Need help with TP fstop-dof graphic

Forbiddenbiker

Forbiddenbiker

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Adam
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We need a tutorial on f-stops, dof and alike... To go with this I've been trying to produce a graphic that shows both f-stops, and dof and why there’s a relationship between the too..

I'm not an expert so I need my idea checking for mistakes and misleading terms, corrects phrases and reasonably accurate details.

Could all and any of you ponder on the way this graphic works, or not; What have I missed? what have I not shown correctly? ..what can I add or take away..?

Its still under construction so please feel free to rip into it peeps ... no point me working on producing something totally pointless...

Firstly, does it work at all in explaining dof ..? ... would it work in conjunction with a tutorial?

I am attempting to put several diagrams together on one ... Much of the information regarding the DoF boxes needs to be added in some way..?



TPDOF.jpg



Second reduced vertion. 11.21am

TPDOF2.jpg


Any easier... ?
 
i think it looks a bit messy in truth, mostly the lines for DOF. perhaps use an actual outline of a dslr as well to help follow the diagram easier
 
Coming at this as someone who is just about coming to terms with dof and such things in a very simplified manner I find your diagram has info overload.

Could it be broken down into component parts? I accept that it might be more easily understood in conjunction with a written text.
 
its graphically too busy, and that will lead to more confusion, also the orange and blue do not mix well. there is a lot of good info, it just needs to be simplified graphically some how.

have you considered 3 identical diagrams stacked on top of each other to show the extremes of DOF? one showing the rays at f1.4, one at f8 and one at f16?
 
Chris Reed said:
have you considered 3 identical diagrams stacked on top of each other to show the extremes of DOF? one showing the rays at f1.4, one at f8 and one at f16?
Click to expand...

:) Yeah have Chris, it kinda started that way ...then I thought why not try and merge it all into one simple diagram... aye lol ... I'd like to try and get this to work cleanly though..

Not quite sure waht to remove or change mind.

Good point about the orange and blue, ...I'll change the orange, what do you suggest.
 
thats a busy diagram there, could it not just be done with a little flash animation were you can slide a bar up and down between the Fstop's and it shows what happens to the image.
if i had time i would nock one up but :( i have 3 sites to design and curantly done 1 page on each :LOL: ooops
 
how about cut down the f stops to f2.8, f8 and f16? it all goes a little above my head but im sure with the text it would make more sense
 
Yeah would have been good animated, but VB doesn't like the flash object in posts, ...although Marcel was going to ponder the problem some months ago .. not sure if I could have done that depthy coding either to be honest.

... Hey, once the first page is done your nearly finished anyway :nuts: ... that’s what I say to myself too ..lol.


I've stuck another version up.. :)
 
fletch5 said:
how about cut down the f stops to f2.8, f8 and f16? it all goes a little above my head but im sure with the text it would make more sense
Click to expand...


I'm hoping someone will suggest some good wording to explain the Dof boxes ..I can't seem to manage it in a simple way ....theirs an awful lot of photography that goes on in that small space so I did want to display it some how..



:thinking: (y)


Keep them coming please guys ... I'm going out in a bit but I'll work on it again this evening.
 
I'm not sure diagrams are absolutely necessary for an explanation of how to use depth of field or avoid DoF problems.

It looks impressive but a bit like a Physics lesson to me, and some of us artistic types ... well, we can't get our heads around diagrams like that.;)

Hope that doesn't sound too harsh ....I'm just trying to put myself in other people's shoes.
 
jerry12953 said:
I'm not sure diagrams are absolutely necessary for an explanation of how to use depth of field or avoid DoF problems.

It looks impressive but a bit like a Physics lesson to me, and some of us artistic types ... well, we can't get our heads around diagrams like that.;)

Hope that doesn't sound too harsh ....I'm just trying to put myself in other people's shoes.
Click to expand...

but a lot of people would like to understand what causes the DoF differences, which i assume is the reason for the diagram, obviously you could avoid the bit if you werent fussed bout it though
 
I hate to admit it but I cannot make sense of it, I never have been good with reading theoretical diagrams/numbers so that could be a major part of it. It looks back to front to me - if I want a larger DoF the lens is longer and if I want a wider DoF the lens is shorter (generally) or do the boxes with the lines though them not represent lenses?
 
Try this....

http://www.canon.co.jp/imaging/enjoydslr/part2/2A.html

Follow the link at the bottom to "Aperture" and you get to play around with DOF effects.

Another thing to play with here....

http://dryreading.com/camera/index.html

By the way, I have two maths A-levels and also Physics and Chemistry. I know enough about DOF to get me by, including making use of the online calculator here - http://www.dofmaster.com/dofjs.html - and I'm afraid I was instantly turned off by the complexity of the diagrams. I didn't even bother to look properly to see exactly what they contained.

I can drive a car very well without knowing the details of how an internal combustion engine or a gearbox works. I can work with Aperture and DOF without understanding the science/mechanics of it. If you really want to know how/why it all works I expect you'll find something here - http://en.wikipedia.org/wiki/Depth_of_field. DOF must have been done to death on the internet. Unless you can improve on what has already been written by others I don't see much point reinventing the wheel. I'm sure a few links to good articles should suffice....

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

http://ronbigelow.com/articles/depth-of-field-1/depth-of-field-1.htm

http://www.luminous-landscape.com/tutorials/understanding-series/dof.shtml
 
To me it would have been too hard to understand when I started, and has too many boxes.

The pic of the lens showing the way the aperture changes the amount of light going through is good because it does show that a low number = wide open, so perhaps move from there perhaps just 3 or 4 examples of much bigger boxes with blurring and a B (for bokeh) in the parts that are thrown out of focus and a clear bit with a IF (for in focus) in the part that would be in total focus at that aperture. You could show how the in focus parts move along the box as the aperture changes :shrug:
 
This would be a good summary diagram at the end of a separate series depicting F-stop sizes, depth-of-field, circles of confusion, bokeh, and possibly hyperfocal distance.

I liked the central portion with the 'Decreased DOF' angled ray traces and the circles with F-stop relative sizes. This could be a good starting point for explaining the core issues. You could then elaborate from there.

The design style of the diagram reminds me of some work done on statistical presentation by Edward Tufte http://en.wikipedia.org/wiki/Edward_Tufte. Worth a look.

Edward
 
Edward, good to find someone who understands what I'm trying to do... it does work reasonably well doesn't…. I very much take on your point...the centre needs developing for viewers to understand how dof comes about ..the basics will follow easily on from that basic understanding if I get it right.

Cheers for your thoughts... Phew, not such a daft mixing of diagrams then.



Kerioak said:
I hate to admit it but I cannot make sense of it, I never have been good with reading theoretical diagrams/numbers so that could be a major part of it. It looks back to front to me - if I want a larger DoF the lens is longer and if I want a wider DoF the lens is shorter (generally) or do the boxes with the lines though them not represent lenses?
Click to expand...

No, not lenses, graphical representations of the focus area and how they get larger or smaller depending on which f-stop is chosen...

The narrowing rays at say f16 providing a longer In focus area (Dof) than the same lens would at say f4 where the rays are wider and the in focus area (DoF) is therefore narrower ..

Is that starting to make sense yet.?



..clearly its not very clear... thanks for your thoughts. :)

tdodd said:
Try this....

.
..stuff
Click to expand...

Thanks for you links Tdodd. .. I may have misunderstood your point or you mine.. excuse me.

Its for a TP tutorial that is yet to be written and it can be used permanently by TP in that section without having to link to other pages or use someone else’s image of possible unknown copyright.

Edit: This diagram I'm hoping will incorporates much more than just a simple dof graphic ... I like to think it shows why the dof changes, the cause and effect of being close or far from the subject... its not intended to be a graph to follow through to an end ...its intended to embellish an article, although I'd like it to be able to stand on its own merits too…hence this thread.

What I need is advice on how to improve it and make it readable by all levels of photographer here at TP...?



susie said:
To me it would have been too hard to understand when I started, and has too many boxes.

The pic of the lens showing the way the aperture changes the amount of light going through is good because it does show that a low number = wide open, so perhaps move from there perhaps just 3 or 4 examples of much bigger boxes with blurring and a B (for bokeh) in the parts that are thrown out of focus and a clear bit with a IF (for in focus) in the part that would be in total focus at that aperture. You could show how the in focus parts move along the box as the aperture changes
Click to expand...

Thanks Susie, some great ideas in that lot … I think as you and others say, reducing the amount of light ray/dof boxes, making them larger and defining what’s happening more clearly with clear terms etc …I can see would help too … I like your ideas on using simple In focus and out of focus, or B for bokeh … that’s the kinda stuff I wanted to know cheers.
 
Good on yer for having a go at this Adam. :clap:

I've considered doing this a few times, and it's not easy. I also have to say that all this info is just a quick Google away and all this basic info is available for people anyway with minimum effort. ;)

I think your diagram is too busy mate and trying to do too much all in one go?

I'd be tempted to do a diagram showing the relationship between ISO, shutter speed and aperture and the way they work together in maintaining a given exposure value, and not try to achieve any more than that. That would be a good job in itself.

Then perhaps follow that up with another on the way aperture affects DOF and the way shutter speed needs to be considered in respect of camera or subject movement. Perhaps even three articles altogether - Parts 1, 2 and 3?

Top geezer though Adam for taking the time! (y)
 
Hi, Forbiddenbiker. I hope I didn't cause offence, as that was certainly not my intention, but I don't see what benefit is to be gained by reinventing the wheel. There are plenty of well respected sites that offer worthwhile tutorials and are frequently referred to by other forums the world over. I applaud your efforts to write something specifically for TP, but DOF is DOF is DOF and it isn't unique to any particular forum.

So, my point is, why do you want to go to the trouble of writing something from scratch when it is a topic that has been covered in such depth (Hah! Hah!) elsewhere? Like I said, if you can improve on what others have written then go for it, but if it will just be the same material (and how could it really be much different?), rehashed in your own words and pictures, I really don't see the point in the effort. But it's your effort, so if you wish to proceed I wish you luck :)
 
I applaud your efforts too :)

I've been too busy with other (diy) things to have much time lately and there are tutorial type things I'd like to see started too.

Have to agree the diagrams are trying to cover too much. Maybe a diagram that explains what depth of field is as a first step and another that shows the extremes?
 
I have to say I think tdodd has summed it up pretty well Adam, and pretty well nailed the reasons I've deffed doing this every time I've considered it. There are so many books and articles out there and that's without even considering what's out there on the web and just a click away. ;)
 
tdodd said:
Hi, Forbiddenbiker. I hope I didn't cause offence, as that was certainly not my intention, but I don't see what benefit is to be gained by reinventing the wheel. There are plenty of well respected sites that offer worthwhile tutorials and are frequently referred to by other forums the world over. I applaud your efforts to write something specifically for TP, but DOF is DOF is DOF and it isn't unique to any particular forum.

So, my point is, why do you want to go to the trouble of writing something from scratch when it is a topic that has been covered in such depth (Hah! Hah!) elsewhere? Like I said, if you can improve on what others have written then go for it, but if it will just be the same material (and how could it really be much different?), rehashed in your own words and pictures, I really don't see the point in the effort. But it's your effort, so if you wish to proceed I wish you luck :)
Click to expand...

No, no worries ... And theirs me was trying not to be defensive ...damn, spotted again.

Personally I think you've all missed the chance to develope a cool tutorial. :nuts: ;) ... but yes, possibly way to much info...

I'll keep it on file for now... (y)
 
RobertP said:
I applaud your efforts too :)

I've been too busy with other (diy) things to have much time lately and there are tutorial type things I'd like to see started too.

Have to agree the diagrams are trying to cover too much. Maybe a diagram that explains what depth of field is as a first step and another that shows the extremes?
Click to expand...

I am trying to explain what dof is in this one Robert, failing miserably so far unfortunately.


... I would like to re-build this type of graphical representation more simply at some stage , even though it hasn't gone down to well I think I can improve on it considerably.

Let me know if you can find a writer and I'll sort it out again... (y)




CT said:
I have to say I think tdodd has summed it up pretty well Adam, and pretty well nailed the reasons I've deffed doing this every time I've considered it. There are so many books and articles out there and that's without even considering what's out there on the web and just a click away. ;)
Click to expand...


Sure I know, just that I thought we needed it for the tutorial section.. thats all. ... People keep suggesting we improve it, no one does much, lol .. you know. (y)
 
Sorry Adam, didn't mean to knock your neck in mate. :wave:
 
I think it's a worthy attempt. It's hard to explain why smaller apertures give rise to increased DOF, and it would be a great result if you can do that in a diagrammatic way.

Unfortunately, I don't think the current diagrams achieve that. Those rectangles where the rays of light intersect are clearly important to the explanation, somehow, but for the life of me I can't work out what they're supposed to be telling me. (And I do understand DOF.) The fact that they're alongsize those circles illustrating the different apertures is confusing too.

I think it's worth another attempt. I really like your approach - very much in the style of Tufte - and you clearly have talent as a graphic designer. The bits of the diagram that illustrate the different apertures are great. But you need to work out how to make the central bit work befoe the diagram as a whole will hang together. Remember, if you have to explain it to people, then at the end of the day you've failed.
 
PS ... Here (near the top of the page) is a graphic that explains very readily why there is such a phenomenon as depth of field. (If you think about it for a moment, it's not immediately obvious why the DOF should have a value which isn't zero and isn't infinite.) If you can incorporate a version of that into your graphic - suitably repeated to represent different f-stop settings - then you could be onto a winner.
 
If I am right, then what Forbiddenbiker is trying to do, is to explain and encapsulate all of the effects of f-stop number, focal plane imaging, physics of ray tracing, and DoF onto one diagram.

In other explanations of these effects, the authors thoroughly go through the concepts step by step, but do not offer (or attempt) a single graphical summary which covers all of the dimensions.

What Forbiddenbiker could have is a diagram that will be useful to those who have gone through the groundwork, but who need one diagrammatic point of reference for the whole subject. It can also be used as a quick aid to revision.


Edward
 
CT said:
Sorry Adam, didn't mean to knock your neck in mate. :wave:
Click to expand...

Hey no worries Cedric. ...serves me right for going ott design wise ... I find The Flash building software kinda addictive, once I start I have to finish the whole box type thing.

I'm gonna try again on this style, then if that fails I go knock up some shutter and dof graphs... or maybe this thread will inspire another member to do some ... or maybe not lol..


StewartR said:
PS ... Here (near the top of the page) is a graphic that explains very readily why there is such a phenomenon as depth of field. (If you think about it for a moment, it's not immediately obvious why the DOF should have a value which isn't zero and isn't infinite.) If you can incorporate a version of that into your graphic - suitably repeated to represent different f-stop settings - then you could be onto a winner.
Click to expand...


Yes that link is exactly what I'm referring too, that pages top graphic (The right hand side anyway) is the same representation I'm trying to show in the central focus part of my graphic. (and the blown up box to the bottom left)...

Actually I can see how void my graphic is of explanation now I see that graphic, I've not really explained the correlation of real DOF against dof at the focal plane at all have I ...

Its really not been easy to get this far nowhere, but your comments have been very useful thanks Stewart... I'll work on it again. (y)
 
Edward Bancroft said:
If I am right, then what Forbiddenbiker is trying to do, is to explain and encapsulate all of the effects of f-stop number, focal plane imaging, physics of ray tracing, and DoF onto one diagram.

In other explanations of these effects, the authors thoroughly go through the concepts step by step, but do not offer (or attempt) a single graphical summary which covers all of the dimensions.

What Forbiddenbiker could have is a diagram that will be useful to those who have gone through the groundwork, but who need one diagrammatic point of reference for the whole subject. It can also be used as a quick aid to revision.


Edward
Click to expand...

Yes, I think somewhere half way to that possibly. it is kinda fundamentally why we get DoF at the other end. .... My idea was to somehow convey why dof changes with different angles of light at the focal plane, whether that be a longer lens or just closing the aperture or both.

I'd need to make the box dof areas more accurate, although still just a representation, possibly even place up a measure of the mirrored DoF of possible distances correlations against then too...although that would be all guess work, I understand why, but to explaine it with word or really with loads of maths ... no way.

I feel I've gotten close to a good way to represent the lot.. even though It makes little sense to most at the moment.

Thanks for getting me .. I can see you struggled, good of you to work through it cheers. :)
 
Not a thing Stewart, :puke: ... it does come in fits and bursts my passion for design no other reason than that.

I've pondered it a few times and decided (like you suggested) it needs the central part (the focal plane) and its relationship to dof at the other side of the lens (just like that diagram you linked to previously) presented clearly first.

So it will have the whole dof picture in the middle (both sides like your link)..That should make it clearer. Then I'll somehow merge that design with this one ... inevitably it is going to be a complexed graphic, but hey, I can't think of any other way... and anything more simplified isn't going to cover the subject properly ...and also will bore the pants of me to design, so that aint gonna happen.

Plenty more cold and wet evenings to keep me in this winter, so I will make some more progress I promise.

:)
 
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