March 2011Page 1 Of 1  


Well done, medium rare, or RAW?

Posted On 2011-03-25 , 7:51 AM

Most modern cameras, and certainly all DSLR's are capable of shooting RAW, but what does it mean? and importantly what can it do for your photography?

Well in short RAW is literally the data as captured by the sensor with no in camera processing and no compression. This doesn’t really explain why its good though - lets split it into those two areas for the good stuff:
RAW options image


No in camera processing: most cameras are capable of processing all jpegs to be for lack of a better term "print ready", some even offer a range of advanced features such as artistic filters(i.e. pinhole camera effect, sepia, various color tints etc) and in camera HDR - so why would you not want to make use of this? Well the simple answer is: Control. Its very hard to get rid of in-camera processing such as sharpening or noise reduction yet there are many photo editing software packages that do both better than any camera. Also the camera processing assume each picture is the same i.e. a snapshot, so it would give the same treatment to a portrait as a landscape or a night time shot of the stars in the sky...

Red sunset with artefacts No compression - without getting too 'techy' about this basically each picture takes up some memory on your memory card, by using compression you can reduce this amount of memory per picture and get more pictures on a single memory card, for this reason the standard picture format is a jpeg(.jpg) which is actually a compression standard not a pictorial one. However the last part of that is bad for taking good pictures, memory efficiency may lump all the colours in your beautiful sunset into just 2-3 shades(the pic on the left has been repeatedly and heavily compressed). Additionally when opening, editing, saving, opening, saving etc the jpeg compresses each time which can lead to a loss of detail over time - for this reason many online tutorials recommend making a copy of the jpeg to be edited so that you always have a master file that has lost the least quality from this compression.


The other side of file formats is bit depth, essentially the number of tones available is greater in Raw files(14bit typically, although 12 and 16bit capture devices are used) versus Jpegs(8bit) - users of film will understand this as a greater 'exposure latitude' which is essentially you can get the exposure not quite right and still recover 'lost' detail by using software to process RAW files.


Now as mentioned above RAW files do require software to process them and this is often seen as a reason for not using RAW. However processing is pretty easy in most software as just a series of sliders and as these allow you to vary the exposure, colours, contrast, sharpening, noise reduction etc your actually doing the kind of processing something like photoshop/elements would normally be used for anyway. I will go into more detail about software & processing in a future blog.
RAW sliders Adobe CameraRAW


RAW toplate of 7D image Now of course having larger files when shooting as RAW does mean not being able to take quite as many pictures, but I would argue that these days memory is so cheap its not really a great excuse to shoot in jpeg only - as an example a Canon 7D/60D/Rebel T2i/Rebel T3i captures 18 megapixel pictures, which are ~7mb as jpegs, or ~25mb each as RAW, this means that you get approx 40 RAW shots per 1gb of memory, so a commonplace 4gb memory card gives you "only" 160 shots. Admittedly this is versus around 500jpegs on the same card but any given photoshoot is not likely to run short due to 'only 160 pictures' especially given that one of the greatest strengths of digital photography is being able to review and delete poor quality pictures on camera.





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Butterflies and hurricanes

Posted On 2011-03-18 , 10:35 AM

First a slight correction, my Last blog entry mentioned a Lunar perigree, this should read "perigee".

Don’t forget tomorrow is the best day to capture the full moon at the closest it has been to earth for many years as it reaches its 'Lunar Perigee' and will be a full moon tomorrow(at the time of writing) on the 19th march.

However since then I have been looking for more info on the subject, I first found out about by reading an article on Yahoo news: http://news.yahoo.com/s/space/20110310/sc_space/willmarch19supermoontriggernaturaldisasters

Having read the above article I can't help but wonder if the proximity of the moon has actually had some influence on the recent terrible earthquake and tsunami that has hit Japan - after all the moon isn’t suddenly going to be a lot closer on the 19th, its been getting closer for a while it just happens that on the 19th it’s the closest point and a full moon at the same time which is pretty rare.
 
comma butterfly image 1



Moon image 1
I know that article says there is no link between natural disasters and the proximity of the moon, and that studies find the moon has little effect on such things, but I cant help but think there may be some link simply due to the great coincidence of the timing(even if its only the equivalent of the proverbial "straw that broke the camels back").

There is very little I can say about the disaster in Japan that has not already been said many times on new channels/websites, but instead it might be better to suggest something that can be done, there are many charitable organisations who will be able to help with the disaster in Japan and other regions and whilst Canon Rebel Camera Accessories is not sponsored or affiliated in any way with any charitable organisation I would recommend giving to one of the larger charities(I suggest this only because larger charitable organisations have more power to mobilise people and supplies to help out):


Relief International:
http://www.ri.org/newsroom/news-article.php?ID=10

American Red cross:
http://newsroom.redcross.org/2011/03/16/disaster-update-earthquake-in-japan-2/

British Red Cross(for donations in GBP[£]): http://www.redcross.org.uk/japantsunami/?approachcode=68816_googlePAD5JpTs&gclid=CIDE57-B1qcCFdFX4Qodij5x9g

Save the Children:
http://www.savethechildren.org.uk/en/japan-earthquake-and-tsunami-appeal.htm?sourcecode=A11038054

Salvation Army:
https://donate.salvationarmyusa.org/site/c.tvI3IeNUJsE/b.5760419/k.2CB3/Donate_Now/apps/ka/sd/donor.asp?c=tvI3IeNUJsE&b=5760419&en=5oIzGIMjG4LIKSOmH3KFKPMxEoKRLXOxEdKFLRNAIkLRK1NIG

International Medical Corps:
http://www.internationalmedicalcorps.org/Page.aspx?pid=1970

US fund for UNICEF:
http://www.unicefusa.org/news/releases/unicef-humanitarian-aid-japan-earthquake-tsunami.html

There are more organisations this is just a few, donating to any as a one off or monthly contribution can help immensely.




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Lunar Perigree

Posted On 2011-03-11 , 7:34 AM

Saturday the 19th of March may not be a well known date for most however this year it marks a rare photographic opportunity - or specifically the evening does.


The moon will be the closest it has been to earth for a good many years as it reaches part of its cycle called the Lunar Perigree, meaning it will appear larger and brighter than ever before, and on the 19th should be a full moon. The moon may appear in the night sky up to 14% larger and up to 30% brighter than normal (depending on where you are in the world) This is a great opportunity to try taking photographs of the lunar surface.

Now I'm sure most of us have at some point tried to take a picture of the moon with a regular kit lens and found it to be tiny white dot with no details, so surely you need massive telescopes and such to capture the moon?
Small overexposed moon








Moon shot small Actually you might be surprised by the kit you need to capture the moon, You can get quite good results with a long telephoto lens, or a fairly normal telephoto lens with a teleconverter. If your budget stretches you can of course buy very long zooms such as the Sigma's 150-500mm OS, or Tamrons 200-500mm, but you can get good results by using a teleconverter such as a Kenro 2x teleconverter plus a budget 70-300mm lens or similar. A good option would be a Canon 75-300mm f/4-5.6 USM III plus a Kenro MC7 DGX 2x Canon AF teleconverter, giving you the 35mm film equivalent focal length of 960mm at the long end; sadly you will lose two stops of aperture due to the teleconverter so at the long end you'll be looking at 960mm at f/11 this means two things, such a long focal length will need a tripod to keep the picture steady, but also the auto-focus system wont function(most consumer DSLR's wont autofocus below f/5.6, pro bodies will focus down to f/8 but even this isn’t good enough for AF at f/11) so you have to use manual focus however all is not lost:

most live view equipped Canons allow you to magnify the view in live view by pressing the + magnifying glass button(usually blue coloured), and if you use a tripod you can take your time to focus exactly right zoomed in. Just be aware that the moon does move through the sky while you are taking pictures so you may need to zoom out from time to time and re-compose to avoid the moon being clipped at the edges of the frame.

In terms of exposure the Moon is actually the brightest object in the night sky, and this often takes people by surprise, if you frame the moon using evaluative metering and the moon is not most of the picture then you will have a bright white circle on a black background, to get around this use spot or centre-weighted metering, or if your not sure how turn the dial to Tv (time value, S on other makes) and turn the shutter speed down until you get a dark enough picture that shows the cratered surface of the moon in detail.

The size and brightness of the moon will vary greatly according to where you are viewing it from but starter settings should be around f/11 1/125thsec @ ISO200, if its too bright you can stop down the aperture to f16 or f22, or else reduce the shutter speed to 1/250th sec. If its too dark you can open up the aperture to f8 or f5.6(assuming a regular telephoto lens, for the 75-300 + teleconverter option try upping the ISO setting by a stop or two to ISO 400 or 800) or lengthen the shutter speed to 1/60th sec although much slower than this is not recommended as the natural movement of the moon may cause problems.

Have fun shooting the moon!
Man snaps moon






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Batteries

Posted On 2011-03-04 , 9:33 AM

Don’t run out of juice…keep spares! Particularly if you have more than one camera and are therefore not charging the same battery/camera every single week. I admit this might be wiser approaching winter when the cold weather can lead to battery problems, but why wait? No battery life means no pictures!

Its easy to be caught out - I have often checked equipment that says fully charged/max battery when first switched on only to find after taking 1-2 pictures its drops to less than 50% battery life. This is usually because the battery hasn’t been charged up recently but still makes a good initial voltage when switched on so it’s a good practice to get into to charge up a battery to top it up prior to any planned shoot. But what about unplanned photo's? wouldn’t it be a good idea to have a spare battery to hand or some kind of alternative?
 
7D battery LPE6

Buyers who are quite tech-savvy will notice that some camera models share battery packs, so for example a Canon EOS Rebel T1i shares a battery with the Rebel XSi, even if you have multiple camera bodies either due to upgrades or simply having obtained a second body for use in the field you can sometimes get away with sharing batteries between models - obviously this still works best if you have more batteries than just what came with each camera body.

In addition battery grips can be used - a useful accessory that attached to the underside of the camera and has an upright section that slide into the battery housing of your camera, this will usually hold 2x standard battery packs and many of the more recent models feature a tray(sometimes an optional extra at extra cost) that accepts regular AA batteries which can extend the life of your shoot well past the battery life of the standard battery pack. These also feature additional buttons so that the camera can be used on its side in "portait" format yet still have a shutter release in the usual place. The downside is of course extra weight and bulk - it makes the camera's shape more upright and much more alike that of pro cameras such as the Canon 1D mkIV, and these attachment battery grips aren’t the cheapest of accessories to buy, plus you need a secondary battery pack to make the fullest use of them
Battery Grip with two batteries



I mentioned cold weather, but what actually happens? Why wont my battery work just as well if its freezing outside? Well this is a case of basic physics at work - essentially all that happens is as the temperatures drop the conducting materials inside the camera and battery get colder, with some materials this means they become a lot more efficient at conducting electricity, if its cold enough this goes beyond the remit of what the batteries were engineered to work in and therefore they start using more power for every operation of the camera, meaning that you can lose battery life very quickly. Its also the reason why as yet only mechanical film cameras have made it to the north pole and still work. So in cold temperatures say under about 10C/50F, and certainly below freezing(0C/32F) you may experience battery trouble. Ideally you should keep spare batteries about your person preferably in an inside coat pocket near your body so that it stays warm, this way when you swap batteries in cold temps it will take some time for the spare batteries to cool down and you should get good battery life until they get cold enough to start draining faster.




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