DOF in focusing confuzled....

Snooky

Snooky

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Andy
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Need to brain pick and straighten me out really.......

The closer you get to a subject in macro photography focusing becomes hard as DOF is reduced? (I think I've read into it right)

So to help focus you make like a "false" DOF by opening up the aperture to get a subject in focus front to back?

Is this right? Or have I just completely taken what I have read somewhere the wrong way?

Hope I haven't confused anyone by what I am trying to figure out :)
 
You close the aperture down so the f number goes upwards from f/4 to f/8 or higher
 
Yes so as you choose an aperture of f4 and above you are opening the focusing field ( false depth of field ) ?
 
WTF is a false depth of field?? Never heard of that.

To increase the dof you need to reduce the aperture. ie a higher f/number.
 
Yes

You increase the f number which makes the aperture smaller giving you a deeper depth of focus.

As the aperture is now smaller you will need (flash aside) to lower you shutter speed or increase your ISO to get the same exposure.
 
So say your taking a shot of a bug close up and your using f2.8 and have only a eye in focus! You stop down the aperture to f8 to increase the focus from just an eye to the rest of the head!
So the way I see it is your creating a type of "false" depth of field to be able to have more of the "scene" /subject in focus!

Or I should just give up now and go do some more homework as I've confused myself!!
 
Snooky said:
So say your taking a shot of a bug close up and your using f2.8 and have only a eye in focus! You stop down the aperture to f8 to increase the focus from just an eye to the rest of the head!
So the way I see it is your creating a type of "false" depth of field to be able to have more of the "scene" /subject in focus!

Or I should just give up now and go do some more homework as I've confused myself!!
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Yeh, you appear to be doing a great job of confusing yourself. You don't shoot macro bugs at 2.8. F/8 I'd say is a bare minimum more like f/11, f/13, or f/16 bif you can and it's not a false dof, it's the dof you are given by the f/stop setting on the particular lens you are using.
 
BRASH said:
Yeh, you appear to be doing a great job of confusing yourself. You don't shoot macro bugs at 2.8. F/8 I'd say is a bare minimum more like f/11, f/13, or f/16 bif you can and it's not a false dof, it's the dof you are given by the f/stop setting on the particular lens you are using.
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F2.8 was just an example, ok bad one in macro terms ok! I think Im getting there now! Cheers all for input :)

( I'll stay away from macro photography for now :) )
 
Snooky said:
( I'll stay away from macro photography for now :) )
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Don't. If that's what you are interested in then get into it. Success is only gained by many failures (f*** me, listen to me being all philosophical and that:D). There's plenty info on here how to go about it. Just read the advisory posts in the Macro section or if yer not sure just ask.;)
 
Snooky said:
So say your taking a shot of a bug close up and your using f2.8 and have only a eye in focus! You stop down the aperture to f8 to increase the focus from just an eye to the rest of the head!
So the way I see it is your creating a type of "false" depth of field to be able to have more of the "scene" /subject in focus!
Click to expand...

You're right but it's nothing to do with creating a 'false' depth of focus.

Different apertures produce a different depth of focus. They're all as 'real' as each other and the one you choose depends on what you're trying to achieve.
 
No such thing as "false" Depth of Field as far as I know. Can you link your reference and maybe we can help interpret it for you?
 
TimmyG said:
No such thing as "false" Depth of Field as far as I know. Can you link your reference and maybe we can help interpret it for you?
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Oh there is. It's a gopping filter applied in photoshop and the like!
 
Lol I have no idea what gopping means or if you are just avoiding swear words. I can't imagine how you can increase dof with a filter...
 
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Andy
an "image" may help
f1.2 verus f16
DOF.jpg


if you have an old "manual focus" lens with the scales indicated that will also help to see the difference distance ranges for each fvalue
 
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TimmyG said:
That's a lot of lighter fluid Bill. What are you plotting? Should we be concerned?
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Tim, not sure why I bought it, memory goes - probably for something that I was doing to one of my Bikes - I used to have a few "older" BMW's - in fact I still have 4

They came in 6 packs from CostCo
 
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BRASH said:
Don't. If that's what you are interested in then get into it. Success is only gained by many failures (f*** me, listen to me being all philosophical and that:D). There's plenty info on here how to go about it. Just read the advisory posts in the Macro section or if yer not sure just ask.;)
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What the fricking hell has happened to you!

Totally agree :D, @Snooky don't avoid macro give it a crack.

I guess you are calling it false dof due to the fact F8 becomes equivalent to f2.8 or such once you get above 1:1.

It's not the correct terminology but that's my guess what you are referring too.
 
Tintin124 said:
When it suits maybe... normally your approach is BRASH!
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I am Brash, get used to it or the next time you take a selfie nobody will recognize youo_O
 
Tintin124 said:
Lmfao back on form.
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You see, such is my skill and technique, I lull you into a false sense of security then when you least expect it you get a DM up the nads.
 
Tintin124 said:
Pink fluffy rabbit slippers you mean! Lol
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Well you may want to reconsider my footwear after (if) you have recovered the power of speech.:D
 
I no it was the wrong terminology with calling it "false" DOF! I understand it abit more after reading the comments and reading more into it! :)

Just trying to understand distance and focusing relationships abit more by using macro as an example!
 
Ah ok cool. Well just yell if anything doesn't make sense.

In the meantime we'll wait for Bryn and Brash to just get a room or something...
 
TimmyG said:
Ah ok cool. Well just yell if anything doesn't make sense.

In the meantime we'll wait for Bryn and Brash to just get a room or something...
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It'll be a rest room for him.
 
BRASH said:
It'll be a rest room for him.
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Now I'm confuzled... are you saying you want to take me to the toilet? I'm not into that sh!te (pun intended) might want to check your local park toilets might find George Michael for that mate. ;)
 
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Tintin124 said:
Now I'm confuzled... are you saying you want to take me to the toilet? I'm not into that sh!te (pun intended) might want to check you local park toilets might find George Michael for that mate. ;)
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I may be a lot of things but I ain't one of them. I was more thinking along the lines of a chapel of rest type room.
 
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