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How can i get more DOF?????
- Thread starter PaulyOly
- Start date
Forrest41926
Forum Pro
True; sharpness is an elusive combination of resolution and contrast, and the text was extremely high contrast. Still, the "arm" of the shelf the bag is on still looks a good deal sharper than the man himself.
That might explain it. Still, it does look slightly backfocused, and I would expect about a 1:2 ( 1/3 and 2/3 ) distrobution of DOF ... intentionally backfocusing a portrait can give the impression of narrower DOF. Just something that struck me, looking at this "portrait."
Yeah, this is a VERY impressive lens, on an aweful lot of levels.
Forrest41926
Forum Pro
There are very mixed opinions on this, and I have seen "portraits" of dogs at play from the f/1.2L ... when they're not particularly cooperative posers. The impression I get about this lens ( from lots and lots and lots of research ) is that the AF is like walking through molasis no matter what, but if you MF it into the ballpark and just rely on AF for fine-tuning, it's very workable. But I've heard a lot of comments about "God save you if it starts to hunt!"
Get the f/1.8 version. If you don't have a clear and compelling need for the f/1.2 aperture or the "dreamy look" the lens takes on, it's not worth giving up: 5x the price, contrast, and AF speed.
The f/1.2 is a specialty lens, and it's in a league of it's own in certain areas, but if you're not going to take advantage of them, you'd be doing yourself a disservice to sink that much into this lens. Take the $1,000 you'd save buying the 1.8 version, and take a vacation somewhere to put the lens to use!
Sam Bennett
Veteran Member
It's been a pleasure. I'd love the extra speed, but at basically 4-5 times the price, I just couldn't justify it. And it is just so fast focusing, it's amazing. I was hooked the second I tried it. 
Now that I'm pushing in RAW, the extra stop isn't totally critical.
Don't get me wrong, I would love having the 1.2, but until it's an "easy" buy, I'm sticking with the 1.8.
Sam Bennett - Photo Guy, Audio Engineer and Web-Apper - http://www.swiftbennett.com
Now that I'm pushing in RAW, the extra stop isn't totally critical.Don't get me wrong, I would love having the 1.2, but until it's an "easy" buy, I'm sticking with the 1.8.
--
Sam Bennett - Photo Guy, Audio Engineer and Web-Apper - http://www.swiftbennett.com
It's the abbreviation for Depth of Field which is the distance of the amount of acceptable sharpness from the focus point or how much of something is in focus.
--
http://www.pbase.com/paulyoly/root
Chris Wyles
Well-known member
For those interested, the formulae for the nearest point of focus and the farthest point of focus are as follows:
(the only assumption used in making these formulae as straightforward as possible is that the object distance (U) is much greater (x10 greater) than the focal length of the lens. This is the normal situation for most photography (except macro of course).
The FARTHEST point in focus = (F^2 x U) / (F^2 - cfU)
and the NEAREST point in focus = (F^2 x U) (F^2 + cfU)
where:
F = lens focal length (F^2 means the focal length squared)
U = object distance (ie: distance from camera to subject)
c = acceptable "circle of confusion" on sensor (ie: what does "IN" focus mean). Take c = 20 microns (Canon use 35 microns in their calculations which I think is too loose). 1 micron = 10E-3 mm or 10E-6 metres.
f = f/number (eg: 2.8 or 16 etc)
Play around with the numbers and you will get a good feel for what has the most effect on near and far point focus. The greatest lever is focal length, by far.
DON'T FORGET TO USE THE SAME UNITS FOR ALL THE NUMBERS WHERE APPROPRIATE. If you get a non-sensical answer, you've used different units somewhere.
If you get a negative answer for the farthest distance (and you've definitely used the same units throughout) it means the far distance is infinity.
This is because the denominator in the equation, ie: (F^2 - cfU) will equal zero if F^2 = cfU and therefore the farthest distance will be (F^2U) (zero) = infinity.
If cfU is greater then F^2, the denominator will become negative which strictly means "greater then infinity" but in the real world simply means infinity!!
Chris
(the only assumption used in making these formulae as straightforward as possible is that the object distance (U) is much greater (x10 greater) than the focal length of the lens. This is the normal situation for most photography (except macro of course).
The FARTHEST point in focus = (F^2 x U) / (F^2 - cfU)
and the NEAREST point in focus = (F^2 x U) (F^2 + cfU)
where:
F = lens focal length (F^2 means the focal length squared)
U = object distance (ie: distance from camera to subject)
c = acceptable "circle of confusion" on sensor (ie: what does "IN" focus mean). Take c = 20 microns (Canon use 35 microns in their calculations which I think is too loose). 1 micron = 10E-3 mm or 10E-6 metres.
f = f/number (eg: 2.8 or 16 etc)
Play around with the numbers and you will get a good feel for what has the most effect on near and far point focus. The greatest lever is focal length, by far.
DON'T FORGET TO USE THE SAME UNITS FOR ALL THE NUMBERS WHERE APPROPRIATE. If you get a non-sensical answer, you've used different units somewhere.
If you get a negative answer for the farthest distance (and you've definitely used the same units throughout) it means the far distance is infinity.
This is because the denominator in the equation, ie: (F^2 - cfU) will equal zero if F^2 = cfU and therefore the farthest distance will be (F^2U) (zero) = infinity.
If cfU is greater then F^2, the denominator will become negative which strictly means "greater then infinity" but in the real world simply means infinity!!
Chris
Hi Paul!
Well, at first I thought you were just joking because the photo is really superb, then I realized that you have been using a 400mm lens. I only have a 200mm and I hasn't fully aware how huge a difference in DOF it is between the two at full zoom. Interesting point...
Well, I guess you better start saving for that new 1DmkII camera with low noise in the high ISO ratings! Or you can learn to be happy with the DOF you have now (I love shooting at f/2.8, but I'm a newbie and weird too, so...) ;-)
--
Best regards, Stoffer
May the Light be with you!
look at this http://takki.fotopic.net/p3100826.html
the front and middle of the bike is sharp, but the rear is out of focus.
i don't like that.
i think i have to use a smaller aperture (bigger f-number).
'look for a great spot,
shoot for a great shot!'
Takki
the front and middle of the bike is sharp, but the rear is out of focus.
i don't like that.
i think i have to use a smaller aperture (bigger f-number).
--I shot this pic from 15 feet or less, probably closer to 13 feet,
at 15 feet my dof is 1.8 inches, at 13 feet it is 1.4 inches, now
in this pic most of the bird appears to be infocus except for the
edge of the tail. Is there anything i can do, beside stopping way
down or moving back, to increase dof? Does an extension tube
affect the dof? Will we ever see a digital slr where you can
control the depth of field using a dial without changing the
aperture? Maybe a sensor that can be stopped down? Am i just
dreaming? I guess my camera/lens are focusing correctly because at
this distance and dof there isn't much room for error. If i stop
down to f18 i can almost get 2.5 inches, i may try that with good
light.
--
http://www.pbase.com/paulyoly/root
'look for a great spot,
shoot for a great shot!'
Takki
Daniella68313
Forum Pro
why do you use a tripod with a IS lens? doesn't that make the IS a bit useless if you don't take advantage of it?
Minë Corma hostië të ilyë ar mordossë nutië të
Mornórëo Nóressë yassë i Fuini caitar.
Un thoron arart’a s’un hith mal’kemen ioke.
Saurulmaiel
--I shot in aperture priority and this is the shutter speed the
camera gave me at f/10 and iso200, I of course shot this on a
tripod and the bird was kind enough not to move very much, i shot
about 8 pics of the same bird at the same time and all but 2 were
sharp. I try not to ask the camera why it does what it does
because it tends to do it very well. The histogram on this shot
was slightly to the left, i ended up adjusting levels by pulling
the right slider in and the left slider in, but twice as much on
the right slider, i believe they are called the black and white
points.
--
http://www.pbase.com/paulyoly/root
Minë Corma hostië të ilyë ar mordossë nutië të
Mornórëo Nóressë yassë i Fuini caitar.
Un thoron arart’a s’un hith mal’kemen ioke.
Saurulmaiel
Daniella68313
Forum Pro
ha yes because my Oly c700 is actualy not 35-380 but 7-50 if I remember correctly. it is only an equivalent of 35-380, not a real one.
that all make sense.
--
Minë Corma hostië të ilyë ar mordossë nutië të
Mornórëo Nóressë yassë i Fuini caitar.
Un thoron arart’a s’un hith mal’kemen ioke.
Saurulmaiel
Daniella68313
Forum Pro
I think if you get more DOF you just ruine the nice OOF area. A bird photo with everything in focus is much less apealing to me than one with a great OOF area. Maybe just a matter of taste. Too bad we cannot cut the DOF precisely to what we want and that one affect the other.
Minë Corma hostië të ilyë ar mordossë nutië të
Mornórëo Nóressë yassë i Fuini caitar.
Un thoron arart’a s’un hith mal’kemen ioke.
Saurulmaiel
--I want LESS DOF, or at least the option to have it, you can
always stop a lens down more and gain DOF, you do need flash or
ISO increase of course.
What you cant do is make a lens have less DOF to create those great
looking surreal images
heres a shot from the 85 1.2L wide open in my local shop
without f1.2 that should would of been pretty boring
--
http://www.pbase.com/bigbad
Minë Corma hostië të ilyë ar mordossë nutië të
Mornórëo Nóressë yassë i Fuini caitar.
Un thoron arart’a s’un hith mal’kemen ioke.
Saurulmaiel
evenstar
Well-known member
In my opinion, the fact that the bird's tail is slightly out of focus gives the bird more DEPTH. Without it, it would look like you pasted a flat the bird onto a blurry background.
It's honestly a wonderful picture, and I think the OOF tail makes the picture stronger.
It's honestly a wonderful picture, and I think the OOF tail makes the picture stronger.
I shot this pic from 15 feet or less, probably closer to 13 feet,
at 15 feet my dof is 1.8 inches, at 13 feet it is 1.4 inches, now
in this pic most of the bird appears to be infocus except for the
edge of the tail. Is there anything i can do, beside stopping way
down or moving back, to increase dof? Does an extension tube
affect the dof? Will we ever see a digital slr where you can
control the depth of field using a dial without changing the
aperture? Maybe a sensor that can be stopped down? Am i just
dreaming? I guess my camera/lens are focusing correctly because at
this distance and dof there isn't much room for error. If i stop
down to f18 i can almost get 2.5 inches, i may try that with good
light.
--
http://www.pbase.com/paulyoly/root
DaShiv
Forum Enthusiast
...and mind you, I own one.
It's very specialized, but it's oh-so-good at what it does: shallow DOF and creamy bokeh. I've taken some candids with cooperative subjects, but I wouldn't dream of using the 1.2 on anything where focus speed is crucial. At least not with the AF on the Rebel. I'm sure the 85/1.8 is a more useful "general purpose" lens than the 85/1.2 is, and at a much more reasonable price as well. But when you really want shallow DOF and bokeh, there's no substitute...
BTW, for Sam, who hasn't seen the 85/1.2 in person yet:
It's a big (but amazing) hunk of glass!
DaShiv
It's very specialized, but it's oh-so-good at what it does: shallow DOF and creamy bokeh. I've taken some candids with cooperative subjects, but I wouldn't dream of using the 1.2 on anything where focus speed is crucial. At least not with the AF on the Rebel. I'm sure the 85/1.8 is a more useful "general purpose" lens than the 85/1.2 is, and at a much more reasonable price as well. But when you really want shallow DOF and bokeh, there's no substitute...
BTW, for Sam, who hasn't seen the 85/1.2 in person yet:
It's a big (but amazing) hunk of glass!
DaShiv
Hagrid
Leading Member
I shot this pic from 15 feet or less, probably closer to 13 feet,
at 15 feet my dof is 1.8 inches, at 13 feet it is 1.4 inches, now
in this pic most of the bird appears to be infocus except for the
edge of the tail. Is there anything i can do, beside stopping way
down or moving back, to increase dof? Does an extension tube
affect the dof? Will we ever see a digital slr where you can
control the depth of field using a dial without changing the
aperture? Maybe a sensor that can be stopped down? Am i just
dreaming? I guess my camera/lens are focusing correctly because at
this distance and dof there isn't much room for error. If i stop
down to f18 i can almost get 2.5 inches, i may try that with good
light.
--
http://www.pbase.com/paulyoly/root
Sam Bennett
Veteran Member
That is one huge chunk of glass (and change) - thanks for the pic!
Sam Bennett - Photo Guy, Audio Engineer and Web-Apper - http://www.swiftbennett.com
--It's very specialized, but it's oh-so-good at what it does: shallow
DOF and creamy bokeh. I've taken some candids with cooperative
subjects, but I wouldn't dream of using the 1.2 on anything where
focus speed is crucial. At least not with the AF on the Rebel.
I'm sure the 85/1.8 is a more useful "general purpose" lens than
the 85/1.2 is, and at a much more reasonable price as well. But
when you really want shallow DOF and bokeh, there's no
substitute...
BTW, for Sam, who hasn't seen the 85/1.2 in person yet:
It's a big (but amazing) hunk of glass!
DaShiv
Sam Bennett - Photo Guy, Audio Engineer and Web-Apper - http://www.swiftbennett.com
Forrest41926
Forum Pro
Depends on the lens. I think I read that this was a 400 mm? That means the 100-400L or the 400/4 DO ( the 400/5.6L prime doesn't have IS ). Both of these are big, heavy lenses, with a lot of magnification.
Even on a tripod ( and probably a tripod that's not 100% tightened down, to allow easy movements ) you'll see some shake in a super-tele lens. And having IS turned on will help remove this kind of shake, just like hand-holding.
This is why lenses like the 600/4L IS are meant to have IS on when shot from a 'pod.
Brian D. Schneider
Veteran Member
--Actually, the sensor could be tilted in the camera & that would do the same as a tilt lens but with any lens. BUT, can you imagine what that would cost.Stopping down the sensor was probably not the right term, i was
just curious if it's possible to make a sensor that you could
control the depth of field with without having to alter the lens
aperture. making the sensor smaller like in point and shoot
digital cameras increases the depth of field so why not a large
sensor that you could turn off the outside pixels and only use the
center to increase the dof when you need it or just when you want
it. Does that make sense?
--
http://www.pbase.com/paulyoly/root
Brian Schneider
Brian D. Schneider
Veteran Member
--Oh ya, I agree with to othets, your picture is perfect, I would be proud to have a shot like that. (spring is coming to the prairies..mayby)
Brian Schneider
I don't have an IS lens Daniella, i have the 400 f5.6L which is not image stabilized, but 'IS' is not a substitute for a good tripod. I use a bogen 3011 legs with 3130 head.
----I shot in aperture priority and this is the shutter speed the
camera gave me at f/10 and iso200, I of course shot this on a
tripod and the bird was kind enough not to move very much, i shot
about 8 pics of the same bird at the same time and all but 2 were
sharp. I try not to ask the camera why it does what it does
because it tends to do it very well. The histogram on this shot
was slightly to the left, i ended up adjusting levels by pulling
the right slider in and the left slider in, but twice as much on
the right slider, i believe they are called the black and white
points.
--
http://www.pbase.com/paulyoly/root
Minë Corma hostië të ilyë ar mordossë nutië të
Mornórëo Nóressë yassë i Fuini caitar.
Un thoron arart’a s’un hith mal’kemen ioke.
Saurulmaiel
http://www.pbase.com/paulyoly/root
I'm not sure what Daniella was responding to, but i did not say this was an image stabilized lens, i'm using the 400mm f5.6L. And i agree that having the IS on when using a tripod with a 400mm lens can have it's benefits, i use the tripod with the head loose for easy movement, i don't stop and tighten it done then shoot, i just shoot and i'm not using a shutter release so IS would help remove any shake caused by me pressing the shutter I assume.
--
http://www.pbase.com/paulyoly/root
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