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09/16/2009 03:11:11 PM · #26
Originally posted by AperturePriority:

Originally posted by pedrobop:

Originally posted by Bear_Music:

This is a challenge where the P&S cameras really have a chance to shine, or at least the ones with programmable apertures do... The shorter the focal length of the lens, the greater the DOF, basically, and those little pocket cams have REALLY short lenses :-)


Thanks for that, but you should consider that the lowest aperture of my camera (for example) is F8.0.

But your f/8 is not the same as an SLR's f/8. On your point-n-shoot camera, an f/8 is roughly equivalent to an SLR at f/32.


That's one thing i didn't know.

But in my case i think the better thing is still use the F/8.0, or no?
In this tonemaped image i used F/6.3, what do you think about the DOF?
' . substr('//images.dpchallenge.com/images_portfolio/95000-99999/99981/120/821713.jpg', strrpos('//images.dpchallenge.com/images_portfolio/95000-99999/99981/120/821713.jpg', '/') + 1) . '

Message edited by author 2009-09-16 15:12:30.
09/16/2009 03:15:50 PM · #27
Maybe it's me, but I can't tell if the background is outside the DOF or if it is just the hazy atmosphere in the city.
09/16/2009 03:17:16 PM · #28
Originally posted by Bear_Music:

Originally posted by cpanaioti:

Focus area includes 1/3 in front of the focus point and 2/3 behind, hence a general rule of thumb, focus 1/3 of the way into a scene and follow steps 1 and 2


This is true when you have a situation where you need to maximize DOF in close shooting, but it is not the case when you are shooting landscapes: if your desired range of focus is from, say, 2 feet through infinity, and you focus "1/3 of the way" into that range, the theoretical extension of the focus will be way beyond infinity and you've wasted all that focal range. This is where the hyperfocal information is invaluable: with a given lens, at a given f/stop, how close can you focus and still have infinity in focus? The answer to that question is the hyperfocal number, and it's a LOT closer than you might think.

In this previously posted image, the actual point of focus was maybe 24 inches into the image, and I have DOF from like 12 inches or less to infinity. Using the 1/3 rule, I'd have focused somewhere at the water's margin and the foreground would NOT be sharp, not even close to it.

' . substr('//images.dpchallenge.com/images_challenge/0-999/596/120/Copyrighted_Image_Reuse_Prohibited_439846.jpg', strrpos('//images.dpchallenge.com/images_challenge/0-999/596/120/Copyrighted_Image_Reuse_Prohibited_439846.jpg', '/') + 1) . '

R.


The water's edge looks like 2/3 in (or 1/3 from the top of the image). 1/3 in would be about at the top of the clump of seaweed in the foreground. From the water's edge up it looks soft but that's probably due to the f stop and the web image size.
09/16/2009 03:42:14 PM · #29
Originally posted by AperturePriority:

Also, keep in mind that extreme smaller apertures (e.g. f/32) is, in many cases, not the most optimum setting for sharpness.

Personally, if I need a very small aperture, I try to always shoot 1/3, 2/3, or 1 stop above the minimum aperture for a particular lens. So, if my lens had a minimum aperture of of f/32, I'll open it up just a bit to either f/28, f/27, or f/25--but more probable would be f/22...one full stop smaller for better sharpness.


F/22 is a full stop more open (larger) than f/32, not "smaller"... A full stop "smaller" than f/32 would be f/45... Then there's always f/64, which is an aperture we use quite a bit in large format photography. But that's on like a 210mm "normal" lens, so it's not that small an aperture *physically*...

R.
09/16/2009 03:47:52 PM · #30
Originally posted by cpanaioti:

The water's edge looks like 2/3 in (or 1/3 from the top of the image). 1/3 in would be about at the top of the clump of seaweed in the foreground. From the water's edge up it looks soft but that's probably due to the f stop and the web image size.


It's not a matter of where it is *in the picture*, it's a matter of how deep into the scene you're getting physically, as the crow flies so to speak. The POINT here is that at f/16 on a 10mm lens, if you focus at, say, 36 inches, then everything from, say, 18 inches to infinity is in focus. If you focus at, say, 30 feet instead, then infinity is no more "in focus" but the DOF extends back only to, say, 7 or 8 feet. By focusing at hyperfocal, you can have MUCH nearer objects in focus if you want that effect.

These numbers, btw, are just guesses; I don't have a DOF calculator running right now. But the principle obtains, even if the numbers are arbitrary. In extreme wide angle near/far compositing, you can (and should) focus in much nearer to the camera than intuition would tell you is possible. The viewfinder is showing you a wide-open DOF, so it's hard to believe sometimes that infinity will come into focus when you stop down, but it *does*...

R.
09/16/2009 03:48:51 PM · #31
Originally posted by Bear_Music:

Originally posted by AperturePriority:

Also, keep in mind that extreme smaller apertures (e.g. f/32) is, in many cases, not the most optimum setting for sharpness.

Personally, if I need a very small aperture, I try to always shoot 1/3, 2/3, or 1 stop above the minimum aperture for a particular lens. So, if my lens had a minimum aperture of of f/32, I'll open it up just a bit to either f/28, f/27, or f/25--but more probable would be f/22...one full stop smaller for better sharpness.


F/22 is a full stop more open (larger) than f/32, not "smaller"... A full stop "smaller" than f/32 would be f/45... Then there's always f/64, which is an aperture we use quite a bit in large format photography. But that's on like a 210mm "normal" lens, so it's not that small an aperture *physically*...

Oops! That's what I meant to say, Robert ... "f/22...one full stop larger for better sharpness".

I sometimes get mixed up when thinking inversely with f-stop numbers to aperture ratios to physical aperture openings.

Thanks.

09/16/2009 04:02:20 PM · #32
Originally posted by Bear_Music:

Originally posted by cpanaioti:

The water's edge looks like 2/3 in (or 1/3 from the top of the image). 1/3 in would be about at the top of the clump of seaweed in the foreground. From the water's edge up it looks soft but that's probably due to the f stop and the web image size.


It's not a matter of where it is *in the picture*, it's a matter of how deep into the scene you're getting physically, as the crow flies so to speak. The POINT here is that at f/16 on a 10mm lens, if you focus at, say, 36 inches, then everything from, say, 18 inches to infinity is in focus. If you focus at, say, 30 feet instead, then infinity is no more "in focus" but the DOF extends back only to, say, 7 or 8 feet. By focusing at hyperfocal, you can have MUCH nearer objects in focus if you want that effect.

These numbers, btw, are just guesses; I don't have a DOF calculator running right now. But the principle obtains, even if the numbers are arbitrary. In extreme wide angle near/far compositing, you can (and should) focus in much nearer to the camera than intuition would tell you is possible. The viewfinder is showing you a wide-open DOF, so it's hard to believe sometimes that infinity will come into focus when you stop down, but it *does*...

R.


Ok, that makes sense. Here's a sample of mine from the recent freestudy...

' . substr('//images.dpchallenge.com/images_challenge/1000-1999/1075/120/Copyrighted_Image_Reuse_Prohibited_816784.jpg', strrpos('//images.dpchallenge.com/images_challenge/1000-1999/1075/120/Copyrighted_Image_Reuse_Prohibited_816784.jpg', '/') + 1) . '

It was shot at f16 with the focus point on the rock in the middle a little ways up from the bottom of the image.
09/16/2009 04:20:19 PM · #33
Originally posted by cpanaioti:


Ok, that makes sense. Here's a sample of mine from the recent freestudy...

' . substr('//images.dpchallenge.com/images_challenge/1000-1999/1075/120/Copyrighted_Image_Reuse_Prohibited_816784.jpg', strrpos('//images.dpchallenge.com/images_challenge/1000-1999/1075/120/Copyrighted_Image_Reuse_Prohibited_816784.jpg', '/') + 1) . '

It was shot at f16 with the focus point on the rock in the middle a little ways up from the bottom of the image.


Right, that's pretty good. But here's the thing of it: the rock on which you've focused is nowhere NEAR 1/3 of the way between the camera and the mountains, see? I mean, not by an order of magnitude. Following the 1/3 rule would have you focusing on the back side of the lake, basically, and that would actually be infinity focus as well.

Now, it's hard to tell from the small image, but it *looks* to me as if the extreme foreground rocks are not quite as much in focus as the one you say you DID focus on. I'd bet dollars to donuts that if you'd focused even closer to the bottom of the frame, the foreground stones would be crisper and the mountains just as sharp, at f/16. It's hard to tell, though, without examining the RAW file closely.

Set up a similar shot on a tripod someday and do a series of exposures with a foreign object of some size placed at the focus point for each new frame, refocusing on the object each time as you walk it back into the image, and watch how rapidly you lose the extreme foreground sharpness as the object moves into the image. Put it right at the bottom, then move it back a couple feet at a time until it's something like 20 feet away, and compare the images by stacking them in a single photoshop file and turning them off one by one from the top down. Watch for when the mountains start to get softer, and you've located your hyperfocal empirically.

R.
09/16/2009 05:16:58 PM · #34
I think i'm getting it. And what about macro shots? This calculator is usefull for macro too?
I'v tried with a distance of 20cm from a subject, with my lens i have this result:
And how do you think a macro shot would go in a DOF challenge?
Subject distance 20 cm


Depth of field
Near limit 20 cm
Far limit 20 cm
Total 0.05 cm

In front of subject 0.02 cm (50%)
Behind subject 0.02 cm (50%)

Hyperfocal distance 11345.3 cm
Circle of confusion 0.005 mm
Depth of field extends from
5672.65 cm to infinity


Message edited by author 2009-09-16 17:17:44.
09/16/2009 05:24:48 PM · #35
Originally posted by Bear_Music:

Originally posted by cpanaioti:


Ok, that makes sense. Here's a sample of mine from the recent freestudy...

' . substr('//images.dpchallenge.com/images_challenge/1000-1999/1075/120/Copyrighted_Image_Reuse_Prohibited_816784.jpg', strrpos('//images.dpchallenge.com/images_challenge/1000-1999/1075/120/Copyrighted_Image_Reuse_Prohibited_816784.jpg', '/') + 1) . '

It was shot at f16 with the focus point on the rock in the middle a little ways up from the bottom of the image.


Right, that's pretty good. But here's the thing of it: the rock on which you've focused is nowhere NEAR 1/3 of the way between the camera and the mountains, see? I mean, not by an order of magnitude. Following the 1/3 rule would have you focusing on the back side of the lake, basically, and that would actually be infinity focus as well.

Now, it's hard to tell from the small image, but it *looks* to me as if the extreme foreground rocks are not quite as much in focus as the one you say you DID focus on. I'd bet dollars to donuts that if you'd focused even closer to the bottom of the frame, the foreground stones would be crisper and the mountains just as sharp, at f/16. It's hard to tell, though, without examining the RAW file closely.

Set up a similar shot on a tripod someday and do a series of exposures with a foreign object of some size placed at the focus point for each new frame, refocusing on the object each time as you walk it back into the image, and watch how rapidly you lose the extreme foreground sharpness as the object moves into the image. Put it right at the bottom, then move it back a couple feet at a time until it's something like 20 feet away, and compare the images by stacking them in a single photoshop file and turning them off one by one from the top down. Watch for when the mountains start to get softer, and you've located your hyperfocal empirically.

R.


That sounds like a neat experiment.
09/16/2009 05:36:24 PM · #36
Robert you are such a good & patient teacher. I'm reading along & enjoying it very much. And, inspired to try it myself.
09/16/2009 05:40:27 PM · #37
Originally posted by pixelpig:

Robert you are such a good & patient teacher. I'm reading along & enjoying it very much. And, inspired to try it myself.


Why, thank you :-) It's actually an exercise I gave my students when I taught photography all those years ago...

R.
09/16/2009 07:00:49 PM · #38
Thanks guys! I'm excited to try with my new camera.
09/21/2009 03:33:58 PM · #39
Really useful conversation here!
09/21/2009 03:57:37 PM · #40
Mind if I chime in? I'm having a little trouble myself with this one. I have three lenses: 15-55 / 55-200 / 18-270. Does it matter which lens I use? I took a bunch of sunset landscape shots last night and not a one would I call crystle. In addition, I can't seem to get my foreground clear enough. Suggestions? I'm sprouting more grey hairs from this one!
09/21/2009 04:23:42 PM · #41
Originally posted by DCrest01:

Mind if I chime in? I'm having a little trouble myself with this one. I have three lenses: 15-55 / 55-200 / 18-270. Does it matter which lens I use? I took a bunch of sunset landscape shots last night and not a one would I call crystle. In addition, I can't seem to get my foreground clear enough. Suggestions? I'm sprouting more grey hairs from this one!


What were your camera settings?
09/21/2009 04:29:24 PM · #42
I tried f/11 - f/16 and out of desperation f/32 - ISO 100 - I was in manual and was fooling around with shutter speed.
09/21/2009 05:20:16 PM · #43
Originally posted by DCrest01:

I tried f/11 - f/16 and out of desperation f/32 - ISO 100 - I was in manual and was fooling around with shutter speed.


Lack of tack sharp focus could also be related to your camera support. Were you using a tripod? What shutter speed did you use?
09/21/2009 05:21:47 PM · #44
I wasn't useing a tripod and I kept changing the shutter speed to try and get clarity, so its safe to say I used them all at one point or another. I will try again tonight with the tripod and see what happens.
09/21/2009 05:47:59 PM · #45
Originally posted by DCrest01:

I wasn't useing a tripod and I kept changing the shutter speed to try and get clarity, so its safe to say I used them all at one point or another. I will try again tonight with the tripod and see what happens.


I can't say for sure but I'm guessing your focus problem was caused by lack of a tripod. f11 or f16 should give you a good DOF towards the 15mm end of your lens. Good luck! Also see ' . substr('//www.dpchallenge.com/images/user_icon/21.gif', strrpos('//www.dpchallenge.com/images/user_icon/21.gif', '/') + 1) . ' bear_music's earlier post about not focusing too far into the scene. Also ' . substr('//www.dpchallenge.com/images/user_icon/21.gif', strrpos('//www.dpchallenge.com/images/user_icon/21.gif', '/') + 1) . ' darnok's post on the first page is a really good one.

Message edited by author 2009-09-21 17:52:42.
09/24/2009 02:49:06 PM · #46
Votes: 115
Views: 190
Avg Vote: 4.0174
Comments: 2
Favorites: 1
come on guys, give me some points here
trying to break in wedding stuff
so need a good CV
09/24/2009 03:42:58 PM · #47
Originally posted by cutout:

Votes: 115
Views: 190
Avg Vote: 4.0174
Comments: 2
Favorites: 1
come on guys, give me some points here
trying to break in wedding stuff
so need a good CV


wrong thread cutout...
This is the right one.
09/29/2009 01:19:46 AM · #48
Did you enter this challenge? Well, did you??

1/3 of you should be ashamed. Rather than deep DOF, I see so many shallow DOF entries. Come on folks. You all need to pay attention.

Shallow DOF entires are getting low scores from me, because they DESERVE it.

Okay, I'm a picky bastard ... but seriously, if you enter a photo of of a super tanker in a flower challenge ... don't expect 10s.
09/29/2009 01:30:43 AM · #49
Originally posted by Dr.Confuser:

Shallow DOF entires are getting low scores from me, because they DESERVE it.

Okay, I'm a picky bastard ... but seriously, if you enter a photo of of a super tanker in a flower challenge ... don't expect 10s.

I think in this case, it was an honest error on the part of many. I have run across many people in discussions on Flickr who only see the use of the term "depth of field" in connection with out of focus backgrounds. So, some folks probably were thinking that a deep depth of field effect meant extremely blurry and separated from the foreground. That being said, I am afraid I am having to low vote them for the same reason, even though some are quite good. I did the same with the motion blurred shots on the missed focus challenge. I am usually pretty flexible as to what fits the challenge, but I think these have been some very clearcut technical effects topics.

Message edited by author 2009-09-29 01:36:37.
09/29/2009 03:27:29 AM · #50
Agreed with comments on missing the target for DEEP DOF challenge. One needs to post a pic that fits the description of the challenge. If you missed the target and get a low score, then it should help to know the reason for a low score was purely aiming the arrow in the wrong direction. It was then a great learning experience and lots of people here went into detail helping with this and explaining this principle. Who needs to go on a photographic course when you have all the help here from gracious members....
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