dwermske

Sensor size is either FF or some smaller fraction. That fraction is the crop factor. The number of pixels in either sensor is irrelevant to the crop factor. That is because pixels come in different sizes determined by the specific manufacturer. Some FF sensors have 20+ MP while others have 50+ MP. Some smaller (cropped sensors) can have 3+ MP all the way up to 40+ MP. Pixel count does not determine the size of a particular sensor, the pixel size determines the pixel count on any specific size sensor. Trying to determine crop size based on pixel count is nonsense. The physical sensor size in relationship to FF determines the crop factor.

SalvageDiver Loc: Huntington Beach CA

Hi Blackest,

The math is easy for me, it’s getting the composition, lighting, focus, etc., correct that’s the hard part.

I suspect that you’re having a conversation with a friend about cameras over a warm pint. So if you masked off your sensor to 6000x4000 pixels limiting your pixel resolution is the same as your friends, you still have the larger sensor, thus better performance, given similar sensor technology.

To address your ‘Extra Credit’ question, here goes.

Yes, diffraction will affect differently. Diffraction is a function of the lens aperture. For a given aperture, the lens produces an Airy disk of a given size projected onto the sensor plane. Pure physics. In your scenerio, both sensors have the same resolution (i.e. 6000x4000), but the smaller sensor having smaller pixels will be more sensitive to the effects of diffraction. The Airy disk covers more pixels on the smaller sensor than the larger sensor. Pixel pitch is 4.88um for the K1 and 3.92um for the D7200. Steve Perry has a good video on this subject, but make sure you listen to his explanation and apply it to your scenario, otherwise, it’s easy to get confused.

https://www.youtube.com/watch?v=N0FXoWdHXTk

To address the print size, the typical human eye with 20/20 vision is capable of resolving about 60 arc-seconds. Based on that, here is a chart, from the DigitalWorkflow Yahoo group, showing viewing distance vs ppi.


(I didn't check the math, but the reference is posted below)

So for your image being viewed at a distance of 2 ft., the print resolution would be 286 ppi. For a 6000x4000 pixel image, that equates to a print size of 21”x14”. Any image printed at a resolution greater than 286 psi, would be unresolved by the typical human eye when viewed at 2 ft. Both prints would look similar.

Here is the article by NorthernLight Images regarding print resolution vs viewing distance at

http://www.northlight-images.co.uk/what-print-resolution-works-for-what-viewing-distance/

Then the question is how would the two cameras affect the print at the same size? It wouldn’t. The sensor resolution is the same for both sensors. But, given your K1@FL=250 vs D7200@FL=200 and using the same f-number and ISO, the FOV will be the same, but the D7200 will have more DOF and noise. So other characteristics of the print will be different between the two cameras. To get the same FOV, DOF and noise from both cameras is an entirely different discussion.
Mike

Longshadow Loc: Audubon, PA, United States

If my photography ever gets this complicated I'll quit and take up basket weaving.

BebuLamar

Don't worry as in the thread tittle it's a math challenge and not a photographic challenge.

Longshadow Loc: Audubon, PA, United States

SalvageDiver Loc: Huntington Beach CA

User ID

You have not understood the OP.

User ID

That "explanation" is totally beside the point.
You have not understood the OP query. When
you finally get it, you will wind up with a 1.23
crop factor.

.

User ID

Your reading comprehension is failing.
This is a new and different question.

SalvageDiver Loc: Huntington Beach CA

Blackest,

I just checked the math used to generate the table for print size based on viewing distance. Apparently the formula at the bottom is incorrect. There is an extraneous 2x term that shouldn't be there. See my attachment below. The table is correct if you take half the viewing distance for the same dpi. So to answer your first extra credit question, the required dpi is 286 when viewed at 12 inches and 143 when viewed at 24 inches. For printing, that would correspond to a 21"x14" and 42"x28", respectively for a 6000x4000 ppi image.

Here is another reference article, "Finding the Right Print Resolution", which provides more detail.

https://www.digitalphotopro.com/technique/photography-workflow/the-right-resolution/

Mike