MF Auto Focus - Joke

[Randal32]

I recently converted to a p30 and Mamiya 645... which I love.

However, one thing I don't understand is why my grandfathers $700 Nikon D40 has better AF than all MF cams.

The 1 point works fine in decent lighting cases, but why can they not make more than 1 point.

Is the demand for this just not strong enough?  Or am I the only one that feels this way?  Or is the R&D too much?

Fortunately when using the p30, I shoot at f8 or smaller, but I dont feel like I could bust out the 80 1.9 and manually focus unless shooting still life.

Any other thoughts on this?

Thanks,
Randal

[snickgrr]

Totally agree with you.  It's prehistoric almost.

[Randal32]

Totally agree with you.  It's prehistoric almost.
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I know we're paying almost 20K for the DB's but it would be nice to have 5 AF points.  It couldn't be that hard.

Maybe I'm just too New School.

R

[MichaelEzra]

Mamiya ZD camera has a decent 5-point AF

[stevecoleccs]

Try adjusting the Focus Area - You can have a Spot focus or Normal Focus
area in the viewfinder.

[yaya]

Current multi-point AF sensors are all designed for 35mm or smaller cameras, therefore using them inside a 48X36 frame with MF lenses would be pointless as they will only be covering a small area in the centre of the frame.

In addition, due to the size and weight of MF lenses, there is a lot more "metal" to move and turn and using bigger or stronger/ faster servos will result bigger/ heavier bodies and lenses.

Yair

[Dustbak]

Current multi-point AF sensors are all designed for 35mm or smaller cameras, therefore using them inside a 48X36 frame with MF lenses would be pointless as they will only be covering a small area in the centre of the frame.

In addition, due to the size and weight of MF lenses, there is a lot more "metal" to move and turn and using bigger or stronger/ faster servos will result bigger/ heavier bodies and lenses.

Yair
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Even with the smaller 35mm area in a MF camera I would be very happy. I have no problems using the AF points of the 1dsMK2 even if it only covers the 24x36 center area of the sensor

At this moment the center is the part where I very rarely put focus. Focus, recompose and take a shot isn't doable with fast lenses wide open so the center AF is unusable in many instances.

The ZD apparently has a 5-point AF so it must be doable. Any ZD owner wants to shed some light on the usability of the AF system?

[Wim van Velzen]

In addition, due to the size and weight of MF lenses, there is a lot more "metal" to move and turn and using bigger or stronger/ faster servos will result bigger/ heavier bodies and lenses.

Yair
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I heard this more often, but always found it strange. The larger telelenses, like a 300 2.8 or 600 4.0, for 35mm are quite heavy also. Actually a lot heavier than even a medium format 180 2.8.

[frankric]

I don't know about five points for the ZD. Mine has three.

There is a centre point and one point on either side. The side points are about one fifth of the way out from the centre, so there is a much lower percentage of the viewfinder area covered than in a typical DSLR.

Via a custom function you can choose to use the centre point (spot) only, all three points together, or select any one of the three points with the selector key on the back of the camera.

The AF works much better than I expected. It's very accurate, quite fast and fairly quiet.

Regards

Frank

[Mort54]

However, one thing I don't understand is why my grandfathers $700 Nikon D40 has better AF than

I also have the Mamiya system, and while autofocus only has a single sensor, and is slow, it is also very precise (better than any 35mm system I've used). I assume this has something to do with the slow gearing and long throw on the lens focus mechanism. Also, I can manually focus very precisely, which I have a lot of trouble doing in the viewfinders of cameras with cropped sensors.

I certainly didn't buy a MF system with a DB to shoot sports and fast action. I got it mostly to shoot fine art landscapes and stock. For these situations, I actually prefer to focus manually, since I can compose my shot and then precisely focus on whatever point I want, no matter where in the frame that point is (if I can see it in the composition, I can focus on it).

[Morgan_Moore]

However, one thing I don't understand is why my grandfathers $700 Nikon D40 has better AF than all MF cams.

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I too find MFDB AF to be a joke.

My thought is that software should be the king

Some form of analysing the data in a live view image should  reveal focus to sofware

at this point the data could be fed back to the camera to control the lens and aperture

Then the camera have could have 'sharp point' (s) moveable around anywhere in the screen

You should even be able to build you own focus (and exposure modes) character using software on a laptop etc

Independent programmers could then build thier own AF alorithyms like face recognition, object tracking, or AUTO depth of field  that could be added as software plugins

Remote control , if required, from a laptop for applications such as shootin off a 5m monopod or inside a waterproof housing would als o be possible

The traditional design even on the new hy6 and blad seems to me a total failure for the maufactuers to 'think outside' the 'design box' of film cameras


SMM

[Randal32]

Sam, that's getting pretty creative.

Thanks for all the input.

The 1 point on my Mamiya works great and is accurate.  Every point on my 5D is just as accurate if not more accurate.

I guess I got so used to relying on AF that I really don't trust myself manually focusing, especially shooting handheld.  And I'm not shooting sports or action, just people.

What can you do though?  I guess hope that the the AFD III will have a few points.

[Morgan_Moore]

Sam, that's getting pretty creative.



I guess I got so used to relying on AF that I really don't trust myself manually .
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I dont think it is that creative at all

$200 compacts have face recognition

it would be very easy to run a bit of software on a set live view image images analysing them for edges and contrast - pretty much how AF works now I think

In terms of focussing with current systems I dont think it is 'soft' to use AF

the resolution is so high compared to the size of view

I only discovered I 'couldnt focus' when I went 16mp

I actually downressed 'out of focus' images to A4 size and realised my errors were smaller than the res of that reproduction

Big 22mp and above shows all user errors!

And in terms of the new cameras Hy6 and H blad I think a lack of AF points was pure design stupidity

It is to do with a cultural history embedded in the designers heads

35mm = moving
645 = static on a tripod at f11

Which is not how I use my back

S