All posts by Ganz Ramalingam

Field of View Crop Factor

Source : http://www.the-digital-picture.com/canon-lenses/field-of-view-crop-factor.aspx

Field of View Crop Factor (Focal Length Multiplier)

With the advent of Digital SLR Camera Bodies, the term Field of View Crop Factor has come into our world. The source of this term is the smaller-than-35mm sensor present in many of Canon and other manufacturers’ DSLR sensors. Canon’s EF Lenses still focus the image on the same plane as before, but sensors smaller than 35mm sensors do not capture the entire image. Thus, the image is “cropped”. The Field of View Crop Factor (FOVCF from here on) refers to the amount of the image that is cropped.

Here is a diagram illustrating the size differences between Canon’s currently available DSLR sensors (I personally don’t expect to see any new sizes introduced by Canon in the near future).

Field of View Crop Factor Comparison

The above image lists the FOVCF and the approximate size of the sensors. The inner rectangle, the 1.6x FOVCF, also has a shaded area around it to indicate the 95%-of-final-image viewfinder found on most of the Canon EOS DSLR camera bodies with this sensor size.

When looking through the viewfinder on Canon’s DSLR cameras, the sensor size is immediately obvious as the viewfinder size generally reflects the sensor size. A full-frame viewfinder is large – and very nice. The 1.6x viewfinders are smaller – nice, but smaller and generally showing only 95% of the final image. One issue with the 95% viewfinder is that you can get objects in your picture that you don’t want – and can’t see during the shot. This is generally not a big deal, but certainly a difference. Canon’s full-frame 1-Series bodies generally have 100% viewfinders. Although it is a full-frame body, the Canon EOS 5D Digital SLR has a 96% viewfinder.

I should also note that what is seen in the viewfinder is also affected by viewfinder magnification which varies across Canon’s EOS line. Viewfinder magnification has no affect on the final image.

The following table illustrates sensor and viewfinder differences across the current and recentCanon Digital SLR models.

Model FOVCF Sensor Pixel Size Pixels/Megapixels Viewfinder DLA*
Canon PowerShot G9 4.6x 7.6 x 5.7mm 1.9µm 4000 x 3000 12.1
Canon EOS Rebel T3i / 600D 1.6x 22.3 x 14.9mm 4.3µm 5184 x 3456 18.0 .85x 95% f/6.8
Canon EOS Rebel T2i / 550D 1.6x 22.3 x 14.9mm 4.3µm 5184 x 3456 18.0 .87x 95% f/6.8
Canon EOS Rebel T1i / 500D 1.6x 22.3 x 14.9mm 4.7µm 4752 x 3168 15.1 .87x 95% f/7.6
Canon EOS Rebel T3 / 1100D 1.6x 22.2 x 14.7mm 5.2µm 4272 x 2848 12.0 .85x 95% f/8.4
Canon EOS Rebel XSi / 450D 1.6x 22.2 x 14.8mm 5.2µm 4272 x 2848 12.2 .87x 95% f/8.4
Canon EOS Rebel XS / 1000D 1.6x 22.2 x 14.8mm 5.7µm 3888 x 2592 10.1 .81x 95% f/9.3
Canon EOS Rebel XTi / 400D 1.6x 22.2 x 14.8mm 5.7µm 3888 x 2592 10.1 .80x 95% f/9.3
Canon EOS Rebel XT / 350D 1.6x 22.2 x 14.8mm 6.4µm 3456 x 2304 8.0 .80x 95% f/10.4
Canon EOS 300D Digital Rebel 1.6x 22.7 x 15.1mm 7.4µm 3088 x 2056 6.3 .80x 95% f/11.8
Canon EOS 60D 1.6x 22.3 x 14.9mm 4.3µm 5184 x 3456 18.0 .95x 96% f/6.8
Canon EOS 50D 1.6x 22.3 x 14.9mm 4.7µm 4752 x 3168 15.1 .95x 95% f/7.6
Canon EOS 40D 1.6x 22.2 x 14.8mm 5.7µm 3888 x 2592 10.1 .95x 95% f/9.3
Canon EOS 30D 1.6x 22.5 x 15.0mm 6.4µm 3504 x 2336 8.2 .90x 95% f/10.3
Canon EOS 20D 1.6x 22.5 x 15.0mm 6.4µm 3504 x 2336 8.2 .90x 95% f/10.3
Canon EOS 10D 1.6x 22.7 x 15.1mm 7.4µm 3088 x 2056 6.3 .88x 95% f/11.8
Canon EOS 7D 1.6x 22.3 x 14.9mm 4.3µm 5184 x 3456 18.0 1.0x 100% f/6.8
Canon EOS 5D Mark II 1.0x 36.0 x 24.0mm 6.4µm 5616 x 3744 21.1 .71x 98% f/10.3
Canon EOS 5D 1.0x 35.8 x 23.9mm 8.2µm 4368 x 2912 12.8 .71x 96% f/13.2
Canon EOS 1D Mark IV 1.3x 27.9 x 18.6mm 5.7µm 4896 x 3264 16.1 .76x 100% f/9.1
Canon EOS 1D Mark III 1.3x 28.1 x 18.7mm 7.2µm 3888 x 2592 10.1 .76x 100% f/11.4
Canon EOS 1D Mark II N 1.3x 28.7 x 19.1mm 8.2µm 3520 x 2336 8.2 .72x 100% f/12.7
Canon EOS 1D Mark II 1.3x 28.7 x 19.1mm 8.2µm 3520 x 2336 8.2 .72x 100% f/12.7
Canon EOS 1DS Mark III 1.0x 36.0 x 24.0mm 6.4µm 5632 x 3750 21.1 .76x 100% f/10.3
Canon EOS 1DS Mark II 1.0x 36.0 x 24.0mm 7.2µm 4992 x 3328 16.6 .70x 100% f/11.6


* DLA (Diffraction Limited Aperture) is the result of a mathematical formula that approximates the aperture where diffraction begins to visibly affect image sharpness at the pixel level. Diffraction at the DLA is only barely visible when viewed at full-size (100%, 1 pixel = 1 pixel) on a display or output to a very large print. As sensor pixel density increases, the narrowest aperture we can use to get perfectly pixel sharp images gets wider.

DLA does not mean that narrower apertures should not be used – it is simply the point where image sharpness begins to be compromised for increased DOF and longer exposures. And, higher resolution sensors generally continue to deliver more detail well beyond the DLA than lower resolution sensors – until the “Diffraction Cutoff Frequency” is reached (a much narrower aperture). The progression from sharp the soft is not an abrupt one – and the change from immediately prior models to new models is usually not dramatic. Check out this specificdiffraction comparison example using the ISO 12233 chart comparison tool. The mouseover feature will show you the degradation at f/11 compared to f/5.6.

The subject framing is significantly different between the various FOVCF DSLRs when using the same focal length lens and the same subject distance.

I’ll say it again – the subject framing is significantly different.

Focal Length Multiplier” is a not-exactly-correct-but-helpful term that many like to use to describe the Field of View Crop Factor. Although the physical focal length of a lens is not actually changed on a FOVCF camera, the subject framing certainly is. By multiplying the lens focal length (or focal length range) by the FOVCF, you get the full-frame focal length lens subject framing equivalent when used at the same distance. For example, if you are looking for similar framing that a 50mm lens (the classic “normal” lens) provides on a full-frame (1.0x crop factor) SLR body, you probably want a 35mm lens on your 1.6x FOVCF body. 35mm x 1.6 = similar framing to a 56mm lens on a full-frame camera body. This focal length is often referred to as the “Effective Focal Length”. The lens is still a 35mm lens, but your final image will only include a crop of the lens’ complete image.

What affect does the FOVCF have on lenses? None – physically. The lenses are the same and retain all of their same physical attributes. But, there are some differences in how these lenses are used that should be mentioned …

First, most lenses produce the highest quality image from near the center of their image circles. Distortion, softness (opposite of sharpness), vignetting … These issues often show up in the outside portion of the image circle. Since the FOVCF DSLRs utilize only the center portion of a Canon EF Lens, they often avoid a lens’ weaknesses. I say “Canon EF Lens” because Canon EF-S Lenses are made specifically for the 1.6x FOVCF DSLR bodies (but still require the same FOVCF to be applied as the standard Canon EF Lenses to get the equivalent focal length comparison). EF Lens hoods are designed for full-frame bodies.

Another difference has to do with Depth of Field (DOF). The acceptable DOF produced by a lens relates to the actual focal length, aperture setting, subject distance, circle of confusion and sensor size. While the size of the sensor affects DOF, the significant change from sensor size to sensor size is the distance from your subject required to get the same desired image framing. All other factors being equal, longer distance to the subject will result in greater acceptable DOF. So, as a generalization, using a higher FOVCF DSLR will yield more DOF in your similarly cropped pictures because you will be farther from the subject. Using a higher FOVCF will make it harder to blur the background and easier to keep/get the subject in focus. The amount of difference is about the same as the crop factor (1.3x, 1.6x). As focus distances approach infinity, this difference goes away. A good way to learn more about this topic is to plug your own numbers into the Depth of Field Calculator at DOFMaster.

I often hear wildlife photographers singing the praises of the high FOVCF (1.3x, 1.6x) DSLRs. They like that they can achieve tight subject framing from a longer distance – or with smaller, less expensive lenses. Using a Canon EF 500mm f/4 L IS Telephoto Lens on a 1.6x FOVCF DSLR yields the same subject framing as an 800mm f/4 IS lens on a full frame body. Adding a1.4x Extender to the kit results in a super-long 1120mm f/5.6 subject-framing-equivalent focal length lens. But, this is not quite all of the story. A 1.0x DSLR with a higher pixel density sensor than a 1.6x DSLR will be able to capture a subject larger (more detail in the picture) than the higher FOVCF DSLR – the 1.0x image would require cropping for the same subject framing, and I’m assuming equivalent individual pixel quality to make the comparison easy. This would be a good point to insert the fact that a higher pixel density sensor places higher demands on the lens being used. Any aberrations present become exaggerated.

Photographers who shoot at wide angles are the ones who dislike the high FOVCF DSLRs the most. Cropping is not an option if the subject is not in the frame. The introduction of the Canon EF-S 10-22mm USM Lens was the answer to this problem for many of these photographers who are using a EF-S lens compatible DSLRs.

A nice point about all of Canon’s DSLRs is that they maintain a 3:2 aspect ratio. A 4×6 will print uncropped, 5×7 and 8×10 prints will need to be cropped. There is no need to be concerned about which FOVCF DSLR was used to take the picture.

As of today, Canon uses APS-C 1.6x sensors in the consumer xx0D and prosumer x0D lines. Canon’s 1D line uses 1.3x sensors, and the 1Ds and 5D lines use 1.0x full frame sensors.

You may find Canon’s Full-Frame CMOS White Paper (1.1 MB .PDF file) informative as well.

I hope that wasn’t too confusing.

 

Rigging 101

http://www.rigging101.com/freestuff.htm

Javier Solsona (a.k.a. Goosh) is a wandered, a traveler, a “Citizen of the World”. He was born in Argentina and grew up in Patagonia. From an early age, he started doing graphics on his Commodore 64 at home, painstakingly painting pixel by pixel. Many years later still in front of a computer he got a B.Sc. in Computer Sciences from the University of Cape Town (UCT), South Africa. During his last year at university in 1995, he was introduced to Multimedia and 3D and there was no looking back ever since.After finishing his degree, he moved to Brazil where he carried on studying 3D animation on his spare time while taking part on various 3D courses. Later, he moved to London, UK where he worked for three years as a freelance graphic artist for various hi-tek companies including Cisco Systems.

He finally moved to Vancouver, BC where after working for a year as a creative director in a small company, decided to leave his secure position and go back to school to complete his education. He studied for six intense months at the Vancouver Film School in their Character Animation program. After his completion, he was awarded a scholarship for his efforts in his final film.

Once out of school, he got a position at Lost Boys Studios in Vancouver working on their 3D department as a visual effects artist doing Commercial Ads, Game Cinematics and Music Videos. Later on, he made the jump to EA Canada. He was one of the cinematic animators on DefJam Vendeta, DefJam Fight for NY and in-game animator on SSX on Tour. He moved on to Propaganda Games, a Disney Interactive Studio, as the lead Creature Technical Director where he worked on the new instalment of Turok.

He can now be found at DreamWorks working as a character TD on Shrek4 and other upcoming movies.

On his spare time, when he is not climbing mountains, he does freelance jobs in rigging and animation. Outside of work, Javier is an avid traveler, photographer, skier, and kite-boarder. His photography work can be found in www.javiersolsona.com

 

None of the rigs, tutorials or scripts may be used for business purposes without specific prior written permission. They are available for free and personal use only.
RIGS

 

GreatDane – Facial (modeled by Chris Baker)
The new GreatDane with the help of Jesse Davis who added the facial setup.
Download model (Maya 2008 and higher)
GreatDane (modeled by Chris Baker)
The Original Quadruped Rig built for the Autodesk MasterClass “Quadruped Animator Friendly Rigging”. Only the segmented mesh with the control rig is available. There is no smooth skin nor facial setup yet.
Download model (Maya 8 and higher)
PackageMan v1.2 How to use (PM modeled by Bob White)
Fully rigged character. Facial Setup, IK/FK spine, IK/FK arms and a whole lot more.
Download model (Maya 5 and higher)
Troll (Troll modeled by Kenn Klick)
Character ideal for animation. Comes fully with facial set-up, IK/FK amrs, IK/FK spine and the works.
Download model (Maya 4 and higher)
Super Gramps (SG modeled by William Vaughan)
Character and rig built in the “Zero to Hero” CD.
Download model (Maya 4 and higher)
IK-Joe (IK-Joe modeled by Daniel Martinez Lara)
Fully rigged character ready to be animated. IK/FK switching, Reverse Foot Lock, IK/FK Spine and more.
Download model (Maya 4 and higher)
IK-Joe v2
A similar, yet different rig to IK-Joe v1 for those that feel comfortable with other controllers. This version is a little bit more advanced and comes with an additional facial setup.
Download model (Maya 5) [Download model for Maya 4.5]
IK-Joe v3
Yet another different rig for IK-Joe. This version has a very nice, simple yet advanced facial setup, plus quite a few new goodies.
Maker sure to read the PDF file for some insight on v3.
Download model (Maya 5)
IK-Joe XSI (Rigged by Stefan Anderson)
Stefan Andersson made available his XSI version of the popular IK-Joe. This time for XSI users.
Download model (XSI 3.5.1)
IK-Jane
Fully rigged character ready to be animated. IK/FK switching, Reverse Foot Lock, IK/FK Spine and more. The ideal companion for Ik-Joe and the same setup as IK-Joe v2.
Download model (Maya 5) [Download model for Maya 4.5]
 
TUTORIALS

 

How to use Utility Nodes
Utility nodes can be an incredible thing to master. They might look scary and confusing in the beginning but once…
Go to tutorial
Solid knee in IK leg.
You need a solid IK knee twist so that the character can do flips and any kind of movement without the knee causing any problems
Go to tutorial
Working with Expressions and Constrains
Expressions and constrains are extremely powerful and a riggers closest friend…
Go to tutorial
Reverse Foot Lock
The Reverse Foot Lock setup is an external set of bones that drive the foot of a character…
Go to tutorial
IK/FK Switching
IK/FK switching set-up is mainly used for the arms. But it can be implemented in other parts of the body, like the feet…
Go to tutorial
Spine Setup
This spine set-up will give you quite a bit of control by keeping things really simple.
Go to tutorial
Elastic Foot using Expressions
Cartoon animation looks great with some squash and stretch. To be able to ‘stretch’ bones you need a set-up that can handle ‘elasticity’
Go to tutorial
Elastic Foot using Nodes
This tutorial differs from the above one in that it’s built using nodes instead of expressions.
Go to tutorial
Cartoony Eye
This tutorial shows how to create a cartoon eye that is not spherical and can have any shape and size that you want.
Go to tutorial
 
MEL SCRIPTS

 

rig101 List Utilities
This script will create a window listing the most significant Maya utility nodes, such as the condition, the multiplyDivide and the setRange.
Download script
rig101 LocknHide
This script will help you control the keyable and non-keyable attribues in your channel box as well as being able to lock and unlock them.
Download script
rig101 Wire Controllers
Creates wire controllers to use as manipulators
Download script
rig101 Template Objects
Templates or untemplates the objects selected
Download script
rig101 Multiple Influence
This simple script let’s you select multiple influence objects and add them to your smooth skin instead of doing them one by one.
Download script
 
OTHER

 

What to put on a Creature TD Reel
Some DOs and DONTs on what to put on a creature TD reel.
Go to document