Infinity Focus


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Zaknafein

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#21
solarii said:
Not to fret... both infinity focus and hyper focal distance are inter-related although they refer to different things.

You can't explain the concept of hyper focal dist without first understanding what infinity focus is, so by reading up, its like killing 2 birds with 1 stone ;)

Anyway it takes some time to decrypt newbie codes.... if they knew how to describe it precisely, they'll probably know whats going on and won't have to ask in the first place!
let me see if i understand this 2 correctly.... am i right to say that:
infinity focus: focussing at long distances so pictures of landscapes, for example, would be sharp...

hyperfocusing: manual focusing at hyperfocal distance, which depends on camera's CoC and aperture settings, to get half of hyperfocal distance to infinity sharp.
 

Zaknafein

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#22
Artosoft said:
Ok, let me try to explain in my Singlish :confused: :

DoF (Depth of Field) its something like this:
CAMERA ..................................... Dnear...... Dfocus................Dfar.

Hyperfocal when set to Dfocus, anything from Dnear to Dfar (infinity) is in focus.

While your mention only from Dfocus to Dfar (infinity) is in focus ;) .

I hope it is clarify everything.

Regards,
Arto.
erm, what i meant by distance X is actually "Dnear"
 

Zaknafein

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#24
no need appologies ahahah ;)
good that i read it again. at least i know now that i understand hyperfocal.

btw do u know of a good way for hyperfocusing if the lens dun indicate the focusing distance? i tried using a subject thats roughly my hyperfocus distance but not accurate...
 

lastboltnut

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#25
Zaknafein said:
ehh i read the link, but i cant figure out where i am wrong at? :dunno:
I think the area you went wrong is:

Zaknafein said:
i think he meant hyperfocal distance (Hyperfocal is X)... where subjects from distance X/2 metres to infinity is focused. subjects before distance X/2 will not be sharp if hyperfocusing is used.
And, you must set your focus at the calculated hyperfocal distance then this effect will take place......its just my guess.:)
 

lastboltnut

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#26
Other then the COC and apterture ,the camera lens focal length plays a part too.

Zaknafein said:
let me see if i understand this 2 correctly.... am i right to say that:
infinity focus: focussing at long distances so pictures of landscapes, for example, would be sharp...

hyperfocusing: manual focusing at hyperfocal distance, which depends on camera's CoC and aperture settings, to get half of hyperfocal distance to infinity sharp.
 

Zaknafein

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#27
lastboltnut said:
Other then the COC and apterture ,the camera lens focal length plays a part too.
i meant distance X as half the hyperfocal length.
and yeah i forgot about focal length, thx for that :)
 

boroangel

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#30
I am probably VERY wrong here....but I tot if you want everything to be really sharp from foreground to background just decrease the DOF by have a smaller aperture?
 

solarii

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#31
boroangel said:
I am probably VERY wrong here....but I tot if you want everything to be really sharp from foreground to background just decrease the DOF by have a smaller aperture?
You are! You've got everything backwards! :bsmilie:

You want to INCREASE DOF by using a smaller aperture....

But when using smaller apertures like f/16 , f/22 etc. image quality starts to take a hit due to diffraction. This phenomenon can't be avoided and affects even high-end glass, so as far as possible, you want to maximise DOF without having to resort to apertures smaller than what is needed.
 

boroangel

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#32
solarii said:
You are! You've got everything backwards! :bsmilie:

You want to INCREASE DOF by using a smaller aperture....

But when using smaller apertures like f/16 , f/22 etc. image quality starts to take a hit due to diffraction. This phenomenon can't be avoided and affects even high-end glass, so as far as possible, you want to maximise DOF without having to resort to apertures smaller than what is needed.
Opps said wrongly...but is my point correct in that increase dof, everything in foreground and backgound is sharp, which is also shooting at hyperfocal length?

http://www.nikonians.org/html/resources/guides/dof/hyperfocal1.html
 

pai

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#33
yanyewkay said:
relax and be tolerant to newbies.
don't worry lah, i'm very relaxed, you never see that smiley face? :cool:

i'm also a newbie, won't dare to yaya. just remembering that not too long ago someone asked the same questioned, and the thread turned into flame war cos ppl can't agree on the answer. this thread is much more civilised and helpful.

main reason i posted was to clarify what the TS was asking.
 

Zaknafein

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#35
boroangel said:
Opps said wrongly...but is my point correct in that increase dof, everything in foreground and backgound is sharp, which is also shooting at hyperfocal length?

http://www.nikonians.org/html/resources/guides/dof/hyperfocal1.html
u will get a deeper DOF, but it doesnt guarentees sharpness of foreground to background.
but in many circumstances, the whole picture will appear sharp when small aperture is used.
but using small aperture issnt shooting at hyperfocal length
 

Zaknafein

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#36
solarii said:
You are! You've got everything backwards! :bsmilie:

You want to INCREASE DOF by using a smaller aperture....

But when using smaller apertures like f/16 , f/22 etc. image quality starts to take a hit due to diffraction. This phenomenon can't be avoided and affects even high-end glass, so as far as possible, you want to maximise DOF without having to resort to apertures smaller than what is needed.
i didnt know that using small apertures will affect image quality. at what aperture size does the quality starts to degrade, or this depends on the quality of the lens itself?
if so, issit true that its better to use a not too small aperture (F5.6) when hyperfocusing?
 

pai

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#37
Zaknafein said:
i didnt know that using small apertures will affect image quality. at what aperture size does the quality starts to degrade, or this depends on the quality of the lens itself?
if so, issit true that its better to use a not too small aperture (F5.6) when hyperfocusing?
depends on the individual lens. understanding lens diffraction
 

lastboltnut

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#38
The reason for back pic when aperture is too small is due to deflection. When the incoming light passes thru the shutter, those at the shutter blade edge will be deflected and creating blur/bad image....when aperture is big enough, the defracted light percentage is small and negligible.....but when aperture is decrease to a threshold size, then the amount of deflected light will become significant and very decernable on the pic.....thus the bad pic.

Again, it should vary from lens to lens, cam to cam...That's all I know on this....:sweat:

Zaknafein said:
i didnt know that using small apertures will affect image quality. at what aperture size does the quality starts to degrade, or this depends on the quality of the lens itself?
if so, issit true that its better to use a not too small aperture (F5.6) when hyperfocusing?
 

lastboltnut

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#39
Hi boroangel,

To explain the situation to you, I have captured some screen shots of the software created by Artosoft. To try the software, see post #8:

Based on a particular camera, assuming you set it to 36mm, f4 and focus to infinity to shot a scenery, from the calculation, you get sharp object from 51.6m to infinity.



But you have a foreground object at 40m away and its blurred....Then to increase your DOF, you decided to shift to f8, you get sharp object from 28.7m to infinity. No doubt, you get the foreground object sharp.



But, if you focus to the calculated hyperfocal distant (64.8m) instate of the shifting the aperture, you get sharp object from 32.4m to infinity and in this case, enough to capture your foreground object also.



So, this conclude that by shifting your focus distance, you can increase your DOF, adj your aperture only when you cannot achieve the DOF you want by shifting the focus....in this way, you can be sure that you won't get bad pic due to small aperture, unnecessarily....:lovegrin:

Artosoft,

Borrow your software screen shoot, ok? If you mind, I will take it down.

Thanks.

boroangel said:
I am probably VERY wrong here....but I tot if you want everything to be really sharp from foreground to background just decrease the DOF by have a smaller aperture?
 

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