Originally posted by dtmateojr ...
See, this is why I didn't want to answer your question because it is so obvious! Of course 16Mp is the same IMAGE SIZE as any other 16Mp REGARDLESS of sensor size. But, dude, they are NOT the same resolution. A 16Mp APS-C or m43 has MORE resolving power than a 16Mp FF sensor.
See if you can figure that out...
Each pixel of the APS-C sensor will be smaller than each pixel of the FF sensor. In a sense, this means the APS-C sensor has greater resolution. It is some the same as looking a ruler with graduations in mm (APS-C) rather than a ruler with graduations in cm only (FF).
However, projection size does matter.
The example scene will be of a Volkswagen car with proper emission controls.
The magnification of the VW will be the same in both images; the front bumper will be aligned with the left edge of both sensors and the rear bumper will be aligned with the right edge of both sensors. So, the size of the door handles will look the same in both finished images. For the door handles to be the same apparent size in both images, some rules of equivalency will be followed (and why to follow the rules will be below).
Alright, standing in the same spot for both exposures, the image taken with the FF will be by using a 43mm lens and the image taken with the APS-C will be by using a 28mm lens. In both cases, the VW will be projected onto the sensor in the same way (not exactly, but pretend so, for the sake of argument). The door handles will be the same relative size on each sensor. If the door handle is .08% surface area of the FF sensor, it will be .08% surface area of the APS-C sensor. The door handle will cover the same number of pixels in both the image projected on the FF sensor and the image projected on the APS-C sensor.
The resolution with respect to that door handle will be the same in both images...
Of course, if we had used the 43mm on the APS-C camera, the VW would be projected larger on the sensor. The door handles would cover a greater surface area of the sensor, they would cover more pixels, and those door handles would be displayed in greater resolution. However, to cover that bet and raise you, I could go hunt a.. 65mm lens for the FF. The lens doesn't exist so I would keep the 43mm on the FF and just step just closer to the car so that the same parts of the car are framed and projected onto my FF sensor as they were on the APS-C sensor.
The reason an element of equivalency, field of view, is important is because I have a picture in mind. I want a picture of the car bumper to bumper. The picture is for Better Homes & Garden magazine and I have no choice :^| So, whatever lens combo I choose between the FF and APS-C, I will have to photograph bumper to bumper.. I can choose different lenses that offer the same field of view on the differently sized sensors or I can use the same lens and walk either toward or away from the car.
With either choice above, I end up with the projection of the VW just covering either sensor so the number of pixels covered by those door handles will be the same... This consideration of projection size also helps explain an argument made by some people that smaller sensors are more demanding of lens resolution, but that discussion is a tangent.
Respect to field of view is important to me when considering FF. I look at the pictures I have taken of stuff in cathedrals. I have a picture of a silver bull with wings taken with APS-C and 77mm lens and it is framed nicely.. When I use the 77mm lens on a FF, I know the field of view will be wider. I know I will want the bull to be framed just the same because I am not going to be satisfied with a smaller flying bull. So, I will have to either get closer to the bull or I will have to buy a 105mm lens. This is where practical considerations of equivalency come into play: considering what is required to record the image you have in mind.
Rather than step closer to my angelic bull or mount the 105mm, I could crop the FF image. If both the APS-C and FF sensors have 16 MP then, yes, the image produced with the APS-C will have more resolution. But this doesn't mean equivalency is a bull with no wings. Besides, the K-1 has 36 MP so I can crop it to equal field of view equal to the same lens on an APS-C and be close enough to 16 MP...
This digital zoom (crop mode of FF) is a reason I am interested in K-1. I will have an option of wider fiend of view with the 77 on the K-1 or I can use 'crop mode' to enjoy the 'longer reach' the 77 gave me on K5. In a way, I will have two lenses in one. Because I am happy with K5 performance, I will not mind sometimes using K-1 crop mode to take advantage of my 'virtual' lens.
Anyway, I think my post wandered a bit at the end. I admit a 16 MP APS-C sensor has smaller pixels than a FF sensor. The graduations on the APS-C ruler are smaller than on the FF ruler. But that doesn't mean an APS-C has more resolution than FF when it comes to subject, composition, and projection size.
Looking at absolute resolution irrespective of composition is no longer photography.
++ Looking at posts subsequent to the one I quoted, I think it is possible there may be a divide across the digital Minnelli. Projection size may be a difficult concept if people have not seen either a slide go into a projector or a negative go into an enlarger... Comparing these things to a digital projector hooked up to an iPhone does not help... there is no constant physical size associated with the iPhone+projector as there is with either the slide projector or film enlarger or image sensor size.
I begin to understand the arguments that a cell phone camera is all any person needs.. after all, why stop the train of thought at either the 4/3 or APS-C stations...
---------- Post added 03-20-16 at 10:32 AM ----------
Originally posted by jsherman999 ... Photographer did a one-in-a-million job.
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The photo could also be used for training: There are two divers on the right and three coral crunching moon walkers on the left.
+ ...the greater resolution of the smaller sensor allows me to see there are actually more than three coral crunchers out there. The whale is surrounded by moon walkers. Guess which few lead the dive :^)
Last edited by Tan68; 03-20-2016 at 08:56 AM.