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Author Topic: Autofocus vs. Manual Focus  (Read 13990 times)

gwhitf

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Autofocus vs. Manual Focus
« on: December 06, 2008, 12:32:57 pm »

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« Last Edit: December 07, 2008, 09:16:27 am by gwhitf »
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Morgan_Moore

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Autofocus vs. Manual Focus
« Reply #1 on: December 06, 2008, 01:10:44 pm »

You are right the thing is to have 'your method' or a bunch of different methods test them and know them

I certainly dont think the eye can resolve beyond 12mp in a 35mm viewfinder or 16mp in a H1 viewfinder unless the subject is very brightly lit

fine if you are shooting 8mp or less

Some methods

D3 - single middle spot focus and recompose

Hassy H1 single middle spot focus and recompose (up to 5.6)

Hassy wide open focus bracket - rock the body between shots assume some will be out

Hassy safe mode - three lights F11

D3 - auto everything setting - this one scares me

etc

I always say the AF works until you need it - in dark and backlit situations

Using the cambos etc are fine choose F11 focus at 5-10m -  that is what they are designed for


I am of the opinion that current technology when used in challenging scenarious - movement low light etc you must bank on a low hit rate

I know my hit rate and change methods accordingly - say shooting one portrait session you may only need 5 sharp frames from the whole shoot so can be risky wheras with cataloge you need a 95% hit rate which will require F4 or 5.6 and lots of light...

Try a waterhousing half in half out when the 'media' air and water have different focus points !

The attached are all sharp apart from the pool diver which needs redoing , mainly H1 at 25 ISO
« Last Edit: December 06, 2008, 01:27:17 pm by Morgan_Moore »
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Sam Morgan Moore Bristol UK

paulmoorestudio

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Autofocus vs. Manual Focus
« Reply #2 on: December 06, 2008, 01:28:22 pm »

I think maybe this forum should be re-titled "16+mp commercial"
so it wouldn't matter if it was an H, or a S or a P or even a C.
« Last Edit: December 06, 2008, 01:28:55 pm by paulmoorestudio »
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tho_mas

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Autofocus vs. Manual Focus
« Reply #3 on: December 06, 2008, 01:48:48 pm »

Quote from: gwhitf
Can you imagine being one of those Cambo/Arca guys, and you drop untold thousands on a body, and then another $25k on a P45+, and then you read the manual and it says "Uh, you've gotta GUESS the focus.
(...) No idea what I'm going to do with my T/S 24 and 45; I guess I'll test that today and try to find a method.
For the view cameras you can use a groundglass and a loupe for focussing and/or a laser distometer... so guessing distance is not inevitable.
Manual focus with 35mm AF lenses is tricky as the angle of rotation of the focus ring is extremely narrow. Small movements on the focus ring have a huge effect on focussing.
The contrary with manual focus lenses... especially the helical focus of Schneider/Rodenstock for the Cambos, Arcas, Sinars ... have an expansive angle of rotation.
But... though e.g. the Contax AF-lenses have quite a comfortable angle of rotation me too sometimes I find it hard to focus accurate manually... with the regular finder screen.
But I use screens with split image (and microprism collar) and still do manual focus. Even in my APS-C DSLR I use a split image screen. And focus failures are zero (for stills ... moving subjects are different for sure).
Without split image screen I totally feel lost because AF (of my cameras) is not (always) that perfect - especially at distances close to (but not quite) infinity and above all with wide angle lenses...
« Last Edit: December 06, 2008, 01:49:27 pm by tho_mas »
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gwhitf

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Autofocus vs. Manual Focus
« Reply #4 on: December 06, 2008, 02:13:15 pm »

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« Last Edit: December 07, 2008, 09:17:14 am by gwhitf »
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tho_mas

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Autofocus vs. Manual Focus
« Reply #5 on: December 06, 2008, 02:28:14 pm »

Quote from: gwhitf
Here's another scary test
I know what you mean and it drove me crazy... until I decided to use a split image screen ;-)
What you have figured out in your last scary test has something to do with the AF construction inside the lenses (with the range in the coupler or whatever) I guess. But a split image screen (with microprism collar) really helps a lot even with regard to this problem.
Nevertheless I always adjust focus of AF lenses by turning the focus ring just in one direction (not back and forth) to avoid those problems (but again: just for stills).
« Last Edit: December 06, 2008, 02:30:17 pm by tho_mas »
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Mark_Tuttle

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Autofocus vs. Manual Focus
« Reply #6 on: December 06, 2008, 08:12:05 pm »

Quote from: gwhitf
That's exactly what my tests showed. Even the slightest touch on the manual focus ring had a massive effect on the actual focus in the file. As though the ring is too crude to the tiny tolerances in the file itself.

Here's another scary test:

1. Put camera on tripod.
2. Tether.
3. Put lens wide open, manual focus.
4. Spin the ring out of focus, then refocus, and shoot.
5. Spin the ring the other way out of focus, then refocus, then shoot.
6. Do that twenty times. Make SURE that you shoot ONLY when you're sure it's sharp.
7. Out of those twenty frames, count how many are truly razor sharp.
8. Do not report the answer back here on this forum.

Issue: what the viewfinder shows is many times nowhere CLOSE to being in focus, especially at f4 or wider.

Did this with my Contax 645 gear, then went through and repeated it with two different bodies, two different prisms and three different styles of screens.  Finally came up with some combination that was consistent.  I have a priority list of components so that if something stops working I can use a replacement and have an idea of what the success ratio will be. These days I'm believing that a high-mp back is just too precise for cameras and/or lenses that were designed for film tolerances.

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bcooter

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Autofocus vs. Manual Focus
« Reply #7 on: December 07, 2008, 02:29:05 am »

Quote from: Mark_Tuttle
Did this with my Contax 645 gear, then went through and repeated it with two different bodies, two different prisms and three different styles of screens.  Finally came up with some combination that was consistent.  I have a priority list of components so that if something stops working I can use a replacement and have an idea of what the success ratio will be. These days I'm believing that a high-mp back is just too precise for cameras and/or lenses that were designed for film tolerances.


Maybe your right.  I have this old Nikon manual 1.2 lens that produces the most beautiful look.

I've done this test a dozen times where I put it on a D-3 and leave it in the studio.  Everytime I walk past it, I turn it on, focus on something and fire a frame.

At the end of the day only about 1 in 5 and tack sharp.

The wierd thing is I have this old Fuji S3, what is that 6mpx or something with the smallest viewfinder ever made.

I can put that lens on the fuji and 8 out of 10 times it's in focus.  Now the problem is I never use the fuji, but that either tells me that something is not right with this lens on the d-3 or the d-3 just resoves so much more than the fuji that it is more obvious.

With my contax's I have a different experience.  If it works on autofocus then it won't focus on manual, or if doesn't focus tight on auto, then I can always hit it on manual.

Makes no sense but we've gone through this about 20 dozen times and each time the process is the same.

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Morgan_Moore

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Autofocus vs. Manual Focus
« Reply #8 on: December 07, 2008, 03:11:32 am »

Quote from: bcooter
Maybe your right.  I have this old Nikon manual 1.2 lens that produces the most beautiful look.

I've done this test a dozen times where I put it on a D-3 and leave it in the studio.  Everytime I walk past it, I turn it on, focus on something and fire a frame.

At the end of the day only about 1 in 5 and tack sharp.

The wierd thing is I have this old Fuji S3, what is that 6mpx or something with the smallest viewfinder ever made.

I can put that lens on the fuji and 8 out of 10 times it's in focus.  Now the problem is I never use the fuji, but that either tells me that something is not right with this lens on the d-3 or the d-3 just resoves so much more than the fuji that it is more obvious.

With my contax's I have a different experience.  If it works on autofocus then it won't focus on manual, or if doesn't focus tight on auto, then I can always hit it on manual.

Makes no sense but we've gone through this about 20 dozen times and each time the process is the same.

I think there are two issues to correct focus..

Is my kit working ? - Teachnical issues - does my kit do what it says it should

Can I focus ? User Issues/Expectations

For example expecting AF to keep up with a black greyhound (dog) running through  a disco strobing light show - it wont happen - a different approach is needed
----------
Technical Issues

Camera build tolerances
-is the chip in the right place for the AF
-is the mirror at 45degrees andthe GG in the right place

Digiback build tolerances
-third party devices eg phase on hassy

Clean interfacing
Any dust/sand under your focus screen or between the Digiback and Camera body will cause missalignment

I think any system where where these issues cannot be tuned out will not provide good focus
D3 can 'tune'
CanDSIII can 'tune'
Sinar Backs can tune with foilstack or could

I am not aware of any other systems that allow 'user tuning' although I am sure repairers/makers can do it

My Mam645 and Proback used to be totally off even though both devices were serviced and described as 'in tolerance'

My Sinar/BLad is mildly off I keep meaning to try sticking some Rizla paper between the camera and the back to raise the chip a little

Testing ones own equipment is therefore critical

One could have a camera where the chip and mirror/gg are all misaligned creating perfect manual focus and duff AF

One could have a camera where the mirror/gg are off but the chip is where the AF expects it to be creating great AF and Duff manual

For the whole pile of cards to stand up across two manufacturers (three if you have custom screen) seems from an engineering point of view unlikely at 60mp and likely at 8mp

I have shots that are 'ear focussed' that once downsized to the client requirement look fine

Alignment of the lens is not that important however unless you need the distance scale to work - like on a cambo where the distance scale is important - the lense must of course be square onto the camera and centred to aviod unintentional 'micro tilt and shift'

S
« Last Edit: December 07, 2008, 03:20:37 am by Morgan_Moore »
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Sam Morgan Moore Bristol UK

paul_jones

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Autofocus vs. Manual Focus
« Reply #9 on: December 07, 2008, 04:08:09 am »



Who knows -- maybe it's just a Canon Thang. Maybe it doesn't apply as much to Hasselblad H, or Contax, or AFI, or Hy6. Maybe you just manual focus and it's perfect. But from what I learned yesterday, testing this Canon, I'll never manual focus again. No idea what I'm going to do with my T/S 24 and 45; I guess I'll test that today and try to find a method. But I'd advise everyone to set up a simple tethered situation, where you can REALLY see what's going on -- none of that zooming in on the LCD -- and really do the test see if AutoFocus improves. It was as if I'd actually bought new sharper lenses, when I shot Autofocus. Maybe there's something in this Technology that just says "Trust Us -- We know how to focus".
[/quote]

i shoot alot at 1.2, and still use auto focus. i use the seperate af button on the back (not the shutter) on one mostly. ive got pretty quick moving the square with the little joystick above the back dial. even with manual focus lenses, just set little square where you want it, and wait until the "beep". you still focus by eye manually, but the beep just confirms it.

i just havnt figured out how to move square to square on the focus grid- it jumps a couple of squares each time. is there a setting that all the focus points available on a mk3?

paul

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Dustbak

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Autofocus vs. Manual Focus
« Reply #10 on: December 07, 2008, 04:42:15 am »

When I use manual focus lenses on my 35mm bodies I almost never have problems getting a pretty high hit rate on the D300. The D200 was much harder to get it 'right'. Most autofocus lenses are a nightmare to focus manually.

When I use the manual focus lenses on the Horseman Digiflex II I get a ridiculous high hit rate. The finder of this thing is kind of horrible, like looking through a small pipe that vignets like crazy. The focus does snap into place everywhere on the focussing screen. I hate the prism in the center because it distracts.

I found it also depends on the lenses. My Zeiss ZF50/1.4 is virtually impossible to focus properly, while my AIS50/1.4 or 1.2 is fairly easy to get it right. Other ZF's like the 35, 50macro or 85 are a lot easier to focus manually.

BTW, I can do most things with AF as well but depending on what I do I find manual focus sometimes giving me better results or more control other times I have no other option than MF.

A good screen makes a world of difference is my experience. A bright & big screen is no guarantuee of an easy manual focus. The other thing that helps is, lots of practice.
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Carsten W

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Autofocus vs. Manual Focus
« Reply #11 on: December 07, 2008, 06:19:29 am »

Quote from: bcooter
Maybe your right.  I have this old Nikon manual 1.2 lens that produces the most beautiful look.

I've done this test a dozen times where I put it on a D-3 and leave it in the studio.  Everytime I walk past it, I turn it on, focus on something and fire a frame.

At the end of the day only about 1 in 5 and tack sharp.

The wierd thing is I have this old Fuji S3, what is that 6mpx or something with the smallest viewfinder ever made.

I can put that lens on the fuji and 8 out of 10 times it's in focus.  Now the problem is I never use the fuji, but that either tells me that something is not right with this lens on the d-3 or the d-3 just resoves so much more than the fuji that it is more obvious.

I would bet on the resolution being the determining factor here, but perhaps the focusing screen in the S3 is also meant for manual focusing, with the typical Canon screens (other than the -S) being meant for bright viewing with AF. These screens make a huge difference.

I went through this whole thing in 2006 with a Canon 5D when I started buying Leica R lenses, culminating in the 80 Lux. I just couldn't get focus with any consistency. I went online and started reading various forum, and after reading FM's Alternative forum for a while, I bought the Brightscreen focusing screen. Nice screen, and my keeper rate jumped, but I was never really happy with it. Then I got the cheapo Canon Ee-S and though my keeper rate initially dropped, once I had learned how to focus with it (I used the shim from the Brightscreen and always focused from infinity and down), my keeper rate with the 80 Lux wide open was well over 50%. Focusing with the Leica R8/R9 in comparison is a total revelation, and the original Leicaflex SL is meant to be the best ever made, with the cost of the focusing screen being insane. Apparently it is some kind of tiny microraster over the whole screen, and focus is just meant to snap.

Once you do learn to read the screens, you can transfer it to other setups. One of my buddies wanted to try his 450D with a Leica 180 Cron I was testing, and I was able to get about 1 in 3 with that setup, and boy, is that ever a shitty manual focus screen.

I always meant to try one on Maxwell's mods, but didn't get around to it. He is kinda hard to contact, and I live in Berlin, Germany. I wish he would make his website more interactive, but at least he has one now, even though it is run by someone else. I might send him my Contax 645 screen for tweaking. It is nice, but I find it a bit dark and slow to manually focus.
« Last Edit: December 07, 2008, 06:20:43 am by carstenw »
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BernardLanguillier

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Autofocus vs. Manual Focus
« Reply #12 on: December 07, 2008, 06:49:37 am »

Live views can be set to show pixel leve sharpness on some bodies like the D3/D3x, I don't know whether the 1ds3 offers this option, but it is IMHO the easiest way to get tack sharp focus, especially when using T/S lenses.

Cheers,
Bernard

Graham Mitchell

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« Reply #13 on: December 07, 2008, 07:05:08 am »

Here's a radical thought: post Canon QC issues in the Canon forum.
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rainer_v

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« Reply #14 on: December 07, 2008, 07:11:48 am »

Quote from: foto-z
Here's a radical thought: post Canon QC issues in the Canon forum.
this i time i vote for you again foto z.    
pure 35mm discussion should be in other forum.
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Streetshooter

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« Reply #15 on: December 07, 2008, 10:20:22 am »

Quote from: foto-z
Here's a radical thought: post Canon QC issues in the Canon forum.

Talk about killing a thread in one sentence, thanks for that. One of the more interesting and informative threads that has appeared here for a long time in my opinion. Who cares where it was posted. Some people need to get a life.

Again IMO.

Pete
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Graham Mitchell

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« Reply #16 on: December 07, 2008, 11:09:19 am »

Quote from: John Schweikert
As we say in the US, you are a one trick pony, 'Sinar, leaf shutters, wrong forum.'

Attacking a poster rather than the post shows a lack of class. Don't expect to be taken seriously.
And apart from the fact that you are wrong, that would be a 3-trick pony.


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bcooter

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Autofocus vs. Manual Focus
« Reply #17 on: December 07, 2008, 12:03:53 pm »

Quote from: paul_jones
Who knows -- maybe it's just a Canon Thang. Maybe it doesn't apply as much to Hasselblad H, or Contax, or AFI, or Hy6. Maybe you just manual focus and it's perfect. But from what I learned yesterday, testing this Canon, I'll never manual focus again. No idea what I'm going to do with my T/S 24 and 45; I guess I'll test that today and try to find a method. But I'd advise everyone to set up a simple tethered situation, where you can REALLY see what's going on -- none of that zooming in on the LCD -- and really do the test see if AutoFocus improves. It was as if I'd actually bought new sharper lenses, when I shot Autofocus. Maybe there's something in this Technology that just says "Trust Us -- We know how to focus".


i shoot alot at 1.2, and still use auto focus. i use the seperate af button on the back (not the shutter) on one mostly. ive got pretty quick moving the square with the little joystick above the back dial. even with manual focus lenses, just set little square where you want it, and wait until the "beep". you still focus by eye manually, but the beep just confirms it.

i just havnt figured out how to move square to square on the focus grid- it jumps a couple of squares each time. is there a setting that all the focus points available on a mk3?

paul

I think it's just strange how most of us could manually focus a Nikon F3 all day long and though we'd miss some, what you would see on the ground glass translated very well to film.  Same with almost any medium format camera though some were more difficult to focus than others.

Now with digital something is different and I don't really know if it is the digital tolerances are so demanding, or we are just much more critical of digital than we were of film.  After all we see digital files on a 30" loupe.

Last months cover of a very high profile magazine was out of focus and it wasn't the printing it just was the fact that probably that one frame was the one the editor, publicist and manager selected so it ran.  I bet the frame before and after that was sharp.

I do know we are still in the film to digital transition.  New Nikons, Canons and Rolleis still look like film camera dirrevatives and in a lot of cases we are still using film camera lenses, so maybe that's the reason.
(I mentioned Rollei so the hall monitor would be happy).

Not actually knowing what RED is doing, I do think the next good "ground glass" we will use will be some kind of live view lcd screen.  It just makes sense and seems that the possibilities of what you see is accurate.

I also find it interesting when I read that Sigma has lenses that out perform Canon and Nikons.   I never would have thought that possible in the past and actually never would have even remotely contemplated buying a sigma lens.   Maybe it's because the new lenses, Sigma included are built to tighter tolerances than their previous film counterparts.

Recently I did a "challanged" end of the day photograph of a model sitting on a train in virtual total darkness.  I first tried he Canons and manual or auto it just wasn't there.  It wasn't even close, not one frame and I even bracketed the focus.   Then I shot the Nikon with an 85 1.4 wide open set on auto focus and found this tiny, tiny little sliver of contrast that it locked on and though I was shooting hand held at 1/15th crammed into a corner to make myself into a tripod, it was sharp so maybe it's just an autofocus world.

Regardless I think in 4 years when were shooting with cameras that are entirely meant for digital capture using a 20billion pixel lcd screen to focus with all of these conversations will be in the past.





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samuel_js

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Autofocus vs. Manual Focus
« Reply #18 on: December 07, 2008, 12:04:11 pm »

F##K! I was just about to post my experiences focusing with my 503CW (digital vs. film).

Sad...
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tho_mas

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« Reply #19 on: December 07, 2008, 12:15:21 pm »

Quote from: John Schweikert
The conversation about autofocus in the Canon can easily be something that applies to medium format cameras which in all comparison SUCK as far as autofocus. So people here are sophisticated enough to perhaps apply a concept to another piece of gear.
And in fact the discussion was intended as autofocus vs. manual focus in general by "ghwitf". So the stuffy "wrong forum" statement was totally out of place here.
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