jerryc41 Loc: Catskill Mts of NY

"Image Size" can mean a lot of things, but to me, it was a surprise. While processing some pictures I took with my D750, I realized that there was less room around the edges than what I shot. When I pressed the Menu button, I saw that "Image Size" appeared immediately. Apparently, I somehow changed the image size from full FX to 1.2. I've never done that intentionally, but there you are. Something to keep in mind.

CO

I bought a D750 just weeks ago. I haven't looked into that yet. I would think it's set on FX image area. Will take a close look.

a6k Loc: Detroit & Sanibel

So when image size is +20% the number of pixels is lower. Sure, that makes perfect sense!

Longshadow Loc: Audubon, PA, United States

Do you mean .8? Where do you get the +120%???
I missed that.

a6k Loc: Detroit & Sanibel

Look in the illustration which appears to be from the manual. The second line-group says 1.2x. The math that I learned says that 1.2 is 1 plus 20%.

I did not say +120%; I said +20%.

Longshadow Loc: Audubon, PA, United States

Crop sensor format, not larger image. (.8)
And what then should +20% be misconstrued as?

LFingar Loc: Claverack, NY

That 1.2 is the crop factor, just as 1 is FX and 1.5 is the DX factor. With 1.2 a 100mm lens would have the view area of a 120mm lens using that factor, just as a DX with it's 1.5 factor would appear as a 150mm lens would on an FX. The higher crop factor numbers denote smaller sensor area. Pixel count is a whole different thing.

a6k Loc: Detroit & Sanibel

If we start with a number, 1000 for example, then +20% is 1200 but +120% is 1000 + (1.2 x 1000) = 2200. This is really not rocket science, more like 5th grade math.

Longshadow Loc: Audubon, PA, United States

yea, but it's not +20% in this case.
It's a 1.2 crop factor.
(1.2x1000 is 1200 on my calculators.)

a6k Loc: Detroit & Sanibel

lfingar's response is right, of course. The problem is that the mfr. is misrepresenting. The underlying problem is that the whole "crop factor" idea is weak. He's only half right about pixel count and sensor area being "whole different thing". That could be correct for two different cameras but for two defined areas on the same sensor then they are exactly the same thing.

If you crop a frame you throw away the edges. That means you have fewer pixels but the resulting frame makes the subject look relatively larger. The problem is that since you now have fewer pixels you cannot make as large a print without upsizing. Larger isn't really larger. The copy of the manual in the first post shows this clearly.

The angle of view is what is being compared but you can change the angle of view with cropping in PP just as well as with using a smaller sensor OR a smaller part of the sensor (as the OP's camera suggests).

My crop frame Sony a6500 takes a picture that is 6000 x 4000. If a FF camera is cropped and does not equal that pixel count, then how to compare? Conversely, if I had a FF camera with a pixel count of 9000 x 6000 and cropped it by 1/1.5 to equal my a6500 then for a given lens the image dimensions would be exactly the same and I could equal it. The a7Rm3 and the D850 as examples have more than 8000 px on the long edge and come close to that. Cameras with lower resolution such as the OP's then not so much.

This is still simple math and not rocket science. Oh, btw, 0.8 x 1.2 = 0.96 but .8333 would work precisely.

Longshadow Loc: Audubon, PA, United States

Not sure for what the .8x1.2 value is intended. I wouldn't use it for anything here.

a6k Loc: Detroit & Sanibel

In earlier post you said..
"Crop sensor format, not larger image. (.8)
And what then should +20% be misconstrued as?"

1/1.2 = 8.333

So .8 is not the reciprocal of 1.2.

Longshadow Loc: Audubon, PA, United States

No, it's 1.0 -.2.
That's why I asked if you meant .8 instead of 1.2 as a multiplier.
I had no idea how you were trying to work a 1.2 crop factor into a size difference.

rhadams824 Loc: Arkansas

Dividing a larger number into a smaller number cannot produce a number larger than the smaller number.
1/1.2 = .833
From the chart FX large = 6012. Reduced to a 1.2 crop factor = 6012 x .833 = 5007.997 rounded to 5008

Dan Mc Loc: NM

1/1.2, 6-122x.833, etc. etc. My hair and toenails now hurt!!