Legacy Series, the Bellow Cam Mk 2 SC GT

Bellow-Cam Mk 2 GT

 Being used to GOTO-telescopes, I also liked my wide-angle camera to be equipped with this feature. OK, it is not a big deal at all to handle right ascension and declination setting circles, pointing the scope/camera by α and δ looked up from catalog or star chart data, but, goto is sooo convenient! After some looking around, I got myself a used MEADE DS-127 mount with an AutoStar #957 computer. Perfect!
Fitting Bellow-Cam Mk 2 to the mount is so simple that I would not like to waist words on this issue. It took a piece of hardwood, two bolts and two nuts to get it all sorted.

Bellow-Cam Mk 2 GT, the wide-angle camera setup on the “autostared” DS-mount, in operation.

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Analysis

It is quiet obvious that this is an azimuthal mount, resulting in field rotation. For real long exposures (i.e. minutes to hours) this is utterly devastating for every image taken.
Here the abilities and power of CCDs are coming into play. With exposure times of a couple of seconds, field rotation does not play any role for the single frame. As long as the CCD amplifier ensures that the charge in a single pixel is high enough to result in a signal greater than the detection threshold we can integrate over several different frames. IRIS offers a very good possibility to register and stack frames which are slightly rotated between one another.
A very very short introduction how an analysis like this could be looking like can be found here.

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Result

The image of M45 was taken 2005 January 9^th. Again I was to lazy to subtract a dark frame. Note the image tilt, that's the sacrifice for compensating field-rotation when using an azimuthal mount. To be noted on the image is amplifier-glow on the upper left corner. The QuickCam appears not to be the best camera, even with the use of non-raw patch, ear-like artifacts still occur.
It is amazing, I think, that the nebulosity of M45 can be recorded using a f=50mm SLR lens and a webcam from a light polluted place like South Holland, on a night with light overcast and quiet poor transparency...

Lagecy Series, the Bellow Cam Mk 2 SC

QC4000pro LX (SC2)

The QuickCam 4000 pro had to go through a long exposure  modification following the "SC2" approach as described by Martin Burri. There is nothing much beyond Martin's remarks to be mentioned. The modification went pretty straightforward. No pins are to be lifted in this way of modifying, cutting PCB traces does the deal. I soldered magnet wire (I have tons of this around for my radio projects) to the pins of the ICs. The individual leads are connected to a kind of "patch panel", the tiny bit of bread-board PCB glued to the camera opposite the USB and microphone connector. Blue wires are making the final connection to the 4011 hidden below the whole mess. The red and the yellow wire (stereo phono cable) are serving as connection to the parallel port of a computer.
BTW, in contrary to the ToUCam, this camera holds an infrared cut filter inside the objective lens bearing, thus no additional IR-filter is needed in a setup like shown here.

Camera front-side, no lens mounted. For reasons of experimentation, the camera is built in tilted...

Additionally I spent money and obtained a Ra-motor for the EQ2. Decent tracking is a necessity for the long exposure times the camera was modified for.

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LX-astro images

You are invited to compare with the images recorded using Bellow-Cam MK1 and Bellow-Cam MK2. Messier 44  gives some impression about the benefits of longer exposures. Exposure time was chosen to be 10s/frame. Conditions on March 13th 2004 when I was acquiring data for the following image were fair (for this site), with the unarmed eye, I could see Orion's sword.


M44, 50mm f/1.8

Legacy series, the Bellow-Cam Mk 2

Bellow-Cam Mk 2

Another Camera

The Vesta fits quiet OK, but not really well.... Philips, for what ever reason, appears do design funky shapes for webcams... Logitech obviously shows some more heart for tinkerers, doing so they designed a ball, long ago, and sticked to that design. Certainly a ball fits better into the bellow-cam... Have another look... you might recognize a QC-4000pro in un-modified state.
The webcam is held by self-adhesive window frame insulation rubber, the circular openings of the bellow are perfect to fit the QuickCam-ball in....
In this stage I have chosen to mount the camera on an EQ2 mount. The Ra and Dec axis allow easy aiming when the coordinates of the object of interest are known, furthermore the mount enables manual tracking.

side view with 50mm lens resulting field of view about 4°	side view, 135mm lens with "dew cap" resulting field of view about 1°30'
front view with 50mm lens	back view
front mount detail, no lens	rear mount detail
the "victim"	the "supporter"

M45 (Pleiades)  recorded with the above setup

Legacy series, the Bellow-Cam

Relatively old stuff from my original web-page... 

 

The Bellow-Cam

A Simple Wide-Angle Camera

Guess what, I am lazy.... So, I tried to find as much "completed work" as possible. Resulting in a rather simple design. All parts can be easily found on fleamarkets or rallies... The basis of all are a photographic bellow, a Vesta pro and a couple of lenses (M42). Cardboard finished the first design, but just have a look...


Vesta-Cam using a 50mm f/1.8 lens (no long-exposure!)

M44 (Praesepe) recorded with the above setup, unguided camera on a simple tripod,
the bright spot on the lower left edge is Jupiter

Street Photography Using the LX7

I am rather new to street photography, however, I think I got some basic understanding of what seems to be the thumb-rule for getting the shot in the street.

1. Speed, the shutter needs to open a quickly as possible.
2. Monochrome images are typical for this genre.
3. Depth of field, usually pretty deep.

Let's see what we can do with the Panasonic Lumix DMC-LX7.
This camera, as you probably already know, hast got 4 memory position for custom settings. In my camera, C1 is taken by bracketing, cf. earlier post. This leaves us with the 3 additional spaces under the C2 position of the quick dial, I choose C2-1, later more about that.

Lets look at what we primarily need, control over the camera with the fewest possible interactions.
The camera sports a nice aperture control ring, so, lets go for aperture priority mode (there are actually more reasons for this, you will see).
=> Step 0: set the camera to "A".

Being as fast as possible, the first priority to me was to use manual focus (MF), which is to be selected by the switch at the lens barrel, in order to loose the time any auto-focus takes. "Manual focus?", you may ask yourself, "the one where you have to fiddle that little 'FOCUS'-thingy?!". Yes, precisely that!
Here comes the trick: in the Setup-menu (page 4), there is an entry 'Lens Resume'. This entry refers to 2 options: 'Zoom Resume' and 'MF Resume'. Both come in very handy for street photography purposes.
=> Step 1: enable lens resume for both options (Setup-menu, page 4), see below


We want monochrome, right? Well, yes and no. B&W images in such cameras are produced by processing data that is provided by sensors having a Color Filter Array (CFA) printed on them. Those filters are red green and blue filters, where green occurs twice in a pixel (cf. Bayer filter array). The individual filter dye used on said array will of course have a specific attenuation.
When recording photos in RAW, we record the data provided by the sensors, as the name suggest. This data, however, represents light filtered by the Bayer CFA. 
I hope that camera manufacturers make use of the knowledge of the light attenuation created by the respective dyes and take it into consideration for the algorithm to convert RGB-data into monochrome images. Consequently, you would want to store not only the RAW file, but also a monochrome JPG file.
=> Step 2: in the Rec-menu, set 'Photo Style' to 'Monochrome'
=> Step 2.1: i the Rec-menu, set 'Quality' to 'RAW + fine'


Point 3 of the above list points towards depth of field. Well, since we are on our way programming the camera in aperture priority, we do not need to bother about that, you will take care about the D.o.F. by using the aperture dial on the lens barrel.
=> Step 3: enjoy the aperture dial of the LX7!


Some further stuff may come in handy:

• ISO limit 800 (Rec-menu, page 1), ISO 800 may already be noisy... hence don't go beyond that
• Quick AF ON (Rec page 2), in case you engage auto-focus
• Metering Mode [(.)] (Rec, page 3), evaluative mode, there is not time for spot metering, still we want to meter where we point, roughly...
• Step Zoom ON (Rec, page 4), see below
• Stabilizer ON (Rec, page 4), good idea, in particular since in this type of photography the photographer is moving quite often
• AF Assist Lamp OFF (Rec, page 4), don't alert your subjects!

Now, save your settings into a convenient custom memory. As mentioned above, I went for C2-1. This can be done by on 'Setup' page 2, item: 'Cust.Set Mem.'. I leave it up to you to figure out the rest.


SEE BELOW points:

Lens Resume
Both settings, the focal length and the focus could/should be set before going on the street.
I recommend a focal length equivalent to either 35mm or 50mm, depending on your preference. This setting will be recalled when you switch on your LX7. Depending on your training, you will see for yourself w/o engaging any viewfinder, what the framing will be.
The more important setting is the manual focus (MF). Put the camera into manual focus mode and set the focal distance to about 3m (using a wide open aperture... the on screen display will show you the range). Now stop down the iris, and you will see how deep the D.o.F. will be. Judging the distance to your subject is just a matter of experience, be it 3m, you may open the lens to the maximum, if you are not sure, just stop it down, thereby increasing the D.o.F.

Step Zoom
Depending on your training, you will see with your own eye what the frame will be when knowing the equivalent focal length of the lens. Helps a great deal when shooting from the hips!


Summarizing:
- Those particular setting will produce a colored RAW image and a monochrome JPG.
- The camera is only controlled by the aperture ring, only defining the D.o.F.
- The settings can be recalled by the mode selector.

CHDK and Fast SD-Cards

Yes, a fast card does make a big deal difference when saving RAW in CHDK.
I know, everybody keeps saying this, and now, I am just one of them.

My first CHDK test using the IXUS 140 where done using 2 different SD-cards. The first to use was an EMTEC 4GB class 4. The second card was a SanDisk 2GB ultra II. Both cards worked fine, even when taking handheld bracketed shots, but there was certainly some waiting whilst the images were written.

Today, I upgraded to a SanDisk 8GB Extreme, which is class 10 and, according to the manufacturer, can write at 60MB/s (marked with 80MB/s, which is the read bandwidth). Actually, I am not really sure about such speeds.
However, when copying CHDK, I noticed a severe difference in speed. Also when taking pictures as digital negatives (DNG), an increase in speed was clearly noticeable.
The 8GB card set me back by €23.-, which is essentially 20% of the camera's price, however, I believe it was worth the additional cost.

Handheld Bracketing w/ CHDK

If you followed this (young) blog, you may know that the first ever post was about handheld HDR using the very fast 11fps of the Lumix LX7.

Lately, I kept myself busy with Canon stuff, in particular the CHDK and cheap P&S cameras. For purpose of experimentation, I bought an IXUS 140 (aka ELPH 130). The 140 is a cute little camera I really like, very pocketable, CHDK, although ALPHA, works as a charm!
The cheap chap that I am, I only afford the camera with a really old Sandisk Ultra II 2GB SD-card. I am sure that there are faster cards available... however, this is what was sitting unused in my desk's drawer, hence, that is what I use(d).

The drawback of using an older generation SD-card is of course the speed in which data can be written to it. In particular when saving data in RAW, this plays a major role.

For matters of experimentation, I took the camera, set CHDK to bracketing in continuous mode and took some shots. Photomatix was used to create the DHR images.

The first HDR image that I would like to share is a shot in which I used 3 frames recorded as DNG (which is essentially raw data). The middle frame was shot with -1 Ev. Lens distortion correction was applied to the final image using RawTherapee.

3 DNGs - lens distortion correction using RawTherapee

If you look closely, the branches in the center of the image display some ghosting. It was a windy scene and I did not go through any major anti-ghosting procedure.

The second shot is an HDR image using 5 JPG frames. Again, the middle image at -1 Ev.
No geometrical correction applied here, mind you, the camera's firmware does something already when recording JPGs... something that actually over compensates at wide angles.

5 JPGs - no correction, note that the camera itself over compensated

Here you have it, even a slow and inexpensive camera can be used for handheld HDR photography. 3 frames in RAW (or DNG) or 5 frames in JPG, w/o a tripod, both demand a very calm hand...
In this shot, I used the anti-ghosting tool of photomatix on the approaching tram.

Here is how I do it, inspired by Discovery Channel reporting about snipers:

1. calmly prepare your camera, making sure all the setting are correct, e.g. exposure compensation
2. stand firm on both legs, feet at shoulder width
3. breath slowly but steadily, wait until you body settles
4. hold your camera with both hands
5. press your arms against your chest
6. relax
7. breath in deeply
8. exhale slowly half pressing the shutter release
9. when your chest is relaxed and your lungs exhaled, gently press and hold the shutter release
10. freeze (not thinking about it!)
11. hold your breath and wait until your camera recorded the 3, 5 or 7 frames you need.

Step 11 may actually take some time, training increases the time you can hold your breath w/o moving.

All in all, handheld HDR photography remains a challenge. It is best done with a fast bracketing camera, such as the Lumix LX7, however if the camera at your disposal is somewhat slower, there is still hope!

Record photons!