Can someone explain depth of field to me in relation to aperture? I understand that the smaller the aperture number or f-stop means that the opening is larger and more light comes in (and larger number = less light). What I can't wrap my head around is why letting in more light gives you a more shallow depth of field and letting in less light gives you more focus of the whole picture. What is the science behind this?
Can someone explain it to me in layman terms!!
I just figured out the relationship between shutter and aperture (the whole water in the bucket analogy helped) and was feeling proud of myself and then I hit a wall with depth of field.
ok, in basic terms for when you don't know all the details of apertures, shutter speed, white balance yada yada, I always recommend books by Scott Kelby for further learning especially since he has a sense of humor and talks for normal ppl, I have The Digital Photographer's Handbook' I think. Anyway...
the smaller the number (Aperture) the less DEEP your camera is focusing... I think its like the depth front to back that will be in sharper focus.. which really gives you a FEELING of space and depth from the foreground and background. So if you want a flower in a garden that is halfway through in focus, but all the other flowers out of focus then set your aperture as low as it will go and focus on your flower and snap away! the HIGHER number you choose the more stuff front and back (shallow and deep along with middle) will be more in focus all together :)
smaller aperture number = LESS DOF
Stand closer to an object and/or zoom in as far as possible = less DOF (same as if you back away and zoom out to the widest possible)
And the direct opposites will result in MORE DOF
Examples:
F/1.8 = very shallow DOF while F/22 = very large DOF
Zoom in all the way, and take a picture of a tiny pebble (getting the lens as physically close as possible while still withing the "minimum focusing distance" of the lens) Will result in LESS/SHALLOW DOF
I'm not sure but I *think* what Kiwi's after is the actual physics behind *why* having a wider aperture reduces what's in "focus", and how "focus" even works in the first place with camera systems.
The science behind is pretty complicated so I'm not sure it's worth worrying about. As others have said, the wider the aperture (the smaller the f/ number) the narrower the depth of field, so less is in focus; the smaller the aperture (the bigger the f/ number) the wider the depth of wield, so more is in focus.
Marne, thanks for the book recommendation and giving a great description. I am sure the others were good, too. I just had time to briefly scan and I liked Marne's description.
thanks everyone! I think everyone is right... the science is not important to think about ...
I got this answer from Rob Barron of My Photo Tutor.
It isn't about more or less light. You always need the right amount of light and this is achieved by balancing aperture, shutter speed and ISO (See my video on Reciprocity for more on this). Try this little experiement: Make a pinhole in a piece of paper. Hold it to your eye and look through it at something that is a few feet away. Do you notice it looks pretty sharp? No lens involved yet that pinhole has a sharpening effect. The same is try of a narrow aperture ;o) http://www.youtube.com/watch?v=BfOC_Msb1dI&feature=email
Cheers,
Rob
Here is a link for the techical speak that made the most sense to me. The larger aperature creates a larger "focus spread". Basically, by lettting in more light, you're also letting in more noise. There's a diagram toward the bottom in the "Depth of Focus & Aperature Visualizaion" section. That helped me understand the science behind it.
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http://www.ephotozine.com/article/Depthoffield-explained-4631
the smaller the number (Aperture) the less DEEP your camera is focusing... I think its like the depth front to back that will be in sharper focus.. which really gives you a FEELING of space and depth from the foreground and background. So if you want a flower in a garden that is halfway through in focus, but all the other flowers out of focus then set your aperture as low as it will go and focus on your flower and snap away! the HIGHER number you choose the more stuff front and back (shallow and deep along with middle) will be more in focus all together :)
smaller aperture number = LESS DOF
Stand closer to an object and/or zoom in as far as possible = less DOF (same as if you back away and zoom out to the widest possible)
And the direct opposites will result in MORE DOF
Examples:
F/1.8 = very shallow DOF while F/22 = very large DOF
Zoom in all the way, and take a picture of a tiny pebble (getting the lens as physically close as possible while still withing the "minimum focusing distance" of the lens) Will result in LESS/SHALLOW DOF
The science behind this is complicated lol
If most of the photo is in focus, it has a wide DOF, like in most landscape photos.
Hope that helps, some of the others have explained the link with aperture for you, but that is what it is.
I got this answer from Rob Barron of My Photo Tutor.
It isn't about more or less light. You always need the right amount of light and this is achieved by balancing aperture, shutter speed and ISO (See my video on Reciprocity for more on this). Try this little experiement: Make a pinhole in a piece of paper. Hold it to your eye and look through it at something that is a few feet away. Do you notice it looks pretty sharp? No lens involved yet that pinhole has a sharpening effect. The same is try of a narrow aperture ;o)
http://www.youtube.com/watch?v=BfOC_Msb1dI&feature=email
Cheers,
Rob
http://www.cambridgeincolour.com/tutorials/depth-of-field.htm