The new EOS3, why so many focus points covering just 23%

[tim_jeffes]

I've just read the review for the new EOS3 and although I'm stunned by

the specs and feel the need to go out and buy one immediately (I

wish!), one thing puzzles me: 45 focussing points is an aweful lot to

choose from, but why do they only cover 23% of the central frame? Is

this not overkill for minimal gains? Surely a more useful

eye-controlled (or manual) system would cover the whole or

substantially the whole frame such that composing, metering and

focussing can be done all at once? Spread them out a little surely?

 

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Think about it, no more exposure lock, re-composing your shots within

4 sec or hold down AElock, switch to manual focus, etc, etc. Simply

compose your shot how you want it (on tripod preferably), select the

point(s) to focus on (or between for DOF), select the point(s) to

meter off and shoot! Multiple subjects, some for focussing on and

others for metering off, almost like a crude mouse driven screen

telling the camera whats what in the frame. Taking pictures could be

as easy as compose, point, point again and shoot, or am I just living

in dream land?

 

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I suspect that its either the eye-control or auto-focussing which

fails on the frame peripheral? Please confirm or explain.

[brad_hutcheson]

I was disappointed in this too. It isn't too bad though. If you look at a diagram of the sensor area it covers a fairly braod area of the screen. Not as much as I had hoped, but better than any other AF camera. I suspect the reason is physical size of the CMOS sensor that is used. If they made it bigger it would end up costing a LOT more. If you have an EOS camera now take the lens off and trip the shutter on bulb. This will move the mirror out of the way, and you can see the sensor. The space it takes up is larger than you would think.

[e.ung___]

I also dream of a camera with 100% AF pt covering, and more

important, without any visible rectangles inside the viewfinder

before focusing confirmed.

[danny_weber]

It's not just the sensor size that's a consideration. The AF sensor

sees through the mirror, which needs a section semi-silvered or

otherwise made translucent. Doing this for the complete image size is

not a trival matter.

[stanley_mcmanus4]

Canon's new autofocus design presents an interesting problem. Is it

an advancment or just a marketing selling point? I recenlty borrowed

a friend's F5 to shoot some moving subjects. I covers about the same

% of the viewfinder as the EOS3 despite having fewer sensors. It

easily tracks subjects as they move from one autofocus zone to the

next. The F100 uses the same layout as the F5. So what does the 45

points buy you on a practical level. Time, and our experience will

tell.

[sean_hester]

i think 45 points is only an advantage for eye selection. with the 5

points on my eos-5 i still have to point to focus, then re-frame to

shoot about 50% of the shots, because what i want to focus on is not

directly under a selection point. but it's better then with 1 point

because the amount i have to re-frame is MUCH less.

 

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with 45 points pretty much everything is under an AF point. (as long

as it's in the central area) so you can just look and shoot as

advertised. i DO wish the AF area covered more of the frame, though.

at least out to the "rule of thirds" verticies, maybe.

[tim_jeffes]

I think I agree with Stanley McManus. I too am of the opinion that at

present 45 focus points so densely packed is a marketing gimmic and

overkill, since other supposed inferior camera systems do the same

job. So why has Cannon done this? My hope is that they share our

vision of complete frame coverage (or at least 2/3rds) in the

long-term but they thought they had better try their algorithm for 45

points first before adding more or spreading them out more, since I

appreciate that 45 points does pose quite a few extra programming

nightmares especially when one tries servo auto-focus. I wrote the

initial posting in the hope to confirm Cannon's long-term plan. I too

appreciate that the CMOS sensor cost rises with increased size, but

the thing is already quite large isn't it? I too appreciate that the

mirror needs to be partially silvered under every focus point, but 45

points must be sufficient to still have full frame coverage surely?

Add 4 more and take it to 49 and have a grid 7x7. No extra cost apart

from larger sensors.

 

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The idea that one can define separate focus point(s) (for single point

focus or DOF) and light metering can only be practically achieved if

full frame auto-focus coverage is done. Personally I find the DOF

setting on my EOS useful, yet at the same time useless (I do mainly

landscape photography). The reason I say this is, DOF is one of the

only things a photographer can't do with manual settings. Sure, he

can guess it, but who truely knows how to judge distances at anything

more than a few meters? What I tend to do is use my DOF setting to

judge focussing distance and aperture, then switch to manual focus and

Av, set the same aperture with Av and leave the focussing unchanged

but more importantly unchangable by my camera too, recompose on a

tripod and shoot. Quite a lengthy debacle. Okay, maybe its my

technique which is wrong here, but I'm sorry I just can't fiddle with

tripods and hold my finger half-down on a shutter release while

recomposing with DOF, then stand back and hit my remote before 4 sec

is up. Neither can I judge DOF accurately enough to know where to set

the focul distance, aperture is generally not a problem - just use the

maximum without getting into silly shutter speeds and close to

reciprocal failure.

 

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If Cannon would give me a system where I could do all the technical

stuff (metering and focussing) on my tripod then the order of

meter-focus-compose could me changed to compose-focus-meter which to

be honest gives the photographer a great deal more time to concentrate

on his art (composure). Correct me if I'm wrong, but is this not the

logical order of events and the only way a wildlife or sports

photographer can really work? I see full frame focus point coverage

as a huge step in this direction. A custom function to set some

preset circle of confusion sizes for DOF calculation would be a nice

addition too. I've heard too many complain that AElock is rubbish if

it only locks for a few seconds and that "wouldn't it be nice if

Cannon followed .... and made AElock permanent", well no recomposing

means no need for AElock usage anymore.

[tim_jeffes]

Sorry, I should have said compose-focus-meter-recompose changed to

compose-focus-meter to stress the gains as I see them.

 

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Thanx to all who responded to my query.

[john_n._wall]

I looked at an EOS 3 at a local camera shop and was surprised at the

amount of viewfinder space the AF area actually covers. Looks like

more than 23% to me.

 

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All the flashing red lights seemed distracting; however, I suspect one

might get used to it.

 

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The goal of multiple focus points is of course to allow AF for the

off-center subject without having to lock focus and recompose.

 

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How far off center one wants the user to be able to AF is the issue.

 

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Only AF over the entire viewing area will permit AF for all potential

subjects, but I suspect that there is an area that if covered would

take care of all but the most unusual compositions.

 

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I would think that if there were AF spots at the points of

intersection in the traditional rule-of-thirds diagram plus the

center, plus one intermediate spot in each direction -- makes a total

of 15 -- that would take care of practically every real-world

situation for most of us.

[sean_hester]

the first rumor i heard about the "new canon 1n replacement camera" a

year ago mentioned 15 AF points. i immediatly immagined what john

just suggested. (actually i imagined the 5 points on my eos-5

replicated 1/3 up the frame and 1/3 down the frame for a total of 15)

i would actually be happier with that then what the eos-3 gives you.

oh well...

[bobatkins]

Tim - the Canon DOF function is just a simple approximation of

the "true" optimal focus point. They don't do any fancy calculation.

They could, but they don't.

Here's a quote from a Canon Technical Specialist on the subject

(from the Canon EOS FAQ files):

 

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"<em>...In any case, the EOS Depth AE calculations involve adding the

defocus amount for DEP 1 to the defocus amount for DEP 2 to ascertain

the total defocus amount. It

then becomes a simple matter to place an intermediate focusing point

7/17 of the way from the near point to the far point. The 7/17 figure

was selected by the EOS

Depth AE system designers based on its accuracy for "normal" subject

distances, not extreme close-up photography...</em>"

[jeff_hallett1]

Are you folks really thinking that that this technology will help

your photography or is it the "be the first kid on the block to

have... syndrome"? Honestly now, will 45 focusing points help your

composition or exposure metering? Do you really "need" this camera or

are holes burning in your pockets to spend money? I submit many people

are enamoured with "bells and whistles" more than real creativity.

This should set off a rash of flames!

[sean_hester]

all you "need" and some film and a box with a hole.

 

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more AF points would make picture taking faster for me. probably not

"better" but less of a hassle. isn't that what ALL camera gadgets

do? internal metering, AF, etc, etc, etc... they're all to make the

process EASIER, not BETTER.

 

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so... "help my photography"? i say YES. it'll make it faster,

which is a help.

[tim_jeffes]

Why is it that Jeff Hallett contributes nothing to this conversation?

What is it that makes a technophobe afraid of technology? Jeff, I

separate photography into two very distinct parts: The ART or picture

taking and the SCIENCE of picture taking. At present, taking pictures

still involves thinking about the ART (composure etc), then doing the

SCIENCE (focussing, metering etc) then back to the ART (recomposure).

If I am given a system where I can first think about the ART then do

the SCIENCE then yes I believe my photography has been improved.

Improved because I will take less time and my creativity (ART) needn't

be spoilt by having to think about the SCIENCE. To think that all

these gadgets will make better pitures involves more than thinking in

terms of the final product. All the features in the world won't

improve my ART, that's obvious and not worth dicussing. But you have

to account for the steps one took to get to a good composition.

Anyone given infinite time, infinite film and a manual focus SLR would

be able to take at least one near perfect picture (by pure chance mind

you, but if all you care for is the final picture then what do you

care how long or to what lengths one went to take it?).

 

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Enough said.

[jeff_hallett1]

My point is Tim, that I believe I can go out shooting ,with you,and

with my humble lowly A2,and produce an ARTFULLY composed and

SCIENTIFICALLY designed image as you would produce with the EOS 3! I

don,t feel that I need ultra- high tech to make me a better shooter

and many pros feel the same way! If you feel that a few more focusing

points and eye control gets you a better shot then go for it!

I think we have overdone this so if you wish to flame again, burn it

it up bud! I feel very comfortable and satisfied with most of my gear.

[sean_hester]

the thing is some people LIKE the "science" part of photography, and

some people don't, and think it only gets in the way of the "art"

part. let those people buy cameras with gadgets to do the science for

them. (it's when you can buy a camera that claims to help you with

the "art" part that i'll get worried)

 

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actually an A2 is a pretty advanced camera. it's doing lots of the

science for you. (unless you turn those features off) i'm

surprised one more feature put you over the edge into thinking that

we've gone too far.

 

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i suppose if you had an n90s right before the f5 was announced, you'd

figure that RGB metering was "too far"?

[jeff_hallett1]

Sean, Ck the features and specs on the EOS 3. I,d say it has a few

more than ONE feature over the A2. Actually my 2nd body is an older

Elan and it works fine for me too. As I said, I am satisfied with my

gear. Been published, won contests, slides continue to improve with

every roll..... OK??? JEEEZZZ. Let,s be done with this.