Depth of Field - DPChallenge Forums

04/20/2002 07:24:34 AM · #1

Is there an easy way to know your depth of field on these digital cams?
I am having trouble with this a lot more than I did with the AE1. I just can't see the display well enough. Is the Nikon 995 just not good at this? HELP!

04/20/2002 07:55:05 AM · #2

David,

I don't know specifically for 995, but this guy at this site worked out a general formula for DOF in digicams. It's something like 'the depth of field for a digital camera with a 1:N (usually 5) focal length equivalence ratio at a given F-setting is the same as that of a 35 mm camera with a lens closed down by N (usually 5) F-stops more. For most digital cameras (excepting a few professional models) N is close to 5, which translates into a five F-stop difference in aperture. '

IN OTHER WORDS: a digital camera at F/2.8 has depth of field close to that of a 35-mm camera with an (F-equivalent) lens at F/16!

Click HERE to read the whole article.

04/20/2002 08:10:17 AM · #3

Or the short summary is, digital cameras have excellent depth of field which makes them really terrible for trying to do creative stuff with. YOu can get some level of blurring if the foreground subject is very close, the aperture is wide open and the background is quite far away.

It's all to do with them having a comparably smaller image sensor.

Probably the best I've managed with my G2 is here

04/20/2002 08:39:44 AM · #4

I think I have a decent depth of field shot here..

//www.pbase.com/image/1749154/large.

But I think the night helped focus the subject better

04/20/2002 08:47:48 AM · #5

Originally posted by hokie:
I think I have a decent depth of field shot here..

//www.pbase.com/image/1749154/large.

But I think the night helped focus the subject better

That is a really cool shot. Very well taken. I'm amazed the floodlight didn't whiteout the whole shot.

Here again though is an example of the excellent depth of field a digital camera has. With an SLR body you could have had a pin sharp glove and almost totally blurred background. Not saying you'd want it for this shot, but you can do it with an SLR, and not with a prosumer digicam, such as a G2.

04/20/2002 08:52:12 AM · #6

cool shots :) ... the e-10 has a slightly bigger sensor so there is 'only' a 4 stop difference in DOF from a 35 mm .. lol

Here's an example:

Railing

04/20/2002 09:01:31 AM · #7

[i]That is a really cool shot. Very well taken. I'm amazed the floodlight didn't whiteout the whole shot.

Here again though is an example of the excellent depth of field a digital camera has. With an SLR body you could have had a pin sharp glove and almost totally blurred background. Not saying you'd want it for this shot, but you can do it with an SLR, and not with a prosumer digicam, such as a G2. [i]

I agree...A film SLR could have really focused the front image. After the shot came out I was glad the players in the back were still somewhat recognizable as players..it helps I think.

The floodlight was perfect. Because this was a highschool field the floods were weaker than a pro field and didn't overpower ths shot.

* This message has been edited by the author on 4/20/2002 9:02:06 AM.

04/20/2002 09:06:11 AM · #8

Originally posted by magnetic9999:
cool shots :) ... the e-10 has a slightly bigger sensor so there is 'only' a 4 stop difference in DOF from a 35 mm .. lol

Here's an example:

Railing

I've managed to get something similar with the G2, but at f2. Even then it still has a lot of detail well into the background. I wonder how well the big changeable lens Digitial SLRs do, like the canon D60.

Probably closer but still not as good, with the approx 1.6 modifier they have working on them.

04/20/2002 09:07:17 AM · #9

Originally posted by hokie:
[I agree...A film SLR could have really focused the front image. After the shot came out I was glad the players in the back were still somewhat recognizable as players..it helps I think.

I think it works really well with them still being recognisable in a more abstract way. Perhaps a less central framing of the glove could have been a bit stronger, but I really like it as it is.

04/20/2002 09:16:25 AM · #10

Hokie, that's a *really* nicely set up shot and i like the tonality you've gotten in this black and white. I wonder though, have you tried selectively lightening the glove? It's a leettle too dark on my monitor, and i think that might elevate it to a truly worldclass photo.

thanks

Originally posted by hokie:
[i]That is a really cool shot. Very well taken. I'm amazed the floodlight didn't whiteout the whole shot.

Here again though is an example of the excellent depth of field a digital camera has. With an SLR body you could have had a pin sharp glove and almost totally blurred background. Not saying you'd want it for this shot, but you can do it with an SLR, and not with a prosumer digicam, such as a G2. [i]

I agree...A film SLR could have really focused the front image. After the shot came out I was glad the players in the back were still somewhat recognizable as players..it helps I think.

The floodlight was perfect. Because this was a highschool field the floods were weaker than a pro field and didn't overpower ths shot

04/20/2002 09:18:01 AM · #11

actually, though, ive been 'leaned' on that big DOF thinking it was bigger than it actually was a lot of times and got an OOF shot : P .. so maybe the G2's stop difference is even greater than 5...

Originally posted by GordonMcGregor:
Originally posted by magnetic9999:
[i]cool shots :) ... the e-10 has a slightly bigger sensor so there is 'only' a 4 stop difference in DOF from a 35 mm .. lol

Here's an example:

Railing

I've managed to get something similar with the G2, but at f2. Even then it still has a lot of detail well into the background. I wonder how well the big changeable lens Digitial SLRs do, like the canon D60.

Probably closer but still not as good, with the approx 1.6 modifier they have working on them.

[/i]

04/20/2002 09:33:51 AM · #12

hey magnetic9999....

....."Hokie, that's a *really* nicely set up shot and i like the tonality you've gotten in this black and white. I wonder though, have you tried selectively lightening the glove? It's a leettle too dark on my monitor, and i think that might elevate it to a truly worldclass photo."...

Thanks for the comment.

I tried giving the shot a bit more light but the glove started to turn a bit green on me. I just took the shot last night (my daughters boyfriend is the catcher) along with about 150 other shots..

Haven't had time to really mess around with these yet. This one just popped out at me on a preliminary browse through them and I did a quick edit.

I could isolate the glove in photoshop and screen the light there and then mess with the hues..we'll see.

At the very least I think the baseball team will have some decent photos :-)

04/20/2002 10:51:29 AM · #13

Originally posted by magnetic9999:
David,

Click HERE to read the whole article.

Thanks 99, I am now lost in the "Circle of Confusion"

04/20/2002 01:30:36 PM · #14

Originally posted by David Ey:
Originally posted by magnetic9999:
[i]David,

Click HERE to read the whole article.

Thanks 99, I am now lost in the "Circle of Confusion"
[/i]

If you mean that in the sense the article did, that could actually be a good thing ; ). But if you mean you're just confused, then that's something else.

Canon EF 28-135mm f/3.5-5.6 IS USM

04/20/2002 11:04:18 PM · #15

My attempt at depth of field with a G2.

drewmedia

Canon EOS-300D Rebel

04/20/2002 11:11:19 PM · #16

To be honest with you, the math on magnetic's article makes me quit reading before I even start. I do enough math in school :)

Anyone maybe want to write a practical tutorial on shooting these good depth of field shot? ahem... maybe someone who posted here with their examples? ahem, gordon? ahem magnetic? heheheheh :D

As if I hadn't already asked Gordon for enough in the tutorial section ;)

Drew

langdon

Canon EF 17-40mm f/4.0L USM

04/20/2002 11:13:21 PM · #17

when writing that tutorial be sure to include how the hell to get results like this. :)

04/20/2002 11:18:01 PM · #18

Originally posted by langdon:
when writing that tutorial be sure to include how the hell to get results like this. :)

That's easy. Spend 5 grand on a camera.... then know how to use it :)

04/21/2002 07:42:08 AM · #19

EY-----
Thanks 99, I am now lost in the "Circle of Confusion"
[/i]
99-----
If you mean that in the sense the article did, that could actually be a good thing ; ). But if you mean you're just confused, then that's something else.

Lets see, if a brown cow gives 1.342845 times as much milk as a black and white cow and I don't know how much the black and white cow gives, I am still in the circle aren't I?
Sorry, lost my head for a second there. Thanks for the input folks. There is so much to learn. I really do appreciate your help and links.

04/21/2002 09:13:32 AM · #20

David .. OK, well, I skipped all the math too .. But the important point was that a digital camera has more depth of field at the same f stop than a 35 mm. It's about a 5 stop diff for most cameras.

For those that don't know, Depth of Field or DOF is how deep the area is that is in focus. So a wide depth of field means that grandma standing 5 feet away from you is in focus, but maybe so also is the tree like 50 feet behind her. But a narrow depth of field might mean that even though you've focused sharply on the tip of grandma's nose, her eyes, only an inch behind, are slightly out of focus.

How does one control this? By changing your aperature. In general, the bigger the aperature, the narrowerthe depth of field. The opposite is also true: the smaller your camera aperature, the wider or deeper your DOF.

Easy enough. Now here's the confusing part for a lot of people. A smaller number is a bigger aperature. Got that? An aperature of 2.8 is a BIGGER hole/opening than an aperature of 16. Why? Because it's really a fraction and they've left out the numerator. Just like 1/2 is bigger than 1/16. Same thing.

Now back to digital cameras. Since they use a smaller area to capture the image than the 35mm film rectangle, they give more DOF at the same aperature. Because remember, the smaller the opening, the deeper the DOF. As a rule of thumb, the diff is about 5 f/stops (aperatures).

If you've ever noticed, they go in certain steps: 22, 16, 11, 8, 5.6, 4, 2.8, 2.0. So if you set your digicam aperature to 2.0, count 5 steps higher, and the equivalent aper on a 35 mm camera is 11. Setting your digicam to 16 though gives you a huge DOF, so huge you could never ever get it on a 35 mm camera. This can be great for getting lots of stuff in focus. The only downside is if you want to do stuff with really shallow narrow DOF, it's a lot harder, because it's always deeper, not narrower, thanks to those small digicam sensors.

Whew!

Make more sense?

Sony 16-50mm f/3.5-5.6 E-mount

04/21/2002 01:37:10 PM · #21

Originally posted by magnetic9999:

Whew!

Make more sense?

[/i]

ABSOLUTELY! Now,lets see. My current stop action entry is 1/250sec f5.1 iso100 and I was about 12 inches from the subject's center. ie:there is subject Â± 2 inches from this. The far and near objects are not in good focus. I would have thought f5 would work but it didn't. Any thoughts on this? If you remember, please look tomorrow at my entry. I had no more time to retake the shot. Thanks, David
and I was about 12 inches from the subject

jmsetzler

Sony Alpha a6000

04/21/2002 02:22:54 PM · #22

I have discovered that a more shallow depth of field may be achieved with a digital camera by stretching the zoom to it's max. If I set my cam for aperture priority and go to 2.1, I can use the full zoom of the camera t allow me to get further away from the subject to better blur the background.

BTW- I turned off the digital zoom capability of my camera so I can't get the full 10x. I have 5x optical and I prefer the photo quality without entering the digital range. There is a significant difference in quality on some shots...

04/22/2002 11:30:18 AM · #23

jim...great picture for the stop motion. I always enjoy new ways of doing old stuff (liquid stop motion)