Terms for DOF, aperture etc...

[Yella Fella]

Just to clarify my daftness... just want to know the correct terminalogy

Wide apertures = low F numbers, big DOF?

Narrow apertures = high F numbers, narrow DOF?

is that correct? I know what it is, just the variant terminolgy confuses me... as i tend to call it lots of DOF for in focus, e.g. F11 onwards etc, and big DOF for wide bokeh pics. Someone correct me please for the terminalogy used as my brain hurts, ta!

[sugarzebra]

Close!
Wide aperture (lower f/stop) shallow DOF
Narrow aperture (higher f/stop) greater DOF

The f/stop is a fraction that expresses the diameter of the aperture in mm (where the focal length of the lens is the numerator and the stop # is the denominator). Thats why as the stop number decreases the aperture increases. Hope this helps more than confuses :D

[Yella Fella]

i know how it works, just the way people talk about it confuses me lol... off to read me books

[Monkeymicra]

just to clirify for my stupidness, if i use F2.7 the BG will be OOF but the FG will be sharp.

if i use F8 (maximum my camera will go) the whole picture will be in focus

[Wilt]

Just to clarify my daftness... just want to know the correct terminalogy

Wide apertures = low F numbers, big DOF?

Narrow apertures = high F numbers, narrow DOF?

is that correct? I know what it is, just the variant terminolgy confuses me... as i tend to call it lots of DOF for in focus, e.g. F11 onwards etc, and big DOF for wide bokeh pics. Someone correct me please for the terminalogy used as my brain hurts, ta!

In my 40+ years, DOF seems to have been referred to most as 'deep' or 'shallow'

[Wilt]

Close!
Wide aperture (lower f/stop) shallow DOF
Narrow aperture (higher f/stop) greater DOF

The f/stop is a fraction that expresses the diameter of the aperture in mm (where the focal length of the lens is the numerator and the stop # is the denominator). Thats why as the stop number decreases the aperture increases. Hope this helps more than confuses :D

Large aperture (f/2) refers to size of the diaphram opening

Small aperture (f/22) refers to size of the diaphram opening

...(not referring to the numerical designation, which is the denominator in the fraction)

[Hermeto]

http://www.canon.co.jp/Imaging/enjoydslr/p_2_007.html

[Wilt]

http://www.canon.co.jp/Imaging/enjoydslr/p_2_007.html

This article refers to 'wide' or 'narrow' for Depth (how deep) of Field! 'Shallow' and 'deep' are more appropriate adjectives for depth! You don't drown in the wide part of a swimming pool, you drown in the deep part! :)

Google 'shallow depth of field' to see how many other publications use that term. 194000 hits on 'shallow depth of field' vs. 36000 hits on 'narrow depth of field'.

[Hermeto]

Okay with me if you like it that way, I call it 'wide' and 'narrow'.

Anyway, my link was not comment to your post Wilt, it was an answer to OP..

[PacAce]

Close!
Wide aperture (lower f/stop) shallow DOF
Narrow aperture (higher f/stop) greater DOF

The f/stop is a fraction that expresses a ratio of the diameter of the aperture relative to the focal length of the lens (where the focal length of the lens is the numerator and the diameter of the aperture is the denominator). Thats why as the stop number decreases the aperture increases. Hope this helps more than confuses :D
Note the correction in RED. :)

[Wilt]

Okay with me if you like it that way, I call it 'wide' and 'narrow'.

Anyway, my link was not comment to your post Wilt, it was an answer to OP..

Open your mouth deep and take a wide breath! :rolleyes: ;)

[Hermeto]

Internet is wide and deep - all kinds of people write all kinds of things on the Internet.
Google just search for these things, it doesn’t qualify them as right or wrong.

If terms wide and narrow are good enough for Canon on their own site, they are most definitely good enough for me..

[jfrancho]

Use a tilt shift and you can acheive a wide narrow DOF.

[Wilt]

Internet is wide and deep - all kinds of people write all kinds of things on the Internet.
Google just search for these things, it doesn’t qualify them as right or wrong.

If terms wide and narrow are good enough for Canon on their own site, they are most definitely good enough for me..

My point for the Google search was about 'common usage' (regardless of whethe or not it is grammatically incorrect). 'deep' and 'narrow' are grammatically correct AND 'deep' but more importantly 'narrow' it is also highest volume of uses, so that is the convention for terminology that the majority follow...which was the point of the OP, to understand what the terminology ought to be, since he saw it used in so many different ways. We are all trying to communicate with one another, and within any area of specialization the commonality of terminology aids in clear communication with one another.

The fact that a Canon site uses it does not make it necessarily correct in a different language. Remember Canon is Japanese company, not English. I have seen owner manuals for Japanese products I owned, referring to 'camela' and 'ladio' :confused: ! Note the web address for the link was .co.jp (.jp=Japan)

[Hermeto]

English is not my first language so I am the last one to discuss semantics.
I agree with you that different languages use different terms for the same thing: e.g. in my native language we use terms big and small.

I didn’t have time to search Canon UK but it seems that Canon US uses the term greater depth of field:


http://www.usa.canon.com/consumer/controller?act=ProductCatIndexAct&fcategoryid=148 (http://www.usa.canon.com/consumer/controller?act=ProductCatIndexAct&fcategoryid=148)


as much as wide depth of field:


http://www.usa.canon.com/consumer/controller?act=ModelDetailAct&fcategoryid=151&modelid=7321 (http://www.usa.canon.com/consumer/controller?act=ModelDetailAct&fcategoryid=151&modelid=7321)


I also agree with you that the main point of OP was understanding and proper use of terminology but since the matter of the fact is that photographers around the world use variety of terms for the same subject, it is important to understand the true meaning of the subject, rather than forcing the use of a "proper" word for it.

To put it in a nutshell: I’m sorry Wilt but you didn’t convince me on this matter..

[Wilt]

Hermeto, the problem arises when apparently conflicting terminology refers to the same situation. 'bigger f/stop'... is that referring to the 'larger aperture' or the 'bigger number'...yet you see people use the term to mean both, although the end result is opposite in effect. Wheter you call it 'bigger DOF' or I call it 'deeper DOF' the concept is still the same, so in this case 'bigger' and 'deeper' debate is actually irrelavant, I agree.

I still come back to what appears on Canon isn't necessarily right...I have worked for companies who have tech writers on staff who don't understand the terminology, they just write (no different than when they were in school) and the technical correctness is not always reviewed, unfortunately!

[jfrancho]

How about "great DOF" used to describe a picture with very little DOF. Should say, "great use of shallow DOF and selective focus."

[sugarzebra]

Large aperture (f/2) refers to size of the diaphram opening

Small aperture (f/22) refers to size of the diaphram opening

...(not referring to the numerical designation, which is the denominator in the fraction)

Exactly; as explained in my post above. My original post should have read

Wide aperture (lower f-stop) shallow DOF
Narrow aperture (higher f-stop) greater DOF

Leo, in his correction has simply stated the same equation from a different perspective, and to avoid any confusion it should read;

The f-stop is a fraction that expresses a ratio of the diameter of the aperture relative to the focal length of the lens (where the focal length of the lens is the numerator and the diameter of the aperture is the denominator). Thats why as the stop number decreases the aperture increases. Hope this helps more than confuses

Thanks Wilt and Leo for pointing out the inaccuracy of my first post. Its a good example of how important proper nomenclature is.....clearly f-stop & f/stop are two different things :D

[Wilt]

Thanks Wilt and Leo for pointing out the inaccuracy of my first post. Its a good example of how important proper nomenclature is.....clearly f-stop & f/stop are two different things :D

:confused:

[Jon, The Elder]

Reckon that clears it up for sure. Feel sorry for the OP.

[300Dplus]

Reckon that clears it up for sure. Feel sorry for the OP.I was thinking the same thing. probably he stopped reading a few posts back:). I had the concept and wording fine and clear in my head...now it is all screwed up:confused:.

[Yella Fella]

im still scratching my head on the terminalogy...

and all i wanted was variations in terminology lol, found this link and its got calculations galore

http://en.wikipedia.org/wiki/Depth_of_field

then they talk about understanding COF before the DOF!

http://www.luminous-landscape.com/tutorials/understanding-series/dof.shtml

[Wilt]

Just to clarify my daftness... just want to know the correct terminalogy

Wide apertures = low F numbers, big DOF?

Narrow apertures = high F numbers, narrow DOF?


im still scratching my head on the terminalogy...


Wide apertures = low F numbers, creates shallow or narrow or small DOF
Narrow apertures = high F numbers, creates deep or wide or big DOF

The choice of word is less important than the concept that a wider/larger aperture provides a lesser/smaller DOF (an inverse relationship in magnitude)

[Hermeto]

Pretty much everything explained:


http://dofmaster.com/articles.html