Depth of field preview

[jamesjaws]

Hi

I've been trying to figure out how to use the depth of field preview feature on the Nikon D300. I understand the basics of depth of field, but I don't quite get how the preview is supposed to help me. I know that it gives me a preview of what the image looks like with the set apeture value, just not sure how to use the preview function in practice.

Eg. When I set the appature to a high f number and press the preview button it darkens the screen, how is this meant to help me? The actual image taken isn't always as dark as what the preview was, I gather this is due to the shutter speed. Please help clear my mind!

:confused:

[erichlund]

It basically gives you a look at what sort of depth of field you will get with the shot. So, if you want to isolate your subject, but when using the DOF Preview, you see the background in focus, you know you need to open up the aperture more.

[Margus]

Read this (http://dptnt.com/2007/10/10-practical-uses-for-the-depth-of-field-preview-button/).

The depth of field preview button does not darken the screen but it sets the aperture to the selected (higher) value at live preview time. As a result there is less light coming through the lens and that's why the image in the viewfinder gets darker. If you are lucky there is still enough light left for you to visually estimate the resulting depth of field in the image with the selected aperture value.

[cdifoto]

All it does is manually stop down the electronic lens to give you a WYSIWYG view of your scene.

[jamesjaws]

Excellent, I think i'm understanding it... It sounds like the DOF preview is less effective in low light (which makes sense). I was experimenting in poorly lit areas and it wasn't making sense because I could barley see anything during the preview.. I will go outside and experiment with proper light. Thanks for your help!

[cdifoto]

Excellent, I think i'm understanding it... It sounds like the DOF preview is less effective in low light (which makes sense). I was experimenting in poorly lit areas and it wasn't making sense because I could barley see anything during the preview.. I will go outside and experiment with proper light. Thanks for your help!

Yeah it's pretty useless in the dark.

[Phill D]

Hey Margus that was an excellent link thanks for posting. 10 really good tips.

[Margus]

Hey Margus that was an excellent link thanks for posting. 10 really good tips.

Thx and you are welcome, have a nice time experimenting! :)

[Margus]

I wonder who will be the first manufacturer to develop an electronic viewfinder with resolution compareable with optical viewfinders. The ability of EVF to brighten up automatically in low light gives it a real advantage over the optical viewfinders. If only the resolution wasn't that lousy :( I guess that it'll happen in 2-4 years when EVF-s will replace the optical viewfinders in digital cameras, including the digital SLRs.

[Paradox]

I wonder who will be the first manufacturer to develop an electronic viewfinder with resolution compareable with optical viewfinders. The ability of EVF to brighten up automatically in low light gives it a real advantage over the optical viewfinders. If only the resolution wasn't that lousy :( I guess that it'll happen in 2-4 years when EVF-s will replace the optical viewfinders in digital cameras, including the digital SLRs.

They won't be SLR's then - The name comes from the viewfinder mechanism, basically. I wonder what they WOULD be called. :confused:

[erichlund]

I wonder who will be the first manufacturer to develop an electronic viewfinder with resolution compareable with optical viewfinders. The ability of EVF to brighten up automatically in low light gives it a real advantage over the optical viewfinders. If only the resolution wasn't that lousy :( I guess that it'll happen in 2-4 years when EVF-s will replace the optical viewfinders in digital cameras, including the digital SLRs.

So, if you have an EVF artificially brightening the scene, how do you properly estimate the exposure adjustments you need to make based on what you see through the viewfinder. The pro and advanced amateur photographers will never let this happen. Personally, I think the camera makers are smart enough to not even try it.

Also, when I have a perfectly good viewfinder now, why would I want a battery operated device that sucks power (ie. pictures) all the time. Thanks, but no thanks.

[Margus]

They won't be SLR's then - The name comes from the viewfinder mechanism, basically. I wonder what they WOULD be called. :confused:

Right you are. No need for reflector inside the camera any more - not SLR :o. Maybe "exchangeable lens camera" or something in the line. Who knows.

[Paradox]

Right you are. No need for reflector inside the camera any more - not SLR :o. Maybe "exchangeable lens camera" or something in the line. Who knows.

A D-ELC? Could catch on I suppose. :p

[Margus]

So, if you have an EVF artificially brightening the scene, how do you properly estimate the exposure adjustments you need to make based on what you see through the viewfinder. The pro and advanced amateur photographers will never let this happen. Personally, I think the camera makers are smart enough to not even try it.

This question has been answered already with all the digital compacts which allow exposure adjustment. The image on the LCD is darkened or brighted up according to the adjustments of photographer.

Actually I do not understand your point above at all. An optical viewfinder which shows you almost invisible image in the dark is a real pain in the ass. The actual picture taken in dark will be still totally ok if the settings were correct, but the optical viewfinder will not help you in any ways in setting the right exposure time or apperture. Or does it?:confused:


Also, when I have a perfectly good viewfinder now, why would I want a battery operated device that sucks power (ie. pictures) all the time. Thanks, but no thanks.

I give you two reasons, open up your own mind to find some other reasons :)
With an EVF you can see the DOF preview in dark lighting conditions and you can the adjust the exposure in WYSIWYG at the same time too. Basically the EVF will always be capable of showing you the actual picture before taking it.

[Razr]

The best way to establish/select a working DOF of course is to know/carry a DOF cheat sheet/chart.
*Unless your camera has a 100% viewfinder with a f/1.2 or f/1.0 lens attached, the corners, which is what really counts, are usually so dark what you would "see" stopped down is not even a fair approximation of what you'll actually get.
Remember, DOF is purely mechanical which means the cheat sheet or DOF chart tells you far more ata glance than what you can see in a viewfinder.

A through knowledge of the "hyperfocusing technique" would also stand you in good stead in that hyperfocal focusing usually establishes the best (or chosen) DOF for any given aperture with any given lens.

One blessing about shooting digital is you can set the f/stop, shoot, then magnify the image and check for corner to corner sharpness.
Of course I cannot perform the above technique with my EOS film cameras, but I can and do with my Panasonic FZ20/FZ30 superzooms and my Olympus E Series DSLRs.

Still, a DOF cheat sheet helps.

[Rooz]

DoF preview is a waste of a button and a useless feature on a dslr.

[cdifoto]

So, if you have an EVF artificially brightening the scene, how do you properly estimate the exposure adjustments you need to make based on what you see through the viewfinder.

With the camera's meter. You can't go by "what you see" regardless of the type of viewfinder you have, unless of course it only darkens or lightens based on adjustments made to show you the scene exactly as it would be recorded on the sensor (like my Fuji F40). Just as an EVF can be brighter than proper exposure, an OVF can be darker than proper exposure. If all you wanted to do is capture things as-seen, there'd be no reason for an exposure meter or adjustment dials at all.

[Rhys]

DoF preview is a waste of a button and a useless feature on a dslr.

I found it so hard to judge with a darkened frame on a film SLR, exactly what was supposed to be in focus that although I demanded a DOF preview lever on every SLR I purchased, that I hardly ever used it. I have it on my Canons but have never used it. I prefer to use a DOF table instead.

[Ray Schnoor]

The best way to establish/select a working DOF of course is to know/carry a DOF cheat sheet/chart.
Have you changed your opinion on DOF charts, because this statement seems in direct contradiction to a statement you have made before...

And you should know depending on math charts is the very worst way to prove DOF in that it measures statistics, not actual lens performance.

From post #18 in this (http://www.dcresource.com/forums/showthread.php?t=34724) thread. My apologies if I have misunderstood.

Ray.

[stever06]

I myself don't use the DOF preview either, but rather the test shot function to gauge my shots/histogram.
As far as an EVF DSLR, It's been termed an "EVIL" camera (Electronic Viewfinder, Interchangeable Lense) on other forums, and has been discussed at great lengths of the pros and cons. The best scenario for gauging exposure would be being able to have a real time histogram display in the EVF, regardless of the auto brightening function, like the FZ-18 does. This would eliminate the necessity of taking a shot, review histogram, adjust and reshoot.

[cdifoto]

Have you changed your opinion on DOF charts, because this statement seems in direct contradiction to a statement you have made before...



From post #18 in this (http://www.dcresource.com/forums/showthread.php?t=34724) thread. My apologies if I have misunderstood.

Ray.

When people make their "expertise" and/or "experience" up on the fly, it tends to vary.

[GaryS]

DoF preview is a waste of a button and a useless feature on a dslr.

Cmon Rooz, don't beat around the bush. Tell us what you really think! :)

I use it fairly regularly, so I would like it to stay. While I agree that its hard to see in the viewfinder, however I find that if I flick it on/off, I can tell what gets sharper which gives me a clue about the DOF.

gs

[erichlund]

I too use DOF Preview a bit. However, I've never even tried in the dark. I suppose, for some, it would matter, but, as Rhys has said, a table will give you all you need to know. That will give you something to use that huge LCD on the back of the camera for. Won't quite blind you as much as a flashlight. The only time I'm using it is when shooting landscapes, to see if I'm somewhere near where I want to be, and then I always have plenty of light. Even there, I do it more out of habit than need. I suppose one could use it for isolation type photos, but I've never had any difficulty estimating the f-stop needed for that. Frankly, I probably wouldn't miss it if it weren't on the camera.

As for estimating exposure, if you are experienced and you still cannot estimate the exposure before you even pick up the camera (or hand held meter), then you need to practice. I'm not saying you should be dead on, but you should be able to ballpark it. It's an important exercise in reading light that will make you a better photographer. There was a time when any decent, experienced photographer could do this. All this exceptional automation has made us lazy.

[Rooz]

take the shot and review. takes less time and is way more accurate in guaging dof. my "dof button" is FV lock now anyway.

[Razr]

Have you changed your opinion on DOF charts, because this statement seems in direct contradiction to a statement you have made before...

From post #18 in this (http://www.dcresource.com/forums/showthread.php?t=34724) thread. My apologies if I have misunderstood.

Ray.
No, I have not.
DOF charts ostensibly (supposedly) set the ideal DOF. At the same time, the aperture you set on any given lens from a DOF chart is no more reliable than what you might possibly glean from a viewfinder.
The real proof is in the shot, not what is set on the lens.
As I further noted, hyperfocal lens settings are more reliable in delivering adeqate DOF shot to shot.

I am often puzzeled why DOf is so often discussed. Unless the photographer is shooting close-ups or macros, DOF is rarely is problem;
unless instead they want good "bokeh" which depends more on lens construction than any other factor.

"Sweet spots" (usually the best hyperfocal seting on any given lens), delivers DOF to infinity, the usual goal**.
**The DOF discussion has bled over into P&S digitals, with some decrying how P&S digitals have too much DOF, as if that was a bad thing.

[Rooz]

I am often puzzeled why DOf is so often discussed. Unless the photographer is shooting close-ups or macros, DOF is rarely is problem;
unless instead they want good "bokeh" which depends more on lens construction than any other factor.

"Sweet spots" (usually the best hyperfocal seting on any given lens), delivers DOF to infinity, the usual goal**.
**The DOF discussion has bled over into P&S digitals, with some decrying how P&S digitals have too much DOF, as if that was a bad thing.

hmmm...confusing comments here. dof, for a portrait photographer especially, is absolutely critical. it creates mood, creates a focal point and sets the context of a scene. along with exposure, it's THE most critically creative part of the photography puzzle.

RE: too much dof on P&S, of COURSE having too much dof is a problem. its actually more than a problem, it's a deal breaker. are you drunk rhys ? :confused:

RE: sweet spots. far too many people try and hit the "sweet spot" of a lens. what people should be choosing is what the correct aperture is for making the shot, not what the correct aperture is from a technical point of the lens. sure there are some instances where aperture isnt relevant, i think peterson calls is "who cares aperture", but in alot of situations your aperture, and consequently your dof, is critical. keep in mind here that FV and iso are also crucial parts of setting dof, not just your aperture.

[TheWengler]

are you drunk rhys ? :confused:

You're talking to Razr. Hard to keep it straight some times, huh? :p

[Rooz]

lol woops, thanks mate.
my humble apologies rhys.

[Rhys]

lol woops, thanks mate.
my humble apologies rhys.

If I ever get to Oz, you'll owe me a schooner :p

No offence taken :d

As I said before - my problem is that by the time the aperture gets down to f8, it's very hard to see anything through the viewfinder let alone to study it to see what's in focus. With smaller viewfinders such as on the 2.0, 1.6, 1.5 and 1.3 crop cameras there's already such a poverty of light that it's pretty hard even at f4. For this reason I wonder whether live LCDs might be the answer.

[Razr]

hmmm...confusing comments here. dof, for a portrait photographer especially, is absolutely critical. it creates mood, creates a focal point and sets the context of a scene. Agreed, but only in part. Shooting a standing Bride for example, we want maximum DOF. For head shots, perhaps only her eyes need be/must be in sharp focus. Most critical is DOF but you also need is being able to check the compostion and moreover, the four corners of the viewfinder for content, thereby eliminating any compositional “surprises”, which DOF preview more often thann not, cannot deliver. . …along with exposure, it's THE most critically creative part of the photography puzzle. Great advice for those who shoot utilizing ground glass focusing, as with my Pentax LX and/or Canon F1, both with interchangeable finders.
Absent being able to focus on the grpund glass in my interchangeable finders, the 35mm and smaller viewfinder, absent very fast lenses, simply sux for determining DOF. RE: too much dof on P&S, of COURSE having too much dof is a problem. its actually more than a problem, it's a deal breaker.
“…deal breaker” for whom?
If a small format (less than 645 medium format) photographer insists on determining DOF, they must utilize an SLR (either) and fast lenses.
But P&S owners should not despair: there are known and varied shooting techniques (one of them using “A”; aperture priority) which can and many times do force a P&S camera to deliver adequate DOF. RE: sweet spots. far too many people try and hit the "sweet spot" of a lens. That I doubt very much, considering how in most instances, the “sweet spot” and the best hyperfocal setting is the same.
Worse, very few "newer" photographers know one jot-one tittle about either.
*”Sweet spot”: generally two stops down from wide open, even for P&S cameras…what people should be choosing is what the correct aperture is for making the shot, not what the correct aperture is from a technical point of the lens. ?…sure there are some instances where aperture isnt relevant, i think peterson calls is "who cares aperture",Ah, anew name for “sweet spot”. …but in alot of situations your aperture, and consequently your dof, is critical. keep in mind here that FV and iso are also crucial parts of setting dof, not just your aperture. Not entirely accurate.
In truth, only the lens aperture setting and focal length have anything at all to do with DOF, unless of course digital imaging has rewritten the laws of physics.
Unless of course you meant to say DOF is the calculus between focal length and the/a chosen aperture. aperture (aperture) n.
1. An opening, such as a hole, gap, or slit.
2.
a. A usually adjustable opening in an optical instrument, such as a camera or telescope, that limits the amount of light passing through a lens or onto a mirror.
b. The diameter of such an opening, often expressed as an f-number.
c. The diameter of the objective of a telescope.
http://www.thefreedictionary.com/aperture

[cdifoto]

Agreed, but only in part. Shooting a standing Bride for example, we want maximum DOF.

You might, but I don't.

[Visual Reality]

I wouldn't either - you'd get everyone and everything behind her in focus.

[Rhys]

It depends on the situation. Some brides would like the background sharp.

[Razr]

You might, but I don't.
The Bride shots I spoke of are usually formals (B/B&G) shots in the church. Details are important in that case, to include her gown.

Outside with busy backgrounds I agree.

[Razr]

take the shot and review.
There are enough situations where review is simply not possible or practical: the sun is going down and your subject needs the present light. Taking time to review may mean the moment (and the light) is lost.

EVery type of lens has its hyperfocal setting, which every photographer ought to know for each lens they own.
Setting the hyperfocal distance eliminates reviewing.

[Rooz]

zzzzzzz. stick to your hyperfocal settings and variable apertures. i'll just review it on my screen thanks.