BACKGROUND

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.

SUPPORT

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, here is the source of my updated gsmart.c file To make use of this, unpack the libgphoto2 version 2.1.1 sources, and replace the camlibs/gsmart/gsmart.c file with this one 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.

REVIEW

Here's my review. The plus points for the camera:

• 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.

Comments that could be a plus or a minus depending on your requirements:

• 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.)

The minus points for the camera itself are:

• 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.

So in 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.

LINKS AND RESOURCES

A page about the gsmart mini2 with some useful information that applies to the mini as well. In particular, there are notes about how to play the movies with mplayer ... if only I could extract the movies from the camera :-(

How to mod the camera to allow the macro mode to focus even closer. Also some useful links.

Till Adam's page (he's the author of  the gphoto2 driver for the camera).

Source code to repair the gsmart mini support with libgphoto2 version 2.1.1

Another review of the camera

Yet another review of the camera

GALLERY

Having said all that, I have now got some useful pictures from the camera.

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.

Here's a view of Sand Bay taken from the top of Worlebury hill. This image is unprocessed.

A couple of "still life" arrangements. These were taken at the far end of our kitchen from the window on a sunny day.

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.

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 ?!

The Lamb public house, Worle. This is straight from the camera too. You can see this was a dull day.

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.)

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.

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!