[Ian Stuart Forsyth]

Shoot bracketed ƒ-stops, pick the best one.

It works way better than fooling around with some app in that you have some playing room for miscalculation,

the most important thing the app tells you is where the defocus blur and diffraction blur is equal, this is something that cannot be easily worked out in the field, the app also give you the useful information of what the final resolution will be if you so choose that DOF and again something that is not easy to know in the field.

Ian, I shoot a K-1 and a K-3. It's really disrespectful to start telling me the difference between 2 MP and 36 MP cameras

Really Pot meet kettle see below

I can only assume that when you don't use the app, you mess up a lot images.

and no its not disrespectful to ask for someone to see photos, Its not really hard to align the DOF for a given image when the image is displayed very small, on the other hand its much harder to place the DOF such that defocus blur, diffraction along with lens characteristics give you the same amount level of resolution throughout the image you are trying to capture when that image is view large as this will show any errors of that users choices. Its not easily done and if as you say its not hard then please show me your work doing such that, walk the walk

I'm not sure why you want to make this so complicated, but to each his own. It's none of my business, until you start posting on the forum.

sorry didn't realise that this was your forum,

So what I'm looking for here is some practical examples showing me how you've improved your photography using this app. Something you couldn't have done without it.

If you would answer this question

If you don't need the app mind telling me at what viewing size does your image need to be viewed for everything to fall in the DOF for that given fstop you have decided? if you can answer that then also tell me what resolution will be capture?

I will post it again for you

The reason why I asked you these questions is that how you display the final image while be the deciding factor on what f stop you will need for the DOF you have decided, what f stop you decide on will influence the final resolution you will have at the time the image hits the screen or the light hits the paper. This is what the app tells you



Using this image as a demonstration you can see the front of the image that in the grass the defocus blur and diffraction are about equal to the defocus blur and diffraction found in the distance, this is what the app calcs based on a model, it is then the users choice to select the best place the DOF based on that information.

A lot of us carry that information around in our heads, and totally don't need the app. As i said, a fraction of a second evaluating a scene using your experience saves hours of messing around with technology.

(Only takes 4 sec to check my app not hours.)


Going back to this, If you can carry around the information in your head what the app tells me, then it shouldn't be too hard to provide us images that show how well you manage DOF and its relationship with resolution and how you place it in the image.
because its so easy to get DOF correct in a 2mp image and much more of a challenging in a 24-46mp image that may involve focus stacking.

You aren't the world's greatest expert on everything.

I know I am not but someone here thinks they are :0 It all boils down to expectations 2mp is not hard to manage DOF, 36mp much harder. any iPhone set to auto and can nail DOF for a 2mp image.

I am not the one proclaiming that they can work out the optimum settings for providing the best all round DOF in an image for a scene and carrying them in one’s head am I ?. That to me sounds like the one professing themselves as the greatest expert.
I am asking you to show me that you can indeed do this,

The capability of the camera doesn't change because of your app. If you always go for the best, then you can't do any better than that. NO use cluttering your brain with useless information.

This is why I use the app it tells me what I want to know where defocus blur and diffraction are equal and at what Fstop, with an idea on the final resolution the image will capture, this way out in the field I can make quick decision on how I am going about to capture the scene.

And on a final note it is not too uncommon for you to demand images from others when they disagree with what you think of as the norm's norm, I think its only fitting that I can ask the same from you

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Last edited by Ian Stuart Forsyth; 12-09-2017 at 07:59 PM.

[angerdan]

One of the app I like to use is not a DOF calculator but one that calculates the combined effect of defocus blur and the effects of diffraction that a person would expect with the settings you select
After selecting your FL you can select the min and max distance you want to be in focus and the app calculates the f/stop and the blur spot dia. This gives you an idea the final image resolution and you can make adjustments to give you the best options.

What is that app called?

OptimumCS

Looks like a good App for iOS.
For Android users there's an alternative solution:
DoF by Jonathan Sachs - Google Play
DoF 4.0 - An advanced, graphical depth of field calculator for Windows and Android

[Ian Stuart Forsyth]

Looks like a good App for iOS.
For Android users there's an alternative solution: DoF by Jonathan Sachs - Google Play DoF 4.0 - An advanced, graphical depth of field calculator for Windows and Android

They are a good app I like them based on that the fact you can quickly look and see where defocus blur and diffraction are equal, most of the time I ignore were they recommend you should focus as that is very lens specific decision.

[normhead]

A few of my recent hyperlocal efforts....







I don't analyze my images in the way you'd do, and I'm not convinced I suffer in any way for that.

I'm still not clear on what you are accomplishing. Maybe you could explain an example where you did just the traditional hyperlocal set up for landscape. ƒ5.6 APS_c or ƒ8 FF and then adjust smaller aperture for more DoF if needed, find something to focus on about 1/3 of the way into your frame. How would the app have told me to change my exposure? You can click on the images and scroll down to see exposure settings.

Any image we take can end up being printed at any size. In my experience, a picture that is darn near perfect small is also darn near perfect big. It's never occurred to me I might want to change an exposure because of the output expected. I just shoot for perfection defined by looking at the image, no technical metrics applied. Images are not valued by their technical metrics.

It's simple, Smaller ƒ-stop = smaller circles of confusion, after ƒ-11 you start to lose resolution to diffraction. By ƒ-22 diffraction will have badly compromised the image in terms of resolution but often not in terms of the viability of the image. I have quite a few images taken at ƒ22, because I wanted maximum DoF. What you are not convincing me of here is the necessity to do what you do. I'd need to see an image with what I do, with one taken beside it with you doing what you do, so I could see how yours is better or if we even ended up with different settings. I'm pretty sure that's never going to happen. But if it does, we'll have to stop in the local bar for some refreshment after.

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Last edited by normhead; 12-10-2017 at 06:33 PM.

[Ian Stuart Forsyth]

I don't analyze my images in the way you'd do, and I'm not convinced I suffer in any way for that.

Your right it all comes down to exceptions, but when someone criticize one’s method that finds the fastest and best way to derive the IQ they are looking for then it then becomes problematic. If you are happy with your method don’t citizens someone else's method if they want to more precisely place the DOF within the resolution that a camera can capture.

If you want to state that " A lot of us carry that information around in our heads, and totally don't need the app. As i said, a fraction of a second evaluating a scene using your experience saves hours of messing around with technology."
you better know that some may have higher expectations(more than those found in your head) and with those higher expectations they are resolution proofing their images for any future size they choose to display them at.
Like I said its easy to get things correct when the image is only 2mp but when its 36mp its a all together different story as your lack of showing 10mp,20mp or even 36mps show us.


One of the inherent problems is where the hyperfocal distance is and the DOF are all based on how you view the final image.

Take for example we have the same image but displayed at 2 different sizes, one shown smaller and the other at twice the diagonal size. For that image taken at the same f/stop one of the images will have a shallower DOF and to keep the distance in the acceptable level of sharpness the hyper focal distance is shifted almost twice the distance away.

One inherent problem when using the DOF model supplied to you on then lens is that it will give only accurate DOF for that standard model . This then leads too many incorrect assumptions to DOF, hyper focal distance and the f/stop. If I want to get the best DOF and resolution for what the camera can capture this model is a lost cause, one of the reasons why I like to have a method of finding the best overall balance of captured DOF and resolution is that no matter what the displayed size is it will give you the very best overall image the camera can capture.

As I have stated earlier if we use the standard model it can miss direct the user on where to focus. If the user wants to accommodate for more DOF that is needed for larger prints this model is also counter predictive. One of the reason is that if I stop down the lens for larger prints the lenses model will tell the user to place the hyper focal distance closer to the camera, this again is not the correct thing to do.
Under most conditions if you want to alter the fstop for more DOF in larger prints you want to use the same hyper focal distance and the model on camera’s lenses tells you the very opposite and to move it.

Any image we take can end up being printed at any size.

This is one of the reason why with very little time 4 -5 secs( fractions smaller than the time it takes for travel and planning) I know how to take the very best I can, this way it’s resolution proofed for the best outcome for any size of print.
Or If I am exposure time limited and i know the final resolution that I want i can greatly reduce the amount of light needed to capture the final image shorter shutter speeds Often times I only need f/4 for front to back DOF for my displayed image.

To no surprise you presented images that really takes no effort to balance and place DOF into the captured resolution.
For other users they often shoot using conditions that they need to balance going from 4 feet to infinity with a 50mm lens and want best resolution they can capture ( short of focus stacking).


Or sometimes they need even more DOF

And that becomes even more problematic.

[normhead]

SO basically you're saying it's good for images where you have to position the DoF for the best image because the DoF doesn't cover the distances in the frame. So my response to that would be as a general rule I avoid those images. Would your last image be more compelling if you lifted the camera to give you 8 feet instead of 4 so you could use ƒ11 or 16 and have everything in focus. It might be the best image you can get, but the foreground is soft is it not? I guess whether or not that's printable image without cropping depends on personal standards. It's not for me, but if it's good for you go with it.

[audiobomber]

Ian, could you please post the exif data for those images?

[Ian Stuart Forsyth]

Ian, could you please post the exif data for those images?

The first one is taken at 50mm iso 100 f/16 1/250sec with a FF

second at16mm iso 100 f/8 1/40 k20d

---------- Post added 12-13-2017 at 12:25 AM ----------

If the image I want to capture requires me to have 4feet to infinity I want to know several important things.

The first is where does the edge of defocus blur starts, this is determined by the selected DOF 4- infinity.

Using the model I know that closer than 4 feet things are going to become more blurry and everything further away will be sharper which brings me to the next thing I want to know.

What is the smallest detail I can resolve at that 4 feet- infinity, 2 things control this the amount of diffraction (f/stop) and that edge where defocus blurs starts. This way I know where defocus blur & diffraction blur are all equal. When I know this I then can compare this and how it relates to the blur from the sensors resolution. For 36mp I know I can get good results with blur no larger than 35-40 microns.

This intersection of the defocus, diffraction and resolutions blur is highly dependent on the resolution of the camera. Take for example if I am shooting using a 24mp camera for the most amount of detail I can capture for that selected DOF I need f/8 when viewed at 100%. A camera the twice the resolution of 50mp to get the same amount of DOF when viewed at 100% I need f/11 I know that I will capture more resolution at f/11 with 50mp than an would at f/8 on the camera with 24mp resolution.

It would not be hard to find out that for that 24mp camera I would need to shoot at f/4-5.6 for the same final resolution as the 50mp camera at f/11 the difference being that the 24mp has a lot less DOF and weaker corner performance . This shows that resolution blur, diffraction blur and the defocus blur are all changing as the cameras resolution increases.

If the point at which diffraction blur and defocus blur become too great for the DOF and the resolution I require then I either have to live with it or focus stack.

[photoptimist]

SO basically you're saying it's good for images where you have to position the DoF for the best image because the DoF doesn't cover the distances in the frame. So my response to that would be as a general rule I avoid those images. Would your last image be more compelling if you lifted the camera to give you 8 feet instead of 4 so you could use ƒ11 or 16 and have everything in focus. It might be the best image you can get, but the foreground is soft is it not? I guess whether or not that's printable image without cropping depends on personal standards. It's not for me, but if it's good for you go with it.

Actually, he's saying that a normal hyperfocal calculator would claim the DoF at a very small aperture would theoretically cover the full foreground-to-background distance but that DoF blur + diffraction blur means both the extreme foreground and background would be blurrier than is acceptable for the resolution of the camera and intended large printing size. A more sophisticated DoF+diffraction app calculator which is no harder to use than the simple DoF-only app calculator enables him to get challenging images or know when the image really won't work or will require focus stacking.

To me, Ian's methods are useful for pushing the envelope for what is photographically possible because sometimes reframing or repositioning to avoid too close a foreground or too diffracted an aperture isn't desirable. For me, at least, there's huge satisfaction from using either experience or using an app to say "yes, the image will work" without even looking through the viewfinder. The ability to predict what will work and being right is very rewarding.

At the same time, no one but the photographer will ever know what images were never attempted because the scene was on the verge of photographic impossibility. And if you live in a beautiful place like you do, normhead, there's so many great foreground-background pictures everywhere you look that can be taken with basic hyperfocal experience that mucking about with a technical app isn't warranted just to get one particular hard-to-get image.

At some level, having a DoF-diffraction blur app is like having a f/1.2 lens. Most of the time, the app or f/1.2 isn't really needed. But sometimes it does make the difference between getting the shot or not getting the shot you want. But if your situation enables you to get the shots you want without DoF-diffraction blur app (or a f/1.2 lens), then that's all that matters.

[bdery]

just to be clear, when you say "is the camera cropping the full frame image", what it is NOT doing is capturing an image on the Full Frame sensor and resizing it.

That is incorrect. The camera does just that.

You should use a aps-c determined hyperfocal distance.

Correct, but not for the reasons you mention.

This is because you are capturing your image on an aps-c sized portion of the sensor.

You are contradicting yourself. APS-C is a crop, like it or not.

If you focus your lens at a certain distance and use a specific aperture, it will give you a certain DoF, from one distance to another. This distance will not change if you switch to APSC mode. It will be the exact same image, except with the edges cut off. The sensor size can not change the image that the lens renders, it can only capture more or less of it, at a higher or lower resolution.

Mostly correct.

Sorry that is just plain wrong. You are ignoring what has to be done to the captured image in order to produce the same sized picture (on screen or in print) It is this "enlargement" (actually less reduction), which changes the DOF and hyperfocal distance.

You are again incorrect.

The ONLY way that the sensor itself influences DOF is relative to the size of its pixels. Smaller pixels are able to resolve smaller details, all other things being equal. The size of the pixels define the circle of confusion, which is the largest circle in the object plane that will be seen as a point in the image plane. So for vastly different pixel sizes, the sensor WILL influence the DOF.

The other two parameters influencing the DOF (indeed, the parameters dominating the effect) are focal length and aperture. Those are not linked to the sensor.

If your logic was correct Medium and Large format cameras would never have left the camera shops shelves

Neither here nor there. Larger formats are interesting because they can give you the a wider field of view for a given focal length, that's all.

[normhead]

The first one is taken at 50mm iso 100 f/16 1/250sec with a FF

And that is exactly my point. Your final exposure is what I would have done on any but my point and shoot cameras.

It would not be hard to find out that for that 24mp camera I would need to shoot at f/4-5.6 for the same final resolution as the 50mp camera at f/11 the difference being that the 24mp has a lot less DOF and weaker corner performance

This obsession with "the same" always leads to me scratching my head. Why wouldn't you want to use the max. resolution you could achieve?

This is fairly easy to check out,

Canon EF 35mm 1.4 max resolution at ƒ11 4135
Canon EF 35mm f/1.4 USM L II - Review / Test Report - Analysis

Same lens on a 24mm sensor at ƒ4... 3810 w'ph center.

I am totally unclear however as to why that's useful information? Interesting though it may be. My way of doing it is to make the best use of every system, which means i would never be trying to match the resolution of one sensor with another. Especially in a case like this where the DoF will be so much narrower on the 24 MP sensor. The reason you buy the larger sensor is more resolution for the same DoF. Why would you buy a more expensive larger system, then "match" the resolution of a lower MP system? Once again, talking about an ƒ4 image and claiming to get the same image with an ƒ11 image on the same sized sensor, you're talking about completely different images.

What am I missing?

[Na Horuk]

So for vastly different pixel sizes, the sensor WILL influence the DOF.

Yep. Smaller sensors usually have higher pixel density, but it is not a rule. There would be a difference in detail (which would also affect the transition between in and out of focus) if you use a 6MP APSC and a 24MP APSC camera (with same lens, aperture and focus distance). But if you use 16MP APSC and 36MP FF, the difference would be negligible, because both have a similar pixel density.
But to me, this is mostly an illusion of DoF. You can really affect how viewers perceive DoF if you play with things like contrast, clarity, selective sharpening. The "concrete" DoF that you use for hyperfocal and zone focusing is mostly a function of focal length, aperture, and focus distance. Then you have effects of lens distortion (DoF can be very curved), pixel density, AA filter, PP, and viewer's own standards (some viewers would consider one thing to be too blurry, while others would consider it perfectly fine).

Actually, I would be interested if Pixel Shift affects the perceived DoF. I don't have a PS camera to do a test, but it would be interesting

[normhead]

At some level, having a DoF-diffraction blur app is like having a f/1.2 lens. Most of the time, the app or f/1.2 isn't really needed. But sometimes it does make the difference between getting the shot or not getting the shot you want. But if your situation enables you to get the shots you want without DoF-diffraction blur app (or a f/1.2 lens), then that's all that matters.

Good analogy, as I understand it. It might be worth it on rare occasion, but you won't suffer much if you don't use it. The difference being you can't guesstimate ƒ1.2. You can guesstimate what this app tells you with a decent amount of experience, if you take a lot of these images. maybe like training wheels on bike. You just don't have that many settings to choose from, and once you get the hang of doing what you want to do, those settings should be pretty much branded into your brain.

[photoptimist]

Good analogy, as I understand it. It might be worth it on rare occasion, but you won't suffer much if you don't use it. The difference being you can't guesstimate ƒ1.2. You can guesstimate what this app tells you with a decent amount of experience, if you take a lot of these images. maybe like training wheels on bike. You just don't have that many settings to choose from, and once you get the hang of doing what you want to do, those settings should be pretty much branded into your brain.

Yes, experience really does matter!

I was going to say "years of experience lets you avoid seconds of app usage" but that snarky comment hides a deeper problem. I've noticed that many photographers (not you or Ian or any of the better people on PF) are so used to automation of exposure, focus, shutter time, aperture, etc. that they never learn anything from experience. They simply do what their camera or app tells them to do without ever paying any attention to what the automation did or why.

Automation can be a tool or a crutch depending on whether one uses it to bootstrap experience (i.e.g, use "auto" and apps but notice what they did and how it turned out) or as a permanent substitute for experience (set the camera to P + app settings + bracket and spray-and-pray).

The OP asked a very important question and I hope they can use our answers to build experience with DoF on different formats.

[normhead]

I was going to say "years of experience lets you avoid seconds of app usage" but that snarky comment hides a deeper problem.

And that's exactly it. I'd say use the app if you need it, but study what you learn from it with a mind to work without it. Digital makes it so much easier. On my PP software the technical info for every images is displayed under every image. There's just no excuse for not knowing what type of exposure you favour in different situations. The importance of paying attention to what works for you can not be over emphasized.

After all, most of us old studio guys could walk into a studio set and guess the proper exposure without looking at the light meter.