raid
Dad Photographer
Are there words missing here:
"Simply put - if your sensor is smaller, you have to the pictures more, "
"Simply put - if your sensor is smaller, you have to the pictures more, "
What happens to effective focal length
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ampguy
Veteran
It's actually pretty simple. Same lens (e.g. not a 25mm for m4/3 vs a 50 for FF) has the same DOF with any given sensor size, if:
1. You print the image such that the subject matter is the same size.
So if you take a photo of a person with the exact same lens, at same distance from lens to subject, and put any of these backs attached: ff film, ff digital, aps-c, aps-h, m4/3, and print so that in each image the person (subject) is the same height, the DOF must be the same.
What DOF master might be assuming is that you are printing exactly what comes off your 24x36 negative or what pixel dimensions come off your sensor which will skew your subject size, and that will affect your DOF.
I urge you to spend a few dollars and hours and test this out for yourself with prints.
1. You print the image such that the subject matter is the same size.
So if you take a photo of a person with the exact same lens, at same distance from lens to subject, and put any of these backs attached: ff film, ff digital, aps-c, aps-h, m4/3, and print so that in each image the person (subject) is the same height, the DOF must be the same.
What DOF master might be assuming is that you are printing exactly what comes off your 24x36 negative or what pixel dimensions come off your sensor which will skew your subject size, and that will affect your DOF.
I urge you to spend a few dollars and hours and test this out for yourself with prints.
crawdiddy
qu'est-ce que c'est?
Exactly. I believe it was meant as a euphemism for "mainframe" applications or systems, when midrange and open systems began to capture more market share of IT.
There was a time when mainframe equated to "dinosaur" among certain IT prognosticators. Mainframes have been going extinct since the nineties. 😉
rxmd
May contain traces of nut
When you try this in practice, you'll find that in order to compare things, you will want your person or subject to appear at the same size in prints of the same size (say, 8 inches in an 8x10 print). You'll also find that as you use the same lens on differently-sized sensors, the angles of view are different across all the pictures.
The camera with the smallest sensor (in your case m4/3) will give you the picture with the narrowest angle of view, so this picture is where the person appears largest. In order to have the person appear at the same size in all the pictures from the other cameras as well, however, you have to crop all those pictures to this narrower angle of view, too (otherwise the person will appear at a different size in each of them).
So in your experiment, either the camera crops the picture for you by means of a smaller sensor, or you do the cropping yourself by the same amount in order to match the angle of view. All you're discovering is that DOF-wise it doesn't matter who does the cropping.
ampguy
Veteran
Here are some facts, that I've previously backed up with example images:
1. If you use the same lens, focused at the same distance to subject, with different sized sensors/film in the back of the camera, that image portion which is common to all formats (the smallest FOV) on all images will have exactly the same DOF.
2. To test the above, prepare 2 (or more) 35mm film frames. One FF unmodified, 2nd frame cropped to APS-x (x=H, C, C variant, etc.), and maybe a 3rd for m4/3.
3. Enlarge the common portion to the same size and print each one at any size, and look at it from any distance to eliminate CoC and angle variables. The DOF is the same.
4. There are many reasons why dofmaster.com is just wrong. Look at the data for different 35mm FF solutions, they use vendor CoC data, which is not exactly the same among vendors, but when your eyes look at an image from x distance, they are not varying depending on whether that image was from a Canon, Nikon, or Leica.
1. If you use the same lens, focused at the same distance to subject, with different sized sensors/film in the back of the camera, that image portion which is common to all formats (the smallest FOV) on all images will have exactly the same DOF.
2. To test the above, prepare 2 (or more) 35mm film frames. One FF unmodified, 2nd frame cropped to APS-x (x=H, C, C variant, etc.), and maybe a 3rd for m4/3.
3. Enlarge the common portion to the same size and print each one at any size, and look at it from any distance to eliminate CoC and angle variables. The DOF is the same.
4. There are many reasons why dofmaster.com is just wrong. Look at the data for different 35mm FF solutions, they use vendor CoC data, which is not exactly the same among vendors, but when your eyes look at an image from x distance, they are not varying depending on whether that image was from a Canon, Nikon, or Leica.
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