Do full frame camera's with the crop mode feature bring in less light while shooting in crop mode? I know a smaller portion of the sensor is used for the photo but I was wondering whether the entire sensor still absorbs light although only a portion of the sensor is used for a photo in crop mode. I was unable to locate any information regarding the gathering of light for full frame cameras in crop mode.
FX DSLR In Crop Mode Question
- Thread starter kamaccord
- Start date
I wonder where this notion started lately?
Where did you hear this?(my bucket numbers are not precisely 3:2 aspect, but I think I'd need more buckets, and my yard is not that large. It is close to 3:2, plenty close enough)
We have very many identical buckets.
Let's imagine we put one array of buckets out in the backyard, say 33x21 buckets, and we call that array FX.
And beside it, we put another array, 22x14 buckets, and we call it array DX.
The FX dimensions are 1.5x the DX dimensions, DX is 2/3 the size.
It rains, and the buckets act like rain gauges, and collect the rain water (much like the sensor cells collecting photons).
We do collect half again more total water in the 33x21 buckets, but the water in each bucket is the same.
EDIT: Oops! Sorry, my hasty error. 1.5x1.5 is 2.25 times more area/water. Still same in each bucket.
Exposure works on the intensity of the light (one bucket, like rain fall), not the total collection over a large area. The lake may be large, but the rain gauge is not. Total collection just depends on the collection site size, which is an arbitrary area.
Wikipedia says "Photometric or luminous exposure Hv is the accumulated physical quantity of visible light energy (weighted by the luminosity function) per area applied to a surface during a given exposure time."."
Said again: Exposure is not the total amount of light that falls on a photographic medium, but instead is the amount of light per area unit (lm*s per m2). Basically, how bright is the light?
Putting more buckets in the yard does not affect how much rain falls (into each).
If the FX exposure was f/8, then DX should be f/8 too. FWIW, a tiny handlheld light meter cell reads it as f/8 too. There must be dozens of camera sensor/film sizes, tiny cell phones and large film sheets, and every one of them would use f/8 here too - assuming same ISO and shutter speed and same uniform scene (they possibly could have different field of view, different metering area, a different argument).
But we do Not have to buy a uniquely calibrated light meter for every sensor/film size. One size fits all.
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Crop is a different argument than exposure. See FX - DX Lens Crop Factor
A FX D610 is 24 megapixels. In DX crop mode, it is cropped to about 10 megapixels, so this is a limitation in reproduction.
A DX D7100 is also 24 megapixels, but it "packs" them into DX space. It has all 24 megapixels "left".
But if same lens (all else the same), it is obviously exactly the same image in either DX space. The only difference is the digital reproduction of that cropped image.
(I am ignoring that 10 megapixels in DX space are obviously larger pixels than 24 megapixels in DX space, which should help noise in low light situations, if 10 megapixels are enough for our use. If FX is not cropped, even better.)
Speaking of image quality, the pixels do not create the image. The lens creates the image, projected onto the sensor. If the same lens , all else the same (subject, focus distance, aperture, etc), then of course the same lens projects the same image onto either sensor area. DX just crops to use a smaller part of it, which then necessarily has to be enlarged more to compare at same size as FX. ( We perceive this DX crop and then enlargement as appearing as a telephoto effect, but we can see exactly the same effect simply by cropping any old image, and then enlarging it back.)
The megapixels merely try to reproduce that existing lens image digitally. A digital copy. Like scanners, more pixels can improve the reproduction, but reproduction can never improve the lens image quality in any way. At best, we hopefully get nearly what we started with.
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That would depend upon which crops you are raising on your farm.
Thanks to everyone for enlightening me on cropping, exposure, and lighting. I was wondering whether I would need to hold onto my D7000 in the event I purchase a D750 which I hope would have a crop mode. Regardless to say, I will be keeping my D7000 if I do end up purchasing a D750. Thanks again.