Reasonable oscilloscope screen shots with digital cameras?

[Joerg]

Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

I am thinking about buying a digital camera and this plus maybe a
few microscope or macro shots of circuit boards would be pretty
much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

Regards, Joerg
http://www.analogconsultants.com

 

[John Larkin]

On Sun, 25 Apr 2004 21:02:10 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

I am thinking about buying a digital camera and this plus maybe a
few microscope or macro shots of circuit boards would be pretty
much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

Regards, Joerg
http://www.analogconsultants.com

We use direct scope shots in our manuals and ads/web pages. I shot
this from a Tek 11801 sampling scope (digital, but a
magnetic-deflection CRT) with an old Sony Mavica camera:

http://www.highlandtechnology.com/DSS/T200DS.html

With current-generation LCD scopes, pics usually look good, but it's
best to get a digital camera that has selectable shutter speed, a long
FL zoom lens (to minimize barrel distortion) and a tripod. The little
wide-angle vacation-type cameras are terrible. We usually shoot a
scope from maybe 5 feet away. What's hard is to get the image really
aligned (not twisted slightly) but the better Photoshop-type software
can fix things.

I find myself shooting lots of scope pics just to document circuits
I'm working on. I scribble comments on a post-it, stick it to the
corner of the screen, and shoot.


John

 

[Joerg]

Hi John,

Wow, that is an excellent picture. If you hadn't just said so I wouldn't
have thought it was a camera shot. No parallax distortion or anything.

Yes, I know that the smallish cameras are no good. You can't change
lenses. I have some Minolta lenses at home so I'll try to find a Minolta
compatible camera, hoping that they didn't change adapters in the
meantime. But that can be tried out before buying.

Regards, Joerg
http://www.analogconsultants.com

 

[Jim Nagy]

In article <408C2856.B4B9B1EC@removethispacbell.net>, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

Can't see why not. You do want a camera with true macro capabilities -

not just close focussing capabilities. A true macro will allow it to
capture all the way to the edges of the image without going fuzzy on
you.

--
Jim Nagy
Elm Electronics

 

[Frank Bemelman]

"Joerg" <notthisjoergsch@removethispacbell.net> schreef in bericht
news:408C2856.B4B9B1EC@removethispacbell.net...

Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

I am thinking about buying a digital camera and this plus maybe a
few microscope or macro shots of circuit boards would be pretty
much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

Single shot events on an oscilloscope might be tough to do,
but steady images are no problem at all. I have done this
with my Fuji finepix 4700 with very good results. Since I
dropped that couple of days ago, I had to replace it. Bought
an Olympus C4000 for 249 euro. This camera is even more
tolerant and seems to be rather clever. Everything I shoot
in automatic mode looks pretty damn nice, CRT oscilloscope
included. With some tweaking in manual mode, and use of a
tripod, I expect razorsharp images. You may need to turn
down the brightness a lot, to avoid blooming.

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)

 

[Ian Stirling]

Joerg <notthisjoergsch@removethispacbell.net> wrote:

Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

I am thinking about buying a digital camera and this plus maybe a
few microscope or macro shots of circuit boards would be pretty
much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

For constant waveforms of 100Hz or better scan rate, the cheapest
point-and-shoot camera will work just fine.

For a digital scope, largely all this goes away.

As I'm feeling especially public spirited, I just took some pictures
with my canon powershot S20.

http://www.mauve.demon.co.uk/img_7694.jpg is a picture of some fish.
Looking at the next few, I see I should have hit 'macro', as it's a
bit close, and hasn't focussed right.
http://www.mauve.demon.co.uk/img_7703.jpg is the 1Khz cal waveform.
http://www.mauve.demon.co.uk/img_7707.jpg is a trigger off a 50Hz noisy
mains signal, with the timebase at about 5ms.
For a digital scope, largely all this goes away.

As I'm feeling especially public spirited, I just took some pictures
with my canon powershot S20.

http://www.mauve.demon.co.uk/img_7694.jpg is a picture of some fish.
Looking at the next few, I see I should have hit 'macro', as it's a
bit close, and hasn't focussed right.
http://www.mauve.demon.co.uk/img_7703.jpg is the 1Khz cal waveform.
http://www.mauve.demon.co.uk/img_7707.jpg is a trigger off a 50Hz noisy
mains signal, with the timebase at about .5ms/div.
http://www.mauve.demon.co.uk/img_7713.jpg is the same waveform, with
the timebase at about .5us/div, in the dark, with scale illum on.

All of these pictures would have come out focussed right, if I'd
remembered to press the macro button.

Going for a digicam with replacable lenses for this is barking mad, utter
overkill, unless you've always wanted one.

It might barely be justified for the times when you need to be able to
stick the camera in a light-tight box along with the scope, and wait
for that once in a minute transient.

Things you need to look for.
The ability to set exposure manually, or you will have many problems.
Being able to lock exposure is a poor second.

If you need to be able to take long exposures, you'll need a camera
that can do this.
The lenses that come with all cameras will be perfectly adequate.

Pictures should be up shortly.

 

[Ian Stirling]

Joerg <notthisjoergsch@removethispacbell.net> wrote:

Hi John,

Wow, that is an excellent picture. If you hadn't just said so I wouldn't
have thought it was a camera shot. No parallax distortion or anything.

Yes, I know that the smallish cameras are no good. You can't change
lenses. I have some Minolta lenses at home so I'll try to find a Minolta
compatible camera, hoping that they didn't change adapters in the
meantime. But that can be tried out before buying.

There is no need to change lenses.
Ok, proper attempt this time.

In defence, the previous shots looked a whole lot better on the viewfinder,
and I've now just looked at them...
http://www.mauve.demon.co.uk/img_7730.jpg is a better example of what
I've got when I've used this method in the past.

With an LCD scope, you can get pretty much perfect pictures, as all the
problems of imaging an analog cathode ray scope go away.

The unfortunate parallax is due to me misjudging the height wrongly,
rather than a defect in the camera.

I've generally used a little clamp affixed to the desk to set the
camera at the right height, and timed release, rather than handheld.

There is little barrel distortion, when the lens is used on maximum zoom,
in macro mode.

 

[Paul Burridge]

On Sun, 25 Apr 2004 22:20:55 GMT, Ian Stirling
<root@mauve.demon.co.uk> wrote:

Joerg <notthisjoergsch@removethispacbell.net> wrote:
Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

I am thinking about buying a digital camera and this plus maybe a
few microscope or macro shots of circuit boards would be pretty
much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

For constant waveforms of 100Hz or better scan rate, the cheapest
point-and-shoot camera will work just fine.

Maybe... if the technique is right. Always use a tripod as the
exposure will be relatively long. Don't set the scope brightness too
high. Actuate the shutter button *very* gently so as not to disturb
the camera on its mount. With conventional film cameras, I would use a
20 foot long air-release for this, but little digi-cameras can't
accept them without expensive adaptors, so smooth and careful
fingerwork is needed to obtain maximum image sharpness.

 

[Joerg]

Hi Ian,

That picture looks good, too. A little barrel distortion on the right but for a
documentation that should not be a problem.

With respect to lenses, if I could use the whole enchilada of Minolta SRT
lenses that would allow a tripod shot from a distance. Some of these lenses are
so great in macro mode that you could even take a shot off a one square inch
section of a circuit board with almost no distortion. But maybe the
manufacturers aren't much interested in enabling people to use their existing
set of lenses. At least that's what I read on the web so far.

Regards, Joerg.

 

[Ben Bradley]

In sci.electronics.design, Paul Burridge <pb@notthisbit.osiris1.co.uk>
wrote:

Maybe... if the technique is right. Always use a tripod as the
exposure will be relatively long. Don't set the scope brightness too
high. Actuate the shutter button *very* gently so as not to disturb
the camera on its mount. With conventional film cameras, I would use a
20 foot long air-release for this, but little digi-cameras can't
accept them without expensive adaptors, so smooth and careful
fingerwork is needed to obtain maximum image sharpness.

There's a trick to this I learned to use with a (film) camera
mounted on a telescope for astrophotography, if the exposure is going
to be over a second or so, and presuming a digital camera does long
exposures the same way a film camera does. Hold a piece of
black-painted cardboard between the camera and the screen [or end of
the telescope tube where light is going in], open the camera shutter,
take your hand off the camera and wait a second or three while the
camera/tripod stops vibrating. Remove the cardboard for your exposure
time, put the cardboard back between the camera and screen, and close
the shutter. The cardboard doesn't touch anything, you just move it to
expose the screen for the appropriate amount of time. It would also
help to do this in a dark enough room that (almost) no light is
reflected off the cardboard into the camera.

 

[legg]

much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

I switched from GPIB to RS232.
Easier to isolate.
Standard interface to a laptop.

RL

 

[Ian Stirling]

Joerg <notthisjoergsch@removethispacbell.net> wrote:

Hi Ian,

That picture looks good, too. A little barrel distortion on the right but for a
documentation that should not be a problem.

There are plugins to graphics programs available that take information
about a lens, and undistort it.

With respect to lenses, if I could use the whole enchilada of Minolta SRT
lenses that would allow a tripod shot from a distance. Some of these lenses are
so great in macro mode that you could even take a shot off a one square inch
section of a circuit board with almost no distortion. But maybe the
manufacturers aren't much interested in enabling people to use their existing
set of lenses. At least that's what I read on the web so far.

I'm assuming that this is a 35mm camera.
The basic problem is that 35mm sensors are prohibitively expensive at the
moment.

I think that they are currently around $11K for a 11MP sensor, which
I believe is 35mm.

However, the best of the smaller cameras, with sensors around 17mm across
can in many ways beat film, for most tasks.
They can work with shorter exposures, while producing a comparable picture,
and the glass is a lot lighter.

(I'm just reporting on the debates going on over in rec.photo.digital,
my best digital camera is the one that took this picture, which only goes
to 3.3Mp)

The problem with trying to use non full-frame sensors with 35mm lenses
is obvious.
With 166 pixels an inch or so, not much glass measures up.

 

[Rich Webb]

On Sun, 25 Apr 2004 21:02:10 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

I am thinking about buying a digital camera and this plus maybe a
few microscope or macro shots of circuit boards would be pretty
much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

As John mentioned, having a digital camera around the lab is very handy.
You'll wonder how you got along without one.

Scope pictures will be easiest if the image is already frozen (single
shot). In any case, use a tripod for "production" pictures.

But it's amazingly handy for just documenting work in progress. Since
the pictures are effectively "free" its great for snapping a pic of the
current setup/breadboard/smoke-emitting-component/whatever...

--
Rich Webb Norfolk, VA

 

[mike]

Joerg wrote:

Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

I am thinking about buying a digital camera and this plus maybe a
few microscope or macro shots of circuit boards would be pretty
much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

Regards, Joerg
http://www.analogconsultants.com

Depends on what you want to capture.
Here's a pix of a scope camera adapter.
I took a random polaroid camera adapter and stuffed some pvc pipe
into it and carved out a holder for an Intel CS330 USB webcam.

http://nm7u.tripod.com/homepage/camadapt.jpg

Here's a typical pix.
http://nm7u.tripod.com/homepage/stdwfm.jpg
It's been downsampled to fit on a webpage.

You can see the reflection of the camera and light leaks.
I never bothered to fill in the space around the camera.
Glueing the camera into alignment would improve the distortion.
I just hated to dedicate a camera to something I rarely used.

Works reasonably well for repetitive waveforms.
What I really wanted was single shot capture of slow waveforms
on my spot welder. I hacked an optoisolator into the snap button
and attempted to pretrigger the camera. Also tried to trigger from
the scope gate to capture the phosphor afterglow. Since the button
has to get recognized by the camera, sent to the driver and back to
the camera, there was no repeatability and the experiment failed.
A digital scope fell into my lap and the experiment was terminated.


I wouldn't call the result "production quality", but for engineering
documentation it should be ok.
mike



--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Honda CB-125S $800 in PDX
Yaesu FTV901R Transverter, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[Terry Given]

"mike" <spamme0@juno.com> wrote in message news:408C67C8.7020801@juno.com...

Joerg wrote:
Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

I am thinking about buying a digital camera and this plus maybe a
few microscope or macro shots of circuit boards would be pretty
much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

One area where I swapped a nice DSO (TDS3xxx) for a 35MHz analogue scope &
digital camera was looking at d-q axis state-planes - feed Id and Iq into
x,y inputs of scope in XY mode. to date all of the digital scopes I have
tried have been extremely noisy in XY mode, and none have stored a complete
circular/hexagonal plot. The old 35MHz CRO worked beautifully though - I
used clamps to hold the camera, a dark cloth over the scop & camera, and
triggered the camera (C3030ZOOM) with its remote control to prevent bumps.

 

[Ian Stirling]

Rich Webb <bbew.ar@mapson.nozirev.ten> wrote:
<snip>

As John mentioned, having a digital camera around the lab is very handy.
You'll wonder how you got along without one.

Scope pictures will be easiest if the image is already frozen (single
shot). In any case, use a tripod for "production" pictures.

But it's amazingly handy for just documenting work in progress. Since
the pictures are effectively "free" its great for snapping a pic of the
current setup/breadboard/smoke-emitting-component/whatever...

Can also be used as a cheap means of logging data.
Camera on 640*480 set to take a picture every couple of seconds, pointed
at a few DMMs can be a handy thing.
Even without software to convert the images into numbers.

Not to mention the serious handiness in logging which screw went where,
and exactly what the position of those gears were, when dissasembling stuff
you'd like to work when reassembled.
Nice high-res pictures of the insides of stuff can also stop you needing
to open it up to check chip numbers or markings that you forgot to
look at first time.

Then there is use in the field, where you can use it to take pictures to
visualise just where that cable you'r reaching for is, or so you can
visually check work later to check you diddn't make a mistake, in case
of later doubt.

A camera cheap enough that it won't ruin your month if it falls in a vat
of boiling chicken soup is probably a good idea.
Having an expensive camera can mean you don't take it anywhere you
might benefit from it.

Hard cases are good.

 

[Robert Baer]

Joerg wrote:

Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

I am thinking about buying a digital camera and this plus maybe a
few microscope or macro shots of circuit boards would be pretty
much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

Regards, Joerg
http://www.analogconsultants.com

Yes! And i use an inexpensive Olympus D-150 zoom camera (older ones
work just as well).
I made a camera holder/lightbox: about 5.5 wide by 5.2 high by 12
inches long; but the bottom extends further away from the scope for a
total length of 15 inches.
That gave me a place to put a pedistal 1.5 inches above it, to use as
the resting place for the camera. I added "L" brackets to use as a left
"stop" and back "stop" for alignment.
Sprayed the whole thing black inside; light from the back seems to
have no effect.
The cross-section fits the rectangular scope face perfectly, and i
added (using epoxy) a thin steel "L" bracket to act as a "hook" (1/16
inch) that catches into the groove at the top of the scope faceplate.
Held on by the hook and gravity (weighs roughly a pound without
camera).
I have no control on the so-called shutter speed, and i zoom in until
i see the CRT screen almost fill the viewfinder; disable flash and
*snap*.

 

[Spehro Pefhany]

On Mon, 26 Apr 2004 00:59:20 GMT, the renowned Rich Webb
<bbew.ar@mapson.nozirev.ten> wrote:

On Sun, 25 Apr 2004 21:02:10 GMT, Joerg
notthisjoergsch@removethispacbell.net> wrote:

Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

I am thinking about buying a digital camera and this plus maybe a
few microscope or macro shots of circuit boards would be pretty
much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

As John mentioned, having a digital camera around the lab is very handy.
You'll wonder how you got along without one.

Scope pictures will be easiest if the image is already frozen (single
shot). In any case, use a tripod for "production" pictures.

But it's amazingly handy for just documenting work in progress. Since
the pictures are effectively "free" its great for snapping a pic of the
current setup/breadboard/smoke-emitting-component/whatever...

Communicating modifications or suggestions to a remote site (a few
minutes drive away or across the globe), recording the way things were
before you take apart that complex mechanical assembly with linkages
etc. You can get color prints made at retail places for really cheap
these days (about US0.20) if necessary. Here's a quick snap (with
tripod, flash turned off, didn't bother dimming the room lighting or
dusting the scope off, no touch-up) from a cheap scope (hmm- trace
rotation could use a bit of trim too) that doesn't have graticle
lighting or display of settings. Using the camera timer is a useful
trick to prevent camera shake.

http://www.speff.com/scope.jpg

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Garrett Mace]

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:408C2856.B4B9B1EC@removethispacbell.net...

Hi All,

Can a digital camera capture oscilloscope screen shots reasonably
well? I mean well enough that the pics could go into a final
document after some polishing on a good image editing software?
Color would be best but monochrome can suffice here.

I am thinking about buying a digital camera and this plus maybe a
few microscope or macro shots of circuit boards would be pretty
much its only purpose. I know that good ones with exchangeable
lenses cost a lot but then all this messing around with bulky
HPIB would not be neccessary.

Regards, Joerg
http://www.analogconsultants.com

It does work.

Back when I was in school (not really that long ago) we had to take photos
of three-phase waveforms in power lab. During the preceding class period,
the instructor told us that we would be limited to three photos per team,
and have to hand-sketch the rest, because there was only one camera for
those scopes and Polaroid film gets expensive when you take a lot of photos
lab after lab. We'd all have to take turns to use the camera.

I decided I would have none of that, and stuffed my webcam in my backpack
along with the laptop. My lab partner Phil was impressed with the idea and
we figured out how to get a good image; I think we put the scope in storage
mode and upped the refresh a bit. You had to adjust the exposure a little
bit in order to get a complete trace because of the camera's refresh rate.

Anyway, that worked really well...we were done with the lab while the other
students were still waiting to use the camera. The teacher came by and was
amazed at how well it worked...then the department head and the lab
technician came by to see it. In lab the next week, they had already
purchased webcams for the lab station computers that were already there, and
were building mounts to clip onto the scopes for easier use.

As far as I know, students still use those cameras. A few hundred dollars
investment for the whole lab; to get the same functionality they would have
had to buy a lot of expensive digital scopes.

 

[John Larkin]

On Mon, 26 Apr 2004 08:05:46 GMT, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

Communicating modifications or suggestions to a remote site (a few
minutes drive away or across the globe), recording the way things were
before you take apart that complex mechanical assembly with linkages
etc. You can get color prints made at retail places for really cheap
these days (about US0.20) if necessary. Here's a quick snap (with
tripod, flash turned off, didn't bother dimming the room lighting or
dusting the scope off, no touch-up) from a cheap scope (hmm- trace
rotation could use a bit of trim too) that doesn't have graticle
lighting or display of settings. Using the camera timer is a useful
trick to prevent camera shake.

http://www.speff.com/scope.jpg

Best regards,
Spehro Pefhany

Nice one. How far away?

John