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View Poll Results: Ideal Pentax Lens Subject Distance
Marco only 15.88%
Three feet or less   00%
Three to five feet 211.76%
Five to 10 feet 529.41%
Ten to 20 feet 423.53%
20 to 40 feet 211.76%
Infinity only 15.88%
With 6mp sensor only (ist,K100,K100S) 15.88%
With 10mp sensor only (K10,K200) 15.88%
K20   00%
Voters: 17. You may not vote on this poll

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10-14-2008, 03:35 AM   #16
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Well folks, this is the kind of personal message I just got from the thread starter today:

Ok, hard case, just between me and you... do you have a problem with me or are you just an ******* to everyone?

I don't know what the rules are in Singapore, much beyond public caning, but let's call our little pissing match a draw ... don't post to my threads, or respond to my posts, and I'll do the same for you. But if you keep getting in my face in this vituprative way, I promise I will cloud up and rain all over your digital parade.
Brian


Aside from being extremely rude to say the least, I stand by what I said earlier that there are just too many variables to come to any meaningful conclusion of lens and ideal subject distance (whatever that may be).

Perhaps such a question comes from a rank newbie who is just blur and needs to brush up his knowledge by shooting more.

I can be a forgiving guy but I won't tolerate such personal messages, so I leave it to all of you to judge if the TS has a problem or not. Since when has threads been the personal property of anyone is beyond me...

10-14-2008, 06:44 AM   #17
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Brian, I would like to participate in this, since to an extent it was me who got you started on it, but I suspect that 10 days won't give me time to do what I want with it. I suspect that both aperture and focus distance both play a part in the varying IQ that I have noted over the decades, and that often, the differences are quite subtle, and requires a really discerning eye to pick out the variance.
Of course, pixel peeping does have it's place in optical benchmarking...

Now, for those who are saying this is a silly or useless thread... fully 75% of the threads on this forum are useless stupid threads that could be answered if the OP was willing to RTFM or do a little research via Google.
This thread is actually more useful than most, since it's goal is to provide, at least anecdotally, what the ideal lens to subject distance is for various lenses IE: at what subject distance does the lens perform best at.
Some of us have several different versions of the same or similar focal length (IE, a person might have the 70mm LTD, 77mm LTD, M85/2 and A*85/4, or they might have several different iterations of 50mm lens).

For me, it would be interesting to know that where one lens is a little weak, another lens in my kit is strong, and as optical properties do vary with lens to subject distance, this is as valid a subject as any of the other anecdotal and meaningless IQ tests (posting a 1000 pixel image to the forum with the title "Proof that the &^$@)mm lens doesn't suck") that gets posted.
It's nice that sometimes people get lucky and get a nice picture, but that doesn't prove the lens doesn't suck, it may just prove that you have found the sweet spot in it's aperture vs. subject distance performance curve to manage a picture that doesn't suck.
Think about it, if that is something you are able to do.
10-14-2008, 06:47 AM   #18
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QuoteOriginally posted by creampuff Quote
Well folks, this is the kind of personal message I just got from the thread starter today:
<snipped for obvious reasons>
One of the first things I learned about the internet was that it is the height of rudeness to make private emails public.
Hopefully you will mature past this sort of behaviour eventually.
10-14-2008, 06:53 AM   #19
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QuoteOriginally posted by creampuff Quote
Ok, hard case, just between me and you... do you have a problem with me or are you just an ******* to everyone?

I don't know what the rules are in Singapore, much beyond public caning, but let's call our little pissing match a draw ... don't post to my threads, or respond to my posts, and I'll do the same for you. But if you keep getting in my face in this vituprative way, I promise I will cloud up and rain all over your digital parade.
Brian
Hmm, attitude problem I would say.

Back to the poll topic, let's say I prefer to keep my distances so I guess it's infinity only!

Cheers!

Abbazz

10-14-2008, 07:22 AM   #20
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QuoteOriginally posted by Abbazz Quote
Hmm, attitude problem I would say.

Back to the poll topic, let's say I prefer to keep my distances so I guess it's infinity only!

Cheers!

Abbazz
Sounds more to me like someone who only suffers fools in silence for so long.
But, if we keep this up, either the thread will be locked or someone will get brigged.
10-14-2008, 07:39 AM   #21
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QuoteOriginally posted by Wheatfield Quote
One of the first things I learned about the internet was that it is the height of rudeness to make private emails public.
Hopefully you will mature past this sort of behaviour eventually.
Well thanks for you kind advice, though I think you're dead wrong here.

If you consider someone posting "Thank you for your thoughful and considerate response" and next moment sending an unsolicited personal message that is rude and frankly offensive is acceptable behaviour, then I can only surmise you don't know what you're talking about.
10-14-2008, 07:40 AM   #22
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QuoteOriginally posted by Wheatfield Quote
Brian, I would like to participate in this, since to an extent it was me who got you started on it, but I suspect that 10 days won't give me time to do what I want with it. I suspect that both aperture and focus distance both play a part in the varying IQ that I have noted over the decades, and that often, the differences are quite subtle, and requires a really discerning eye to pick out the variance.
Of course, pixel peeping does have it's place in optical benchmarking...

Now, for those who are saying this is a silly or useless thread... fully 75% of the threads on this forum are useless stupid threads that could be answered if the OP was willing to RTFM or do a little research via Google.
This thread is actually more useful than most, since it's goal is to provide, at least anecdotally, what the ideal lens to subject distance is for various lenses IE: at what subject distance does the lens perform best at.
Some of us have several different versions of the same or similar focal length (IE, a person might have the 70mm LTD, 77mm LTD, M85/2 and A*85/4, or they might have several different iterations of 50mm lens).

For me, it would be interesting to know that where one lens is a little weak, another lens in my kit is strong, and as optical properties do vary with lens to subject distance, this is as valid a subject as any of the other anecdotal and meaningless IQ tests (posting a 1000 pixel image to the forum with the title "Proof that the &^$@)mm lens doesn't suck") that gets posted.
It's nice that sometimes people get lucky and get a nice picture, but that doesn't prove the lens doesn't suck, it may just prove that you have found the sweet spot in it's aperture vs. subject distance performance curve to manage a picture that doesn't suck.
Think about it, if that is something you are able to do.

I would have been good if the OP had fleshed out the question this well - if that's what was intended, then it's a fair question - as originally posted, though, it's almost meaningless.

And regarding the PM posting - the PM sounded to me like a threat. creampuff, IMO, has every right to shine a light on something like that. There are of late some very angry people finding their way here for whatever reason, and when stuff like that starts happening, things can go downhill fast. It's a good idea to keep an eye on these folks and maybe be a bit selective about what posters (and what IP addresses) are allowed in after strike three (or four...).


.
10-14-2008, 08:11 AM   #23
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In order to center the discussion on the origonal question, I will ignore a lot of posts and start with a little math.

Image size = object size / object distance x focal length

This is for distant objects (not macro and close up) and I will assume that the first thing we want is a certain image size.

After that, everything else is a subjective selection (focal length, apature, specific lens for bokeh, etc) to achieve the image you want. or perhaps with a preselected lens, you flip the formula around to give you the image size you want.

There is no "optimum distance" to my knowledge, with the exception of Macro lenses, which are specifically omtimized to function sharper at close focus, as well as being flat feild lenses (i.e. focus on a flat plane as opposed to a spherical surface like most lenses)

It may be true that some lenses are at thier best when focusing on a closer object than an infinte one, but this could be highly variable in my opinion

10-14-2008, 08:31 AM   #24
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QuoteOriginally posted by jsherman999 Quote
I would have been good if the OP had fleshed out the question this well - if that's what was intended, then it's a fair question - as originally posted, though, it's almost meaningless.
I think the problem was assuming people had read the discussion in another thread that led to this one. In the context of that other discussion, the poll *does* make sense, but if you are coming into it cold, I can see how it would it could be misinterpreted.
10-14-2008, 09:01 AM   #25
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QuoteOriginally posted by FHPhotographer Quote
... if some of you don't want to participate why not just ignore the thread? Why go to the trouble of posting just to criticize even asking the question? Now my flippers really are tired swimming upstream against all of this.
Brian
I think we're trying to say in our own clumsy way that we don't understand the question. The problem is that the poll allows only one response, and it doesn't make sense (to me at least) to have to choose between distance as a response and a camera as a response. And even if the choices were only distances, then on what basis do we choose a response? Some lenses (macro lenses, for example) are better at some distances than others. So I don't see how choosing a distance conveys any useful information. But maybe I'm just obtuse... :-(
10-14-2008, 09:02 AM   #26
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QuoteOriginally posted by Marc Sabatella Quote
I think the problem was assuming people had read the discussion in another thread that led to this one. In the context of that other discussion, the poll *does* make sense, but if you are coming into it cold, I can see how it would it could be misinterpreted.
What's the other thread? I'm curious to see if it would clarify the question for me...
10-14-2008, 09:11 AM   #27
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Original Poster
Bits and bytes...

QuoteOriginally posted by creampuff Quote
Well folks, this is the kind of personal message I just got from the thread starter today:

Ok, hard case, just between me and you... do you have a problem with me or are you just an ******* to everyone?

I don't know what the rules are in Singapore, much beyond public caning, but let's call our little pissing match a draw ... don't post to my threads, or respond to my posts, and I'll do the same for you. But if you keep getting in my face in this vituprative way, I promise I will cloud up and rain all over your digital parade.
Brian


Aside from being extremely rude to say the least, I stand by what I said earlier that there are just too many variables to come to any meaningful conclusion of lens and ideal subject distance (whatever that may be).

Perhaps such a question comes from a rank newbie who is just blur and needs to brush up his knowledge by shooting more.

I can be a forgiving guy but I won't tolerate such personal messages, so I leave it to all of you to judge if the TS has a problem or not. Since when has threads been the personal property of anyone is beyond me...
My my my. Such outrage from somebody who likes to cheap-shot in public but can't take a private response. Well, I wanted to keep it private, just between us guys; we maybe could have worked it out or reached some accomodation to keep peace on the Forum. You chose to make it public. So be it, t's bits and bytes at 20 paces, boyo...
Brian
10-14-2008, 11:40 AM   #28
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QuoteOriginally posted by Marc Sabatella Quote
I think the problem was assuming people had read the discussion in another thread that led to this one. In the context of that other discussion, the poll *does* make sense, but if you are coming into it cold, I can see how it would it could be misinterpreted.
As one who obviously came in from the cold - it doesn't make any sense to me. I could interpret it, but I'd probably get it wrong...
10-14-2008, 11:53 AM   #29
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This is the thread that led to to this poll:

https://www.pentaxforums.com/forums/general-pentax-photography/39068-iq-subje...ance-test.html

The idea, as I understand it, is to compile a chart that lists each lens along with information about how it performs at different subject distances. Eg, to quantify the conventional wisdom that a given "macro" lens is sharp when used very close up but suffers at infinity compared to a non-macro lens of the same focal length, or that a given "portrait" lens is sharpest at 4-10 feet but not so good either closer or further, or that the kit lens is especially soft when focusing closely at 55mm, or whatever. Not that I necessarily think there is any real solid objective usable information that would come of it, but in principle at least, I can see why it might be interesting to at least try to collect this sort of data.
10-14-2008, 12:15 PM   #30
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If I interpret the post referenced by Marc correctly the real question here is for each possible lens, is there either a single subject distance or range of subject distances that yeild the maximum resolution of the lens at that distance, and all other distances are somewhat less.

If that is the question, aside from real generalities, as people ahve already stated, such as Macro's are optimized to work close, I doubt there is any answer.
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