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3 October 2003
Reformatted page using new style
3 October 2003
Added gsmart.h file required for building libgphoto2 support
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| :: NAVIGATION :: |
main page :: Back to main page
gallery :: Photos I've taken with the gsmart mini
old page :: Old version of this page
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| :: SOFTWARE LINKS :: |
gphoto
gimp :: The GNU image manipulation program
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| :: CAMERA-RELATED LINKS :: |
Till Adam :: Till Adam's page (he's the author of the gsmart port of gphoto
gsmart mini2 :: A page about the
gsmart mini2 with some useful information that applies to the mini as well
focus mod :: How to modify the camera to focus closer
review :: Another review
review :: Another review
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background |
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I decided to get a digital camera. However, I was on a limited
budget, so I looked at the cheap end of the range. My goal was to get a
few photos for emailing to people rather than to produce a masterpiece!
I also wanted something small, easy to carry around, and inexpensive in
case it got lost or damaged. Especially since the kids were sure to
want a go with it!
One of the cheapest cameras
around at the moment is the Mustek Gsmart Mini. I paid about 30 pounds
for it, including VAT. A major constraint was that I needed a camera
which is supported by gphoto2,
because I run Linux exclusively on my PC. Once I established that
gphoto2 had support for this camera (albeit experimental) I decided to
take the plunge. Very few other cameras at this end of the price range
appeared to have any support in gphoto at all.
Despite endless googling
for information about this camera (reviews, real-life experiences etc),
I found hardly anything. In fact, I think I found a couple of sketchy
reviews and 1 sample photo. Also, I found absolutely no information
about how well the gphoto2 support worked. This state of affairs
motivated me to write this page. Hopefully anybody making the same
choice about whether to buy this camera can now make a more informed
decision.
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linux software support |
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This section discusses how well the camera is supported by the
gphoto2 driver. First of all, I have to thank Till Adam (the
driver's author) that support exists at all. Without his previous
work, I wouldn't even have considered buying the camera.
In the current released version of libgphoto2 (currently 2.1.1), the
640x480 modes seem to work sometimes. I don't think I got the
320x240 mode to work at all, and the movie mode isn't supported at all.
The 640x480 mode fails if a picture contains more than 64kbytes of
image data. In this case, the driver only downloads the remainder
modulo 64kbytes from the camera and all subsequent frames are
downloaded with the data skewed out of position, leading to wraparounds,
colours casts etc. This makes the enhanced 640x480 mode virtually
useless, and even the standard 640x480 mode fails sometimes.
In the CVS version, the 320x240 mode works as well.
Since then, I've been working with Till to fix the remaining
problems. We believe the driver is now fully functional : all
640x480 images now seem to download correctly, and the movie mode is
supported.
Since I don't know when these fixes will appear in a released version of
libgphoto2, the download section just below contains the files you need to
replace in the camlibs/gsmart directory.
To make use of this, unpack the libgphoto2 version 2.1.1 sources, and replace
the camlibs/gsmart/gsmart.c and camlibgs/gsmart/gsmart.h files with these
before compiling. It currently emits a lot of verbose debugging information
which I used when I was debugging the driver. Feel free to edit out this stuff
before building! - unless you especially want to read it all. I'm afraid that
once I got the code working, I never got round to tidying it up.
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download |
./gsmart.c :: C source code to replace file from libgphoto2 v2.1.1
./gsmart.h :: Header file to replace file from libgphoto2 v2.1.1
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good points |
- It's really small - less than the size of a credit card. Most of
the body is less than a centimetre thick (although the lens protrudes
almost another centimetre from the front). This means it's really
convenient to carry everywhere you go - it just slips into a pocket.
- It can hold 100 pictures at 640x480 resolution in its internal
memory. (Or 200 at 320x240, or 50 at 640x480 in higher quality.)
It also claims to hold 10 short movie clips, although the capacity
tends to be lower if the movies have lots of detail in them.
- The enhanced 640x480 pictures are largely free of jpeg artifacts,
and can be scaled up to 800x600 with very good results. I'm not so
sure of the results when scaling up to 1024x768.
- It's very quick to switch on, line up and shoot. (Compared to
setting up a film camera anyway).
- It has a macro mode which can focus down to 20-30cm. This seems
to work pretty well, allowing useful close-ups to be taken.
- It's got a small LCD display on the back showing the current
picture resolution, and the number of pictures that will fit in the
remaining memory.
- The movie mode is really fun to use. Even though the movies
are only 320x240 in size, they give more of a feel of the event you're
recording than still pictures ever can. Each movie lasts 15.4
seconds at 10 frames per second. The gphoto driver produces AVI
files with the frames in mjpeg format. You can play this back
using mplayer, for example.
- You can delete the previous picture, or all the pictures.
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good or bad points |
These are either good or bad points, depending on your perspective.
- The lens seems quite wide-angle. I guess this helps with the
depth of field, given that there's no real focussing to worry about
(only macro or normal). So you can get a lot in your picture. On the
other hand, you have to get in close if you want the picture to
concentrate on one subject.
- The camera is almost silent in operation. The buttons are very
quiet to operate and there are no beeps or anything like that. So the
camera would be good for candid work or for taking pictures in quiet
places, but some people might be unsure whether the camera has operated
given the lack of audible feedback. I'd suggest checking the LCD
display on the back if that's a problem, to see if the image count has
decremented.
- It comes with an optional wrist strap. Whilst making it harder
to lose the camera, this rather detracts from the convenience of
slipping it into a pocket. I haven't bothered with mine.
- The camera has an internal rechargeable battery. This is charged
through the USB cable whenever the camera is connected to the computer.
On the plus side, you don't have to buy any batteries for the camera.
On the minus side, when the battery runs down you risk losing the
pictures unless you can download to your computer fairly soon, and you
won't be able to take any more until you recharge. You've no standby
power option with this camera. Also, once the rechargeable battery
dies, the camera is probably useless. The quoted battery life before
needing a recharge is 1 hour switched on, or 2 weeks in 'standby' (where
I think 'standby' means refreshing the SDRAM to keep the stored
pictures alive, but doing nothing else.)
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bad points |
- No flash means that you need at least reasonable lighting.
Pictures taken in artificial light, for example, will usually need a
pass through gimp to
make them useful. If the ambient light is too low, it will be
impossible to recover a useful picture even with post-processing. (See
examples in the gallery below.)
- In poor lighting the shutter speed is slow (it goes down to 1/15
second), so you have to be very careful about camera shake. This is
accentuated by the size of the camera - it's very hard to hold it still
due to its lack of inertia! It seems easier to hold it still when
held up with the viewfinder against the eye. When holding the
camera 'freehand' it's very prone to shaking.
- In the movie mode, if you pan the camera too fast in low light,
each frame is just a smeared blur.
- Also in the movie mode, the exposure setting for the entire movie
seems to be calibrated right at the start. So if the scenes you're
shooting change brightness significantly during the movie, the later
frames will be either very washed out, or very dark. For example,
if you start filming inside a room, then pan to look out of the window,
the window will just look like a white sheet with no outdoor detail
visible at all.
- There's no display on which to review the pictures. The first
chance you get to review them is when you've downloaded them to your
computer.
- It's quite hard to line up the shot accurately, although it can
be done with practice even when not using the viewfinder. Parallax is
obviously a problem in the macro mode.
- I've found noticeable jpeg artifacts on a few standard 640x480
images. Parts of the image look fuzzy when viewed at normal size. When
zoomed in, the artifacts are apparent. However, if the image is
downsampled to 320x240 it's fine. The enhanced 640x480 mode avoids
this also.
- In some scenes with brightness changing rapidly (e.g. looking
through some railings at a bright background), I've occasionally seen
false colours appearing (a bit like the effect on PAL TV where colour
bands appear when someone's clothing has rapid brightness variations.)
I assume this is due to limitations in the camera's front-end
interpolation algorithms.
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summary |
- When it works, it produces very acceptable 640x480 pictures
considering its price and convenience, especially in good lighting.
Also, the "marketing spiel" for the camera appears to be wrong or
misleading in at least these respects:
- Mustek's website, and all vendors' pages I've seen, claim this is
a 850k pixel camera. I wondered before I bought it how this squared
with it basically being a 640x480 device. I found out when an errata
sheet dropped from the box admitting it's actually a 350k pixel camera.
So the chance of getting an 850k pixel camera for 30 pounds was too good
to be true in the end!
- The spiel claims a 1024x768 "software enhanced" mode. What this
appears to mean is a mode where a 640x480 image is stored as a higher
quality JPEG allowing software interpolation later without too many
artifacts showing up.
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example photos |
overview |
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This section contains some photos I've taken with the gsmart
mini, so you can make your own mind up about its capabilities.
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gallery |
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Here's me sitting in front of the computer. This was taken
with a 60W bulb in a desklamp shining in my face. The two pictures show
the raw image the camera produced, and the result after rotation +
brightness/contrast adjustment using Gimp.
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Here's a view of Sand Bay taken from the top of Worlebury
hill. This image is unprocessed.
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A couple of "still life" arrangements. These were taken at
the far end of our kitchen from the window on a sunny day.
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Boxes of toys. These were taken indoors, in a room with a
large window, on a sunny day. I used jpegtran to rotate the Lego
picture, otherwise it's untouched. The other is straight from the
camera.
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The lakes at the Aztec West business park, north of Bristol.
One is untouched. In the other I used Gimp to remove my own shadow from
the grass. Can you work out which is which ?!
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The Lamb public house, Worle. This is straight from the
camera too. You can see this was a dull day.
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This is a picture of our spare room (in dire need of tidying
up), taken at night, illuminated by just the 100W ceiling light (with
lampshade). The raw picture from the camera is shown. So is my best
attempt at recovering this with Gimp. It's pretty obvious that the
degradation in the original has gone beyond what can be recovered; this
shows the limits of the camera with too little indoor lighting. The
carpet and wall colours are badly corrupted (they should be light brown
and light blue respectively.)
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Here's an indoor view. Lighting this corner of the room are
3x60W bulbs on the ceiling, and a 500W uplighter (on about 3/4 power)
behind the TV. This lighting level seems sufficient to get an
acceptable picture from the camera even without post-processing.
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Sand bay on an overcast day.
The first image came direct from the camera and was taken in
"enhanced" 640x480 mode. The second was scaled up to 800x600 from
this using djpeg, pnmscale and cjpeg. Note the filesize is
considerably smaller than the original even though the image is bigger!
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