If shooting at f/22, is a fast 1.8 lens still considered fast?

Started Apr 17, 2011 | Discussions
edwardaneal
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so you finally admit you dont really know - - thank you
In reply to noirdesir, Apr 27, 2011

Okay - you want circumstantial evidence that Nikon does in fact use this type of sensor - how about the fact that in the scientific test I posted Nikon had higher low light accuracy with fast lenses than Canon did

If Canon were the only manufacture to have these special sensors wouldn't you expect it to give them the advantage with fast glass?

Canon doesn't really tout the fact they have these sensors, they only point out that they are only active when fast glass is mounted. Perhaps Nikons sensors are always active and they dont think it is a big deal

Fact is you have no clue if nikon camera can or cant take advantage of lenses faster than f/5.6 - you are only guessing - and you just admitted it

Finally - thank you

noirdesir wrote:

Two simple reasons:> - (1) Only Canon talks about these f/2.8 AF sensors, nobody else does. Why would Canon trumpet its advantage but no other camera maker does it? Canon very openly tells you which of their AF points get additional precision from f/2.8 lenses and which AF points do not. Following your logic that Nikon and Canon have the same technologies at their disposal, if Canon only adds these f/2.8 sensors to some of its AF points so would Nikon. And why would Nikon then withhold the information which AF points profit from f/2.8 lenses?

This is only circumstantial evidence but pretty strong one

  • (2) You can very simply test whether there are AF sensors for other apertures beyond the f/5.6 ones by adding a blocking ring at the exit of your lens that blocks the f/5.6 ring, as indicated in red in the image below. People have done this with Nikon bodies and the result was no AF action at all. If there were f/2.8 sensors, they would not be blocked and the AF system would be able to focus.

What you provide as evidence that faster lenses have faster and more precise AF is also only circumstantial evidence as it is comparing different lenses, not the same lens manually stopped down to either f/2.8 or f/5.6. And that AF motor speed and accuracy can vary a lot between different lenses is not exactly an unlikely idea, nor is the idea that different optical qualities (think of it in terms of SLRgear-type blur indices) can have an influence on AF accuracy and speed that far-fetched.

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noirdesir
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Re: so you finally admit you dont really know - - thank you
In reply to edwardaneal, Apr 27, 2011

edwardaneal wrote:

Okay - you want circumstantial evidence that Nikon does in fact use this type of sensor - how about the fact that in the scientific test I posted Nikon had higher low light accuracy with fast lenses than Canon did

And what does this prove beyond that the overall AF system in Nikons seems to better? There are so many variables that are different when comparing the performance of different systems using this a proof is just plain foolish.

It is like saying a car must have a V12 engine because it is faster than another car with a V12 engine. If you fail to see the fallacy of this kind of logic, I am afraid I cannot help you.

If Canon were the only manufacture to have these special sensors wouldn't you expect it to give them the advantage with fast glass?

No, because AF systems are quite complex, one single feature does not determine overal performance.

Canon doesn't really tout the fact they have these sensors, they only point out that they are only active when fast glass is mounted. Perhaps Nikons sensors are always active and they dont think it is a big deal

Always active would mean all AF sensor points have both f/2.8 and f/5.6 sensors. And yes, that would be possible, except that my second point in my previous message clearly disproves that.

But again, you do not respond to arguments that might show you are wrong. Please, until you explain to me why my second argument is not conclusive as to the absence of f/2.8 AF sensors in Nikon cameras, I consider your argumentation as phoney, as in wilfully ignoring arguments (and not providing an explanation as to why you ignore them).

Fact is you have no clue if nikon camera can or cant take advantage of lenses faster than f/5.6 - you are only guessing - and you just admitted it

I have no absolute proof unless Nikon makes an unambiguous statement or somebody disassembles a Nikon camera. Nikon could naturally be wilfully disabling AF when somebodies tries to test for the presence of f/2.8 sensors by blocking the f/5.6 ring just in order to keep it a secret that it uses f/2.8 sensors.

The point is that the vast majority of people who understand the basic technic principles behind phase-detect AF (which you at the beginning of this thread certainly did not) have come to the conclusion that Nikon only uses f/5.6 AF sensors. Nobody has ever brought up any explanation as to why the blocking-the-f/5.6-ring test would stop the AF if there actually were f/2.8 sensors.

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DRode
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Re: If shooting at f/22, is a fast 1.8 lens still considered fast?
In reply to cuteo100, Apr 27, 2011

Fast simply refers to to maximum aperture. Typically any lens that opens to f/2.8 or wider is considered "fast glass". That does not mean it cannot be used at narrow apertures effectively.

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edwardaneal
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noirdesir - really?
In reply to noirdesir, Apr 27, 2011

Noirdesir

you posted here that there was no advantage in AF with lenses faster than f/5.6 as if it were a hard fact in every possible mode.

you then admit that in other focus modes such as would be used in live view that the AF system could in fact take advantage of the faster glass

so you misled people

You also told the people here that because if the design than NO nikon phase detect AF system can take advantage of apertures faster than F/5.6

again you misled people by posting things as if they were fact and now you have admitted you are speculating

So basically everything you posted has been worthless - you have given no facts to back up your statements and in fact you have admitted that your statements are based on an unverified assumption that Nikon used a limited design of phase detect auto focus like the one in your only example*

I on the other hand have posted a link to Canons statement that one of the advantages of faster glass is better low light focus (this article makes no reference to it only being an advantage on some of their cameras that have special AF sensors so it would seem it must be an advantage on all - if not they are risking getting in trouble for false adversing)

I have also posted a link to an article lensrental.com that also states that faster lenses auto focus better with Phase detect AF systems because with more light comes increased contrast - this article makes no reference to it only being a Canon feature and is backed by references to 13 other sources.

And finally I have posted a link to a scientific cross brand test of focus accuracy that shows that on every brand of camera the highest degree of focus accuracy was achieved using the manufactures lenses with apertures between f/2.8 and f/4)

who do you think the people should trust ? My links to reliable sources and an actual test - or your misstatements and speculation?

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noirdesir
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Re: noirdesir - really?
In reply to edwardaneal, Apr 27, 2011

edwardaneal wrote:

you posted here that there was no advantage in AF with lenses faster than f/5.6 as if it were a hard fact in every possible mode.

you then admit that in other focus modes such as would be used in live view that the AF system could in fact take advantage of the faster glass

so you misled people

Reading comprehension, reading comprehension, dear Edward, is really your weak point. My very post here said:

Anything faster than f/5.6 (or probably f/5) is lost on the phase-detect AF (except on some Canon bodies which have a few special f/2.8 focus points). The phase-detect AF sensor in all Nikon bodies only sees light coming from the 'f/5.6 ring'.

I said phase-detect AF on Nikon cameras is limited to f/5.6 and you later accuse me of having said that any kind of AF is limited to f/5.6. What should people think of somebody who is shamelessly lying just to be able to accuse me?

You also told the people here that because if the design than NO nikon phase detect AF system can take advantage of apertures faster than F/5.6

again you misled people by posting things as if they were fact and now you have admitted you are speculating

Well, I also speculate that the Earth is round and not flat. I have no definite statement from God that the Earth is round but all the evidence available has led me and most sufficiently educated people to come to the conclusion that it is round, in as much that most people would say it is a fact.

So basically everything you posted has been worthless - you have given no facts to back up your statements and in fact you have admitted that your statements are based on an unverified assumption that Nikon used a limited design of phase detect auto focus like the one in your only example*

Again have you verified that the Earth is round and not flat? I guess not, but you still would state is as if it were a fact.

who do you think the people should trust ? My links to reliable sources and an actual test - or your misstatements and speculation?

I think the answer to that is very simple, people will trust the person who has presented the more logical and convincing arguments.

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edwardaneal
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I asked Nikon - and they say it is bad information
In reply to noirdesir, Apr 27, 2011

I just e-mailed Nikon about an hour ago - this is what I asked them

"I was recently told by a camera store that Canon DSLR's have special auto focus sensors that allows them to take advantage of the extra light and contrast provided by lenses with apertures that are f/2.8 and faster. I was also told that Nikon DSLR's do not have any sensors like this and will not auto focus any better in low light with an f/2.8 lens than they will with an f/5.6 lens

Can you please tell me if this is true

Thank you"

this is the reply I just got

" Subject
Fast lenses

Discussion Thread
Response Via Email (David D.) 04/27/2011 04:14 PM
HI

Thanks for the question. It sounds like you got some pretty bad info! I'd guess what you were told is related to the difference between cross-type and line-type AF sensors. In an autofocus system some of the spots use cross type sensors (which are what it sounds like, two sensors that cross) and some sensors are just a single line.

A cross-type sensor is generally better because it can focus on a subject that has horizontal and vertical contrast while a line type is best for just horizontal subjects.

In some model Canon cameras (their lower end I believe) they have more cross type sensors than our comparable cameras but only the center AF point benefits from the faster lens in their system

Of course there is so much more to performance than the type of AF sensor that all of this is really just speculation since the camera's CPU, lens CPU, lens motor, actual subject, lighting condition, etc are really what determine performance.

I hope this helps.

-David

Thanks for using Nikon products!
Nikon Inc. (USA) Support / Service
http://support.nikontech.com "

sounds to me as if David is saying that Nikons AF does in fact benefit from faster lenses and the following comment: "only the center sensor benefits from faster lenses in their system" sure makes it sound to me like he is saying that with Nikon you dont have this limitation.

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noirdesir
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Re: I asked Nikon - and they say it is bad information
In reply to edwardaneal, Apr 27, 2011

edwardaneal wrote:

I just e-mailed Nikon about an hour ago - this is what I asked them

"I was recently told by a camera store that Canon DSLR's have special auto focus sensors that allows them to take advantage of the extra light and contrast provided by lenses with apertures that are f/2.8 and faster. I was also told that Nikon DSLR's do not have any sensors like this and will not auto focus any better in low light with an f/2.8 lens than they will with an f/5.6 lens

Can you please tell me if this is true

Thank you"

this is the reply I just got

" Subject
Fast lenses

Discussion Thread
Response Via Email (David D.) 04/27/2011 04:14 PM
HI

Thanks for the question. It sounds like you got some pretty bad info! I'd guess what you were told is related to the difference between cross-type and line-type AF sensors. In an autofocus system some of the spots use cross type sensors (which are what it sounds like, two sensors that cross) and some sensors are just a single line.

A cross-type sensor is generally better because it can focus on a subject that has horizontal and vertical contrast while a line type is best for just horizontal subjects.

In some model Canon cameras (their lower end I believe) they have more cross type sensors than our comparable cameras but only the center AF point benefits from the faster lens in their system

Of course there is so much more to performance than the type of AF sensor that all of this is really just speculation since the camera's CPU, lens CPU, lens motor, actual subject, lighting condition, etc are really what determine performance.

I hope this helps.

-David

Thanks for using Nikon products!
Nikon Inc. (USA) Support / Service
http://support.nikontech.com "

sounds to me as if David is saying that Nikons AF does in fact benefit from faster lenses and the following comment: "only the center sensor benefits from faster lenses in their system" sure makes it sound to me like he is saying that with Nikon you dont have this limitation.

He tries to create that impression without actually saying it (and mainly tries to move away the discussion from that issue by talking about cross sensors and how the overall system is what counts). Any Nikon representative would avoid at all cost to admit that a competing system is better in some regard, so evasive answering is to be expected.

There have been a lot more people before you who have tried to get an answer about that issue from Nikon, all of them got this kind of evasive answer. As others and I have said repeatedly, only Canon is willing to unambiguously go on the record about f/2.8 AF sensors.

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edwardaneal
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well we will find out
In reply to noirdesir, Apr 27, 2011

okay - I just sent a follow up question a few minutes ago - this is what I asked

"so are you saying that a Nikon DSLR like the D300 can in fact focus more accurately in low light with a f/1.4 lens or an f/2.8 lens than it might be able to under the same conditions with an f/5.6 lens

Thanks again"

If David comes back and says yes then I think it will be clear that Nikon does have sensors that can use the faster apertures. On the other hand if he says no then I will let everyone here know you were right and I was wrong. And if on the off chance that the answer is less than straight forward I will update the question as many time as it takes to get an answer that both you and I accept.

Is this okay with you?

noirdesir wrote:

There have been a lot more people before you who have tried to get an answer about that issue from Nikon, all of them got this kind of evasive answer. As others and I have said repeatedly, only Canon is willing to unambiguously go on the record about f/2.8 AF sensors.

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Lenses worth mentioning owned and sold– 12-24 f/4, 17-55 f/2.8, 35-70 f/2.8, 80-200 f/2.8, 20mm f/2.8, 35mm f/2, 50mm f/1.8, 50mm f/1.4D, 60mm f/2.8D, 85mm f/1.8, 105mm f/2D-DC, 180mm f/2.8, 300mm f/4D-ED

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edwardaneal
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so here is nikons final answer
In reply to edwardaneal, Apr 28, 2011

As you know from my post above I followed up my first question to nikon with a very simple and staight forward second question as follows:

"so are you saying that a Nikon DSLR like the D300 can in fact focus more accurately in low light with a f/1.4 lens or an f/2.8 lens than it might be able to under the same conditions with an f/5.6 lens

Thanks again"

And this is his answer

"Discussion Thread
Response Via Email (David D.) 04/27/2011 10:45 PM

HI

Sure, a fast lens lets more light in to the AF system which allows it to work more effectively and thus acquire and lock focus faster. Thanks

-David

Thanks for using Nikon products!
Nikon Inc. (USA) Support / Service
http://support.nikontech.com "

so Nikon has now flat out stated that f/1.4 and f/2.8 lenses " let in more light into the af system which allows it to work more effectively and thus acquire and lock focus faster "

Personally I think this pretty much settles our debate

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Lenses worth mentioning owned and sold– 12-24 f/4, 17-55 f/2.8, 35-70 f/2.8, 80-200 f/2.8, 20mm f/2.8, 35mm f/2, 50mm f/1.8, 50mm f/1.4D, 60mm f/2.8D, 85mm f/1.8, 105mm f/2D-DC, 180mm f/2.8, 300mm f/4D-ED

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edwardaneal
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well?
In reply to edwardaneal, Apr 28, 2011
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Lenses worth mentioning owned and sold– 12-24 f/4, 17-55 f/2.8, 35-70 f/2.8, 80-200 f/2.8, 20mm f/2.8, 35mm f/2, 50mm f/1.8, 50mm f/1.4D, 60mm f/2.8D, 85mm f/1.8, 105mm f/2D-DC, 180mm f/2.8, 300mm f/4D-ED

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edwardaneal
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hello - Noirdesir - Steve - where are you?
In reply to edwardaneal, Apr 29, 2011

Nikon has just flat out stated that their AF systems do in fact benefit from the extra light provided by f/2.8 and f/1.4 lenses.

Suddenly you are silent?

Come on guys - - - it is time to man up

only loosers dont admit when they made a mistake

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SB800, SB600 and other misc lighting equipment

Lenses worth mentioning owned and sold– 12-24 f/4, 17-55 f/2.8, 35-70 f/2.8, 80-200 f/2.8, 20mm f/2.8, 35mm f/2, 50mm f/1.8, 50mm f/1.4D, 60mm f/2.8D, 85mm f/1.8, 105mm f/2D-DC, 180mm f/2.8, 300mm f/4D-ED

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HSway
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Excuse my humble remark gents
In reply to edwardaneal, Apr 29, 2011

but I too think it is one of factors that plays the role, perhaps one of the most important ones. And I base it solely on my empirical experience shooting low light n low contrast scenes. My last and rather striking observation was made on Tokina 11-16/2.8 shot side by side the Sigma 8-16 on same body, same moment (d7000) which is very dark in over lapping range f5- 5.6. While Sigma’s behavior was an unpleasant find for me I was ready to accept. It’d mean I have to take adjusted measures shooting the lens in low contrast conditions which in uwa shooting is mostly possible. Not like it does not matter with the uwas as I hear sometimes (the precise focus). I had 4 copies and there were all the same in this respect. Tokina is just a joy in use in comparison, reliable. - AF &LV alike.

I now say something less technical: I just felt in my gut it is because of the light the Tokina was visibly working with.

Hynek

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DRode
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Re: so here is nikons final answer
In reply to edwardaneal, Apr 29, 2011

Thanks for getting this straight from Nikon. I was always told that faster glass benefits the Nijkon AF system. In fact, my own experience would seem to support this. But recently I've read a number of comments that this was not the case. One poster even referred to some kind of "baffles" that would damp the light down to f/5.6 even if the lens were capable of much wider apertures.

There are many things that affect AF performance. Fast glass IS one of them.

edwardaneal wrote:

As you know from my post above I followed up my first question to nikon with a very simple and staight forward second question as follows:

"so are you saying that a Nikon DSLR like the D300 can in fact focus more accurately in low light with a f/1.4 lens or an f/2.8 lens than it might be able to under the same conditions with an f/5.6 lens

Thanks again"

And this is his answer

"Discussion Thread
Response Via Email (David D.) 04/27/2011 10:45 PM

HI

Sure, a fast lens lets more light in to the AF system which allows it to work more effectively and thus acquire and lock focus faster. Thanks

-David

Thanks for using Nikon products!
Nikon Inc. (USA) Support / Service
http://support.nikontech.com "

so Nikon has now flat out stated that f/1.4 and f/2.8 lenses " let in more light into the af system which allows it to work more effectively and thus acquire and lock focus faster "

Personally I think this pretty much settles our debate

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My kit - D200, 10.5mm f/2.8D, 35mm f/1.8G, 50mm f/1.4G & 70-300VR
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Lenses worth mentioning owned and sold– 12-24 f/4, 17-55 f/2.8, 35-70 f/2.8, 80-200 f/2.8, 20mm f/2.8, 35mm f/2, 50mm f/1.8, 50mm f/1.4D, 60mm f/2.8D, 85mm f/1.8, 105mm f/2D-DC, 180mm f/2.8, 300mm f/4D-ED

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noirdesir
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Re: so here is nikons final answer
In reply to DRode, Apr 29, 2011

DRode wrote:

Thanks for getting this straight from Nikon. I was always told that faster glass benefits the Nijkon AF system. In fact, my own experience would seem to support this. But recently I've read a number of comments that this was not the case. One poster even referred to some kind of "baffles" that would damp the light down to f/5.6 even if the lens were capable of much wider apertures.

These 'baffles' are real (see the green parts below to understand what they do), even Edward has accepted that. He is just of the opinion that Nikon must use both f/2.8 and f/5.6 PD-AF sensors because Canon uses them (and Nikon would be stupid not to use them as well, probably similarly to Nikon using FF sensors prior to 2007 because Canon was using them). And that Nikon has designed its AF system such that a simple test for the existence of f/2.8 AF sensors (which is done by blocking the light to the f/5.6 sensors as indicated in red in the drawing, if there are f/2.8 sensors, the AF should continue working, if there are none, it should not work, which is what is observed) would fail, so the existence of f/2.8 AF sensors in Nikon cameras could be kept secret.

The e-mail from Nikon shows no sign that the person is actually understanding how PD-AF works, otherwise he would be more specific and say that Nikon uses both f/2.8 and f/5.6 AF sensors.

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DRode
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Re: so here is nikons final answer
In reply to noirdesir, Apr 29, 2011

I'm not about to join the debate. It's overly technical for me and I lack the knowledge or interest to chime in.

My fast lenses have always outperformed my slower lenses in general and especially in dim light. However, my fast lenses are typically better overall lenses, so that likely makes a difference as well.

The "why" is only important to me out of curiosity. In practice, I rely on my own experience.

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edwardaneal
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dont you ever stop?
In reply to noirdesir, Apr 29, 2011

you keep posting these ancient diagrams of how a phase detect system might work if it were limited to only one type of sensor, one sensor location, one baffle width on every sensor, - - dont you get it? Seriously any one can look at your symplistic drawing and see how easy it would be to make minor changes that would allow it to work with faster apertures yet still function perfectlly with slower lenses especially in a system that has multiple sensors and can optomize them for more that one paticular aperture, but for some dumb reason you dont think the engineers at Nikon have been smart enough to figure this out.

Nikon has flat out stated that their AF system will in fact focus faster and more accuratly with f/2.8 and f/1.4 lenses. yet here you are hanging desperatly on to the argument

And earlier you called me "hard headed" WOW

Real men admit it when they make a mistake - - - - - Only sore loosers keep making excuses.

I am done here - you are wrong, it is a fact that has been verified by the people at Nikon - - - - deal with it !!!

noirdesir wrote:

DRode wrote:

Thanks for getting this straight from Nikon. I was always told that faster glass benefits the Nijkon AF system. In fact, my own experience would seem to support this. But recently I've read a number of comments that this was not the case. One poster even referred to some kind of "baffles" that would damp the light down to f/5.6 even if the lens were capable of much wider apertures.

These 'baffles' are real (see the green parts below to understand what they do), even Edward has accepted that. He is just of the opinion that Nikon must use both f/2.8 and f/5.6 PD-AF sensors because Canon uses them (and Nikon would be stupid not to use them as well, probably similarly to Nikon using FF sensors prior to 2007 because Canon was using them). And that Nikon has designed its AF system such that a simple test for the existence of f/2.8 AF sensors (which is done by blocking the light to the f/5.6 sensors as indicated in red in the drawing, if there are f/2.8 sensors, the AF should continue working, if there are none, it should not work, which is what is observed) would fail, so the existence of f/2.8 AF sensors in Nikon cameras could be kept secret.

The e-mail from Nikon shows no sign that the person is actually understanding how PD-AF works, otherwise he would be more specific and say that Nikon uses both f/2.8 and f/5.6 AF sensors.

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My kit - D200, 10.5mm f/2.8D, 35mm f/1.8G, 50mm f/1.4G & 70-300VR
SB800, SB600 and other misc lighting equipment

Lenses worth mentioning owned and sold– 12-24 f/4, 17-55 f/2.8, 35-70 f/2.8, 80-200 f/2.8, 20mm f/2.8, 35mm f/2, 50mm f/1.8, 50mm f/1.4D, 60mm f/2.8D, 85mm f/1.8, 105mm f/2D-DC, 180mm f/2.8, 300mm f/4D-ED

 edwardaneal's gear list:edwardaneal's gear list
Sony Alpha NEX-7 Sigma 60mm F2.8 DN | Art Carl Zeiss Touit 1.8/32
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xtm
xtm
Contributing MemberPosts: 713Gear list
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Re: dont you ever stop?
In reply to edwardaneal, Apr 29, 2011

why do you keep responding to him Edward? lol

 xtm's gear list:xtm's gear list
Nikon D750 Nikon AF-S Nikkor 200mm f/2G ED-IF VR Nikon AF-S Nikkor 58mm f/1.4G Nikon AF-S Nikkor 20mm f/1.8G ED +1 more
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noirdesir
Forum ProPosts: 11,218
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Re: so here is nikons final answer
In reply to DRode, Apr 29, 2011

DRode wrote:

I'm not about to join the debate. It's overly technical for me and I lack the knowledge or interest to chime in.

My fast lenses have always outperformed my slower lenses in general and especially in dim light. However, my fast lenses are typically better overall lenses, so that likely makes a difference as well.

The "why" is only important to me out of curiosity. In practice, I rely on my own experience.

And I am perfectly fine with this, I am just against people making a technical argument ('the AF is faster because the lens lets in more light') if they do not understand the technology.

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edwardaneal
Senior MemberPosts: 9,101Gear list
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Re: so here is nikons final answer
In reply to noirdesir, Apr 29, 2011

even when Nikon says it about the autofocus system that their engineers designed and built?

I know you questioned my reading comprehension, but aparently it is you that has the problem - so just in case you missed it - this is the quote from nikon when flat out asked if an f/1.4 or f/2.8 lens would autofocus better on a nikon camera than an f/5.6 lens:

"Sure, a fast lens lets more light in to the AF system which allows it to work more effectively and thus acquire and lock focus faster."

aparently you think technology cant advance beyond your symplistic understanding of it - - - what a loser

noirdesir wrote:

I am just against people making a technical argument ('the AF is faster because the lens lets in more light') if they do not understand the technology.

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My kit - D200, 10.5mm f/2.8D, 35mm f/1.8G, 50mm f/1.4G & 70-300VR
SB800, SB600 and other misc lighting equipment

Lenses worth mentioning owned and sold– 12-24 f/4, 17-55 f/2.8, 35-70 f/2.8, 80-200 f/2.8, 20mm f/2.8, 35mm f/2, 50mm f/1.8, 50mm f/1.4D, 60mm f/2.8D, 85mm f/1.8, 105mm f/2D-DC, 180mm f/2.8, 300mm f/4D-ED

 edwardaneal's gear list:edwardaneal's gear list
Sony Alpha NEX-7 Sigma 60mm F2.8 DN | Art Carl Zeiss Touit 1.8/32
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