the physical zoom controls (or simulated key clicks)?
For example:
set_zoom(20)
shoot
reboot the camera
click the zoom key until zoom reaches 20 (you can display zoom level in OSD)
shoot the same scene
compare the pictures
This will tell us whether CHDK is messing up the distortion correction, or it's just how the canon firmware deals with it.

It's also worth noting that image processing programs can do the same kind of software distortion correction that the camera does. This is normally done with raw, but it should be possible to do with jpegs as well.

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mphx

210

Re: Multi-camera setup project.

« Reply #222 on: 08 / October / 2014, 05:09:34 »

@reyalp

Let's see...

1.With manual zoom , there is no distortion.

2.Here is the samples you asked

DSLR --> https://www.dropbox.com/s/7cwwfdqyjichvqp/DSLR.JPG?dl=0
A2500 --> https://www.dropbox.com/s/2wr3nq3r1zoo3x0/A2500.JPG?dl=0
S4 --> https://www.dropbox.com/s/wex6zk2c8tchuhg/20141007_130626.jpg?dl=0

Download them , and zoom in at the wall at the right side of that green window in the building...the difference in noise is clear there..

All these problems can be solved with cheap ways... we can correct distortion and lighting issues with photoshop lets say...as far as the corrections/fixes are similar to ALL 64 photos and can be applied in short time.
Otherwise it will get a lot of time and it's useless since there is already more 3d work to be done for every shot...

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reyalp

14114

Re: Multi-camera setup project.

« Reply #223 on: 08 / October / 2014, 22:55:01 »

Quote from: mphx on 08 / October / 2014, 05:09:34

1.With manual zoom , there is no distortion.

Again sample images would be interesting.

Quote

Download them , and zoom in at the wall at the right side of that green window in the building...the difference in noise is clear there..

Agree the S4 is less noisy, and sharper over all. The A2500 isn't quite at minimum ISO, but its very unlikely that will make up the difference.

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mphx

210

Re: Multi-camera setup project.

« Reply #224 on: 09 / October / 2014, 05:37:02 »

Quote from: reyalp on 08 / October / 2014, 22:55:01

Again sample images would be interesting.

I don't know if we have the samples saved.I'll check.

Quote

Agree the S4 is less noisy, and sharper over all. The A2500 isn't quite at minimum ISO, but its very unlikely that will make up the difference.

As i see the A2500 sample is at iso-125.I think the minimum is iso-100 , so yes it won't make any big difference.

We tried to take a photo with the cameras in daylight conditions to see if the noise we see in the studio is result of the lighting conditions there.If there was minimum noise in daylight we would throw more lights in the studio.
But as you can see , it's just a matter of low quality camera

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msl

1280
A720 IS, SX220 HS 1.01a

Re: Multi-camera setup project.

« Reply #225 on: 09 / October / 2014, 07:00:17 »

With F8.0 (A2500) you get a lower depth of field than with F2.2 (S4). There is also a difference with the ISO values, A2500 => ISO 125 and S4 => ISO50.

Use the same conditions with both devices and compare the images, preferably as raw files.

msl

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mphx

210

Re: Multi-camera setup project.

« Reply #226 on: 09 / October / 2014, 07:59:46 »

Quote from: msl on 09 / October / 2014, 07:00:17

With F8.0 (A2500) you get a lower depth of field than with F2.2 (S4). There is also a difference with the ISO values, A2500 => ISO 125 and S4 => ISO50.

Use the same conditions with both devices and compare the images, preferably as raw files.

msl

The whole point of the "experiment" wasn't to compare results with dslr or s4.We wanted to see if the noise is reducing with brighter scenes (daylight conditions).And as you can see , noise is still in high levels.

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waterwingz

12140

Re: Multi-camera setup project.

« Reply #227 on: 09 / October / 2014, 08:55:42 »

Quote from: msl on 09 / October / 2014, 07:00:17

With F8.0 (A2500) you get a lower depth of field than with F2.2 (S4).

Isn't that the other way around? Although on those little lenses, F8 might be approaching the diffraction limit?

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msl

1280
A720 IS, SX220 HS 1.01a

Re: Multi-camera setup project.

« Reply #228 on: 09 / October / 2014, 09:25:54 »

Quote from: waterwingz on 09 / October / 2014, 08:55:42

Isn't that the other way around?

Yes, you're right. I meant the hyperfocal distance. Regardless of this the test should be performed with the same settings.

F8.0 is difficult for the A2500 with the small sensor.

msl

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waterwingz

12140

Re: Multi-camera setup project.

« Reply #229 on: 09 / October / 2014, 10:08:41 »

I assume the A2500 does not have an adjustable aperture so the f8.0 setting is either at the end of the zoom range or the ND filter has kicked in?

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