Multiplying aperture time crop factor
May 25, 2014 15:35:22 #
I have never thought about this but it make sense. it's a little disappointing my Canon 100mm f2.8 isn't really an f2.8 on my 7D but thats how it is.
I thought some of you might find it interesting. its a long video, but if you have the time take a look. I would be interested in your thoughts on this.
http://www.youtube.com/watch?feature=player_embedded&v=DtDotqLx6nA
I thought some of you might find it interesting. its a long video, but if you have the time take a look. I would be interested in your thoughts on this.
http://www.youtube.com/watch?feature=player_embedded&v=DtDotqLx6nA
May 25, 2014 15:41:07 #
The f stop is determined by the ratio between the lens focal length and the width of the iris wide open. It has only to do with the lens, not the camera body. So your lens is really f 2.8.
May 25, 2014 15:52:41 #
photoninja1 wrote:
The f stop is determined by the ratio between the lens focal length and the width of the iris wide open. It has only to do with the lens, not the camera body. So your lens is really f 2.8.
but if my 100mm is multiplied by the crop factor (1.6) it equals 160mm field of view. so that changes the equation right?
May 25, 2014 16:09:49 #
amehta
Loc: Boston
stableduck wrote:
but if my 100mm is multiplied by the crop factor (1.6) it equals 160mm field of view. so that changes the equation right?
Your lens is a 100mm f/2.8, it isn't a 160mm lens.
When you use a crop sensor camera, the basic exposure values, shutter speed, aperture, and ISO, do not change. I think the basic point of the video, though he doesn't say it this way, is that the field of view, depth of field, and noise change with different sensor sizes, and all are related to the "crop factor". The "lie" is to talk about one, the field of view change, without acknowledging the other two.
May 25, 2014 16:18:19 #
amehta wrote:
Your lens is a 100mm f/2.8, it isn't a 160mm lens.... (show quote)
what I understood (which I am probably wrong)is the smaller sensor does not capture the same amount of light as a ff sensor with the same lens, making it equivalent to a higher f stop :?:
May 25, 2014 16:26:42 #
amehta
Loc: Boston
stableduck wrote:
what I understood (which I am probably wrong)is the smaller sensor does not capture the same amount of light as a ff sensor with the same lens, making it equivalent to a higher f stop :?:
Yes, the smaller sensor does not capture the same amount of light as a full frame sensor. But the exposure depends on the "light per area", not the total amount of light. If you take a picture with the same shutter speed, f-stop, and ISO on a point & shoot, micro 4/3, APS-C (Canon 1.6x), full frame, medium format, or large format camera, you will get the same exposure.
May 25, 2014 16:40:39 #
this should be a required viewing before anyone is allowed to post a sensor size related question.
May 25, 2014 17:46:12 #
oldtigger wrote:
Try researching in the FAQ section.this should be a required viewing before anyone is allowed to post a sensor size related question.
FAQ: Sensor Sizes Chart & Comparative Format Views
http://www.uglyhedgehog.com/t-26503-1.html
Also, do not confuse "Effective aperture" of a macro lens, with physical aperture:
FAQ: What is Effective Aperture for Macro?
http://www.uglyhedgehog.com/t-114166-1.html
May 29, 2014 19:44:18 #
Crop Factor is the best description the experts were able to come up with. It describes what it would be like using 35mm film in a 2-1/4 camera. A reduced field of view.
I generally ignore it. The camera captures the image you choose.
I generally ignore it. The camera captures the image you choose.
Jun 4, 2014 18:27:01 #
The crop factor shows you a lens with an equivalent angle of view. That's all.
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