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Archive 2013 · Are you calculating dof in your head as you shoot?

  
 
popinvasion
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p.1 #1 · p.1 #1 · Are you calculating dof in your head as you shoot?


Are you a human dof calculator with your shots? I generally have a rough estimate but do get it wrong at times. This is one area where I want to improve, I want to be a more accurate shooter and shallow dof is great when you get it right.


Oct 07, 2013 at 12:47 PM
robstein
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p.1 #2 · p.1 #2 · Are you calculating dof in your head as you shoot?


Um NO I have a decent idea but human calc... not a chance...

I assume you know but the Canon bodies have the preview button which is handy sometimes.... I know it's limited with shallow. There are some decent iphone/droid apps out there that can help.



Oct 07, 2013 at 01:27 PM
abqnmusa
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p.1 #3 · p.1 #3 · Are you calculating dof in your head as you shoot?


depth of field preview button on camera / review pic on screen to check


Oct 07, 2013 at 01:30 PM
popinvasion
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p.1 #4 · p.1 #4 · Are you calculating dof in your head as you shoot?


robstein wrote:
Um NO I have a decent idea but human calc... not a chance...

I assume you know but the Canon bodies have the preview button which is handy sometimes.... I know it's limited with shallow. There are some decent iphone/droid apps out there that can help.


I am not attempting to be clinical but I do want a little better idea than I currently have, the apps are fine but again too clinical for every shot. I am just wanting to accomplish better accuracy and I think if I put a little effort into this my shots would improve but I don't want to make shooting a constant math problem but some fluency helps. I find the dof preview to be almost useless.



Oct 07, 2013 at 01:31 PM
trenchmonkey
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p.1 #5 · p.1 #5 · Are you calculating dof in your head as you shoot?


I pretty much know the DOF at a given distance/aperture for the glass I regularly shoot workin'
the rodeo arenas. Same goes for BIF Years of shootin' the same stuff breeds familiarity. I'm
probably within 6" with things that move. Hey, that's what SHE said.



Oct 07, 2013 at 01:39 PM
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p.1 #6 · p.1 #6 · Are you calculating dof in your head as you shoot?


what genre to start with? macro or........
thats the first question anyway



Oct 07, 2013 at 01:56 PM
dgdg
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p.1 #7 · p.1 #7 · Are you calculating dof in your head as you shoot?


I agree with the above recommendations:
1. Use your lens enough such that you know based on aperture and target distance, what your result will be.
2. Use the depth of field preview button if you are not sure before you shoot.
3. Review a 'test' image on the lcd screen and zoom/pan. Re shoot if needed.
For what I shoot (people, landscapes, wildlife) I already know in my head what I need to use for aperture. I think it eventually becomes second nature.




Edited on Oct 07, 2013 at 02:00 PM · View previous versions



Oct 07, 2013 at 01:59 PM
gdanmitchell
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p.1 #8 · p.1 #8 · Are you calculating dof in your head as you shoot?


popinvasion wrote:
Are you a human dof calculator with your shots? I generally have a rough estimate but do get it wrong at times. This is one area where I want to improve, I want to be a more accurate shooter and shallow dof is great when you get it right.


In my experience, very few photographers actually calculate DOF. More commonly we take a more seat-of-the-pants approach to this. An idea that I've discussed with a few other photographers is that we more typically take one of three approaches:

1. If we are concerned about having enough DOF, we simply stop down to whatever smallest aperture we think is reasonable, perhaps stopping down a bit more than necessary, but knowing from experience that it will work and produce a fine photograph, or...

2. If DOF isn't an issue, for example when shooting a relatively flat subject that is parallel to the sensor plane, we pick some generalized default aperture along the lines of the old "f8 and be there" concept. (Note: f/8 isn't always the right choice.) Or...

3. If we want to limit DOF we typically either open up as wide as we can or think reasonable or we might moderate this a bit if a slightly smaller aperture will work.

If you are very concerned about the DOF effects of aperture and you shoot a modern DSLR from the tripod, it can be far more useful and accurate (in the meaningful photographic sense) to use live view. Once you focus on your primary target while zoomed in to 10x magnification, press the DOF preview button and "pan" around the image to directly check the sharpness of various elements in the scene and adjust focus and/or aperture as necessary to get what you want.

Dan



Oct 07, 2013 at 02:00 PM
snapsy
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p.1 #9 · p.1 #9 · Are you calculating dof in your head as you shoot?


A feel for DOF is developed over time and experience. Speaking generally, the closer you are to a subject the more careful and aware of DOF you'll need to be since it's easier for it to be too shallow, esp for subjects with 3-D features like human faces and dogs with long snoots


Oct 07, 2013 at 02:08 PM
Rajan Parrikar
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p.1 #10 · p.1 #10 · Are you calculating dof in your head as you shoot?


My approach takes the form Dan has described above. To that I would add that keeping in mind Merklinger's thumb rule is a good idea. It is explained here -

http://www.luminous-landscape.com/tutorials/digital%20focusing%202.shtml



Oct 07, 2013 at 02:21 PM
Roland W
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p.1 #11 · p.1 #11 · Are you calculating dof in your head as you shoot?


I work mostly via "seat of the pants" or use live view, as others have mentioned above. One thing that most modern lenses lack is a depth of field scale. That was so common back in the manual focus film days, but is mostly gone now. But the Canon manual focus Tilt Shift lenses have a reasonable "throw" on the focus ring, and a few depth of field markings to help you out. The Zeiss ZE manual focus lenses that fit Canon bodies also have depth of field scales on them, all though I have never used one of those lenses. Anyway the old fashion way is another alternative to keep in mind for knowing what your depth of field is, especially if you own a Canon TS-E lens.

Most current Canon lenses can report the distance they are focused at back to the camera, which is used for flash photography exposure calculations. There is no reason why a camera could not display the focus distance the lens is set at, as well as calculate the depth of field and display the far and near distance values, as well as calculate the size of the depth of field. I would guess that the distance information reported by the lens is not super accurate, so that may be why we do not get the information right now. But even if the distance has some error, the depth of field calcualtions would still be very handy. I have never seen that feature built in to modern cameras, but it might exist out side of the Canon world. Obviously you would need to interpert the distances and try to make sense of them in the scene, which could be hard to do, but if you are good at estimating distances, it could be handy, especially compared to trying to open an app and estimate the shooting distance and enter the current aperture and lens focal length values.

Using live view to check and inspect at the stopped down shooting aperture is very useful when you are on a tripod and have the time. But is can be slow to check the near and far with only the one zoom in box. It would be very nice to have a second or even a third zoom in box available, so you could watch up to three points zoomed in while you adjust focus. This is another feature that some cameras might now have, but I am not aware of it.

Another thing that would help with live view focusing is to add some display readout scale that interperts a given live view zoom in box, and shows how well that part of the image is in focus, in a way that could be seen without careful close inspeciton of the live view screen. Something like a little bar along the side of the zoom in box, that gets short as focus improves. I do not know how hard that is right now, but it should be easier with the new sensor style used in the 70D, that can report focus information from every dual pixel on the screen during live view.




Oct 07, 2013 at 02:45 PM
AJSJones
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p.1 #12 · p.1 #12 · Are you calculating dof in your head as you shoot?


One key concept that I keep in my head is some guess/idea/hope on the size at which I think I am likely to print the image. If it's only ever a small image then I worry less about the fine points of DoF, diffraction, aperture etc, but for something I am capturing with a desire to make a large print, I'll pay more attention. DoF values are generally calculated assuming ~8x10-12" viewed at a distance of the diagonal of that. When I make a big print I will usually not be under those conditions (either big print and same viewing distance or nose up against the print (So I stop down accordingly).


Oct 07, 2013 at 03:15 PM
Photon
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p.1 #13 · p.1 #13 · Are you calculating dof in your head as you shoot?


popinvasion wrote:
Are you a human dof calculator with your shots? I generally have a rough estimate but do get it wrong at times. This is one area where I want to improve, I want to be a more accurate shooter and shallow dof is great when you get it right.

I've emphasized one phrase of your post because it implies a different issue from what you would typically try to get from DOF tables or calculators, DOF preview, etc. (although Dan touched on it in discussing live view). Shallow dof involves a tradeoff between sufficient depth to render your subject appropriately and sufficient background blur for the effect you want. One example would be a portrait shot at an oblique angle when you didn't want only the near eye in focus. You would want to have maybe 2-3 inches of DOF to work with at the same time that (perhaps) you wouldn't want more because you're trying to blur the background.

Observations on my own example:
I don't memorize DOF tables, nor use DOF preview when shooting portraits.
I know that for a given magnification (face size within my composition) DOF for a given f/stop will be independent of lens FL used to get that size.
Therefore, I've gotten a working knowledge that for certain framings at certain angles I'll need f/4, 5.6, etc. to get both eyes in focus.
I know that degree of background blur depends greatly on FL, so if it works in other ways I can go to a longer FL to blur the background without opening too wide to cover my subject.
When I want maximum background blur for a given framing and perspective (camera, subject, and background positions fixed) I open the lens all the way and do my best to focus on the optimal spot, even if parts of my subject are rendered soft.

It all comes down to what all the others have said about practicing and getting a feel for it. You can also try DOF bracketing when the subject allows. Pick the f/stop you think will be best, but also try others.



Oct 07, 2013 at 04:00 PM
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p.1 #14 · p.1 #14 · Are you calculating dof in your head as you shoot?


I personally just saturate, if I am trying to keep two parts of the photo in focus (at different distances), I will try to focus at he point one third in back of the closest one (or two thirds in front of the farthest one), shoot a bunch of different apertures, and then pick out the one that works best in post.

I do the same when I think I might have use for varying the DOF, like shooting something up close with some depth to it. Once you get the hang of it, it doesn't take very long to turn a dial and press a button a few times. Still sometimes I wish that you could bracket it.



Oct 07, 2013 at 04:12 PM
jimmy462
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p.1 #15 · p.1 #15 · Are you calculating dof in your head as you shoot?


Hi popinvasion,

I'll jump in only to add to the chorus of it being a "you get a feel for over it time" kind of thing.

I will add, though, that DOF an FL truly go hand-in-hand for me when I'm shooting hand held and moving around amongst various subjects. I know that when I've got a short tele mounted that I'm gonna get a good throw (as in "thrown out of focus") on my background if I'm grabbing a medium-close portrait regardless my f-stop...and I know that if I want to contextualize my subject more with their surroundings that I need to either "go wider and move in" or "move back and go longer" (aka reframing via FL, in both cases) and stop-down (in both cases) to get the same subject size in my frame. All settings, of course, depending on the level of blend or pop I'm "looking for".

Here's a suggestion for anyone, like yourself, looking to get a "feel for things" with DOF and FL...At your next gathering of friends or family just walk around with something like a 24-70mm or 24-105mm and just work the crowd. Go for the long shots, go for the short shots, shoot 'em at different focal lengths, shoot 'em at different f-stops, get close, move away. When you get home later review your shots and the EXIF data...and you'll begin to get that "feel" process going in no time. Trust me, this should be a lot easier, and cheaper, and quicker thing to learn than it was back in the film days!

FWIW, the only math I ever used while shooting was to figure out how many rolls I could afford to shoot in a week based on my dishwasher pay.

Hope this was helpful,
Jimmy G



Oct 07, 2013 at 04:13 PM
jcolwell
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p.1 #16 · p.1 #16 · Are you calculating dof in your head as you shoot?


I use my intuition, based on experience. Sometimes, my intuition tells me to use a tilt-shift lens, when I want "everything" in focus. When I want really shallow DOF, I select a fast prime and shoot wide open. When I want something in between, I shoot according to experience, and sometimes use two or three different apertures.


Oct 07, 2013 at 04:22 PM
popinvasion
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p.1 #17 · p.1 #17 · Are you calculating dof in your head as you shoot?


I love the replies everyone. I appreciate the thoughtful responses and i think many of the opinions and thoughts will better my skills so thank you. I will add more a bit later. I am in the middle of a job. I do have a feel for it from practice and I get the theory behind it but I just want a little more accuracy. As a musician, music theory is similar not necessary to rock, but a little theory can get you out of trouble so it's not required but nice to have. My mind likes a little more theory to support my efforts, I like to constantly improve and practice but it has to for me to be based on something rather than just muscle memory for a lack of a better phrase.


Oct 07, 2013 at 04:23 PM
gdanmitchell
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p.1 #18 · p.1 #18 · Are you calculating dof in your head as you shoot?


Roland W wrote:
I work mostly via "seat of the pants" or use live view, as others have mentioned above. One thing that most modern lenses lack is a depth of field scale. That was so common back in the manual focus film days, but is mostly gone now...


I also started back in the ancient era when lenses had DOF scales on the barrel. They were, of course, rough approximations, but they were useful for making estimates.

They aren't gone entirely. The beautiful little 14mm f/2.8 lens I use on my Fujifilm X-E1 reveals the scale if you slide the barrel back to switch the lens to MF mode. On a lens with a short focal length like this (angle-of-view equivalent to 21mm of full frame), there is enough DOF at largish apertures that the old system of manually setting it to hyperfocal distance and turning off AF can work reasonably well for certain kinds of shooting.

On a related topic, I do find that such a wide lens has some application for street photography.

Dan



Oct 07, 2013 at 06:25 PM
EB-1
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p.1 #19 · p.1 #19 · Are you calculating dof in your head as you shoot?


No, but I eyeball check a few lenses.

EBH



Oct 07, 2013 at 06:36 PM
UCSB
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p.1 #20 · p.1 #20 · Are you calculating dof in your head as you shoot?


Experience and DOF Calculator on my Samsung Galaxy Note 2 are my tools. I have never understood why Canon does not display this info on our LCD. It takes almost no resources to calculate. Just another missed opportunity. I'm talking about an approximation of DOF ... familiar with all the technical arguments and issues around different output sizes and media. I will use DOF Calculator before a shoot to double check my planned lens choices if it is important enough before I start shooting. Another good rule of thumb I've noticed is that when doing AF MA at 50x focal length, the DOF is relatively constant at different focal lengths. This can give you a another reference point if you do enough AF MA.

Added: The DOF Calculator I use on my Android device is DOF Calculator by Cunning Dog Software. I tried a number of them ... this was the best for me.



Oct 07, 2013 at 07:08 PM
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