FF verses Crop magnification: Forgive me folks, I am old and not the brightest star to begin with. But as I see it the monitor size is where it's at. If you shot with a 100mm lens with...

fhuhman Loc: Jefferson City, MO

Forgive me folks, I am old and not the brightest star to begin with. But as I see it the monitor size is where it's at. If you shot with a 100mm lens with a FF at a house that completely filled the monitor screen. Then shot with the same settings with the crop, and put that picture on a monitor that was 2/3 or 3/4's the size of your regular monitor and the two monitors were setting beside each other. The windows,doors,bricks etc. would be the same size as on your regular monitor, but you would only see 2/3's of the house, but when you put the crop pic on your regular monitor it would be as if you shot with a 150mm FF lense?

SteveR Loc: Michigan

Dupe.

SteveR Loc: Michigan

No. It would not be as though you shot with a 150mm FF lens. A 100mm lens is a 100 mm lens. If your house is in the center of the composition, the house will be the SAME size on the crop sensor as on the full frame sensor. The difference is, that because the full frame sensor takes in a wider view, the crop sensor has a larger angle of view.

See the link below. It shows very clearly how both the crop sensor and full frame sensor see the same image at the same size. The circle is the "round" image projected by the lens.

http://www.google.com/search?q=crop+vs+full+frame&client=firefox-a&hs=S1q&rls=org.mozilla:en-US:official&tbm=isch&tbo=u&source=univ&sa=X&ei=Xbq4UYnRJImEyAH43IHwBg&ved=0CDgQsAQ&biw=1978&bih=866#facrc=_&imgdii=_&imgrc=r9SOPeD1yoAKnM%253A%3BohOxB0R6MlhkNM%3Bhttp%253A%252F%252Flowenddslr.com%252Fimg%252Fcrop-circle.jpg%3Bhttp%253A%252F%252Flowenddslr.com%252Ftutorials%252Fcrop-factor.php%3B450%3B450

lporrel Loc: California

I don't think this is quite right.

If you shoot using a 50mm lens with a full frame 24 MP sensor and a APS-C (crop) 24 MP sensor, the APS-C will give you a de facto focal length of 75mm.

In other words, all other things being equal, the APS-C gives you longer reach (even though "a 100mm lens is a 100mm lens" ). This is why the whole industry talks about equivalencies, using full frame as the benchmark. This is why wildlife photographers tend to prefer APS-C.

SteveR wrote:

No. It would not be as though you shot with a 150... (show quote)

Sheila Loc: Arizona or New York

One way to think about the way full frame and crop sensors handle lenses is to think of full frame as a rectangle. Then imagine the crop sensor as a smaller rectangle centered inside the larger rectangle. If you have a 50mm lens on the camera, the full frame sensor enables the camera to record the entire area of the large rectangle. If you are using the crop factor (dx) camera with the same lens, it only is able to record the area of the smaller rectangle. It looks as if you are working with a longer lens (75 mm in this case 1.5 crop factor) because you are only able to record the viewing area of the smaller rectangle.

lighthouse Loc: No Fixed Abode

I think you are way overcomplicating things.
If you get to this stage of thinking - then it is time to just take 4 steps backwards and say "Hey thats what it looks like through the viewfinder, that is what the full image looks like, who cares about how it compares to a different crop camera."

fhuhman wrote:

Forgive me folks, I am old and not the brightest s... (show quote)

SteveR Loc: Michigan

lporrel wrote:

I don't think this is quite right.

If you shoot using a 50mm lens with a full frame 24 MP sensor and a APS-C (crop) 24 MP sensor, the APS-C will give you a de facto focal length of 75mm.

In other words, all other things being equal, the APS-C gives you longer reach (even though "a 100mm lens is a 100mm lens" ). This is why the whole industry talks about equivalencies, using full frame as the benchmark. This is why wildlife photographers tend to prefer APS-C.

Did you open the link? You can call it "reach" if you like, but the images projected by the lens onto both sensors are the same size. It will appear to be 1.5x larger, not because it actually is, but because of a smaller angle of view. Basically, the image in the center portion of the crop sensor takes of a larger percentage of the sensor than it does on the full frame sensor. Again, pull up the link and it will help you understand it. In the link, Half Dome is the same size on both the crop sensor and full frame sensor. You can't escape that.

James R. Kyle Loc: Saint Louis, Missouri (A Suburb of Ferguson)

SteveR wrote:

No. It would not be as though you shot with a 150... (show quote)

++++++++++++++++++++++++++++++++++++

Yep! Well Explained...

This is good info. I too have read this before (in fact I have saved it to show other and my students) .

blackest Loc: Ireland

SteveR wrote:

No. It would not be as though you shot with a 150... (show quote)

I don't understand how a lens on a crop sensor can have a larger angle of view.

I mean lets say we have a tripod concreted in front of a wall with 1 foot bricks. On the full frame we might see 10 bricks across the frame, with the crop sensor say 6 bricks (just for sake of argument) surely thats a narrower angle of view, isn't it?

Depth of field should be the same too, wouldn't it?

SteveR Loc: Michigan

blackest wrote:

I don't understand how a lens on a crop sensor can have a larger angle of view.

I mean lets say we have a tripod concreted in front of a wall with 1 foot bricks. On the full frame we might see 10 bricks across the frame, with the crop sensor say 6 bricks (just for sake of argument) surely thats a narrower angle of view, isn't it?

Depth of field should be the same too, wouldn't it?

Actually, you're correct. I was in error when I said the crop sensor has a larger angle of view. Actually, it has smaller field of view and a narrower angle of view.

lporrel Loc: California

Yes, I did open the link, and it is misleading.

For the given area, all other things being equal, the APS-C sensor, covering a smaller area with a greater number of pixels, captures a greater amount of detail. For practical purposes, then, the APS-C sensor with a 50mm lens works exactly like a 75mm (i.e., 1.5x telephoto) would on the full frame sensor.

To get 16 MP of coverage with a full frame sensor on just what would be the APS-C portion of the frame, you would need a full frame sensor with a total of 24MP.

At the end of the day, regardless of whether you are using a 16MP APS-C with a 50mm lens or a 16MP full frame with a 75mm lens, you end up with an image that is, in terms of coverage, identical: 4608 x 3456.

SteveR wrote:

Did you open the link? You can call it "reac... (show quote)

SteveR Loc: Michigan

lporrel wrote:

Yes, I did open the link, and it is misleading. br... (show quote)

We're not talking about how different sensors might affect the situation....actually a better sensor on the crop camera would just give you better resolution, not a larger image. A 50mm lens will project the same size image onto whatever sensor it is projecting to.

Again, the only real reason is that the same sized image appears larger on the crop sensor is because it takes up a larger portion of the crop sensor than it does on full frame sensor.

lporrel Loc: California

I think we are answering different questions. I was speaking to what I understood to be the OP's question about how images appear on various monitors. However, I just went back to ensure that I was speaking to the question, and I realized that I don't understand the question. It makes a lot of assumptions about monitor pixel size. It doesn't make much sense to me.

I am also not sure what you mean by "better sensor". If by "better" you mean higher pixel count, then you would get a larger image on a computer monitor. But I doubt that is what you mean. If by "better" you are simply talking about IQ, then I am with you. As long as an image, full frame, APS-C, 2/3, or whatever has the same number of MPs, the image will be exactly the same size on the monitor, (regardless of focal length). The only thing that changes is coverage and the proportion of pixels devoted to any given object.

SteveR wrote:

We're not talking about how different sensors might affect the situation....actually a better sensor on the crop camera would just give you better resolution, not a larger image. A 50mm lens will project the same size image onto whatever sensor it is projecting to.

Again, the only real reason is that the same sized image appears larger on the crop sensor is because it takes up a larger portion of the crop sensor than it does on full frame sensor.

SteveR Loc: Michigan

lporrel wrote:

I think we are answering different questions. I wa... (show quote)

The OP confused two different subjects by talking about images as they appear on monitors, and then asking if the 100mm lens would yield a 150mm image. I don't think you can get one coherent answer from the question as posed.