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10-04-2008, 09:08 AM   #1
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The lost art of zone focusing

Hello everyone,
How many of you use zone focusing with your primes? Most of my prime lenses have zone calibrations next to the distance scale on the barrel. I find it very useful, not to have to focus constantly using this feature. It ensures that you don't miss that special shot. It is especially useful in low light where you have a little working distance from the subject. You should try it with your manual focus primes. I think that you will find it useful.

Dave

10-04-2008, 09:18 AM   #2
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You are talking about using the depth of field scales engraved (printed) on many oldīprimes and more recently almost lost on new lenses, especially zooms.

Of course I do use them, at least when shooting on studio set up for close up subjects. But of course, since the digital (read: instant review possibility), then using dof preview on viewfinder and checking shots, has been a bit more practical.

Robert B
10-04-2008, 09:54 AM   #3
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Robert,
I think what is practical depends on the situation and the photographers preferrences. Having to focus for every shot and previewing is counter productive in a fast moving enviroment.

Dave

QuoteOriginally posted by rburgoss Quote
You are talking about using the depth of field scales engraved (printed) on many oldīprimes and more recently almost lost on new lenses, especially zooms.

Of course I do use them, at least when shooting on studio set up for close up subjects. But of course, since the digital (read: instant review possibility), then using dof preview on viewfinder and checking shots, has been a bit more practical.

Robert B
10-04-2008, 10:03 AM   #4
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QuoteOriginally posted by Big Dave Quote
Robert,
I think what is practical depends on the situation and the photographers preferrences. Having to focus for every shot and previewing is counter productive in a fast moving enviroment.

Dave
With my film cameras I used the orange markings on the 28/3.5 as a good guide for snapping general landscapes. For those who have not seen the M lens markings, the 28 had the f/8 mark in orange and also one of the focus distances. Set it and you were at the hyperfocal distance for the lens for 8x10 inch prints. Very useful. Most of the K and M wide angle lenses had the hyperfocal markings, I think.

10-04-2008, 11:20 AM   #5
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Most of my primes are/were built for 35mm CoCs. The DoF scales don't work for APS-C. Plus what is sharp and what is not is subjective and dependant on the viewer, medium, planned viewing distance, and even the optics (as well as focal length, distance to subject, aperture, etc).

That being said, most of the time, I carry a rough idea of the limits in my head. If I: have time and I need to be as careful as possible, I'll use a personally modified version of software that's readily available online, kept on my ipod touch. If I'm really paranoid, I'll focus bracket and run it through PhotoAcute if I have to.

I rarely have to geek out that much though.
10-04-2008, 11:26 AM   #6
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For those new to this, here are some good links:

Hyperfocal Focusing For Better Landscape Photographs

Hyperfocal Focusing Photography Tips - Digital Camera Techniques

and of course, the online DOF calculator:

Online Depth of Field Calculator
10-04-2008, 12:11 PM   #7
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QuoteOriginally posted by Canada_Rockies Quote
With my film cameras I used the orange markings on the 28/3.5 as a good guide for snapping general landscapes. For those who have not seen the M lens markings, the 28 had the f/8 mark in orange and also one of the focus distances. Set it and you were at the hyperfocal distance for the lens for 8x10 inch prints. Very useful. Most of the K and M wide angle lenses had the hyperfocal markings, I think.
My Olympus XA (sub-miniature 35mm film camera) has a similar feature. F/5.6 is marked in orange as is 8ft on the focus dial. In daylight conditions at ISO 200, you are basically a point-n-shoot for many subjects. (It should be noted that those settings are far from the hyperfocal for the 35mm lens on that camera, but usually good enough.)

Steve

Last edited by stevebrot; 10-04-2008 at 12:17 PM.
10-04-2008, 12:23 PM   #8
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QuoteOriginally posted by Frank Fletcher Quote
Most of my primes are/were built for 35mm CoCs. The DoF scales don't work for APS-C.
Good statement. The DOF scales on 35mm lenses are based on a CoC of about 0.025mm. APS-C has a CoC of 0.020mm and will yield somewhat greater DOF than what is indicated on the lens scale.

Steve

Edit: My statement above is incorrect. Smaller CoC means smaller DOF for a given focal length and aperture.


Last edited by stevebrot; 10-05-2008 at 09:18 AM. Reason: Gross inaccuracy!!
10-04-2008, 07:41 PM   #9
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Steve,
I don't see why, but if the DOF with APS_C is better then the lens calibrations, there should be no problem using them.

Dave

QuoteOriginally posted by stevebrot Quote
Good statement. The DOF scales on 35mm lenses are based on a CoC of about 0.025mm. APS-C has a CoC of 0.020mm and will yield somewhat greater DOF than what is indicated on the lens scale.

Steve
10-04-2008, 08:11 PM   #10
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I think that would be because he made a booboo. The smaller the CoC, the smaller the DoF. For instance, if I plug in a 0.019 (pentax aps-c) CoC into DoFMaster, using a 50mm at f5.6, with subject distance of 10ft, I get a Total DoF = 2.62ft.

If I plug in a 0.025mm (35mm FF) CoC, using the same lens settings as above, I get Total DoF = 3.49ft.

Thus - you can't accurately use the DoF zones on 35mm FF prime lenses.
10-05-2008, 06:14 AM   #11
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My understanding is that when using DA lenses we have more dof than 35mm (because the lens focal length is 1.5X shorter for same fov). When using 35mm lenses on APSc sensor we are enlarging image 1.5 more during viewing/printing to match size of medium. Any time there is more magnification there is less DOF.
thanks
barondla

I do use zone focusing with digital. Especially with 10-17 fisheye. Also use it with 35mm lens. Yes the scale is a little off, but remember dof depends on final print size etc anyway. Its an estimate. Not exact.

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10-05-2008, 09:15 AM   #12
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QuoteOriginally posted by Frank Fletcher Quote
I think that would be because he made a booboo. The smaller the CoC, the smaller the DoF. For instance, if I plug in a 0.019 (pentax aps-c) CoC into DoFMaster, using a 50mm at f5.6, with subject distance of 10ft, I get a Total DoF = 2.62ft.

If I plug in a 0.025mm (35mm FF) CoC, using the same lens settings as above, I get Total DoF = 3.49ft.

Thus - you can't accurately use the DoF zones on 35mm FF prime lenses.
I did make a Boo Boo. (Mea culpa, mea culpa, mea maxima culpa!)

From the DOF Masters DOF Calculator:

35mm film, f/16, 55mm lens DOF = 12.3ft
Pentax K10D, f/16, 55mm lens DOF = 7.04ft

I read the assertion that smaller CoC = greater DOF somewhere else. It sounded weird at the time, but I fell for it. I guess I should have known better since the true case is intuitively correct!

I should remember this as another reason why I would prefer FF! Perhaps that is one of the reasons why they do not print the DOF scales on DA lenses?

Steve

Last edited by stevebrot; 10-05-2008 at 09:21 AM.
10-05-2008, 03:18 PM   #13
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QuoteOriginally posted by stevebrot Quote
I did make a Boo Boo. (Mea culpa, mea culpa, mea maxima culpa!)

From the DOF Masters DOF Calculator:

35mm film, f/16, 55mm lens DOF = 12.3ft
Pentax K10D, f/16, 55mm lens DOF = 7.04ft

I read the assertion that smaller CoC = greater DOF somewhere else. It sounded weird at the time, but I fell for it. I guess I should have known better since the true case is intuitively correct!

I should remember this as another reason why I would prefer FF! Perhaps that is one of the reasons why they do not print the DOF scales on DA lenses?

Steve
If you use lenses with identical field of view (e.g. 43mm on FF and 31mm on APS-C) you should have the same image ratio and the same depth of field.
10-05-2008, 03:45 PM   #14
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Good point Big Dave,

here's one more thing I came across when practicing the 'lost art':

Try to check your infinity mark carefully. Do some full open infinity shots til you have the exact position of full open infinity for this lens on that camera. Checking on the K100D in 12x review mode was good enough for me to find the exact spot. More often than not, this goes well inside the inf. mark, probably for tolerances in the whole setup and the manufacturer not wanting to have people complaining so much. I guess manual lenses were manufactured to go beyond infinity at least 1 full stop (not the AF lenses cause they can move beyond the inf. mark per se).

So that's the first conversion factor I have a hard time remembering. The second is the mentioned APS-C shrinking of DOF. In practice, I cut off one stop on both ends to remain safe and try to adjust infinity on the lenses when way off (very easy sometimes). Would be nice to see some funky curves for DOF vs. FL vs. format to get an idea of it.
All the best, Georg (the other)
10-05-2008, 07:33 PM   #15
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QuoteOriginally posted by flyer Quote
If you use lenses with identical field of view (e.g. 43mm on FF and 31mm on APS-C) you should have the same image ratio and the same depth of field.

35mm film, 43mm lens, f/8, 10' = 9.2'
APS-C, 31mm lens, f/8, 8.64' = 9.22'
APS-C, 35mm lens, f/8, 10' = 9.3'

APS-C, 43mm lens, f/8, 10' = 5.58'
APS-C, 31mm lens, f/8, 10' = 13.4'
35mm film, 31mm lens, f/8, 10' = 34.5'

Online Depth of Field Calculator

Steve
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