[panonski]

Roughly 1/3 of the perceived depth of field is in front of the focus point. But that ratio changes depending on aperture and distance to the focus point.

yes I know that of course. This part 1/3 in a front of is all I wanted to know

Our brains do mental sharpening based on visual clues triggering our memory and we tend to mentally extend perceived sharpness towards the background, not towards the foreground. It seems to me that if you get one recognizable object in the foreground clearly focused, our brain fills in more out of focus areas than if you focus on something we can't tell if it is in focus or not because we don't know what it looks like in real life, or if the foreground is noticeably out of focus, we tend to see the in focus parts in the background as blurry.

Hm... interesting point of view, I would say it's possibly very true

[RGlasel]

You should really have a look and a play with the DoF charts and plug some figures in and then shoot some images using the figures or shoot first an plug figures in afterwards.

Maybe you can remember the specifics of a couple dozen typical scenarios calculated in advance, but I certainly can't. I guess it depends on how much time you want to spend preparing to take a photograph versus actually taking photographs and how varied the scenes that you photograph are. Going back to Norm's comments, sometimes you see things on your large monitor that you miss looking through a viewfinder or on the camera's display. With digital cameras the only extra expense from taking more pictures is your developing time, so spray and pray is often a good strategy.

[TonyW]

Maybe you can remember the specifics of a couple dozen typical scenarios calculated in advance, but I certainly can't. I guess it depends on how much time you want to spend preparing to take a photograph versus actually taking photographs and how varied the scenes that you photograph are. Going back to Norm's comments, sometimes you see things on your large monitor that you miss looking through a viewfinder or on the camera's display. With digital cameras the only extra expense from taking more pictures is your developing time, so spray and pray is often a good strategy.

No I cannot remember a couple of dozen scenarios and lens factors and it is rather pointless trying to calculate in advance unless you are studio shooting or perhaps shooting landscape or architecture where you may have time to take a more contemplative approach and have the necessary tools for calculations to hand such as on your mobile phone, ipad or other device and the time to implement.

The problem with spray and pray is also that you can still miss the "decisive moment" quite easily and will not necessarily help the OP anymore than quoting specifics for DoF such as charts or the 1/3 in front mantra. Which is really the point I was trying to get across suggesting that no one can answer but the OP himself after testing and being aware of the limitations.

Perhaps a better suggestion would be to set the aperture to give a decent DoF for the subject but keep AF tracking on the subject at all times

[pacerr]

Have a look here, that may help Online Depth of Field Calculator. Typically 1/3 before and 2/3 behind the focused distance.

Spend some quality time with the DOF/hyper-focal charts concentrating on the distance, apertures and lenses/bodies you use. Then do some practical experimentation - one of the wonderful benefits of digital photography is the advantage of no-cost, hands-on answers.

Re the range of DOF: I'd note that it's very rare you'd need anything in front of the subject(s) on stage in sharp focus suggesting that manually pre-focusing very slightly behind the subject may optimize the hyperfocal window-of-sharpness; especially with slowly moving targets.

I've found that the thoughtful planning involved in manually pre-focusing (ambushing?) a shot often beats randomly snapping away counting on dynamic AF to understand what I want.

[One difference between a great lens and a poor one is the size of your waste basket/Delete key and your willingness to use it.]

[osv]

I have found my mirrorless cameras (samsung NX20 and Lumix G1) very educational for seeing the depth of field - the advantage of the EVF is it doesn't get dimmer when you stop down (up to say f11 anyway, depending on ambient light), it auto-compensates the brightness. And the high mag focus assist means you can really zero in.
I've not found the stop down preview functions on my pentaxes so useful.

this ^^^ liveview is far superior for focusing purposes, because you can use magnification to focus exactly on the object that you want to be in sharpest focus, and you can also use magnification to examine how out of focus other areas of the photo will be, it eliminates all of the hyperfocal guesswork... liveview in the lcd can be used for this.

for the ovf crowd, who are unable to set accurate manual focus, the hyperfocal charts are another way of evaluating dof, but there is also the Harold Merklinger method, see the comparison further down the page: Kevin Boone's Web site

if you are on crop, the first rule is to never stop down further than f/8 unless absolutely necessary, because that's the beginning of the range of visible diffraction... if your lens is mushy on the sides at that aperture, get a better lens.

[stevebrot]

and you can also use magnification to examine how out of focus other areas of the photo will be, it eliminates all of the hyperfocal guesswork... liveview in the lcd can be used for this.

I won't argue the fine details with you here, but I don't believe you have this straight. Magnified is magnified is magnified and as such does not translate to what might be seen on a print or display monitor or even on the rear LCD. That is one of the drawbacks of all TTL displays, whether optical or electronic.

As for those poor OVF folk and focus accuracy, I believe your assertion indicates a lack of experience with the tech and unsupported faith that what is seen in an EVF represents the optical reality at the focal plane or the final displayed image. To be fair, I lack deep EVF experience (they give me headaches and dizziness), but am willing to do a head to head with my K-3/KatzEye combo against your A7R in crop mode at 100 yards and again at 10 feet with identical lenses (best of five). Of course the K-3 will have to be downsampled to make it fair. If you like, we can match one of my obsolete film SLRs shooting RR 80s against your camera full frame with the film evaluated using a microscope rather than scanned. Struck out...grand standing...


Steve

[pacerr]

The conventional figure of 0.02mm (for COF) is pretty arbitrary, to be honest, but it is well established. [from Kevin Boone's Web site ]

And that's an important point. There's nothing absolute about this topic of acceptable sharpness. It's both subjective and situational.

One needs to either adopt an accepted 'standard', or at least a specific definition, and proceed to adapt it to the personal task in hand through patience and experimentation or else employ one of the many usable automated software pre-set solutions available.

Sounds just like the arguments over using camera Scene Modes doesn't it?

[ Being satisfied today doesn't preclude upgrading one's standards in the future. ]

[osv]

I won't argue the fine details with you here, but I don't believe you have this straight. Magnified is magnified is magnified and as such does not translate to what might be seen on a print or display monitor or even on the rear LCD. That is one of the drawbacks of all TTL displays, whether optical or electronic.

versus having to take a wild guess at how focused it'll be with the obsolete hyperfocusing technique and marks on the lens barrel? no contest liveview wins even with a dslr.

of course you'll chimp it in the lcd afterwards anyway, which is really no different than focusing it with liveview in the first place.

[reh321]

this ^^^ liveview is far superior for focusing purposes, because you can use magnification to focus exactly on the object that you want to be in sharpest focus, and you can also use magnification to examine how out of focus other areas of the photo will be, it eliminates all of the hyperfocal guesswork....

So when taking photographs of moving objects, I can use the lens markings to get it right before I take my picture, and you can use the LCD to do a postmortem.

[pacerr]

Obsolete? Oh, please say it ain't so.

Must I stop pre-setting a 'walk-around' hyperfocal distance then? (Mmmm, even when using AF lenses without distance scales?)

[stevebrot]

versus having to take a wild guess at how focused it'll be with the obsolete hyperfocusing technique and marks on the lens barrel? no contest liveview wins even with a dslr.

of course you'll chimp it in the lcd afterwards anyway, which is really no different than focusing it with liveview in the first place.

Nah...I may chimp sometimes, but only to check the histogram. I know the focus before I push the big button on top.


Steve

[reh321]

versus having to take a wild guess at how focused it'll be with the obsolete hyperfocusing technique and marks on the lens barrel? no contest liveview wins even with a dslr.
of course you'll chimp it in the lcd afterwards anyway, which is really no different than focusing it with liveview in the first place.

Something is not obsolete if it works. When I take a picture of a 40+mph train, I need to know that it is completely in focus before I press the shutter button. The marks on the lens barrel have been doing the job for over 35 years, and I still trust them to do it. "Chimping" has been available to me for 8 years - not nearly as reliable a record and not nearly as trusted. No contest, liveview loses. The ultimate test is to look at the image using my desktop computer, but by definition that is not a field test.

[indy]

I was just trying to find out, is nail focus begin more in the front, exactly front, or closer to the middle of, what we called acceptable sharpness.

If I nail singer, from 3,4 m away, and he move after focusing 30 cm to me, with his body, will he be in focus if I choose for example f8 or even f11?
Or on the opposite side, If he move away 30 cm from me, after focusing.

There is an app called hyper focal pro that gives you this information. You enter camera, lens, aperature and subject focus distance, and it will show you exactly how much of the image in front and behind your subject are in focus.

[stevebrot]

There is an app called hyper focal pro that gives you this information. You enter camera, lens, aperature and subject focus distance, and it will show you exactly how much of the image in front and behind your subject are in focus.

I use an Android app simply called "DoF Calc" that provides near/far focus limit as well as the hyperfocal distance, all at a glance. My only complaint is that the distance units are a little course.


Steve

[osv]

Something is not obsolete if it works. When I take a picture of a 40+mph train, I need to know that it is completely in focus before I press the shutter button.

that's another easy manual focus situation, because you can pre-focus exactly where you want the sharpest part of the pic, just hit the shutter button when the train reaches the spot... train speed is irrelevant.

---------- Post added 04-12-16 at 04:13 PM ----------

So when taking photographs of moving objects, I can use the lens markings to get it right before I take my picture.

"right" is subjective... did you, for instance, point a laser measuring device at the object to measure the distance? and of course you've previously tested and confirmed that the markings on the lens barrel are accurate at their respective measured distances? doubtful, especially in the case of a zoom, or a lens that doesn't have any distance markings on the barrel to begin with.

fwiw, the batis lenses have an oled distance readout, if it's accurate you don't need to measure the distance to be exact, that's probably a scenario where hyperfocal calculations might make sense.