Help! Can’t understand “Understanding Exposure” by Bryan Peterson

[Bruceter]

Specifically, the chapter on “Storytelling Apertures”. He describes how to overcome the lack of a depth-of-field scale on SLR lenses by using the distance settings.

He writes; “And, since every storytelling composition relies on maximum depth of field, you would first choose to set your aperture to f/22 and then align the distance above your distance-setting mark on the lens. Your focal length will determine which distance you choose.”

I don’t understand the last sentence. HOW does the focal length determine the distance at which you focus? If you select f/22; at what distance do you focus?

Any help appreciated.

Thx,
Bruceter

 

[KEITH-C]

This advice , which is unclear , relates to the use of the so called hyper-focal distance settings. Google 'hyper-focal' on the Net. Many modern digital lenses do not have the relevant markings & this advice goes back to the use of film cameras.

In general if you use the smaller apertures to increase depth of field & get a focus lock on the main subject of interest then that should be sufficient. The danger in landscape shots is that nearby objects may be slightly OOF & in such cases focusing just short of the main subject may give more suitable DOF which then includes the foreground - the main subject should still fall within the focus range but there will then be a slightly quicker fall off in focus beyond that range.

Keith-C

 

[aardvark7]

Many lenses have an indication of depth of field relating to a particular f-stop on the top. So that when you focus at, for example, 20 feet and are using f8, then you can look at the guide on the lens and read of the minimum focus distance and the maximum focus distance; hence depth of field.

You will immediately notice that the marks get wider apart, and the depth of field greater, the smaller the aperture, the larger the f number.

In theory you don't have to have a focus screen if you were a good judge of distance by simply looking at the top of your lens but this is not very practical.

 

[Bruceter]

Thank you all for your replies.

My lenses (the 2 zoom kit lenses for the Pentax K100D) do not have any depth of field or aperture markings -- all you have is the focal length markings and the distance markings. Aperture settings are seen in the viewfinder and the top LCD. I think this is similar to many modern DSLR's and their lenses.

I was hoping the book had a method to relate depth of field to aperture (with the same degree of precision as the "old" lenses provide with their depth-of-field scale).

I'll check Google for 'hyper-focal', but I may have to get some depth of field charts to get an idea of the depth of field available at different apertures and focal lengths. Or, I could use the depth-of-field preview in the viewfinder -- if i have enuf light.

Bruceter

 

[Wayne Larmon]

... you would first choose to set your aperture
to f/22...

Don't use f/22 unless you are using a FF camera. Diffraction effects will cause the image to be soft. Smaller sensors have a smaller (numerically) aperture diffraction limit. The last I heard, it was f/13 for a six megapixel APC camera, and f/11 for an 8 megapixel APC sensor camera.

A while back there was an anguished story told here about somebody that read the Bryan Peterson book, then went on a once-in-a-lifetime vacation. For most pictures, he set his DSLR up on a tripod, used mirror lockup, and remote release. But set the aperture to f/22 because this is what the Bryan Peterson book said to do. Too bad. All his pictures came out soft.

APC sensors have a larger DOF than FF sensors do so you aren't losing anything in DOF by not going to f/22. Assuming that you want a large DOF.

Wayne

 

[Krzycho]

Hello,

Sorry for digging out such an old topic, but my case is really related with this, so I don't want to start a new one.

I'm reading 'Understanding Exposure' by Bryan Peterson but I use M43 system (G85 Lumix), so I have some doubts:

- as you said it seems that F22 rule applies only to FF systems (I guess that this is not stated in the book, even that my edition is 2014)

From my experience for M43, focal length for everything in focus is F11, F16-F22 is noticeable softer.

- accordingly for aperture called 'who cares?' I think that I should apply something like 5.6, instead of recommended F8-F11, right?

Another case is focus mode for everything in focus. I do not have distance indications depicted for my lens (12-35 lumix), so is the good idea instead:

- set aperture to F11, switch to manual mode and set infinite?

Thanks a lot!

 

[Confused of Malvern]

Another case is focus mode for everything in focus. I do not have distance indications depicted for my lens (12-35 lumix), so is the good idea instead:

- set aperture to F11, switch to manual mode and set infinite?

No!

There is always more depth of field behind the point of focus than in front of it. If you focus at infinity then you are not maximising you're depth of field; you're in effect 'wasting' part of the depth of field that would otherwise be available.

There are some simple apps available to download that will calculate the available depth of field at any given apeture/focal lenth /focus distance. For any given focal length and aperture, the focus distance which gives the maximum depth of field whilst still keeping infinity within acceptable focus is called the hyperfocal point. For example. with your camera set to:

• 12mm f8, if you focus 4ft away (the hyperfocal point) then everyhting from 3.5ft - infinity should be within acceptable focus
• 35mm f8 - the hyperfocal point is approx 33ft and which should give everything from 16ft - infinity within acceptable focus

I don't suggest you stand there checking the hyperfocal distance for each shot you take (even if you could accurately measure how far away 33ft is - I know I can't!) nor would I worry too much about trying to understand the science behind it. I would suggest:

1. just remember the broad concepts that smaller aperture (f8 rather than f2) = greater depth of field (but don't go much beyond f11 or you'll suffer the effects of diffraction) and shorter focal length = greater DoF
2. keep experimenting until you get a 'feel' for depth of field
3. as a starting point, use the old rule of thumb of focussing approx one-third of the way into the scene; and
4. if in doubt, bracket several shots taken at different focus distances to see which works best.

 

[D Cox]

Many lenses have an indication of depth of field relating to a particular f-stop on the top. So that when you focus at, for example, 20 feet and are using f8, then you can look at the guide on the lens and read of the minimum focus distance and the maximum focus distance; hence depth of field.

You will immediately notice that the marks get wider apart, and the depth of field greater, the smaller the aperture, the larger the f number.

In theory you don't have to have a focus screen if you were a good judge of distance by simply looking at the top of your lens but this is not very practical.

I had several film cameras that had no focus aids, so you had to estimate the distance and set it on the lens. The depth of field marks were very useful.

This no longer applies today, and that book is not suitable for learning about digital photography.

 

[Krzycho]

Thanks a lot, that is helpful.

In the meantime of waiting for an approval from moderators I found the hyperfocal concept so I think I get the idea.

I guess that it doesn't matter if I use AF with focus point in the desired distance instead of MF, right?

 

[sybersitizen]

Specifically, the chapter on “Storytelling Apertures”. He describes how to overcome the lack of a depth-of-field scale on SLR lenses by using the distance settings.

He writes; “And, since every storytelling composition relies on maximum depth of field

He's already giving highly questionable advice. Every composition?

you would first choose to set your aperture to f/22

If you want diffraction to impair image sharpness.

and then align the distance above your distance-setting mark on the lens. Your focal length will determine which distance you choose.”

I don’t understand the last sentence.

It's incomplete advice.

I hope the rest of the book is better.

 

[David1961]

There are many DOF calculator apps available, most are free.

I have one on my phone. In the settings you input your camera make and model so the app knows your sensor size. To find the DOF for a situation, you simply input your aperture, focal length and distance to subject. The app then displays the DOF, both in front of and behind the subject and hyperfocal length if you want it.

Your favourite app store should have plenty of DOF calculators to choose from. Just search for DOF Calculators.

But when I must have everything sharp from front to back I prefer to use focus stacking.

 

[Confused of Malvern]

I guess that it doesn't matter if I use AF with focus point in the desired distance instead of MF, right?

Correct.

 

[Bob]

Specifically, the chapter on “Storytelling Apertures”. He describes how to overcome the lack of a depth-of-field scale on SLR lenses by using the distance settings.

He writes; “And, since every storytelling composition relies on maximum depth of field

He's already giving highly questionable advice. Every composition?

Your conclusion that the author provides highly questionable advice will live forever in the Internet. Just going by the OP’s out of context excerpts instead of actually reading the book is irresponsible armchair punditry.

you would first choose to set your aperture to f/22

If you want diffraction to impair image sharpness.

More armchair punditry. The author makes a case for high DOF using small apertures and has several examples illustrating why the resulting diffraction need not be such a major concern.

and then align the distance above your distance-setting mark on the lens. Your focal length will determine which distance you choose.”

I don’t understand the last sentence.

It's incomplete advice.

I hope the rest of the book is better.

It is. It’s a fantastic book. Recommended by many DPR members.

 

[justinwonnacott]

Specifically, the chapter on “Storytelling Apertures”. He describes how to overcome the lack of a depth-of-field scale on SLR lenses by using the distance settings.

He writes; “And, since every storytelling composition relies on maximum depth of field, you would first choose to set your aperture to f/22 and then align the distance above your distance-setting mark on the lens. Your focal length will determine which distance you choose.”

I don’t understand the last sentence. HOW does the focal length determine the distance at which you focus? If you select f/22; at what distance do you focus?

Any help appreciated.

Thx,
Bruceter

The short answer is to set the lens to the hyperlocal distance for the focal length in use BUT hyperlocal distance and sharpness charts are crummy guides especially for modern lenses and digital sensors because new ff gear often outresolves film which means a modern chart is necessary. I say this because the "SHOOT AT F22" advice is bunk. I have seen students who did everything "right" get fuzzy files on a tripod off a tripod mirror up and carefully focused because of diffraction softening of the image. When they focused carefully and used a wider aperture things improved a lot. The depth of field may be "better" at f22 but the overall sharpness even on the focus point was unacceptably soft.

Try it!

What worked on film in terms of an acceptable circle of confusion is not good enough for good lenses and modern cameras. The physics of hyperfocal distance is the same as it ever was ......although f22 might give you a deep zone of reasonable sharpness on flm which is more forgiving ...the diffraction softening ing gets eaten up with light scatter in the film emulsion and on the prints ya made....viewing distance of the image is also an important consideration too.

 

[sybersitizen]

Specifically, the chapter on “Storytelling Apertures”. He describes how to overcome the lack of a depth-of-field scale on SLR lenses by using the distance settings.

He writes; “And, since every storytelling composition relies on maximum depth of field

He's already giving highly questionable advice. Every composition?

Your conclusion that the author provides highly questionable advice will live forever in the Internet.

OMG. I'm soooo embarrassed. Or not. Let that live forever on the Internet, too.

Just going by the OP’s out of context excerpts instead of actually reading the book is irresponsible armchair punditry.

That single quoted phrase about every storytelling composition is extremely clear, and it sounds more like dogmatic punditry than anything I've said.

you would first choose to set your aperture to f/22

If you want diffraction to impair image sharpness.

More armchair punditry. The author makes a case for high DOF using small apertures and has several examples illustrating why the resulting diffraction need not be such a major concern.

The Internet is full of examples showing why it is a concern, as are many books. Let those live forever as well.

and then align the distance above your distance-setting mark on the lens. Your focal length will determine which distance you choose.”

I don’t understand the last sentence.

It's incomplete advice.

I hope the rest of the book is better.

It is. It’s a fantastic book. Recommended by many DPR members.

Well, then it's gotta be good. Except for the parts quoted above.

 

[Pixel Pooper]

I hope the rest of the book is better.

Unfortunately not, it gets much worse. Some parts are so bad they read like satire:

“To better understand the effect of ISO on exposure, think of the ISO as a worker bee. If my camera is set for ISO 100, I have, in effect, 100 worker bees; and if your camera is set for ISO 200, you have 200 worker bees. The job of these worker bees is to gather the light that comes through the lens and make an image. If both of us set our lenses at the same aperture of f/5.6 meaning that the same volume of light will be coming through our lenses – who will record the image the quickest, you or me? You will since you have twice as many worker bees at ISO 200 than I do at ISO 100″ - Understanding Exposure, Bryan Peterson

 

[Pixel Pooper]

It is. It’s a fantastic book. Recommended by many DPR members.

That's probably why so many DPR members don't understand exposure. It is a terrible book and should not be recommended to anyone.

Here is another out of context excerpt where he dismisses white balance and histograms as over rated hysteria:

"Are you confused about White Balance? It's my opinion that next to the histogram (aka "hysteria-gram"), the White Balance setting is one of the most overrated controls on a digital camera. I have actually seen forums on the Internet discussing white balance, and there are some very strong feelings by some about the importance of white balance in your photography. But until someone can show me otherwise, I will continue leaving my white balance set to Daylight 99 percent of the time..." - Understanding Exposure, Bryan Peterson

 

[sybersitizen]

I hope the rest of the book is better.

Unfortunately not, it gets much worse. Some parts are so bad they read like satire:

“To better understand the effect of ISO on exposure, think of the ISO as a worker bee. If my camera is set for ISO 100, I have, in effect, 100 worker bees; and if your camera is set for ISO 200, you have 200 worker bees. The job of these worker bees is to gather the light that comes through the lens and make an image. If both of us set our lenses at the same aperture of f/5.6 meaning that the same volume of light will be coming through our lenses – who will record the image the quickest, you or me? You will since you have twice as many worker bees at ISO 200 than I do at ISO 100″ - Understanding Exposure, Bryan Peterson

Wow. Now there's something that deserves to live on the Internet forever.

 

[Krzycho]

What I can say personally is that I really enjoyed this book, it gave me a lot of ideas, good practices and ways to improve my photos and things to try out in the field. I can say that I wish it would be written more for mirrorless system.

Please remember that 'every describing exposure' in Peterson's naming convention is a exposure which shows maximum DOF with a good focus like landscapes (as it was attached in the thread).

I only wonder that Bryan shoots with Nikon D300 APS-C, recommends F22 for a maximum DOF with a good sharpness. In fact he recommends always the maximum aperture value, even F32 and so on..

He shows a comparison of F8 vs F22 photo (with 200 % crop) to prove that diffraction doesn't ruin the image.

But for my m43 g85 it looks really bad.

So I wonder what is the truth here: is it only APS-C vs M43 case? He is a really experienced photographer, so what is the case? Regards!

 

[seuadr]

Wow. Now there's something that deserves to live on the Internet forever.

no kidding. that is a.. whew. that is definitely a thing that was said there. (please don't let this statement stay on the internet forever.)