High Definition with Elphel model 333 camera

Odd Nydren · January 16th, 2008, 04:42 AM

Quote:

Originally Posted by Matteo Pozzi

or better :
a upper green arrow if the current frame is bigger than the previous 2...
:-)

Hmm since it's just a value representing the sharpness of an area...I could write a little flash app that plots a little graph + does the arrow business on a continous basis.

It will not be of much help on a mobile device (maybe a small piece of php would work on those) but on a pc it should give pretty fast response!

I bought my 353 yesterday and I'll make that app as soon as it's arrived!! :)
(and post here of course)

cheers
//O.

Oscar Spierenburg · January 16th, 2008, 03:52 PM

That's great to see more people using the 353.
I have to put everything together again to use mine, but I have to get a new IR filter (I couldn't prevent it from braking when I cut out the piece for the viewfinder.) .(
In the meantime, I'm building a rod support for the Elphel and all other parts (adapter or lens, batteries and things like that.)

Elphel camera's come powered with 48v DC (unless you get a custom made version with 12v). What are the possibilities to use battery power?
Is there some affordable voltage doubler(or 4x when using 12v) available?

Odd Nydren · January 16th, 2008, 06:23 PM

Quote:

Originally Posted by Oscar Spier

Elphel camera's come powered with 48v DC (unless you get a custom made version with 12v).

Ah! I didn't know I could get one custom made for 12v...hmm too bad.

The 48v issue should be possible to fix using a DC to DC converter...I'll have to read up on that been a long time since I did electronics.

We should probably ask Andrey...

Andrey Filippov · January 16th, 2008, 07:15 PM

I don't know of any existent ones for the correct power, this is something I was planning to build - a simple 48VDC power injector that will take power from lower voltage source. It is even possible to make one that will take 5V power from 2 USB ports (1 is not enough)

Oscar Spierenburg · January 16th, 2008, 08:05 PM

Maybe we can keep in mind, lots of the batteries for 'consumer' DV camcorders are 7,2v. Is it also possible to convert that to 48v ?

Odd Nydren · January 18th, 2008, 12:54 PM

Quote:

Originally Posted by Andrey Filippov

I don't know of any existent ones for the correct power

That explains why I couldnt find any when browsing the net ;)

Quote:

Originally Posted by Andrey Filippov

this is something I was planning to build - a simple 48VDC power injector that will take power from lower voltage source.

..is it still in the works - just postponed?

It would be real cool with a solution that doesen't involve modifying the camera itself, but instead something to hook between the camera network connector and a battery source.

If you decide to make that power injector Andrey, please put me on a pre-order list ;) hehe I'd love one thanks!!

Odd Nydren · January 18th, 2008, 12:59 PM

Has anyone seen a good solution to hook up a Canon EF lens to C mount? The only one I found was birger.com's _very_ expensive solution...

I have a few C mount adapters & EOS extension tubes on order from Ebay, hoping to find a way to make one - with or without a groundglass.

Anyone tried this?

I saw the shots of your EOS experiments Andrey and that got me inspired! Btw I got the camera today!! Thanks for the excellent packaging and the extra body! Much appreciated! Doing my first tests now...

Andrey Filippov · January 18th, 2008, 01:55 PM

Odd,

Large (EOS) lens makes sense _only_ with the ground glass (or similar) adapter. If you just use EOS-to-C-mount adapter you will get quality worse than with the modern C/CS mount lenses, the sensor pixel is just 2.2 um x 2.2 um. The sensor size is about 5 time smaller than 35mm frame, so to get 5MPix resolution you need a 35mm lens capable of (5 x 5) x 5Mpix = 125MPix resolution

Odd Nydren · January 18th, 2008, 02:25 PM

Quote:

Originally Posted by Andrey Filippov

The sensor size is about 5 time smaller than 35mm frame, so to get 5MPix resolution you need a 35mm lens capable of (5 x 5) x 5Mpix = 125MPix resolution

Ah! But of course...doh! Thanks for the clarification!
This is very much a learning process to me. :)

What I really want is to do a groundglass solution as I want the depth of field you get using the whole lens... - the EOS directly to C mount was more of a starting point.

Well you made it quite clear I better go for the groundglass solution right away. I better go read up on optics. ;)

Andrey Filippov · January 18th, 2008, 02:38 PM

Odd,

As the lens is removable, I would recommend to use a fancy one with a ground glass and just a C-mount type one as an alternative. To get the full resolution you need a really good one, but just to experiment with the camera operation, you can probably get 1/2" format C/CS-mount lens for the same price or cheaper than the adapter.

Odd Nydren · January 18th, 2008, 02:50 PM

Definitely!
I've already put a bid on a cheap c mount lens just for tests :)

I really want a groundglass solution. I do photography with an Canon 20D camera and have a few real good lenses that would be real cool to use with the Elphel.

I need to read up on macro lenses & how to make a simple solution to focus on the ground glass...any ideas Andrey? ..or know of a good site that I should have a look at?

The EOS mount part & groundglass is pretty much solved via the info at http://www.jetsetmodels.info

Andrey Filippov · January 18th, 2008, 03:10 PM

I'm sure you can find more info on it even in this forum, but if I had to build something like that I would use two standard lenses on the camera side, not just one. The closest one to the camera (1/2", C/CS-mount), let's say, f=5mm, the second one - five time longer - f=25mm (perfect ratio you can get as a ratio of a 35mm frame size to the sensor size). The first lens will go to the camera thread in normal way, the second - attached other way - facing outer side (designed for infinity) to the first lens. This second lens should be a 35mm format - the ground glass will be on it's back side. Maybe it is better to start with somewhat longer focal lengths, some 8-12mm for the first one and proportionally more - for the second one.

Such arrangement will reduce aberrations - each lens is used as it is is designed to - one side - to infinity, other - to an object in focal plane. That might turn out to be important as I think most ground glass adapters were designed for camcorders, not for the high definition (forgive me if I'm wrong - I am not an expert in this area).

The space between faces of 2 lenses is an ideal place for an IR filter - we tried to use it as thin as possible (t=0.3mm), but still spherical aberrations introduced by a glass plate can be eliminated completely if the filter is in the parallel beam.

Oscar Spierenburg · January 18th, 2008, 07:58 PM

Quote:

Originally Posted by Andrey Filippov

The space between faces of 2 lenses is an ideal place for an IR filter - we tried to use it as thin as possible (t=0.3mm), but still spherical aberrations introduced by a glass plate can be eliminated completely if the filter is in the parallel beam.

I'll be able to test this... because I broke my IR filter. I'm very curious if it'll get better results. I'm rebuilding/improving my 35mm adapter right now, so I can choose/experiment where to put the IR filter.

Odd, I'm using a microcrystalline wax screen. I prefer this because of it's image character and lack of electronic parts (no power needed)
A normal (non moving) ground glass would be far to grainy for a high resolution camera. Also, a moving ground glass, can also get a small movement in and out of the focal plane and blur the image a bit.

Andrey Filippov · January 18th, 2008, 08:25 PM

Do they use ultrasound actuators to vibrate the ground glass too?

Or maybe it is possible to use running waves (probably surface ones as compression one will have too high frequency for required wavelengths)?

Oscar Spierenburg · January 20th, 2008, 07:36 PM

Andrey... and others, this doesn't seem so different than the one I've made: http://www.pstechnik.de/en/digitalfi...viewfinder.php
It seems that my optical viewfinder will also prove to be perfect for focusing, but I can only check when I can compare with HD footage from the Elphel, focusing on a focus pattern.

Now, can anyone tell me how a viewfinder extension works? it shouldn't be to complicated. Could it be home-made?

(I've finished my Elphel rod support. I'll post pictures tomorrow.)

January 16th, 2008, 07:15 PM	#874
Andrey Filippov Major Player Join Date: Apr 2006 Location: Magna, Utah Posts: 215	48v converter I don't know of any existent ones for the correct power, this is something I was planning to build - a simple 48VDC power injector that will take power from lower voltage source. It is even possible to make one that will take 5V power from 2 USB ports (1 is not enough)

January 16th, 2008, 03:52 PM	#872
Oscar Spierenburg Major Player Join Date: Jan 2005 Location: (The Netherlands - Belgium) Posts: 735	That's great to see more people using the 353. I have to put everything together again to use mine, but I have to get a new IR filter (I couldn't prevent it from braking when I cut out the piece for the viewfinder.) .( In the meantime, I'm building a rod support for the Elphel and all other parts (adapter or lens, batteries and things like that.) Elphel camera's come powered with 48v DC (unless you get a custom made version with 12v). What are the possibilities to use battery power? Is there some affordable voltage doubler(or 4x when using 12v) available?

January 16th, 2008, 08:05 PM	#875
Oscar Spierenburg Major Player Join Date: Jan 2005 Location: (The Netherlands - Belgium) Posts: 735	Maybe we can keep in mind, lots of the batteries for 'consumer' DV camcorders are 7,2v. Is it also possible to convert that to 48v ?

January 18th, 2008, 12:59 PM	#877
Odd Nydren Regular Crew Join Date: Jan 2007 Location: London, UK Posts: 88	Has anyone seen a good solution to hook up a Canon EF lens to C mount? The only one I found was birger.com's _very_ expensive solution... I have a few C mount adapters & EOS extension tubes on order from Ebay, hoping to find a way to make one - with or without a groundglass. Anyone tried this? I saw the shots of your EOS experiments Andrey and that got me inspired! Btw I got the camera today!! Thanks for the excellent packaging and the extra body! Much appreciated! Doing my first tests now...

January 18th, 2008, 01:55 PM	#878
Andrey Filippov Major Player Join Date: Apr 2006 Location: Magna, Utah Posts: 215	Odd, Large (EOS) lens makes sense _only_ with the ground glass (or similar) adapter. If you just use EOS-to-C-mount adapter you will get quality worse than with the modern C/CS mount lenses, the sensor pixel is just 2.2 um x 2.2 um. The sensor size is about 5 time smaller than 35mm frame, so to get 5MPix resolution you need a 35mm lens capable of (5 x 5) x 5Mpix = 125MPix resolution

January 18th, 2008, 02:38 PM	#880
Andrey Filippov Major Player Join Date: Apr 2006 Location: Magna, Utah Posts: 215	Odd, As the lens is removable, I would recommend to use a fancy one with a ground glass and just a C-mount type one as an alternative. To get the full resolution you need a really good one, but just to experiment with the camera operation, you can probably get 1/2" format C/CS-mount lens for the same price or cheaper than the adapter.

January 18th, 2008, 02:50 PM	#881
Odd Nydren Regular Crew Join Date: Jan 2007 Location: London, UK Posts: 88	Definitely! I've already put a bid on a cheap c mount lens just for tests :) I really want a groundglass solution. I do photography with an Canon 20D camera and have a few real good lenses that would be real cool to use with the Elphel. I need to read up on macro lenses & how to make a simple solution to focus on the ground glass...any ideas Andrey? ..or know of a good site that I should have a look at? The EOS mount part & groundglass is pretty much solved via the info at http://www.jetsetmodels.info

January 18th, 2008, 03:10 PM	#882
Andrey Filippov Major Player Join Date: Apr 2006 Location: Magna, Utah Posts: 215	I'm sure you can find more info on it even in this forum, but if I had to build something like that I would use two standard lenses on the camera side, not just one. The closest one to the camera (1/2", C/CS-mount), let's say, f=5mm, the second one - five time longer - f=25mm (perfect ratio you can get as a ratio of a 35mm frame size to the sensor size). The first lens will go to the camera thread in normal way, the second - attached other way - facing outer side (designed for infinity) to the first lens. This second lens should be a 35mm format - the ground glass will be on it's back side. Maybe it is better to start with somewhat longer focal lengths, some 8-12mm for the first one and proportionally more - for the second one. Such arrangement will reduce aberrations - each lens is used as it is is designed to - one side - to infinity, other - to an object in focal plane. That might turn out to be important as I think most ground glass adapters were designed for camcorders, not for the high definition (forgive me if I'm wrong - I am not an expert in this area). The space between faces of 2 lenses is an ideal place for an IR filter - we tried to use it as thin as possible (t=0.3mm), but still spherical aberrations introduced by a glass plate can be eliminated completely if the filter is in the parallel beam.

January 18th, 2008, 08:25 PM	#884
Andrey Filippov Major Player Join Date: Apr 2006 Location: Magna, Utah Posts: 215	Do they use ultrasound actuators to vibrate the ground glass too? Or maybe it is possible to use running waves (probably surface ones as compression one will have too high frequency for required wavelengths)?

January 20th, 2008, 07:36 PM	#885
Oscar Spierenburg Major Player Join Date: Jan 2005 Location: (The Netherlands - Belgium) Posts: 735	Andrey... and others, this doesn't seem so different than the one I've made: http://www.pstechnik.de/en/digitalfi...viewfinder.php It seems that my optical viewfinder will also prove to be perfect for focusing, but I can only check when I can compare with HD footage from the Elphel, focusing on a focus pattern. Now, can anyone tell me how a viewfinder extension works? it shouldn't be to complicated. Could it be home-made? (I've finished my Elphel rod support. I'll post pictures tomorrow.)