Author Topic: Looking for some guidance please....  (Read 4223 times)

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Offline Debbie13

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Looking for some guidance please....
« on: December 14, 2010, 10:18:31 AM »
Because I have finished my assignments for the term a week early, I have been given an extra assignment exploring depth of field and differential focus with black and white film.
Obviously, the one difference with this is I cannot see the results until the film is developed (Love the darkroom, hate the film photography, lol)
The one thing I am confused about is how to get differential focus? What sort of settings am I looking at and what do I focus on. This is an independent assignment and I have looked it up in the books but end up confused about aperture and f stops. I understand the largest number is the smallest aperture etc but putting it into practice as far as differential focus is concern is flooring me. Add that to the fact that I managed to load the same film twice and double exposed one film and developed and unused film, I am not getting off to a good start :lol: :lol:
Any help would be greatly appreciated as long as it is in words of two syllables or less, :lol: :;))
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Offline fother

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Re: Looking for some guidance please....
« Reply #1 on: December 14, 2010, 10:33:12 AM »
Apologies if this is too simple, but starting with the basics...

f2.8 means narrow depth of field
f32.0 means wide depth of field


Offline Debbie13

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Re: Looking for some guidance please....
« Reply #2 on: December 14, 2010, 11:15:51 AM »
So the higher the number the more fore ground to background sharpness? And the lower the number the more defocus? So with the lower numbers, all I have to do is focus on the subject I want sharp and the rest will be out of focus?
You say it sounds simple, yes Fother, it sounds far simpler than the books explain it.....so why do I get so confused? :lol:
Maybe I am just not cut out for all this technical know how ;)
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Offline Faldrax

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Re: Looking for some guidance please....
« Reply #3 on: December 14, 2010, 12:01:21 PM »
Debbie,

It is all about 'Depth of Field'.
When you focus on a particular point you will see that objects close to it (in front and behind) also appear to be in focus - how big this in focus area is is called the Depth of Field.

It is determined by a combination of four things; Aperture, Focal Length, Distance to Focus Point and Sensor Size (APS-C, Full Frame, M43, etc).

The Smaller the Aperture (F4 is smaller than F2.8!) the larger the depth of field.
The Greater the distance to the subject the larger the Depth of Field.

Sensor size is only an issue if you are comparing different cameras.

See: http://www.cambridgeincolour.com/tutorials/depth-of-field.htm for more details.

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Offline Debbie13

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Re: Looking for some guidance please....
« Reply #4 on: December 14, 2010, 01:53:33 PM »
Does that apply the same with film?? I will have a read of this in more depth when I get home from college, thanks Faldrax. :)
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Offline Clive

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Re: Looking for some guidance please....
« Reply #5 on: December 14, 2010, 04:56:07 PM »
Hi Debbie

Here is an OLD page I made about apertures and DOF. Applies to film and digital. (Bad formatting on this page.) This shows the relationship between aperture, shutter speed and DOF.

Here is a handout as well.

Good luck

Clive 

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Offline Debbie13

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Re: Looking for some guidance please....
« Reply #6 on: December 14, 2010, 05:53:47 PM »
Thank you Clive, Its certainly given me some much lacking info. In fact thank you all for you help. :)
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Offline Faldrax

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Re: Looking for some guidance please....
« Reply #7 on: December 15, 2010, 01:36:56 PM »
If you need to know the actual Depth of Field for a particular situation (or conversely want to know the combination of settings to get a particular DOF) you can get applications for both iPhone and Android to do the calculations for you.

The Android one I use is : 'Depth of Field Calculator'.

If you don't have a smartphone, then you can get similar apps for a PC and print out charts, though this is obviously less flexible.

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Offline Debbie13

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Re: Looking for some guidance please....
« Reply #8 on: December 15, 2010, 01:39:24 PM »
Thanks Faldrax, but I don't have a smartphone, just my dumb-brain :lol:
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Offline thebird

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Re: Looking for some guidance please....
« Reply #9 on: December 15, 2010, 11:57:38 PM »
Yes Deb, I have a hard time with the tech stuff as well. What I need is for some one to show me so my brain can take it in. It makes it hard sometimes for me. I guess I am a show me type person. One side of my brain works a little better than the other. I have a hard time in my brain working out the aperture and depth of field thing myself. Clive guides do help but until I try it for myself it just does not click...no pun intended. You are not alone. I just keep moving forward and some time it will sink in.
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Offline Faldrax

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Re: Looking for some guidance please....
« Reply #10 on: December 16, 2010, 01:06:40 PM »
Well, the very simple version is

Large Aperture and close = narrowest depth of field
Small Aperture and Distant = maximum depth of field

:)
It is difficult to explain to white mice that black cats are lucky...

2 x A900/VG, A6000
CZ 16-35 f/2.8, Sigma 24-70 f/2.8 HSM, Tamron 70-200 f/2.8 Di USD, Sony 70-300G,
Tamron 150-600, Sony 50 f1.4, Minolta 85 f1.4 G RS, Sony 100 f2.8 Macro
Manfrotto 055CXPro3 + 410 Junior Geared head,
Flickr : http://www.flickr.com/photos/36503683@N08/

Offline Theresa

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Re: Looking for some guidance please....
« Reply #11 on: January 11, 2011, 02:45:28 PM »
Does that apply the same with film?? I will have a read of this in more depth when I get home from college, thanks Faldrax. :)

Yes, the same for film.  One thing about the smaller apertures (larger f/ number), you begin to lose sharpness at about f/11 because of diffraction around the aperture blades.  I still find f/16 and f/22 useful though.  I miss the days of tray developing 4"x5" sheet film in the darkroom.  I could tell how far along the development was by the feel of the negative so it made it easier to use the zone system.  Then taking it to the big enlarger and making wonderfully large (in those days 11"x14", lol) b&w prints.  I would love to learn to do platinum printing even now.
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