thom w Loc: San Jose, CA

How does F stop effect depth of field. Not what is the effect, I know that. How does it work? Years ago I played with pinhole cameras. Is it like that. Is a high F stop (small aperture) like adding another element? If I should just go read a book I can do that. Thank you anyone who answers.

dirtpusher Loc: tulsa oklahoma

lightcatcher Loc: Farmington, NM (4 corners)

:thumbup: :thumbup:

oldtigger Loc: Roanoke Virginia-USA

ok, i read the artical a couple times;
now, how does F stop alter depth of field?

lightcatcher Loc: Farmington, NM (4 corners)

:?: :?: :?:

dirtpusher Loc: tulsa oklahoma

the photo should have explained that.

think about this. small number shorter D/F...

CaptainC Loc: Colorado, south of Denver

You must be an engineer. I know you really want to know the physics of this.
I had to deal with the "engineer mentality" when I sold cameras. You guys like to know how and why things work. An admirable trait if you are designing cameras. Useless to a photographer. :-)

Better you spend your time actually taking images and improving that skill than learning the physics of optics that has absolutely nothing to do with getting better pictures.

I've been doing this for 50-ish years and I know how to control DOF and never gave 2 seconds thought to why it works.

But I know you just have to figure this out. :-)

oldtigger Loc: Roanoke Virginia-USA

i agree dirtpusher that in trying to answer questions of this nature it can be difficult to determine where to draw the line between adequate and too technical an answer.
I think this OP understands DOF as a subjective judgement about a generally accepted degree of blur.
I think he really wants to know something about the effect the aperture has on contrast, acutance, resolution, circle of confusion etc...

Apaflo Loc: Anchorage, Alaska

You are exactly right! That article shows what happens, but didn't explain how or why it happens.

About 3/4ths of the way down this page is a section titled "DEPTH OF FOCUS & APERTURE VISUALIZATION", with a very good graphic that show exactly how aperture affects DOF.

http://www.cambridgeincolour.com/tutorials/depth-of-field.htm

dirtpusher Loc: tulsa oklahoma

i started to post that same page. but decided not. after he started asking different questions then give him more detail info. bombarding with trig. an algebra math wasn't gonna do it.

am not trying to impress to anyone what i know and don't know, more the latter. if he is still inquiring then more can be provided. i've seen lot of people on here try to flash with boggling info. that strait simple ones... and it will never stop. :roll: :roll: :roll:

i try to let thm tell me where there going with questions! :roll:

rook2c4 Loc: Philadelphia, PA USA

Are you specifically asking for the mathematical equation? Obviously, the article doesn't delve that deep into the precise physics involved.

oldtigger Loc: Roanoke Virginia-USA

dirtpusher has a handle on the problem.

We have a refererance section. Why can't we have a prepackaged set of the best links, (like cambridge color) and explanations and just send them there to read at their own speed or level of interest.
Rehashing the same old boring basics drives me nuts cause you guys are loaded with in depth skills and knowledge i would much rather be tapping.

Apaflo Loc: Anchorage, Alaska

I think the OP merely wanted to know exactly what he asked! No more or less. Not what happens to DOF when the aperture is changed, but why it happens. Not about contrast, acutance etc., just about DOF.

And knowing why may not be necessary for some, but is essential for others. We could shoot studio portraits for a lifetime and just a chart on the wall that tells what happens is good enough! But to do macro photography at greater than 1:1 the physics of how aperture, focus distance, focal length, and magnification interrelate is essential.

Regardless of whether any one particular person can understand it or needs to know it, it is one of the more unfortunate quirks of human nature that people try to minimize, and denigrate, knowledge they cannot understand. People in photography forums commonly make derogatory remarks about anyone that takes any subject beyond their level. Cracks about "over technical", "engineering" or "artsy fartsy" and even about things being too academic are common. They are always inappropriate too. Not every discussion has to help me, or even be useful to me or be understandable by me. Or any one particular person.

The example I always think of is music, something I have zero talent at making, but I hugely enjoy the results of others learning the artistic and technical aspects of. It would be stupid of me to insist that no Internet discussions about music should be allowed that are over my head! And the same is true of those who would restrict the range of discussion about photography to only their level...

dirtpusher Loc: tulsa oklahoma

i don't know about all that. but do try at other peoples pace.

they do have freq. asked questions. some use it some don't. to much work sorting things. easier to just ask. you will see same questions asked over and over. we all can use patience. lol :thumbup: :thumbup: :thumbup:

Apaflo Loc: Anchorage, Alaska

I don't see the connection between this thread and those comments.

The OP made only one post and asked only one question, which he explained very carefully.

The cite I gave was not to trig or algebra, and nobody else has cited any math either. The cite was specifically to a graphic chart that shows specifically what the OP specifically asked about.


But why not just answer the OP's question to start with? Does he have to ask twice? Five times? Or more?

Most of the "boggling info" was not boggling, and none of it was an answer to the OP's question! (I agree with you that such posts are meant to be boggling and that people are interested in telling everyone what they know rather than answering the OP's question.)