Luminous Landscape Forum
Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: semillerimages on June 28, 2005, 10:03:17 pm

Nor was I referring to you. Sheesh.
*steve

Intellectual superiority also entails one understanding the deficiencies in explaining a subject not perfectly understood by a layman.
You know what the poster meant about focusing beyond infinity.
You responded like a jack ass.
Stating the obvious.
It's a sorry state here that courtesy, civility and understanding cannot be the first step forward.
The put it in a way you *might* understand.
Speak only if you have something nice to say otherwise you pollute a great forum for learning by your insipid ways.
*steve

Ok guys,
try and put down the text books for a minute and think about this from the point of using a camera and not talking about it.
Look at it this way.......
Set up a camera on a tripod and start walking away from it. After one pace you will probably be at the closest point the lens can focus. After another 10 paces, perhaps half way around the travel of the focus ring. At some point not long after that the lens will need to be set at infinity to have you on the focus plane.
If you keep walking past this point..... Yup... you are beyond infinity. IN THE TERMS OF THE ORIGINAL QUESTION

If you keep walking past this point..... Yup... you are beyond infinity. IN THE TERMS OF THE ORIGINAL QUESTION
No you're not. Infinity can be approached, but you can't go beyond it.
What sort of fish is best for hammering lag bolts into concrete?

FWIW  last night I took my 50mm 1.4 and no matter how far away I tried to focus, there was always a small amount of latitude to move the focus from the AF point to the point where the focus ring stopped. Didn't try on any other lenses though and that might be peculiar to my copy.

I think the solution to this squabble is to allow into the lexicon the new word that dazzajl has coined: "infinty."
I propose that henceforth (at least on this thread), "infinity" shall mean what it has meant for many centuries  the point that is beyond anything else; while "infinty" (without the third "i") shall mean pretty goshdarn far away, or as far away as I am interested in at the moment.
But, since "infinty" looks so much like "infinity", the difference might be made clearer by using instead the term "dazzajlinfinty".
Eric

Hello all!
OK, this is the question:
Does depth of field have any effect when taking a picture of subjects that all of them are beyond the infinity range? Is the aperature have any effect on the details results in such a situation?
hope you understand the question
10x
Cookielida

It's a tough question, because the word "infinity" can mean different things in different contexts.
In this context, such "infinity" concepts do exist but there are more than one of them, since not all infinite sets have the same size. So there does not exist any one single "infinity" concept; instead, there exists a whole collection of things called "infinite cardinal numbers".
In other words, the question is: does there exist some topological space (that is, a set of objects plus a definition of what convergence means) which, as well as including the familiar real numbers we are used to, also includes an "infinity" concept to which some sequences of real numbers converge?
Just take the photos good or bad is a photo
BlasR

The only entitity I'm aware of that regularly visits "beyond infinity" is Buzz Lightyear. And I'm fairly sure that my earlier comment would fall under the category of stating the obvious as well. If you see a woman with her skirt unintentionally tucked into her panties, pointing it out may embarass her, but not pointing it out will result in even more embarassment in the long run. But sometimes she'll hate you for pointing it out anyway. "Subjects beyond infinity range" definitely qualifies as an intellectual panty tuck.

DOH!!
Double post

Once you are focused on this infinty distance, anything beyond that (no matter how far) will be covered by the plane of focus. Hyperfocal distance has absolutley nothing to do with it.
In fact, if you want to get into the whole techy debate thing, there is no such thing as hyperfocal distance as there is really no such thing as depth of field.
This statement is completely incorrect. Like I said, what you're talking about is a function of the hyperfocal distance. There is no such thing as the "infinity distance" you're talking about, only hyperfocal distance, which does vary depending on aperture, focal length, and one's definition of "in focus" which is tied to the CoC value you use. If you doubt this, there are numerous DOF calculators on the net you can consult to confirm what I'm saying. If you look up any glossary of terms related to optics, you'll find mention of hyperfocal distance, but you will not find any mention of infinity distance. It does not exist. It is a figment of your imagination.

The question was about objects BEYOND THIS POINT. Objects that are BEYOND (the point that the scale on the lens calls) INFINITY.
No, it all goes back to your persisting in the totally madeup and absolutely incorrect use of "infinity distance" to describe hyperfocal distance. You have made up your own description of hyperfocal distance which is a patently obvious contradiction of the word "infinity" and are persisting in that foolishness even after having had the correct term and how to calculate it pointed out to you more than once. If you actually bothered to check into a DOF calculator, you would learn why the infinity mark on the EF 1740/4L is just past the 1m mark, but on the EF 135/2L the distance scale goes to 10m before the infinity mark. I'll give you a big hint: the hyperfocal distance for the 1740 happens to be a lot shorter than that of the 135. Just because you insist on calling a derivation of hyperfocal distance "infinity distance" doesn't make it so, any more than someone calling you a "genderconfused goat tapeworm" would make you one. The act of someone writing or speaking that phrase directed at you would not magically transform you into something disgusting living in a goat's bowels.
In case you haven't noticed, the distance marks crowd closer together on any given lens' focus scale as the scale approaches infinity. On the 1740, the interval between the 1 and 1.5 foot marks is nearly twice that between the 1.5 and 3 foot marks. The interval between 3 and infinity is smaller yet. But the infinity mark still corresponds to infinity distance, not 45 feet. Mounted on a body with sufficiently precise AF, and given a sufficiently magnified view of the focus scale you would discover that that there is a very small but measurable focus position difference between 45 feet and something closer to infinity, like the sun, or a mountain peak 50 miles away. At some point the difference in focus position and true infinity becomes too small to measure, and people don't bother any more. But that doesn't mean that the lens has an "infinity distance" which is some clearly defined distance less than infinity, it just means someone has made an executive decision regarding how many focus distance marks can be practically crowded in next to the infinity mark.

If the world at large can benifit from the awful typing of this poor snapper, then glad to be of service. :: :laugh:

You cannot have any object BEYOND infinity, thus your question makes no logical sense.

Cookielida,
If it makes you feel any better, I often have a good laugh at the high and mighty tone that some members of this forum use when addressing questions from others. Some here have an excellent grasp of the technical, but fail miserably in the public relations realm. It's unfortunate, because there are plenty of people who most likely could learn a few things from the expertise of the some of the members, but the attitudes put forth by these people are quite horrendous.
*steve

Ahh heckorama batman.
The comment was intended for jon, I thought I made my comment clear enough...
No offense to anyone else and actually no offense to jon either, just stating the obvious.
*steve

You know what the poster meant about focusing beyond infinity.
You responded like a jack ass.
Stating the obvious.
It's a sorry state here that courtesy, civility and understanding cannot be the first step forward.
I merely pointed out that the original poster's patently silly misuse of "beyond infinity" was most likely occasioning laughter at his/her expense. Which is both obvious, and true. And then answered the question he/she probably meant to ask. I did not use any insulting terms like "stupid", "dumb", "moron", or even "ignorant", which one could certainly argue is relevant and applicable.
On the other hand, you compared me to a "jack ass". Who is being rude and insulting here?

No I mean the infinity distance.
Lets say that a hypothetical lens reads infinity as 45 feet, everything at 45 feet or beyond will be sharp with the lens set to infinty, rather than the hyperfocal distance.

You know what the poster meant about focusing beyond infinity.
Well I sure don't, so please enlighten me...

Of course you can have "beyond infinty", when in the context of distance from a lens. Every lens has a point at which further distances from the lens are no longer relevant in terms of focus. This distance is called infinty. It is not a real infinity and hence may lead to some confusion.
No  not true. See this link to the DOF calc (http://www.dofmaster.com/equations2.html)
For the far focus point the calculation divides by the Hyperfocal Distance minus the focus distance. When that = 0 you have infinity. Actually, if I remember my highschool math division by 0 technically not inifinity, but simply "undefined".
The hyperfocal distance is defined as the distance such that everything from 1/2 that distance to infinity is acceptably sharp. Infinity is used in the normal sense of nothing bigger than.
The only context that's meaningful here is the context of "in focus" and once you start to change the technical meaning of the words it becomes very difficult to communicate meaningfully.

On the other hand, you compared me to a "jack ass". Who is being rude and insulting here?
Yes, it was insulting, and quite simply it was meant to be.
Take some of your own medicine. Step down from your lofty tower, and try to be helpful in a nice way for a change.
My rant is now over, apologies to others who find it to be cumbersome to the reading of the original questions and answers.
*steve

You are all getting yourselves tied up in knots. You cannot focus on objects which are at, close to or beyond infinity. Nothing in any of your pictures has anything to do with infinity. except very indirectly in terms of the mathematical formulas and concepts used by engineers to design your lenses.
Objects which are further than the nearest in focus distance correlating with that infinity sign on the lens can never be as sharp as objects that are at that distance because they are unavoidably smaller, but they are as sharp as they can be because they are in focus. As the distance beyond that point increases, the objects will become unrecognisable and eventually disappear.
Just adding this for a bit of fun, feeling a bit saddened by the demise of Didger.

I'm trying to educate you in the importance of correctly understanding the process and technology of photography
All very kind and noble of you but it had nothing to do with answering the question did it.
As someone, who like you, shoots images for a living I am well versed in the technical aspects of the many formats I have to use but I'm quite happy to drop the jargon when someone wants the answer to a simple "can I do this or that" question.
The most important thing in making sure that photography continues to thrive is the passion of those new to it's pleasures. Therefore it is the duty of people like us to answer questions without patronising and waffling on with pages of techo this and jargon that.
The original poster wanted to know if DoF would have any impact on a shot if the entire frame was far enough away to be past (what they saw as) the infinty distance on the lens. So what is your probelm with saying the area of focus in the shot will be the same (in all but some extreme circumstances) with the lens wide open or stopped down?
Also, for what it's worth, in the course of my career I have come to find the ability to shut up and listen to clients (often people that have no idea about photo tech but know what they want to see) is a far more useful skill in regards to producing the shots they want than knowing the physics of how I made them.

Huh?
Yes. Apparently he died recently on a trip in the High Sierras. Check out 'about this site'. Even though I disagreed with a lot he said, I enjoyed the conflicts and found his 'rediscovery' of photography in the twilight of his life and his rigorous questioning of photographic issues interesting and stimulating.
I have some sort of inexpressible sadness at his death.

When a lens is focused at infinity, there will be a wide range of distances where objects will appear to be "in focus".
So, "beyond infinity" as used by the original poster presumably means "beyond the point from which objects start to appear to be in focus". Loose language, for sure, from a mathematical standpoint, but Dazzajl understood this anyway and answered the question. Hyperfocal distance, if I understand this (but may be in too deep here), helps you to move this point even closer. But that does not seem to have been the original question.

Beyond infinity is right next to the verge of reality, give or take a few light years.

attitudes are quite horrendous
C'mon. I meant no harm. Sheesh.

I was a math major and can prove to you there are an infinite number of infinities  it takes about 7 chalkboards to actually PROVE that BTW
However, infinity in optics usually means everything beyond 1000x the primary focal length of the lens. And since we are dealing in three dimensions of our phyisical world and not the Ndimensions available to us in mathematics, you simply cannot get farther away than basic infinity while doing photography.
And FTR, neither this nor my earlier comment were meant to appear as a "horrendous attitude" toward the poster...
Cheers,

Of course you can have "beyond infinty", when in the context of distance from a lens. Every lens has a point at which further distances from the lens are no longer relevant in terms of focus. This distance is called infinty. It is not a real infinity and hence may lead to some confusion.
I'll try to take some heat for Jonathan.
By whom is the thing you describe "called infinty"? It certainly isn't by any of the many photographers or mathematicians that I have associated with over the past fifty years. And it certainly isn't what lens makers have in mind when they put that sideways figureeight symbol on the distance scale of a lens. That refers to infinity, beyond which one cannot go (as a rough, but finite, approximation, one can say that infinity is the distance from here to the most distant star that you can see. And if you find yet a more distant star, beyond the first one, then the distance to that star is a better approximation, and still is not "beyond infinity".)
Eric
P.S. While I was ranting, Tim has explained it quite clearly and accurately. And yes: division by zero is "undefined" and not "infinity."

I think another, more useful response (if the OP hasn't already left these forums for other, Velviagreener pastures) might be:
The infinity marker on your lens may not (seem to) actually indicate actual, optical infinity, depending on a variety of reasons. More experienced people should fill in/correct me as needed.
 temperature variations
 lens adapter "changing" infinity
 badly calibrated lens
For temperature variations, many lenses have the ability to focus beyond infinity. If they can focus far enough beyond infinity, this can also help with certain lens adapters for those times you use otherwise incompatible lenses with your camera.
Badly calibrated lenses is another issue entirely.

If all the objects in the frame are at or beyond the infinity distance for that lens then they will all be sharp with the lens wide open.
I think you mean "hyperfocal distance", not "infinity distance". As has been pointed out numerous times in this thread by now, there is no such thing as "beyond the infinity distance".

A simple answer to the question is, no it wont make any difference. If all the objects in the frame are at or beyond the infinity distance for that lens then they will all be sharp with the lens wide open.
Even though I am not a pro, I will act like one and screen out the gigles and insults about the degree of my intelligence.
As quoted above, this is the exact answer I was looking for: straight and simple.
Thank you dazzajl
Chen

It's all in the confusion and imprecision of verbal languge as opposed to the more precise mathematical language.
Cameras cannot focus on infinity. It's an impossibility. Infinity has no tangible exisitence. It's purely a concept in the mind. It exists nowhere outside of the mind. It's a metaphor for great distance.

No no no no no
You are so wrapt up in your desire to bang on about hyperfocal distance and DoF calculators that you are missing the point by a mile.
This has absolutley nothing to with DoF....... at all.
It's sooooo simple, stop for a minute and think about it.
Lets use a canon 1740 f4 L lens as an example here. Focus on an object about 45 feet away and look at the distance scale. It reads infinity.
The question was about objects BEYOND THIS POINT. Objects that are BEYOND (the point that the scale on the lens calls) INFINITY.

feeling a bit saddened by the demise of Didger
Huh?
http://www.luminouslandscape.com/cgibin....2;t=681 (http://www.luminouslandscape.com/cgibin/forum/ikonboard.cgi?act=ST;f=12;t=681)

(which can improve the quality of your work if accompanied with appropriate creativity and talent)
All of your technical proficiency has obviously not helped in the slightest in this realm.
*steve

A link to a Fred Miranda thread about focusing beyond infinity (http://www.fredmiranda.com/forum/topic/245336)

As stated already, it is impossible to have an object at a distance beyond infinity, unless you have made some mathematical/theoretical physics breakthrough and have successfully calculated the value of (infinity + 42). If not, go find a dictionary, look up the definition of infinity, and be aware that everyone reading this thread is having a laugh at your expense.
If, on the other hand, the subject distance merely approaches infinity (distant mountains, stars, etc.) there are two things to keep in mind:
1: As focus distance approaches infinity, so does depth of field, regardless of aperture. You can't use selective focus on objects in deep space.
2: Aperture's effect on exposure level is completely independent of focus distance. You'll get a 1stop exposure difference between f/8 and f/5.6 regardless of focus distance, as long as shutter speed and ISO remain constant.

On the off chance that the original poster may return .... and excluding the bit about lenses focusing beyond infinity for various variation or calibration reasons.
A simple answer to the question is, no it wont make any difference. If all the objects in the frame are at or beyond the infinity distance for that lens then they will all be sharp with the lens wide open.
D

Lets say that a hypothetical lens reads infinity as 45 feet, everything at 45 feet or beyond will be sharp with the lens set to infinty, rather than the hyperfocal distance.
There is no possible way to go beyond infinity, therefore "beyond infinity distance" is impossible and is a complete contradiction of the terms " beyond" and "infinity". What you're referring to IS the hyperfocal distance; the shortest focus distance which will result in objects near infinity (distant mountans, stars, etc) being "in focus" for a given lens and aperture. Hyperfocal distance is less than infinity, both in practically observable terms as well as the position of the focus ring at which it is achieved. Hyperfocal distance varies with aperture; it will be greater at wider apertures than smaller ones. A DOF calculator can calculate what it will be for a given lens and aperture; I have one in spreadsheet form here (http://www.visualvacations.com/Photography/dof_calculation.htm).
Referring to hyperfocal distance as "infinity distance" does not make it so, any more than calling a tail a "leg" makes it one. And doing so makes you look similarly foolish.

feeling a bit saddened by the demise of Didger
Huh?

I think the diferences we are having here come down to a simple difference in approach. I was simply trying to answer a question relating to how a lens will act when taking a photograph, where as you seem to be more interested in swaggering around quoting text book ideals and being insulting (which is quite amusing btw ).
At some point the difference in focus position and true infinity becomes too small to measure, and people don't bother any more
Exactly, because it doesn't make any difference when you are taking the photograph. Going back the simple illustration of walking away from a camera and where you appear on the focus scale, at some point (and I dare not mention it by name) you cease to need to adjust the focus.
You can spout as much technical theory as you like but none of it will change the answer to the original question about where to focus when everything in the scene is futher away than the inf...... almost said it there. :laugh:

Probably an old joke even then but I laughed and it still brings a smile – perhaps because that was long ago (seems longer every day) and reminds me of those days ….
The professor wrote 8 / 0 = "infinity sign" on the chalkboard and launched into a lecture on limits, defined expressions, undefined expressions, infinity, etc. The class took it all in, or so he thought. A few days later, he gave the class a test. One of the problems on the test was: 5 / 0 = ? Of course, one student gave the answer as “5 on its side” (you’ll have to use your imagination here since I can’t make a 5 in landscape orientation).
Thereafter, we always called the infinity symbol the “lazy eight”.
Well, it was funnier when the characters could be drawn on the chalkboard.

I beg to differ. When I was in college during the late 60's, I definitely remember several instances when I went beyond infinity and came back a few days later. I rapped with Jimi when I was there.
Peace, brother.

Jonathan,
You seen to have a penchant for rather long and wordy posts, I'm going to try and keep this one short and simple so I hope it still makes sense to you.
Of course you can have "beyond infinty", when in the context of distance from a lens. Every lens has a point at which further distances from the lens are no longer relevant in terms of focus. This distance is called infinty. It is not a real infinity and hence may lead to some confusion.
Once you are focused on this infinty distance, anything beyond that (no matter how far) will be covered by the plane of focus. Hyperfocal distance has absolutley nothing to do with it.
In fact, if you want to get into the whole techy debate thing, there is no such thing as hyperfocal distance as there is really no such thing as depth of field.
D

For temperature variations, many lenses have the ability to focus beyond infinity. If they can focus far enough beyond infinity, this can also help with certain lens adapters for those times you use otherwise incompatible lenses with your camera.
It is true that many lenses allow additional focus adjustment beyond the infinity mark for the reasons you mentioned. But that certainly does not mean that the actual subject distance is beyond infinity. It's simply an allowance for some variation in the focus ring position that actually corresponds to infinity focus.

but they are as sharp as they can be because they are in focus
Which essentially means we are saying much the same thing.
The problem here is that some people are talking about infinty as the concept of distance/number without measure and others about the distance represented by the symbol on a lens.

As you stated in an earlier post, it's all in the terminology. The terminology you've been using is madeup and nonstandard. When a lens is focused at infinity, there will be a wide range of distances where objects will appear to be "in focus". Understanding how DOF is calculated (and hyperfocal distance in particular) will help you figure you how far away something has to be for it to be just as wellfocused as a distant star, as well as when it is advantageous to set the focus distance to something less than infinity to get the widest possible range of distances in acceptably sharp focus, and what aperture one should use while doing so.
Understanding the underlying technical concepts and issues are critically important in photography. I make my living from photography and shoot over 50,000 frames per year. I'm not just spouting irrelevant technobabble because I can, I'm trying to educate you in the importance of correctly understanding the process and technology of photography (which can improve the quality of your work if accompanied with appropriate creativity and talent) and the correct terminology, so that you can have meaningful discussions with others about photography without looking and sounding foolish and ignorant. Knowing the technical stuff inside and out will make you a better photographer; don't neglect it.