DOF question
Oct 2, 2012 19:22:15 #
I took this shot at f/5.6 focal length 32mm(appox) and was wondering if anyone had a definitive reason for why the reflection in the mirror wasn't affected by the shallow setting. The DOF in the mirror appears to be much deeper. Opinions and thoughts welcomed. A friend and I have been going around and around for 2 days on this! lol
Oct 2, 2012 19:28:46 #
On a flat mirror, the image of a point in a mirror is the same distance behind the mirror as the object is in front of it. The rays of light from a given point of the object reflect off the mirror as if they had come directly from the corresponding image point behind the mirror.
Oct 2, 2012 19:31:21 #
snails_pace
Loc: Utah
Interesting pic and question. I think external car mirrors are convex .... a bit "fisheye". Looks like that overides the DOF effect of the camera lens.
Why not repeat the photo with a flat mirror and compare the results?
Why not repeat the photo with a flat mirror and compare the results?
Oct 2, 2012 19:50:37 #
Oct 2, 2012 20:04:13 #
Oct 2, 2012 20:20:00 #
BigBear wrote:
Convex mirrors make objects appear closer than they actually are.
Plus the writing on passenger mirrors, as well as the one in the caption states, has this printed on the mirror! :shock:
Oct 2, 2012 20:23:11 #
Another neat trick, though deviating from the original post, when wanting to read a needle type gauge or similar instrument, use a mirror because it will show a truer straight on reading if held correctly.
Oct 2, 2012 20:25:09 #
AlyG wrote:
Big Bear, that was MY first response when asked why!
That and Canon makes things look better. :P
Oct 2, 2012 22:45:26 #
Oct 2, 2012 22:50:27 #
AlyG wrote:
you make me wish I had paid more attention in physics class! Thanks for your reply. :?
Nah, just being observant! Something I'm not good at very much, I find everyday. :thumbup:
Oct 2, 2012 23:19:43 #
You are focused on the MIRROW, not the reflection. The mirrow is a solid object. You are being confused by the reflection.
Oct 2, 2012 23:31:29 #
Bangee5 wrote:
You are focused on the MIRROW, not the reflection. The mirrow is a solid object. You are being confused by the reflection.
The image in the mirror is more in focus than the
mirror itself. Look at the frame of the mirror. It's not sharp.
Focus appears to be toward the rear of the window.
Oct 3, 2012 05:24:17 #
Because you focused on the person reflected in the mirror. The mirror itself and background are out of focus. Aperture sizes, point of focus and distance from object of focus are 3 elements that affect DOF.
Oct 3, 2012 07:47:25 #
GoofyNewfie wrote:
The image in the mirror is more in focus than the
mirror itself. Look at the frame of the mirror. It's not sharp.
Focus appears to be toward the rear of the window.
Bangee5 wrote:
You are focused on the MIRROW, not the reflection. The mirrow is a solid object. You are being confused by the reflection.
The image in the mirror is more in focus than the
mirror itself. Look at the frame of the mirror. It's not sharp.
Focus appears to be toward the rear of the window.
Look at the image being refected compared to what is around the auto. Everything near and far is in focus. That means the camera focued on the mirrow, not the reflection it self. This is how a mirrow telescope works.
Oct 3, 2012 08:26:52 #
I think the mirror is just like you would expect a photo of a landscape painting.....eveything in the painting would be in focus even if it had a forground pasture with distant mountains in the background.
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