D800 Crop Modes

D800 quotes the 1.5 Crop mode as being 24 x 16Mp and Full 36 x 24Mp so how does the 1.5 crop mode only create 15Mp?


P.

Not following your question entirely but I believe you are asking if shooting in FF mode, the full 24x36mm of the sensor is used delivering a 36+ megapixel image. When shooting in crop mode only 16x24mm of the sensor are used. The rest of the info is tossed away. The resulting image will then be about 15mp.

gjl711 wrote in post #18107186
Not following your question entirely but I believe you are asking if shooting in FF mode, the full 24x36mm of the sensor is used delivering a 36+ megapixel image. When shooting in crop mode only 16x24mm of the sensor are used. The rest of the info is tossed away. The resulting image will then be about 15mp.

In the D800 it has a few cropping options - two of which are 1.5 and 1.2, using the 1.5 DX crop it says it crops to a 24 x 16Mp image, so my question is - how does 24Mp become 15Mp? because by using basic math cropping 36Mp by 1.5 is 24Mp - 36/1.5 = 24 thats how i work it out hence why I am a bit confused with the math.
Another way of looking at it - cropping 1.5 is only throwing away 1/3 of the sensor leaving 2/3 still in use meaning 36/1.5 = 24 total Mp left

P.

I think your mixing up "mp"as in megapixels and "mm" as in millimeters. In crop mode it uses just the center section of the sensor measuring 24mm by 15mm. The resulting area results in 15 megapixels of the sensors 36 megapixels left in the image.

It's area. A 1.5x crop actually has 1.5x1.5=2.25x fewer pixels.

I think whats throwing me is in my D7100 with 24Mp sensor of 24 x 16(same figures at the DX crop mode in the D800) in the D7100 there is also a 1.3 Crop mode that still leaves 15Mp.

So my math may not be to great but I can not get my head round why firstly - the DX mode has the same crop size area as the D7100, and secondly 1.5 crop size or DX in the D800 does seem to crop a lot compared to the 1.3 mode in the D7100.

Sorry for my lack of math understanding or just blinkered view


P.

Pagman wrote in post #18107194
In the D800 it has a few cropping options - two of which are 1.5 and 1.2, using the 1.5 DX crop it says it crops to a 24 x 16Mp image, so my question is - how does 24Mp become 15Mp? because by using basic math cropping 36Mp by 1.5 is 24Mp - 36/1.5 = 24 thats how i work it out hence why I am a bit confused with the math.
Another way of looking at it - cropping 1.5 is only throwing away 1/3 of the sensor leaving 2/3 still in use meaning 36/1.5 = 24 total Mp left

P.

The figures mentioned on page 80 of the user manual are in MILIIMETRES.

john crossley wrote in post #18107251
The figures mentioned on page 80 of the user manual are in MILIIMETRES.

So does that mean its the same phsical size in mm as the D7100 of 23.5mm x 15.6mm but with less pixels?

P.

Pagman wrote in post #18107259
So does that mean its the same phsical size in mm as the D7100 of 23.5mm x 15.6mm but with less pixels?

P.

Yes indeed.

The D800 has a 36x24 sensor with 36MP. If you do a 1.5X crop, you basically take the center 24x16 region of the sensor, which has 36/2.25 = 16MP.

The D7100 has a 24x16 sensor because it is a crop camera, but it has 24MP. The pixels are obviously smaller to fit so many into the same area.

And this is the reason for the perennial debate, especially among long lens aficionados on whether it is better to use a crop camera, or to use a large MP camera and crop in post. It is clear that if you are interested in pixels on the subject, it is better to use a crop camera like the D7100 than to use the 1.5X crop mode on the D800. Now, a D800 pixel may have better noise characteristics than a D7100 pixel, so there are other considerations, but there's no question that you can place more pixels on the subject using the D7100 than using a 1.5X crop mode on the D800.

Scrumhalf wrote in post #18107282
Yes indeed.

The D800 has a 36x24 sensor with 36MP. If you do a 1.5X crop, you basically take the center 24x16 region of the sensor, which has 36/2.25 = 16MP.

The D7100 has a 24x16 sensor because it is a crop camera, but it has 24MP. The pixels are obviously smaller to fit so many into the same area.

And this is the reason for the perennial debate, especially among long lens aficionados on whether it is better to use a crop camera, or to use a large MP camera and crop in post. It is clear that if you are interested in pixels on the subject, it is better to use a crop camera like the D7100 than to use the 1.5X crop mode on the D800. Now, a D800 pixel may have better noise characteristics than a D7100 pixel, so there are other considerations, but there's no question that you can place more pixels on the subject using the D7100 than using a 1.5X crop mode on the D800.

Thanks for that sam, I used to own the D7100 and used the 70-300VR on it, currently I'm camera-less but have looked at cheaper crop possibilities like the D7000, my money no object fave is the D800 and i guess using the same type of lens and the crop mode in the D800 its ability would be way better - IQ, Noise, Focusing etc than the D7000.
It does look like a Fabulous Camera.

P.