A reminder for some memebers as to what the F stop is all about.

Started Jan 26, 2014 | Discussions
bobn2
bobn2 Forum Pro • Posts: 62,482
Re: Um...

pwilly wrote:

And also, the image circle isn't very tightly coupled to the format in use. I would guess that if you removed the baffles, most SHG lenses would produce pretty much a FF image circle. It's one of the things that is done to give 'edge to edge' sharpness, make the image circle large and just use the centre of it. Long FL lenses in particular tend to have big image circles.

If you removed the baffles you would need to call the ghost and flair busters!

Maybe, it varied from lens to lens - a well designed and coated lens shouldn't have so much internal reflection that the baffles make a big difference. Probably they make some difference, but it's that last little bit.

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Bob

Brent Lossing Forum Pro • Posts: 10,460
Re: Very OT: Japanese drinking customs

That was wonderful - and! - I actually feel like I have learned some new things.

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windsprite
windsprite Senior Member • Posts: 2,707
Re: Very OT: Japanese drinking customs

Brent Lossing wrote:

That was wonderful - and! - I actually feel like I have learned some new things.

See, equivalence threads aren't so bad after all! :^)

There are a lot of interesting and lovely aspects to Japanese culture.  I'm glad you enjoyed reading.

Julie

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bobn2
bobn2 Forum Pro • Posts: 62,482
Re: Very OT: Japanese drinking customs

windsprite wrote:

Brent Lossing wrote:

That was wonderful - and! - I actually feel like I have learned some new things.

See, equivalence threads aren't so bad after all! :^)

So, you're saying that 150ml is equivalent to 568ml?

Or 1 pt = 1 pt = 1pt.

There are a lot of interesting and lovely aspects to Japanese culture. I'm glad you enjoyed reading.

It's very interesting indeed - I would tell you about an 'interesting' night I had in Kōchi - but I can't remember so much about it after the special gaijin cocktail I got served in the retired railwaymans' bar.

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Bob

Roger Engelken
Roger Engelken Veteran Member • Posts: 5,439
Re: Think of a fat lady and thin supermodel on the beach

robert1955 wrote:

Roger Engelken wrote:

Lab D wrote:

A fat lady and a thin supermodel are laying on the beach. Who will get sun burnt faster? Answer: both will burn/tan the same despite the fat lady having 4x the skin area.

Maybe they need a good UV filter.

Anyway, Four Thirds is the hot supermodel.

This begs the question, when will the Fat Lady sing and put a merciful end to this thread?

When she weighs in at 150 [metric]

This is true.  Thank heavens for that!

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Roger Engelken
Roger Engelken Veteran Member • Posts: 5,439
Re: Think of a fat lady and thin supermodel on the beach
2

Bmoon wrote:

Lab D wrote:

A fat lady and a thin supermodel are laying on the beach. Who will get sun burnt faster? Answer: both will burn/tan the same despite the fat lady having 4x the skin area.

Maybe they need a good UV filter.

Anyway, Four Thirds is the hot supermodel.

But the million dollar question is which one requires more sunscreen to reduce their exposure to the sun ?

Well, it would need to be SPF 150.  Given this thread, a lot of SPF 150, if for nothing else than equivalency.

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John Byrne Veteran Member • Posts: 7,174
Re: When will the "equivelance" torture end.
4

It comes in two very different forms, one in a tin, and the other by way of relentless ear bashing.

One you can choose to eat, the other, is forced down your throat, and if you don't accept it as being correct you are some kind of heretic. Either way, the topic does absolutely nothing to improve one's photographic abilities, and therefore should be rightly filed under "Useless Information."

The preachers of this grossly booring and somewhat dubious theory have never once suggested how acknowledgement will help any of us achieve greatness, therefore IMHO their relentless ear bashing is far less useful than having "a hip pocket added to a singlet" or even owning a "left handed ring spanner".

The stuff in a tin is called SPAM. Maybe the subject of this relentless attack to which we are constantly subjected could be also.

John Byrne.

Roger Engelken
Roger Engelken Veteran Member • Posts: 5,439
Re: When will the "equivelance" torture end.
3

John Byrne wrote:

It comes in two very different forms, one in a tin, and the other by way of relentless ear bashing.

One you can choose to eat, the other, is forced down your throat, and if you don't accept it as being correct you are some kind of heretic. Either way, the topic does absolutely nothing to improve one's photographic abilities, and therefore should be rightly filed under "Useless Information."

The preachers of this grossly booring and somewhat dubious theory have never once suggested how acknowledgement will help any of us achieve greatness, therefore IMHO their relentless ear bashing is far less useful than having "a hip pocket added to a singlet" or even owning a "left handed ring spanner".

The stuff in a tin is called SPAM. Maybe the subject of this relentless attack to which we are constantly subjected could be also.

John Byrne.

The tenor of this thread is much like elementary school children on the playground. Children, it seems, will fight on the playground, "grow up", then fight on a forum giving so many others a taste of the torture all over again. I do not remember that in those days (when I can remember those days) the fights were over equivalency, but whatever it was, this thread does remind me that the more times change, the more things stay the same.  It is possible to be a kid again.

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dave gaines
dave gaines Veteran Member • Posts: 9,187
What the F stop is & Off Topic
5

This thread is about the f-stop of a lens, not equivalency. F-stop is, in simple terms, a ratio of the aperture opening to the focal length. Nothing else. It doesn’t matter what format you’re using. Whatever sensor you have is what you have to work with.

It’s of no use to say my Olympus 90-250 f/2.8 would be a 90-250 f/2.8 on “FF” (or argue it’s an f/5.6) because the lens will never be used on a FF sensor. And it doesn’t matter a bit that you can have a 600 mm f/4 lens on a canikon “FF”. Or that it would be a 1200 mm f/4 on 4/3 if only you could find an adapter, because it's never going to be put on a 4/3 format camera.

This argument is a waste of time and energy. People here chose Olympus 4/3 and m4/3. They don’t care and it doesn’t matter what a 35 mm sensor can do.

It's unfortunate that someone or several people have hijacked this thread to start an argument about equivalency with as many people as they can get angry enough to reply. Some will keep it going by bending the subject in every post to fit their ever-changing opinions.

I wish people would stop responding to this inane argument, ignore people who post these off-topic flames and Complain when they get abusive.

Off-Topic is one of the categories of Complaint when you hit that option. Flame baiting is another option. These arguments fit both of those categories. I regret that I can only hit the Complain button a couple of times a day. But all of you could hit it collectively many times. Let the moderators know you don’t appreciate this hijacking of every other thread in the forum.

You don't have to attend every argument you're invited to.

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Dave

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Great Bustard Forum Pro • Posts: 43,248
1, 2, and 3
5

Roger Engelken wrote:

John Byrne wrote:

It comes in two very different forms, one in a tin, and the other by way of relentless ear bashing.

One you can choose to eat, the other, is forced down your throat, and if you don't accept it as being correct you are some kind of heretic. Either way, the topic does absolutely nothing to improve one's photographic abilities, and therefore should be rightly filed under "Useless Information."

The preachers of this grossly booring and somewhat dubious theory have never once suggested how acknowledgement will help any of us achieve greatness, therefore IMHO their relentless ear bashing is far less useful than having "a hip pocket added to a singlet" or even owning a "left handed ring spanner".

The stuff in a tin is called SPAM. Maybe the subject of this relentless attack to which we are constantly subjected could be also.

John Byrne.

The tenor of this thread is much like elementary school children on the playground. Children, it seems, will fight on the playground, "grow up", then fight on a forum giving so many others a taste of the torture all over again. I do not remember that in those days (when I can remember those days) the fights were over equivalency, but whatever it was, this thread does remind me that the more times change, the more things stay the same. It is possible to be a kid again.

http://www.dpreview.com/forums/post/53004872

Wow, must be a slow news day. 3 threads about equivalency are now bantering about.

The interesting thing is, this debate often ends up putting people on two extremes of the debate. Am I the only one that actually sees little conflict between the two sides?

On the one side, an f stop is an f stop is an f stop and on the other more photons or total light makes for less noise.

Of course, both statements are true. I don't think anyone that is on the total light side of this 'fence' is saying exposure changes with sensor format.

http://www.dpreview.com/forums/post/53005507

If this is the way you see the debate, John, there is only one group of people expressing extreme views. AFAIK, nobody who accepts the idea that more photons or total light make less noise, has ever rejected the idea that an f-stop is an f-stop. In fact, it's built into the total-light calculations, so they simply don't see any conflict between the two positions. OTOH, there is a group who insist that f/2.8 is f/2.8 but reject the idea that more total light makes for less noise. The way you have posed the question, this latter group turns out to be the only extremists. So I guess that means that there are lots of people in the middle, and no, your position isn't particularly unique.

http://www.dpreview.com/forums/post/53007014

Yes - that's true. That's a hard position to take or understand if you've shot both formats for many years where you are totally cognizant of the total light benefit.

dave gaines wrote:

This thread is about the f-stop of a lens, not equivalency.

Guess what? Equivalence is all about the f-ratio of the lens and how it relates to the visual properties of the recorded photo.

F-stop is, in simple terms, a ratio of the aperture opening to the focal length. Nothing else. It doesn’t matter what format you’re using. Whatever sensor you have is what you have to work with.

It’s of no use to say my Olympus 90-250 f/2.8 would be a 90-250 f/2.8 on “FF” (or argue it’s an f/5.6) because the lens will never be used on a FF sensor. And it doesn’t matter a bit that you can have a 600 mm f/4 lens on a canikon “FF”. Or that it would be a 1200 mm f/4 on 4/3 if only you could find an adapter, because it's never going to be put on a 4/3 format camera.

This argument is a waste of time and energy. People here chose Olympus 4/3 and m4/3. They don’t care and it doesn’t matter what a 35 mm sensor can do.

What was the title of this thread again?

It's unfortunate that someone or several people have hijacked this thread to start an argument about equivalency with as many people as they can get angry enough to reply. Some will keep it going by bending the subject in every post to fit their ever-changing opinions.

I wish people would stop responding to this inane argument, ignore people who post these off-topic flames and Complain when they get abusive.

What was the title of this thread again?

Off-Topic is one of the categories of Complaint when you hit that option. Flame baiting is another option. These arguments fit both of those categories. I regret that I can only hit the Complain button a couple of times a day. But all of you could hit it collectively many times. Let the moderators know you don’t appreciate this hijacking of every other thread in the forum.

You don't have to attend every argument you're invited to.

For a fact, yet here you are.

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