Reversing the Inverse Square Law.
A great article on light and how it works in relationship to flash and distance from subject/background. The article also does a good job on describing f-stops, ISO and shutter speed and their relationships.
16 Saturday Jun 2012
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inReversing the Inverse Square Law.
A great article on light and how it works in relationship to flash and distance from subject/background. The article also does a good job on describing f-stops, ISO and shutter speed and their relationships.
12 Thursday Apr 2012
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in11 Wednesday Apr 2012
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in19 Sunday Feb 2012
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inA post about what focus stacking is and how it’s done from www.digital-photography-school.com written by Chen Wey Li
A guest post by Chen Wei Li from www.bythewei.com.
After weeks of preparation, i finally set out to the Singapore Botanical Gardens to nail the shot above using the technique called focus stacking.
Focus stacking is a technique used to increase depth of field in a shot with post production. This works especially well for shots using long lens and in this case, a macro lens. Let’s go back to some photography 101 here. There are three factors that will affect depth of field or ‘bokeh’:
1. Focal length. Essentially the longer your lens, the more shallow your depth of field is.
2. Distance to subject. The nearer you are to your subject, the shallower your depth of field is and it very much applies to macro lens.
3. Aperture settings. The more you open up the aperture of your lens, the resulting image has a shallower depth of field. This, however, does not matter as much where the photo above is concerned.
I am happy to say that the experiment above has been a great success!
A little more background story.
It all began on 15 May 2010, when i was making my usual walk around the Singapore Botanical Gardens to take photos. I spotted this interesting looking cactus and ran a few shots at it. When i came home and uploaded the photos, below what was i got:
I’m pretty pleased with the composition and stuff. But i hated the shallow depth of field and the resulting ‘bokeh’. Some might argue it helps to lead viewers eye to the core but i believe the cactus lines have done enough a job in that department (Go find out more on leading lines for composition if you are not sure what i am talking about). I wanted other parts of the photoraph to be focused as well.
I told myself surely i had to come back again to work on the same shot… But how?
Thankfully, i remembered a friend of mine who once mentioned the use of focus stacking for food photography.
So exactly how does focus stacking work you may ask. Well, focus stacking simply means taking multiple photos of the same subject, each with a different focused spot. This is followed by the use post-processing software like Adobe Photoshop CS4 to align the focused portion of each image into one final-and-focused image. It is a really simple technique that everyone can use on their photos.
In the mean time, here’s what I needed:
1. A very very very very steady tripod. I’m not referring to those free tripods that comes with your DSLR purchase. Technically it works but i can bet a million bucks these tripods will give you hell before anything else. In my case i used a Manfrotto 055XPROB and Manfrotto 410 junior gear head. Both are, in my honest opinion, a very hardcore combination in terms of stability, durability and precision.
2. A macro lens. To achieve my desired composition, i had to go really close. This means that even if i am shooting at f/8, the depth of field remains shallow. Not to say that other lens won’t work but you probably will have to crop the shot and risk losing overall image quality. In my case, I was using a Canon EF 50mm f/2.5 compact macro paired with a LED ring light (not particularly useful on a sunny day though)
3. Super precision matt focusing screen for manual focusing. Locking your camera on a tripod means you cannot move the camera (duh) and rely on your in-camera focus points to focus different parts of the image. Here, i used a Canon Es-S focusing screen and paired it with my 5D Classic. Awesome screen for manual focusing may i add.
4. A lot of patience. I spent no less than 30 minutes under the sun (where the cactus was conveniently situated at the time of the day) just to get the composition, the tripod positioning and lighting right.
5. Last but not least, you need a proper post processing software to handle focus stacking. Thankfully, Adobe CS4 has that feature
Ok moving on to the shooting part of focus stacking. The shot you see about actually consist of four different shots aligned and merged into one single shot, thanks to Adobe Photoshop CS4.
Now let’s look at the four photos, notice how each of them is focusing at a different spot:
Hopefully by now, you get the drift. Basically i’m taking the focused part of each photo and merging into one sharp and focus shot.
Now with the four photos, here’s what you need to do with CS4:
See! It’s that simple.
Do go out and have some fun with focus stacking. Remember, a sturdy tripod really helps to make life easier here
PS: I stumbled upon this online discussion where people are calling focusing stacking the new HDR. Technically, they are right. HDR requires taking several bracketed shots and merged them into one shot while focus stacking required several (and differently) focused shots of the same subject and merge into one. Some of them also correctly pointed out that people are going overuse this technique just like HDR. Well, let’s just leave this topic for another day shall we?
About the Author: Chen Wei Li is a freelance photographer based in Singapore and is nominated for the Top Photography Blogger in Singapore Award. His portfolio can be viewed at www.bythewei.com. He can also be found on Twitter as @bythewei
Read more: http://www.digital-photography-school.com/an-introduction-to-focus-stacking#ixzz1mq1aHhzE
15 Wednesday Feb 2012
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inBY Stella Violano on Tue February 14th, 2012depixtions exhibitexhibitiPhone as a Cameraiphoneography
All iPhoneography buffs take note! Orange Studio in Orlando, Florida has announced an exciting upcoming exhibit featuring photographs exclusively taken using smartphones and iDevices. The exhibit, entitled Depixtions, is free and open to anyone wishing to submit their iDevice photos.
Images must be submitted by Feb. 17 via the online submission form. Images chosen to be exhibited will be available for sale as prints. All the proceeds will benefit the charity New Hope For Kids, which helps children who are grieving the loss of a loved one or who are battling a life threatening illness.
The entry guidelines are simple, as stated on the Depixtions website:
- One entry per person
- The photo must be taken by the registrant. Images found to be copyrighted or from another person will be rejected from the show
- ALL submissions MUST be taken with your camera phone. You can use any phone application such as Instagram, Hipstamatic, etc. to ‘process’ your image if you’d like. Uploaded images taken with an SLR or regular cameras that are just filtered using apps will NOT be accepted.
- Photos must be in a square format with a minimum resolution of 600 x 600 at 72dpi and saved as a jpeg (.jpg). File sizes should not exceed 1MB.
- Images will be printed on 4″ x 4″ photo paper for use and display in the show.
- By submitting your entry, you grant us permission to print, display and sell the image for use in the show and any collateral.
The images that have been rolling in so far are a collective look at everyday life which should make the exhibit a fascinating event. So hurry up and enter! The deadline is just a few days away.
The Depixtions Exhibit opens on Saturday, Mar. 10 at 7:00 a.m. and is open to the public at the Orange Gallery located at 1121 N. Mills Ave., Orlando, FL.
Do you need some inspiration to get started? Check out our iPhoneography Applist. Do you have an image that would be perfect but is too dark or otherwise needs correction? Check out our review of PhotoForge2. If you want to plan an amazing shot that will blow away the competition you may want to look into The Wedding Photographer app.
So, how many AppAdvice readers are going to enter? If you do enter please post in the comments and add your entry for us to enjoy. If enough readers do it I will pester the AppAdvice Staff to join in too! Chat it up in the comments.
10 Friday Feb 2012
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inPhotoshop training in Tampa hosted by Scott Kelby on March 13th – Photoshop Guru
27 Friday Jan 2012
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inByR Butler | Published Oct 18, 2011 | Technology |
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The Canon EOS-1D X is the latest in the company’s professional range of DSLRs. Its job is to replace both the sports-orientated 1D series and the high-resolution, studio-focused 1DS range of cameras. As is usual for upgrades in this class of camera, the changes are incremental and subtle but aim to raise the bar of what is possible.
The biggest specification change to the 1D X is its new sensor – an 18MP full-frame CMOS chip capable of shooting at 12 frames per second. This represents a big change over the 1D Mk IV (it represents a move away from the smaller APS-H format that Canon has previously used in its sports cameras), and a decrease in pixel count compared to the 1DS series. However, as Rick Berk, Technical Specialist in Canon USA’s Pro Engineering and Solutions Division says: ‘there’s more to image quality than just resolution.’
The move from APS-H up to full-frame is enabled by a sensor with faster data readout explains Chuck Westfall, Technical Advisor in Canon USA’s Pro Engineering and Solutions Division: ‘The new sensor has 16-channel, dual line readout, compared to 8-channel, single line designs in the previous generation of chips.’ This lets the company offer a large sensor (and the low-light capability that brings) for 1DS users, with the fast capture speeds that current 1D Mk IV users need. ‘It’s clear the time has come for the 1DX to replace the whole 1D series,’ says Westfall.
Under the skin, the big change is the more sophisticated metering sensor. A move from the 1D Mk IV’s sensor to a new 100,000 pixel unit affords the camera a much better understanding of the scene and this information is fed into the camera’s autofocus system to improve the quality of its AF tracking. This isn’t a new idea (Nikon’s sports cameras have done something similar for several generations), but it’s a sensible way of improving what’s already an impressive system.
The other big change to autofocus is simpler configuration. The 1D X does away with the complex inter-related network of custom settings that defined AF behavior in previous models, instead offering six presets for different shooting situations (see table below). Each of these can be adjusted for ‘Tracking sensitivity’ (which defines how doggedly the camera attempts to stick with the originally chosen target or whether it will re-focus on nearer subjects if they cross in front of the target), ‘Acceleration/Deceleration tracking’ and AF point auto selection (how readily the camera should move off the selected AF point).
Westfall acknowledges the complexity of the previous systems could prevent users getting the most out of previous cameras: ‘A common response to the 1D III and 1D IV was that people loved the idea of a high spec AF system but they wanted an easier way of get the most out of it. The improvements from the 1D III to the 1D IV were substantial but also incremental – to make a bigger step forward this time we needed to start from scratch.’
Canon EOS-1D X AF mode presets, defined by subject behavior: | |
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1. Versatile multi purpose | 4. Subjects that accelerate or decelerate quickly |
2. Continue shooting, ignore obstructions | 5. Erratic Subject Movement |
3. Instantly refocus suddenly with obstructions | 6. Subjects that change speed and move erratically |
In addition to making the system more accessible, the 1D X has the first entirely new AF arrangement since the launch of the (film-era) EOS 3 in 1998. The new 61-point AF sensor has 21 cross type AF points at the center, which are sensitive enough to be used with lenses with maximum apertures as slow as F5.6. The central five of those points also have diagonal AF elements that are active with F2.8-and-faster lenses. All other AF points are sensitive to horizontal detail with lenses faster than F5.6, while 20 of these (in two flanks towards the outer edges of the sensor), act as cross-type points with F4 maximum aperture lenses or faster.
As with the EOS 7D, the AF point selection can be narrowed-down to a series of sub-sets of local AF points. It’s also possible to adjust what factors are considered during AF tracking: AF info only, AF and color information or AF and face detection information.
When asked to for the biggest improvement in the new camera, Westfall stresses that every aspect of the camera has been re-assessed but finally concludes: ‘If you had to highlight just one thing, I’d say the sensor. It’s a new level for us in terms of image quality.’
‘There’s a couple of things that we consider when we think about IQ: number one on this sensor is noise. It’s clear the noise level is better than in the 1D Mk IV or the 1DS III. The pixel size is larger than in the 1DS III or 5D Mark II (6.95 microns, versus 6.4) and the difference is even more striking compared to the 5.7 micron pixels in the 1D Mark IV. That helps us in terms of light capturing ability and increases the signal to noise ratio. In turn, that does nothing but help the dynamic range of the camera.’
And its this improvement in image quality that Westfall believes will make the 1D X appeal to 1DS as well as 1D users. ‘I think the factor that’s going to make that a reality is the noise level is better than anything we’ve seen before. With cleaner images, people are going to feel much more comfortable up-rezing an image. Not many people need a 21MP file to begin with, so they’re going to love the IQ of this camera and the quality’s good enough that those people who do need those huge files will find the images clean enough to use them.’
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The body of the 1D X closely resembles previous 1D cameras, but close examination reveals a series of changes. The most significant is perhaps the addition of a second joystick on the rear of the camera, to ensure all functions remain available when using the portrait orientation grip. The camera also features twin buttons next to the lens, in either orientation. These are customizable, allowing you to access features such as the electronic level gauge or jump to registered AF point.
Beyond this, the camera gains a direct live view button, a ‘Q’ button to jump to the ‘Quick’ function menu, and has had its flash exposure lock button re-dedicated as a customizable function button.
As you’d expect, the camera’s processing has received a considerable refresh, Westfall explains: ‘You’ve got dual Digic 5+ processors, which our engineers are telling us are 17x faster than the Digic 4s used in the existing models.’ In addition, the metering sensor, given its added complexity and the need to interpret its output to feed into the AF system, gets its own Digic 4 processor.
This processing power allows the camera to conduct a wider range of lens corrections. In addition to the vignetting correction that could be conducted by the 1D Mark IV, lens profiles can be uploaded using EOS utility and the camera will correct for geometric distortion and chromatic aberration (both lateral and axial) in real-time. These corrections are all optional and can be engaged separately.
Another benefit of more processing power, combined with an improved sensor is an expansion of ISO range, says Westfall: ‘The ISO range on this camera, just the standard range, goes from 12,800 on the 1D Mark IV and 1600 on the 1DS Mark III, up to 51,200. And this can be expanded up to 204,800 – that’s going to be an enabler of all sorts of new possibilities for a lot of people.’
The final processing option is the ability to shoot multiple exposure images. Four combination methods are available, which can be used to create composite images either from consecutive shots or from an existing Raw file and an additional exposure.
The faster sensor and greater processing power are combined with a new carbon fibre shutter and revised mirror mechanism to allow 12 frame per second continuous shooting. The camera can shoot at 14fps if you’re happy to lock the mirror up (and hence lock focus), and capture only JPEG images. The shutter has a rated lifespan of 400,000 cycles (a 30% improvement on before, despite the additional demands of the faster continuous shooting). The company also says it should be more accurate at high shutter speeds. It also offers an X-sync speed up to 1/250th of a second.
At first, the move from 10 to 12 frames per second doesn’t sound terribly impressive – until you remember that the camera is now based around a larger sensor, so there’s a much bigger mirror to move. Westfall is keen to stress this: ‘The high-speed rate is greatly improved. Our full-frame cameras up until now have only been able to offer up to five frames per second, whereas this can shoot at 12fps, or 14 if you’re willing to shoot JPEG. The 1D X means you can have full-frame quality and high speed.’
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The EOS-1D X gains twin customizable buttons next to its lens mount – one set for each orientation |
Of course it’s no longer enough for a camera at this level to just be able to shoot stills, and the EOS-1D X is Canon’s most capable movie shooter yet. Although the headline spec (1080p at 30, 25 or 24 frames per second), isn’t exactly groundbreaking, it’s clear that Canon has had movie shooters in mind.
The 1D X offers two compression options, including ‘All-I,’ a very low compression format that offers high image quality and editability but at the cost of immense files (a 16Gb card will hold around 6 minutes of footage). The alternative is a more standard IPB compression that takes up around 1/12th of the space. To prevent these large files limiting the camera, the 1D X is the first Canon to be able to split a single piece of footage into multiple files, overcoming the 4Gb limit of the card file system, and allowing videos of up to 29 minutes, 59 seconds to be recorded.
In addition the camera can keep track of how long it has been recording, using standard timecoding methods. There’s also greater-than-ever control over the microphone input volume, with 64 manually selectable levels, auto and a wind-cut filter. It’s also possible to mute sound recording while shooting.
Westfall believes the 1D X has the features that pro shooters will want: ‘I think people are looking for a balance between cost and performance – the cameras offering 60P at the kind of bit rates that we can offer tend to be in a higher price bracket. And we can offer 720p at 60 frames per second,’ he says.
‘People we’re dealing with are tending towards using 24 – to match the filmic look. There are cameras offering 60P in the consumer market but they haven’t got the bit rate we’re offereing. Many of them are limited to less than 30mbps while we’re bumping up against 50. This is a clear difference – we think this product keeps moving the ball forward. With this product the focus was improving the compression. The other thing people were requesting was the ability to shoot longer clips and on this model we can shoot for up to nearly 30 minutes.’
‘Within this range of products we offer, this is going to assume the flagship postition,’ he says: ‘It will be the most desirable product for people wanting movie shooting in a DSLR.’
Beyond the big changes is a move to twin CF cards. As before these can either be set to duplicate images onto both cards or overflow from one to the next. You don’t have the option of separately storing movies and stills, however. The upgrades to the camera also extend to a revised dust-reduction system for the sensor. The wave-motion of the shake system is being called 2nd generation dust prevention by Canon.
Another change to the 1D X’s storage is the addition of an Ethernet 1000 Base-T network port. This allows faster transfer speeds and the use of longer cables (the limit is 100m, rather than around 3.5m for USB).
The final significant change is another gain from the EOS 7D – an electronic overlay on the viewfinder, allowing AF points and the level gauge to be shown in the viewfinder. Other than that, the camera retains essentially the same viewfinder specs as the 1DS Mark III – a huge 0.76x, 100% coverage pentaprism that 1DS users will be familiar with and 1D series owners will really appreciate after years of using cropped APS-H finders.
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The views and opinions expressed in this article are those of the author and do not necessarily reflect the views and opinions held by dpreview.com or any affiliated companies.
23 Monday Jan 2012
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inGoing to my first meeting for photographers on February 2nd. Does anyone have any experience with this club or any other clubs in the Tampa Bay Area?
http://www.photographicartsociety.org/html/about-the-photographic-art-society.html
22 Sunday Jan 2012
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inI will use this blog to showcase some of my work and share some of my ideas. Please check back as I will be adding more blogs shortly.