The GAS is building

[DrEntropy]

I keep looking at the D850 pricing, for used ones on Ebay... and thinking about pixel density in comparative relationship with the D7500's APS-C sensor.

Many showing up seem to be there so the sellers can offset the move into mirrorless systems. Some of the D810's are going for sub-$1K now. When the average cost of a used D850 body gets to about what the D7500 was when I got that, well...

 

[Basil]

Just for fun, I took a look at the specs for the camera you have (D7500) and the D850. Here is what I see:

ISO: Your 7500 has ISO 100 to 51,200, expandable to 50 to 164,000. The 850 is 64 to 25,000 native, so slightly better on the low end but not as good on the high end (but who shoots at ISO 51,200?)

Shutter Speed: both can shoot 30secs to 1/8000th

Frames per Second: The 7500 is actually a little faster (8fps RAW vs 7fps for the D850.

Built-in intervalometer: Both have this

Card slots: The D850 has two slots - 1 SD slot and 1 CFExpress, where your 7500 only has one SD slot. This may or may not be a concern. Professionals who make a living from things like weddings, etc prefer two cards so they can record to both. For most people 1 slot is sufficient. My R5 has two slots like the 850 and I use the CFExpress, which is much faster card, for video (4k).

Wireless: Both have WiFi and bluetooth

Image Stabilization: 7500 has "digital" IS, but the 850 has no IS. Not having IS may or may not be an issue depending on whether your lenses have IS. I have found IS to be very helpful when shooting in low light at lower shutter speeds, but not having it just means you have to pay closer attention to your shutter speed relative to focal length.

LCD screen: Both have 3.2 inch tilting touch screens but the D850 has much better pixel density (2.36million dots vs only 922k for the 7500). Whether that matters is up to you. If you always shoot through the optical view finder then the pixel density of the rear screen may not be an issue.

Sensor Size and Pixel Density. Now comes the big factor of pixel density. You mentioned you were thinking about pixel density for the 850 relative to the 7500. The 850 is a full frame sensor with effective 45.9 meg pixels. The 7500 is a 1.5 crop sensor with 20.9 Meg pixels. The RAW image dimensions for the D850 is 8256 x 5504 pixels. The image size for the 7500's crop sensor is 5568 x 3712 pixels. However - and this might surprise you - the 7500 actually has more pixel density than the D8500. How can we tell? Well, if you multiply the pixel dimensioned for the 7500 by 1.5, you would get 8352 x 5568, If you multiply those together you get 46.5Meg pixels. In other words, if you took a picture with the 850 and cropped in to 1.5 times, the resulting image would have less pixel density (slightly less) than the 7500 shooting the same image without cropping.

In conclusion, there may well be reasons to upgrade to the 850 (desire for a full frame camera (usually better low light performance), dual card slots, better pixel density of LCD screen), but actual pixel density would not be an advantage for the 850. Is does have more pixels, but those pixels are in a full frame sensor so the density is slightly less than the 7500 (close enough in my opinion to be a wash really).

 

[DrEntropy]

In conclusion, there may well be reasons to upgrade to the 850 (desire for a full frame camera (usually better low light performance), dual card slots, better pixel density of LCD screen), but actual pixel density would not be an advantage for the 850. Is does have more pixels, but those pixels are in a full frame sensor so the density is slightly less than the 7500 (close enough in my opinion to be a wash really).

The only real reason for the 850 would be the better low light sensor resolution and to a lesser extent the two card slots. Though I've not really missed the two slot feature with the D7500. The D7200 has two (both SD), they're set to keep RAW & JPG images separately. No big issue tho. The 850 is a bit larger physically, that may make it a bit easier to manipulate the controls with my big mits. I'll need to "fondle" one for a while to find out.

The issue of cropping an image, full-frame vs. crop sensor, is more-or-less a wash, too. The focal length of any optic is the "crop factor" with the APS-C, in-camera. And as you've explained, the pixel density is basically the same.