-=THE X FILES=-
10,000,001 Posts on the X-Factor
Or,... the "Sticky of Shame" 
Haven't edited this in some time, but thought I'd just add this right here for those that don't want to click links and want a good answer;
SkipD wrote:
When camera manufacturers started designing digital SLR's, they decided that they should be about the same physical size of their 35mm SLR's. For that reason, they concluded that they could use the line of lenses they already had for their 35mm SLR's on the new digital SLR's.
All lenses designed for 35mm cameras project an image circle onto the film that covers the 24x36mm rectangle. The 35mm camera records the portion of that image circle that is defined by the opening behind the shutter for the film (24x36mm in size). A digital SLR with an APS-C sized sensor only records the smaller area (approximately 15x22mm) of the image circle projected by the lens.
When you put a 100mm lens on a 35mm camera and take a photograph, then put the same lens on a DSLR such as the Rebel XT and take the same photograph - same subject, same position for the camera - with the same lens, and then enlarge both photographs to the same size print (4x6 inches, for example), it will appear as though the photo from the Rebel XT was taken with a longer lens. That is because the image recorded by the Rebel XT was of a SMALLER PORTION of the image circle projected by the lens - cropped, if you will - compared to the image recorded by the 35mm camera.
A very important fact to realize is that nothing about the characteristics of a given lens change when you put it on different format camera bodies (such as 35mm film or an APS-C digital body such as a 20D). The focal length stays the same. The maximum aperture and the aperture range stays the same. The only thing that changes is the field of view, and that is because the APS-C cameras record a smaller portion of the image projected into the camera by the lens.
The "crop factor" has only one valid use. Here's an example: Joe took a photo of Mount Rushmore with a 35mm camera from a particular place using a 200mm lens. You want to replicate that photo with your 20D. What focal length do you need to do that from the same location that he took his photo? Divide the 200mm by 1.6 and you get the answer - 125mm.
If you are changing bodies and will be using your existing lenses on a new format (the 1D vs an XT, for example), you can use the "crop factor" calculations for each to figure out how the field of view will change when using the different bodies. Going from an APS-C camera (your XT) to a 1D will give you a "wider" field of view with all the lenses you put on it as compared to using them on your XT.
When camera manufacturers started designing digital SLR's, they decided that they should be about the same physical size of their 35mm SLR's. For that reason, they concluded that they could use the line of lenses they already had for their 35mm SLR's on the new digital SLR's.
All lenses designed for 35mm cameras project an image circle onto the film that covers the 24x36mm rectangle. The 35mm camera records the portion of that image circle that is defined by the opening behind the shutter for the film (24x36mm in size). A digital SLR with an APS-C sized sensor only records the smaller area (approximately 15x22mm) of the image circle projected by the lens.
When you put a 100mm lens on a 35mm camera and take a photograph, then put the same lens on a DSLR such as the Rebel XT and take the same photograph - same subject, same position for the camera - with the same lens, and then enlarge both photographs to the same size print (4x6 inches, for example), it will appear as though the photo from the Rebel XT was taken with a longer lens. That is because the image recorded by the Rebel XT was of a SMALLER PORTION of the image circle projected by the lens - cropped, if you will - compared to the image recorded by the 35mm camera.
A very important fact to realize is that nothing about the characteristics of a given lens change when you put it on different format camera bodies (such as 35mm film or an APS-C digital body such as a 20D). The focal length stays the same. The maximum aperture and the aperture range stays the same. The only thing that changes is the field of view, and that is because the APS-C cameras record a smaller portion of the image projected into the camera by the lens.
The "crop factor" has only one valid use. Here's an example: Joe took a photo of Mount Rushmore with a 35mm camera from a particular place using a 200mm lens. You want to replicate that photo with your 20D. What focal length do you need to do that from the same location that he took his photo? Divide the 200mm by 1.6 and you get the answer - 125mm.
If you are changing bodies and will be using your existing lenses on a new format (the 1D vs an XT, for example), you can use the "crop factor" calculations for each to figure out how the field of view will change when using the different bodies. Going from an APS-C camera (your XT) to a 1D will give you a "wider" field of view with all the lenses you put on it as compared to using them on your XT.
belmondo wrote:
Here's my attempt at visualizing the actual affect of the .6X crop factor in the 10D vs. a 35mm or full frame sensor.
Area bounded by the black circle represents the image as the lens records it. The red rectangle bounds an area equal to the image as seen by a 35mm film or FFS digital camera. The blue rectangle represents the image area recorded on the 10D sensor. There is no magnification; it's just a smaller portion of the same image.
Tom
Here's my attempt at visualizing the actual affect of the .6X crop factor in the 10D vs. a 35mm or full frame sensor.
Area bounded by the black circle represents the image as the lens records it. The red rectangle bounds an area equal to the image as seen by a 35mm film or FFS digital camera. The blue rectangle represents the image area recorded on the 10D sensor. There is no magnification; it's just a smaller portion of the same image.
Tom
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O-kay.. maybe not ten million... but;
Here's a most recent one that evolved into a a very interesting read with some of POTN's top minds contributing.. well worth it to get to the good parts...
Skip-D, rdenny, Wilt etc.. take on the X-Factor!
Belmondo's Visual Aid
The Longest thread on the X-factor
X-Factor and 17-40mm lens hood
Lens Hoods And The Crop Factor
X-Factor, Perspective, and Depth of Field
X-Factor, and Depth of Field MkII Simple explanation and equation
"Final Word" on the X-Factor.. hahaha
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Term "X-Factor" is coined
X-Factor and EFS
Pixel Density, Megapixles, 5D, XT and 1D mKII
At this point things start to get plain ridiculous.. and threads start to get locked
X-Factor and 1/1 focal length/shutter speed rule
MORE! On the Crop Factor and Shutter speeds
A particularly needlessly long thread on the subject!
Watch closely as a question turns into a debate on X-factor, ending in a battle of wills...
...in todays chapter;
What defines camera format?
A simple straight forward question recieves a simple straight forward answer...
Clearly this could not be a thread on the X-Factor!
Only in the Twilight Zone!!!
Crop Factor?
The release of the 40D not only confuses one individual re: Canon's continued use of APS-C sensors,..
But also seems to confuse many more on what an APS-C sensor really does,.
40D = APS-C = Disappointed?
And as always, is one dozen page thread on Crap Factor ever enough at one given time? Is it ever possible to contain the viral spread of the X-Factor once the subject is broached? Could we ever see a time when one thread is running that people would simply keep posting in that same thread?
NO!!!!!!! I give you also;
Crop Factor Vs. Megapixles
Noink? Crop Factor? Why not argue that here too? On a Canon Board? Why not I ask again?
The latest thread reaches new lows.. now the X-Factor is a reason for both Bigotry and inferiority complexes!!!
Apparently the whole phenomena has achieved a similar status to "Shell Shock: in it's impact on the human psyche.
So folks we have a new award winner for the stupidest thread on the X-Factor yet,. IN:
Aaaw, Did the X-Factor Hurt your feelings?
Post more links to this age old "discussion" as you find them
CyberDyneSystems wrote in post #3650588
This thread is for links to discussions and or faqs with examples or articles on the X-Factor
Please do not use this thread for debate or discussion
the links above are to those threads that contain such discussion
Posts in this thread that do not meet that goal will be moved to one of the existing linked threads where appropriate.
This thread is for links to discussions and or faqs with examples or articles on the X-Factor
Please do not use this thread for debate or discussion
the links above are to those threads that contain such discussion
Posts in this thread that do not meet that goal will be moved to one of the existing linked threads where appropriate.
The Fine Print:
CyberDyneSystems and the majority of sane members of POTN feel that the X-Factor has been discussed beyond any reasonable measure. Therefore any post or thread on the X-Factor as subject matter is forfeit all normal POTN rules and due process and therefore subject to immediate closing on sire, as well as public ridicule of those involved. Only posts with valuable new content, as judged by ME, stand any chance of remaining.
