- compact flash:
- the most popular card for high end cameras
- fast, sturdy, large memory size, relatively cheap BUT BEWARE damaging
pins by incorrect insertion - this may render your camera useless!
- come in various speeds which is very useful for digital SLRs as these
cameras can generally write images faster with faster cards - for most
dSLRs, the Extreme III speed is adequate:
- Sandisk Ducati (announced
- Sandisk Extreme IV
(announced mid 2006)
- 40Mb/s, can operate -25 to +85degC, 2-8Gb
@$US160 for 2Gb
- Sandisk Extreme III (2004) - 20Mb/s, 1-4Gb
- Sandisk Ultra II - 10Mb/s, 512Mb-4Gb
- Sandisk standard (Extreme I) (2003)
- beware of buying fake inferior quality CF cards on Ebay - see here
- see usage with Olympus cameras:
- very popular, versatile, small card - no bent pins to worry about
- Sandisk Extreme III (2004) - 20Mb/s, 1-2Gb
- Sandisk Ultra II - 10Mb/s, 512Mb-2Gb
- Sandisk standard (Extreme I) (2003) - sDHC card available in 4Gb but
- Panasonic Class 4 SD cards (2005?) - 1-4Gb; 4Mb/s;
- Panasonic Class 6 SD HC cards (2007) - 1-4Gb; 6Mb/s up to 20Mb/s
- similar to sD but only for a few brands such as Olympus, Panasonic
- have a special panoramic image capability but can't be used for
- M+ xD cards (2008) are 1.5x faster than M xD cards
- Sony cards and memory sticks:
- mainly for Sony products only
- hint: ALWAYS use a protective UV filter on your lens!
- cleaning coated optical surfaces is the
single-most damaging action that will be done to
them, short of actual physical damage or breakage
- CLEAN ONLY WHEN ABSOLUTELY
NECESSARY. In most cases, dusting alone will lead to
tremendous improvement in performance and overall light
- Your optical glass MUST be dusted when:
- a flashlight held obliquely against the glass reveals a
uniform and fairly thick layer of dust, etc;
- when POLLEN is on the glass, as leaving pollen will result
in "pollen sap" leaving a very difficult-to-remove
stain on the surface;
- ALWAYS prior to cleaning the glass with the solution and
technique which is on the above website.
- DON'T use compressed air to dust as risk of liquid droplets
being expelled from can is great
- for small spots or spots the ASO technique won't remove, consider
using a Lens Pen as they lift off grease
and oil without smearing it around and they don't seem to leave any residue either. Just go easy with it and don't use it too long.
Replace it if it gets grit on it. Alternatively, just try >90%
isopropyl alcohol at humidity < 65%.
digital SLR CCD sensors:
- digital SLR cameras which allow lens removal are subject to dirt on the sensor
which degrades images - an example of the problem:
- "I have been enjoying digital astrophotography for a while now and
recently moved from my trusty Nikon 995 to a Canon 20D. The 20D is a great camera but being a DSLR , it has a problem.
I am now at odds on how to remove the stubborn bits that can cling so solidly to the sensor. Using Canon's
recommended sensor cleaning technique fails to dislodge many of the particles and f22
whitescreen shots confirm that I cannot blow them away and I am accumulating them. It appears my Canon and I have an
Achilles heal. UGH!
- Given that lens changes etc are a frequent occurrence when using these cameras with a variety of telescopes etc, these " dust bunnies"
start to severely effect the quality of astrophoto's shot at the envelope of the camera.
- Olympus E-series, newer Canon, Sony and Pentax cameras have inbuilt ultrasonic dirt removal
- but seems only the Olympus is effective:
- other cameras need
- take preventive action:
- naturally it's best to avoid the contamination in the first place,
and you will doubtlessly become much more fastidious in your
lens-changing practices, once you have suffered through this!
- avoid changing lens in dusty or windy environments
- Placing charged objects (brushes blown by
air, for example, in contact with even the glass of the filter in
front of the chip can zap pixels and kill them.
- Evidence of foreign objects having been
used on the sensor may void any warranty repair issues.
- Nothing more than a blast of air from a
"Hurricane" style blower should be directed into the
mirror chamber and all precautions should be taken to ensure that
dust and moisture from the face and breath are not introduced into
the chamber. If matters do get out of hand it is most advisable to
return the camera to the qualified people to effect the maintainance.
- Always carry the camera with a lens
attached in preference to using just the body cap
- When changing lenses, turn the camera OFF
before removing a lens of body cap.
- Turn the camera face down before removing
the lens and during the replacement of the alternative lens.
- Dust and stuff will still get in. It will
be pumped in through lenses as they are zoomed back and forth.
Helical focus threads will transmit stuff. Loose lens flanges and
the 'imperfect' fit of body caps will only present an obstacle at
best - they will not perform as air-tight stoppers.
- regularly take an image of the blue sky, using f/22 and raw
mode then stretch the resulting image, and if there are any black spots,
then clean the sensor. F/22 makes all dust very sharp on the sensor. With f/2.8
it is harder to see the dust, but it does cause real effects even then.
- if you MUST try cleaning itself instead of using a professional then
you can consider the following but I don't recommend any:
- Rainer's cleaning method:
- use a mixture of 90% Isopropyl Alcohol 99.999% pure and 10% Ether. Ether is very volatile and helps the alcohol to evaporate without leaving any residues on the sensor filter.
- apply very little of this on the cleaning pad. The more you apply the
higher is the risk that it will leave drops.
- the most necessary thing is to have patience and wipe slowly over the
sensor, just as fast as the fluid evaporates.
- NB. I am not sure of the availability and wisdom of using ether!
- Be sure you either have a full battery or use the power cord as you don't want the shutter to close while you're working.
- Visible Dust's Sensor Brush - Canadian - available in Australia from
Borge's imaging but even a sterile version may mark the sensor!
- Copperhill's Sensorsweep - USA - available in Australia from http://www.qualitycamera.com.au/
- see also:
- most camera manufacturers produce their own underwater housings for their
- other options include:
- www.ewamarine.com/ -
waterproof cases for shooting photos
- www.ortlieb.com - Very fine
travel bags, waterproof, excellent quality, but it needs a little work packing the camera compared to normal bags.
- www.uwimaging.com - Light&Motion
uw housings - the housing has a bullet-proof reputation and a price tag 5x the cost of the camera it houses!
- see also:
Depth of field:
- see also: http://www.ph.tn.tudelft.nl/Courses/FIP/noframes/fip-_Noise.html
- digital noise in modern digital cameras is generally very low for short
exposures at low ISO settings.
- at long exposures digital noise due to thermal noise increases with the
length of the exposure but can be reduced by either cooling the sensor as
with specially designed astrophotography sensors or more practically, taking
a subsequent photo with the lens cap on ("dark frame") and
subtract this from the original image - many cameras now do automatic dark
frame noise reduction for you if you set it to do so when exposures exceed
approx. 1 sec. In addition, the camera and sensor design determines how much
noise there will be for a given ambient temperature of the sensor, so that
cameras such as the Canon digital SLR's have much lower thermal noise than
the cheaper consumer cameras.
- at high ISO settings, what you are doing is really applying an amplifier
to the sensor and thus any existing noise becomes more amplified. The amount
of this noise is largely related to the dynamic range of the sensor (see
above) which in turn is better with newer technology and with larger sensor
photon cell size. Thus full frame sensors can be expected to have lower
noise than smaller sensors with the same number of pixels and same
- depending on the camera, the noise has differing degrees of gray-scaled
noise and the generally more objectionable chromatic or coloured noise.
- other than dark frame subtraction, noise reduction processing in the
camera generally is a trade off between noise and image sharpness.
- note, in addition to noise there are also digital artefacts such as moire
and blooming (occurs when a cell is filled and photons spill over into
adjacent cells, a potentially big problem in astrophotography especially)
- also, "noise" can be introduced by malfunctioning sensor sites -
dead & stuck pixels can usually be eliminated by using the camera's
pixel mapping feature.
- dead pixels are due to a totally not working photo site and
result in black pixels
- stuck pixels are photo sites that are always "on" and
produce a white pixel.
- hot pixels are photo sites that given an increasingly light
response with longer exposures even if no light is hitting them in a
more exaggerated manner than applies to normal photo sites and thermal
- source types of digital noise:
- photon noise:
- photons in light do not hit the sensor in a constant stream but
obey the laws og quantum mechanics and thus the average photons
detected per time period obey a Poisson distribution resulting in
the signal to noise ratio being proportional to the log of the
(photon intensity x exposure time).
- thermal noise:
- electrons can be freed from the sensor itself as part of thermal
vibration and these can be recorded by the photon cell just like
- this noise also is of Poisson distribution and is proportion to
the temperature of the sensor and exposure time.
- as mentioned above the average noise can be reduced by subtracting
the "dark current" but this still leaves a reduced dynamic
range due to the standard deviation of this noise.
- on-chip readout noise:
- this is due to the process of reading the signal from the sensor
and relates to the electronics utilised in the sensor
- this can become evident particularly when the light levels are
very low and is a particular problem in astrophotography
- KTC noise:
- this is noise associated with the gate capacitor of the sensor
& is proportional to the square root of the absolute temperature
but can be eliminated with proper design.
- amplifier noise:
- this is additive noise of a Gaussian distribution and increases
with the degree of amplification, hence tends to be more pronounced
in the blue channel as this usually requires more amplification than
the red or green channels, and also with higher ISO settings.
- quantization noise:
- this is noise introduced by the analogue to digital conversion
step and depends on the maximum possible value of the digital
output, the higher it is the better the signal to noise ratio. This
is usually only a small component of the noise.
- see macro
- using an achromatic triplet - a technique used by Jens Birch on the
- "Inside certain SLR zoom lenses are built around a so called achromatic triplet that has extremely good colour correcting and
imaging properties and at the same time acts as a very strong magnifier.
I (and many others) have bought second hand Sigma Zoom-Master 35-70mm lenses and dis-assembled them to get out the triplet. It can then
be mounted in front of the C5050 lens to produce macros like this one: http://myolympus.org/document.php?id=405
- I don't know of anyone who has made it with the C5060. As it has a retracting lens upon zooming, the triplet will have to be attached to
the lens barrel (as opposed to the C5050 which can use a fixed length lens tube).
- With such high magnifications, you need to use f/8 and hence also need a flash. The on-board flash is ideal since it has TTL-
functionality but it will not reach the subject because it is just 20mm from the lens. In that case, you can make a hole in the bottom
of a white styrofoam cup, place it around the lens and use it as a
diffuser for the on-board flash."
Backing up images:
- how much effective telephoto effect do you get:
- this is proportional to the horizontal number of pixels on the
sensor (ie. the square root of total number of pixels) and the
maximum focal length in 35mm equivalence
- perhaps the easiest way to understand this is to determine how
many pixels would cover the diameter of a full moon which is approx.
0.5 degrees - the more the better:
- number pixels = diameter of moon in degrees * (number of
pixels horizontally) / FOV in degrees (horiz))
- Canon S30 = 2048 pixels with equiv. 105mm focal length
= 52 pixels
- Canon S50 = 2592 pixels with 105mm = 66 pixels
- Canon S70 = 3072 pixels with 100mm = 75 pixels
- Olympus C5050 = 2560 pixels with 105mm = 65 pixels
- Olympus C8080 = 3264 with 140mm = 111 pixels (155 pixels
with 1.4x teleconverter)
- Olympus E100RS = 1368 pixels with 380mm = 126 pixels
- Panasonic FZ20 = 2560 pixels with 432mm = 268 pixels
- Nikon Coolpix 8800 = 3264 with 350mm = 278 pixels
- Panasonic FZ30 = 3264 pixels with 420mm = 333 pixels
- digital SLR's depends on lens used
- Canon 350D 8mp dSLR 3456 pixels on a 1000mm telescope
at prime focus with 1.6x crop factor = 1342 pixels
- Olympus E500 8mp dSLR 3264 pixels on a 1000mm
telescope at prime focus with 2x crop factor = 1584
- another example is Jupiter at opposition which has a diameter of
~48 arc secs which is 1/38th size of the moon:
- 12mp FourThirds sensor (4000x3000 pixels) with 2x
teleconverter and 10" f/5.6 telescope (~5700mm focal length
in 35mm terms) = 124 pixels (moon would be 4650 pixels)
- let's imagine we have a 2Gb CF card in our camera and have just filled it
up and need to back up those images so we can empty the card and continue
- 1st need to get images from CF card to our PC or laptop:
- copying images directly from camera using USB 1.1 (eg. most Olympus
- remove CF card from camera and connect to PC using a USB 2.0 card
- copying images directly from camera using USB 2.0 (eg. most new
- now its preferable to ensure you have at least 2 copies at all times,
so we now have to back those up from the PC to another storage device:
- 2nd hard disk drive in the PC/laptop (but this is still a risk - eg.
your laptop may get stolen):
- USB 2.0 powered 2.5" hard disk drive:
- my one transfers images at about 11.7Mb/s thus should take about
- USB 2.0 3.5" hard disk drive:
- USB 2.0 3.5" hard disk drive attached to a storage router on a
- via 54mbps wireless from laptop:
- on my system, this takes ~1Mb/sec = approx. 30min
- via direct ethernet 10/100 cable connection to router:
- ethernet network storage 3.5" hard disk drive attached to a storage router on a
- via 54mbps wireless from laptop:
- on my system, this takes ~1.6Mb/sec = approx. 21min
- via direct ethernet 10/100 cable connection to router:
- on my system, this takes ~3.2Mb/sec = approx. 10min
- burn to DVD:
- single speed will take about 60min, 8x speed should thus take
Scanning images and image manipulation:
- in summary, you will need:
- 75-100dpi for scanning an image to display on computer
- 300dpi for scanning an image and printing same size (ie.
like a photocopier)
- 1200-3000dpi for scanning negatives or slides
- as much dynamic range as possible
- infrared ICE detector to remove dust and scratches from
images (but does not work with Kodachrome or silver halide
- flatbed scanners do not usually give as good true
resolution, shadow detail or contrast as a good dedicated
film scanner, although the Epson V750 and V700 scanners do a
pretty good job
- ability to scan medium format film as well as 35mm:
- Nikon Coolscan 9000 film scanner
- Minolta Multi Pro film scanner with scanhancer
V750 Pro Scanner flat bed scanner - only ~$US799 not
quite as good shadow detail as the Coolscan but cheaper.
- Epson V700 Scanner - almost as good quality as the
V750 and cheaper but you don't get full versions of the
excellent Silverfast software
- ability to wet mount if wanting to scan Kodachrome or
silver halide B&W film.
- eg. Epson
V750 Pro Scanner - but wet mounting takes
practice to do well and may not be worth it for 35mm.
- apparently can wet mount using the Nikon Coolscan 9000
- ability to scan 35mm film only:
- good scanner software:
Highly regarded inexpensive scanner software which works
on most film scanners.
Scanning software. More professional, flexible and
expensive than VueScan.
- for fine art results, particularly silver halide B&W film
where ICE technology does not work, you will probably need to resort
to wet-mounted film:
- pseudo-wet-mount scanning:
- "smart" diffusers which mimic effect of wet
for the discontinued Minolta DImage Scan Multi Pro film
- Imacon Flextight
- wet-mount film on flat bed scanners:
- wet-mount film on drum scanners:
- online tutorials:
Digital camera workflow
for professional output:
- shoot in RAW mode to ensure maximum use of available dynamic range
- use ICC colour-managed environment:
- your cameras, operating system, software, and output devices all need
to be set up for ICC colour management.
- for printing, use Adobe RGB (1998) colour space which has a wider
gamut (sRGB clips some CMYK colours used in printing)
- for web use, use sRGB as this is the standard for most monitors and
the web is not ICC colour managed so waste file size by embedding ICC
- calibrate your monitor with a hardware device (not just human eye) to the
almost universal standard of D65 and Gamma 2.2
- hardware devices available from Gretag
Macbeth or ColorVision
- monitors should be recalibrated monthly and CRT monitors allowed to
warm up for 30min prior to use
- only do minimal sharpening as final unsharp sharpening should be done only
AFTER image is resized for the final print, and thus best done by the
- embed copyright & usage in the file via Photoshop File Info
- save files in the required format:
- for printing:
- do NOT convert to CYMK unless you know the device and its
requirements as CYMK is device-dependent
- eg. use 8 bit TIF uncompressed in Windows byte order or jpeg at level
12 compression, at 300ppi (dpi).
- for web use:
- provide a html or pdf README file including information such as colour
space used, copyright, usage information and disclaimers such as
virus-checking needs, any supplied prints are not contact proofs and are not
useful for assessing color but are just guides to content and that image
editing was done using a monitor to D65 standards and thus should be viewed
on such a monitor.
- burn onto a CD using ISO 9660
- see also: http://www.acmp.com.au/digitalguide.htm