[normhead]

You know dudes, the easy way to do this is to take a few images with your camera, with any lens you might use at different settings, until you can understand the DoF characteristics of each lens... charts schmarts.. you have to do this for every lens you own, just to pretend you're a photographer. A basketball player isn't the guy who determines the amount of force needed to make a 3 pointer from one foot behind the line. The basketball player is the guy who does it, not in his brain, but in muscle memory. Same with photography. You don't have to understand a thing about the physics of DoF, to use DoF. You can use DoF productively without having a clue what causes it. A basic understanding can't hurt, but is totally un-necessary. I was using DoF for years before I even knew what it was called. My course in lens design while useful in discussing the physics of light, made absolutely no difference to my photography.

Or as the Buddha would say..."There's no necessity to know there is a god, to achieve perfection."

Knowing how lenses work, how DoF is calculated etc. does not excuse you from getting to know your camera... it doesn't even make it easier after a very rudimentary basic understanding. You still have to become an expert on each lens and configuration in the real world.

[amoringello]

This is all going back to the original post which was asking why it was stated that a larger image plane (film, sensor, etc...) would give greater DOF control. I could certainly have told the OP to go use his equipment a few more years until he becomes fully aware of the physical properties, but that seems like an unfair and rude answer.
Of course, it sounds like something a TV show monk might say... "go to the mountain top and meditate until you full understand the meaning of the circles of Confucius, er, um , confusion." :-)


When you reach a "limitation", it is good to know whether it is because of your equipment or just a lack of information.
i.e. do you need to spend the $10K to upgrade your entire kit from crop to FF, or can you spend $1K for a lens that will give you the same result (or maybe use your existing equipment for no more $$)?

At some point that basketball player needed to be told there was a line where the basket was worth three points rather than just two, etc... Simply throwing the ball in his back yard might never have given him that kwoledge. You would not put a very skilled basket-shooter into a game without the proper knowledge of the rules.

At some point you do need to be educated to make good financial as well as creative choices.
Being ignorant of the options and leaving others ignorant of them is not lead to a path of enlightenment. :-) :-)

[normhead]

As I said, rudimentary knowledge will help... but that's all you need. The "what you need" is experience with enough camera systems to know which one will do what you want. I'm constantly amazed at how many on here think this stuff is important.

Simply throwing the ball in his back yard might never have given him that kwoledge. You would not put a very skilled basket-shooter into a game without the proper knowledge of the rules.

The rules can be explained in a time out or sitting on the bench during a breather, and pretty much anyone can learn them. Becoming a skilled shooter... it doesn't matter how much they work, some very good basketball players, never become skilled shooters. Photography tends to be the same. That was a horrible analogy.

[jsherman999]

Still true.

Still false. Enlarging a crop changes the resulting image DOF, noise, and DR. You can argue against that all day long, and you will be wrong all day long

.

Since you're changing your distance, you are not maintaining an equivalent image circle projected from the lens.
Thus DOF cannot be maintained... . Pure mathematics.

Open your aperture 1 stop and your two images will have nearly identical background blur because you have mathematically balanced and maintained DOF.

Seems as though you're conflating two different posts, now. Cropping does not 'change distance'. Are you responding to something else?

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---------- Post added 04-01-14 at 12:00 PM ----------

i.e. do you need to spend the $10K to upgrade your entire kit from crop to FF, or can you spend $1K for a lens that will give you the same result (or maybe use your existing equipment for no more $$)?

10K to upgrade to FF?!?

IMO, one of the unfortunate conclusions people come to is that they can stick with aps-c, but buy something like $1500+ Zeiss MF prime lenses, and their photography will change appreciably. I've shot a whole lot of glass on two formats, expensive and inexpensive, and I think the greatest change you will see - beyond a move from a kit to a good lens - comes from a format change.

For my type of shooting, my $110 50 f/1.8D on the D700 gave me slightly better images than my 31ltd on aps-c, and more DOF control as well. (meaning: I could isolate and 'float' the subjects just a bit more, or I could stop down and get real sharpness with the same subject isolation the 31ltd gave me wide-open - and my 31ltd wasn't really super sharp wide open, and had some CA.)

Being ignorant of the options and leaving others ignorant of them is not lead to a path of enlightenment. :-) :-)

Exactly. In a world where FF DSLR bodies can be had for $1500, closing that path off to consideration is not an enlightening course of action.

Perhaps if this Panasonic rumour is true (Panny getting out of m43 and concentrating on FF bodies) It points to Ricoh being closer to the same conclusion than we know.

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[Lowell Goudge]

Snip...........You still have to become an expert on each lens and configuration in the real world.

And herein lies the problem. No body wants to work out how to take images on a new format. No body wants to learn how to use their equipment, They all want to simply copy what was done for 35mm without thinking how to solve the issue for APS -C or any other format.

The other thing they forget, is depth of field on its own is a useless discussion. It is all about the combination of depth of field, along with relative foreground to background magnification that is important.

[amoringello]

Still false. Enlarging a crop changes the resulting image DOF, noise, and DR. You can argue against that all day long, and you will be wrong all day long

Ignorance is bliss, I guess...
Just please, keep it to yourself and do not attempt to spread your ignorance to others.

Noise and DR are completely independent of DOF.
I am not sure what argument you're trying to make now, but it shows a pretty clear lack of understanding of what is going on.

---------- Post added 04-01-14 at 03:18 PM ----------

IMO, one of the unfortunate conclusions people come to is that they can stick with aps-c, but buy something like $1500+ Zeiss MF prime lenses, and their photography will change appreciably. I've shot a whole lot of glass on two formats, expensive and inexpensive, and I think the greatest change you will see - beyond a move from a kit to a good lens - comes from a format change.

For my type of shooting, my $110 50 f/1.8D on the D700 gave me slightly better images than my 31ltd on aps-c, and more DOF control as well. (meaning: I could isolate and 'float' the subjects just a bit more, or I could stop down and get real sharpness with the same subject isolation the 31ltd gave me wide-open - and my 31ltd wasn't really super sharp wide open, and had some CA.)

...and I was not talking about image quality here... it is about the capability to give same DOF between sensor sizes.
You keep wanting to sidetrack onto tangents not dealing with DOF.
Bring your comments back to center with the main issue of DOF and you might even learn something.

---------- Post added 04-01-14 at 03:47 PM ----------

Seems as though you're conflating two different posts, now. Cropping does not 'change distance'. Are you responding to something else?

I may be confusing with someone else. The quoting system in this forum sometimes loses context with indented quotes, so I may have cross-commented. Sorry.

Someone stated: "Except you went down a rabbit hole along the way by maintaining that cropping/enlarging has no effect on image DOF". Someone else mentioned something to the effect that you need to crop to maintain the same image, thus changes distance thus changes DOF, a affects b affects C or something to that effect. Basically both are referring the same problem in understanding what DOF is and what affects DOF.

The point is that cropping has no effect. And it has been shown here with example after example.
Only by re-defining what DOF means or by ignoring physics does one come to the conclusion that cropping has any affect what-so-ever.

[jsherman999]

Ignorance is bliss, I guess...
Just please, keep it to yourself and do not attempt to spread your ignorance to others.

Actually, I understand this issue front to back, have for years. I think you yourself are the one spreading a certain level of misinformation, and have even contradicted yourself a little bit between posts. Your first post in this thread is a good example - a few nuggets of truth mixed in a very scattered narrative, with some effusive 'conclusions' that conflate what's being asked by the OP with what you think was being asked. It's almost like you're arguing against something you read somewhere else.

Noise and DR are completely independent of DOF.

When you're working within an equivalence framework, they are not entirely independent, and are affected by the same parameters... but to a more direct point, image noise, image DR and image DOF (percentage of image in 'acceptable focus' as compared to image height) all change when you crop and enlarge that crop. Understanding this is more than a little bit important. There is absolutely nothing controversial or incorrect about that statement. If you try to obscure it, or argue against it in some sort of odd face-saving maneuver, you're kinda just wasting everyone's time here.

.

...and I was not talking about image quality here... it is about the capability to give same DOF between sensor sizes.

Which I mentioned as well, in that very post. Tell me, how do you match the 50 f/1.8's higher-aperture FOV and DOF capabilities on FF, on aps-c with an existing aps-c lens? You can come close with a Sigma 35mm f/1.4, but it costs about 8 times as much and is larger.. and still doesn't quite match it. This speaks directly to the OP's original question, I think.

.

I may be confusing with someone else. The quoting system in this forum sometimes loses context with indented quotes, so I may have cross-commented. Sorry.

You have been doing that a bit throughout the thread, I think, and it makes me wonder how many times I thought I was following up on something you said in reference to me when actually you were confused, and were speaking to some other point. Would explain the wheel-spinning feeling I have here.


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Last edited by jsherman999; 04-01-2014 at 02:06 PM.

[amoringello]

.... with some effusive 'conclusions' that conflate what's being asked by the OP with what you think was being asked. It's almost like you're arguing against something you read somewhere else.

From the OP; "Both are FF-compatible and I have a FF-senor camera and a mFT camera with adapter, so I can use both lenses on both cameras.
Why would anyone say using the FF camera he get's "more DoF control" using any of the lenses?"

You may want to go back and read it yourself! It's all about DOF.

When you're working within an equivalence framework, they are not entirely independent, and are affected by the same parameters...

Equivalence framework? You are going way beyond DOF into display and printing.
If you do not understand the scope of the terms, please do not use them in your arguments.

Which I mentioned as well, in that very post. Tell me, how do you match the 50 f/1.8's higher-aperture FOV and DOF capabilities on FF, on aps-c with an existing aps-c lens? You can come close with a Sigma 35mm f/1.4, but it costs about 8 times as much and is larger.. and still doesn't quite match it. This speaks directly to the OP's original question, I think.

If you had actually read anything I wrote instead of quickly making counter arguments, you would easily be able to determine exactly what you ask. I trust you can comprehend simple math and work it out yourself. Although if you'd like I will explain it again.

You have been doing that a bit throughout the thread, I think, and it makes me wonder how many times I thought I was following up on something you said in reference to me when actually you were confused, and were speaking to some other point. Would explain the wheel-spinning feeling I have here.

And as you must certainly have noticed, that was a direct quote from you.
The satirical irony was apparently lost and your further attacks therefore misplaced.
The confusion seems to be all on your side at the moment.

---------- Post added 04-01-14 at 05:52 PM ----------

Honestly, I am not sure it is something you will take the time to figure out yourself so I'll spoon feed it out for you....

Lets say you have the two camera/lens combinations. (very common for each)...

1) Full Frame camera with 24-70 f/4.0 lens.
You set the camera on a tripod to frame your subject at 24mm focal length.
Set Aperture to f/4.0.

2) Crop sensor camera with 16-50 f/2.8 lens
You set the camera on the same tripod above at the same location to frame your subject.
You must change the focal length to 16mm focal length to retain framing.
Set Aperture to f/2.8. (and the magic happens)

Since distance to subject remained static (did not change), a change in focal length from 24mm to 16mm is required to maintain the identical field of view and relative size of subject.

Since you change one property of DOF, you must change another to balance the equation.
Setting aperture from f/4.0 down to f/2.8 will do that and bring the DOF back to what was in the FF original.

Final result.....
DOF as well as the field of view and framing of subject are all maintained in both FF and Crop.
You may do similar balancing of properties when going from FF to medium or full frame.

Now, if the FF camera had a f/1.4 lens... you would be hard pressed to get a lens on a crop body to balance things out.


Don't know how to simplify it any further than that.

Hi, I didn't intend to start a fight here.

My question was about the use of a certain term and focused on the "more ... control" wording/aspect of it. And only around the parameter "DoF", not quality, not noise, not anything else - and there is a lot of "else".

That has been answered to my full happiness.

Funny little distraction:
If I absolutely wanted to replicate the DoF and FoV of a 50/1.8 on FF on APSC, I'd buy a cheap old used NEX or Fuji-X and put a China-made wide-angle-converter ("speedbooster") on it and then use the exact same cheap lens. That shrinks the image projected on the inner backside of the body and with shrinking it you gain more angle (suddenly a whole lot more picture fits on the same size sensor), less noise (light gathered is concentrated on small area) and less perceived DoF (CoC sizes changes).
It's the image circle of the lens that counts, not absolutely necessarily so much the sensor area for DoF, if I understand the theory of teleconverters and wide-angle-converters. It's really about the total light-gathering capabilities of the optical system. Just image a Pentax 645 lens with a wide-angle-converter attached which concentrates all the light on APSC. That would be fun.

[BrianR]

I'm left wondering, if a photo is taken in the woods and no one develops it to looks at it, does it have a DoF?

Hi, I didn't intend to start a fight here.

Then you should never have asked about DoF on an online forum, any such discussion comes with a free fight. I mean 'free friendly discussion'

[jsherman999]

Equivalence framework? You are going way beyond DOF into display and printing.

This is funny, because right below, you try to use an equivalence relationship. I've tried to keep it there the whole time... it's great you're catching up, I guess.

Lets say you have the two camera/lens combinations. (very common for each)...

1) Full Frame camera with 24-70 f/4.0 lens.
You set the camera on a tripod to frame your subject at 24mm focal length.
Set Aperture to f/4.0.

2) Crop sensor camera with 16-50 f/2.8 lens
You set the camera on the same tripod above at the same location to frame your subject.
You must change the focal length to 16mm focal length to retain framing.
Set Aperture to f/2.8. (and the magic happens)

Since distance to subject remained static (did not change), a change in focal length from 24mm to 16mm is required to maintain the identical field of view and relative size of subject.

Since you change one property of DOF, you must change another to balance the equation.
Setting aperture from f/4.0 down to f/2.8 will do that and bring the DOF back to what was in the FF original.

Final result.....
DOF as well as the field of view and framing of subject are all maintained in both FF and Crop.
You may do similar balancing of properties when going from FF to medium or full frame.

I'm curious, how is anything you wrote above in contradiction to anything I wrote in this thread, or ever? Are you actually trying to use a basically equivalent combination** to prove some point you think you need to make? On a side note, if you feel you need to explain something so basic as the above... have you never encountered my numerous posts on this subject before?

** You got the F-stop wrong, it would be closer to f/2.5 than f/2.8 to make the images equivalent.

Now, if the FF camera had a f/1.4 lens... you would be hard pressed to get a lens on a crop body to balance things out.

Exactly. Thus, at higher apertures, you could even say that the larger format has more DOF control, no? Also, it doesn't need to be an f/1.4 lens. What gives you the same FOV/DOF (& FL range) combination on aps-c as your garden-variety 24-70 f/2.8 zoom on FF? (spoiler: nothing. Sigma 18-35 f/1.8 comes close, but isn't quite as wide or long.)


.

[amoringello]

Yeah, you got me there. I'm not sure how the converter affects the image.
I've heard conflicting info about what effect they have... not surprising if you've followed half this thread. :-(
And as they usually just cause poor quality, I have never been interested in finding out.

The Speedbooster sounds interesting. At least it has had some good press. Dunno how much of that is just marketing.

[jsherman999]

Funny little distraction:
If I absolutely wanted to replicate the DoF and FoV of a 50/1.8 on FF on APSC, I'd buy a cheap old used NEX or Fuji-X and put a China-made wide-angle-converter ("speedbooster") on it and then use the exact same cheap lens. That shrinks the image projected on the inner backside of the body and with shrinking it you gain more angle (suddenly a whole lot more picture fits on the same size sensor), less noise (light gathered is concentrated on small area) and less perceived DoF (CoC sizes changes).

A lot of folks are doing just that, and I heard it works pretty well. Depending on the lens it can make the edges a little mushy, but I also read that most lenses look pretty good with a speedbooster... so yeah, not a bad idea in a way.


.

[amoringello]

This is funny, because right below, you try to use an equivalence relationship. I've tried to keep it there the whole time... it's great you're catching up, I guess.

You're kidding right?
Where are your arguments for noise, and print size, crop, and everything else?
Get backed into a corner and all that doesn't just go away.

Troll.


Lets change subject... How about RAW v.s. JPEG?

[jsherman999]

You're kidding right?
Where are your arguments for noise, and print size, crop, and everything else?

You want to talk about noise? I thought you were trying to keep it to DOF only - you've made claims like that several times in this thread, should I quote you?

Anyway, what do you want to say about noise? Photon shot noise, or read noise, or all of the above? If aps-c vs. FF is a sore spot by now, we can talk about aps-c vs. 1/2.3'' sensors.

For example, the equivalence ratio (crop factor) between 1/2.3" and APS-C is 3.7x. Let's say 4x to make the math easier.

So, 10mm f/2.8 1/100 ISO 100 on the 1/2.3" sensor camera is equivalent to 40mm f/11 1/100 ISO 1600 on the APS-C camera, since the entrance pupil diameters are the same (10mm / 2.8 = 40mm / 11 = 3.6mm) and the shutter speeds are the same.

But the APS-C camera could shoot the scene instead at 40mm f/11 1/6 ISO 100, motion blur and/or camera shake permitted, thus putting 16x more light on the sensor, resulting in 1/4 the noise for equally efficient sensors. Alternatively, the APS-C camera could shoot the scene at 40mm f/2.8 1/100 ISO 100, again putting 16x more light on the sensor, but this time with 1/4 the DOF.

For equivalent photos (same DOF and shutter speed), all systems put the same total amount of light on the sensor. The advantage of larger sensor systems here is when they can use longer shutter speeds at base ISO and/or wider apertures (entrance pupils) at higher ISOs (necessarily resulting in a more shallow DOF).

Any other direction you want to take it? I don't want to go down a route you don't want to follow, waste my time, etc.

Get backed into a corner and all that doesn't just go away.

You're the one in a corner, but I'm more than willing to help you out of it!