Depth of Field differences in cams

[antere]

Hi there.

I was just playing around with a film SLR(Nikon F801 with 28-70mm lens) and another fixed lens digicam(Fuji S5000).

I tried focusing on a subject with F3.1(small DOF) for both cams and also with almost similar focal length. I've noticed that when using the SLR, the back objects gets blurred out significantly. When using the digicam, the back object still appear rather sharp.

From this, can I say that DOF of fixed lens is bigger than SLRs?

[Helbreath]

i read from somwhere that DOF of SLR is much shallower that compact digicams due to the smaller sensors of digicams

f/2.8 in digicam is roughly equal to f/8 of SLR

[antere]

Originally Posted by Helbreath i read from somwhere that DOF of SLR is much shallower that compact digicams due to the smaller sensors of digicams f/2.8 in digicam is roughly equal to f/8 of SLR

that makes sense.
Thanks for this info.

[sehsuan]

i may be misguided, but it seems to be the smaller absolute diameter of the compact cameras. slr's have apertures (when wide open) that hit easily 1 cm across, but it's not common to have anything that big on a compact digicam. i think (yet to figure out everything) it affects the circle of confusion etc, so bring about a much lesser bokeh.

Fundee explained to me on paper before during a SEED, using a diagram and an analogy of a pinhole camera - the hole (aperture) is a much smaller absolute figure on compact digi's compared to that of slr's, and once you align this analogy to a pinhole camera, you'll see that slr's are like pinhole cameras with larger "holes", and the bokeh effect is more obvious (similar to shallower DOF), and the compact digi's have a much smaller absolute "hole" (which translates to a deeper dof for the equivalent angle of view).

[antere]

Originally Posted by sehsuan i may be misguided, but it seems to be the smaller absolute diameter of the compact cameras. slr's have apertures (when wide open) that hit easily 1 cm across, but it's not common to have anything that big on a compact digicam. i think (yet to figure out everything) it affects the circle of confusion etc, so bring about a much lesser bokeh. Fundee explained to me on paper before during a SEED, using a diagram and an analogy of a pinhole camera - the hole (aperture) is a much smaller absolute figure on compact digi's compared to that of slr's, and once you align this analogy to a pinhole camera, you'll see that slr's are like pinhole cameras with larger "holes", and the bokeh effect is more obvious (similar to shallower DOF), and the compact digi's have a much smaller absolute "hole" (which translates to a deeper dof for the equivalent angle of view).

hey Sehsuan, this is a very good explanation! Now this clears the air!

Now I'll try to dump my S5000 for the SLR if doing bokeh shots.

[sehsuan]

if you can understand what i wrote, good. and don't thank me, thank my ShiFu Fundee....

[Helbreath]

Originally Posted by sehsuan i may be misguided, but it seems to be the smaller absolute diameter of the compact cameras. slr's have apertures (when wide open) that hit easily 1 cm across, but it's not common to have anything that big on a compact digicam. i think (yet to figure out everything) it affects the circle of confusion etc, so bring about a much lesser bokeh. Fundee explained to me on paper before during a SEED, using a diagram and an analogy of a pinhole camera - the hole (aperture) is a much smaller absolute figure on compact digi's compared to that of slr's, and once you align this analogy to a pinhole camera, you'll see that slr's are like pinhole cameras with larger "holes", and the bokeh effect is more obvious (similar to shallower DOF), and the compact digi's have a much smaller absolute "hole" (which translates to a deeper dof for the equivalent angle of view).

ok so it is the hole not the sensor...... thanks for pointing out

[antere]

Originally Posted by sehsuan if you can understand what i wrote, good. and don't thank me, thank my ShiFu Fundee....

THANK YOU FUNDEE!

[antere]

Hmm, I came across this thread as well. They are talking about the similar topic.

http://www.photo.net/bboard/q-and-a-...?msg_id=006IsN