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Author Topic: Much Anguish About Focus  (Read 13667 times)
John R Smith
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« on: April 05, 2010, 12:30:37 PM »
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Folks

I'm just looking for some general guidance here. Since Christmas, I have been shooting digital for the first time on my beloved Hasselblads using a CFV-39 back. I suppose that there are not that many people in my position, where I am using exactly the same cameras, lenses and accessories which I have used for many years, and now instead of a film magazine there is a 39MP digital device hung on there instead. Well, only users of Hasselblad V-system and Contax 645, perhaps.

By now I have shot about 150 frames I suppose (the CFV had to go back to Denmark to be fixed under warranty, so I lost a month). And I am having so much trouble with focus and depth of field it is driving me insane. Where before, with scanned film, I would reckon to get at least 90% or more of my shots correctly focused and with adequate DOF, now it is about 50% if I am lucky. My DOF seems to have disappeared - using the DOF scale on the lens is pointless, and hyperfocal focusing (which I used to use a lot) is a total write-off. The other crazy thing is how sensitive the camera has become to camera shake - I am even getting blur from camera shake when shooting off a tripod, unless I am terribly careful and use the mirror pre-release religiously.

The really annoying thing is, that some shots are absolutely perfect, even hand-held at lowish shutter speeds. I try just as hard to get the focus pulled on every shot, but my results have become completely inconsistent, so I will get one brilliant result and the next frame will be pants.

Are digital sensors really so demanding?

John
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TMARK
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« Reply #1 on: April 05, 2010, 12:43:10 PM »
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I shot the same Mamiya AFd and RZ cameras for years with film and then with Leaf and Phase backs.  

You are right, digital is more demanding.  The image plain is really flat, not like a piece of film.  You are also looking at a less than 645 crop of a what was a 6x6 frame, which means the way you used to shoot with film is not up to the task of the effectively tighter field of view with teh small chip.  You are also looking at it at 100%, which, if you think about it, is ridiculous.

I think the 645 cameras are a bit better for digital, because thye optics and viewfinders are better matched for the close to 645 sensors.  Things like VF magnification with the 645 cams is closer to what you need than an unmagnified waistlevel 6x6 finder.  Maybe try the Chimney finder, if its magnafied.  

You also might want to have your 500 series camera CLA'd.   This might help.

Good luck.  

Quote from: John R Smith
Folks

I'm just looking for some general guidance here. Since Christmas, I have been shooting digital for the first time on my beloved Hasselblads using a CFV-39 back. I suppose that there are not that many people in my position, where I am using exactly the same cameras, lenses and accessories which I have used for many years, and now instead of a film magazine there is a 39MP digital device hung on there instead. Well, only users of Hasselblad V-system and Contax 645, perhaps.

By now I have shot about 150 frames I suppose (the CFV had to go back to Denmark to be fixed under warranty, so I lost a month). And I am having so much trouble with focus and depth of field it is driving me insane. Where before, with scanned film, I would reckon to get at least 90% or more of my shots correctly focused and with adequate DOF, now it is about 50% if I am lucky. My DOF seems to have disappeared - using the DOF scale on the lens is pointless, and hyperfocal focusing (which I used to use a lot) is a total write-off. The other crazy thing is how sensitive the camera has become to camera shake - I am even getting blur from camera shake when shooting off a tripod, unless I am terribly careful and use the mirror pre-release religiously.

The really annoying thing is, that some shots are absolutely perfect, even hand-held at lowish shutter speeds. I try just as hard to get the focus pulled on every shot, but my results have become completely inconsistent, so I will get one brilliant result and the next frame will be pants.

Are digital sensors really so demanding?

John
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vandevanterSH
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« Reply #2 on: April 05, 2010, 01:01:53 PM »
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Quote from: John R Smith
Folks

I'm just looking for some general guidance here. Since Christmas, I have been shooting digital for the first time on my beloved Hasselblads using a CFV-39 back. I suppose that there are not that many people in my position, where I am using exactly the same cameras, lenses and accessories which I have used for many years, and now instead of a film magazine there is a 39MP digital device hung on there instead. Well, only users of Hasselblad V-system and Contax 645, perhaps.

By now I have shot about 150 frames I suppose (the CFV had to go back to Denmark to be fixed under warranty, so I lost a month). And I am having so much trouble with focus and depth of field it is driving me insane. Where before, with scanned film, I would reckon to get at least 90% or more of my shots correctly focused and with adequate DOF, now it is about 50% if I am lucky. My DOF seems to have disappeared - using the DOF scale on the lens is pointless, and hyperfocal focusing (which I used to use a lot) is a total write-off. The other crazy thing is how sensitive the camera has become to camera shake - I am even getting blur from camera shake when shooting off a tripod, unless I am terribly careful and use the mirror pre-release religiously.

The really annoying thing is, that some shots are absolutely perfect, even hand-held at lowish shutter speeds. I try just as hard to get the focus pulled on every shot, but my results have become completely inconsistent, so I will get one brilliant result and the next frame will be pants.

Are digital sensors really so demanding?

John

Same experience with my CFV(16).  I have upgraded my tripod system, my view finder and use MUP and remote release almost exclusively.  The  number of OK and throw-away shots are the majority.  However the ones that are near "perfect" are amazing.  I think that there are significant differences in the "physics" of the depth of the silicon sensor vs film but also pixel "peeping" the digital files has increased the psychological threshold for what is excellent.  The SWC + CFV still works pretty well for hand held shots.

"brilliant result and the next frame will be pants."

Major advantage of digital...not changing film after 12 shots...You might also try DOF bracketing.

Steve
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Dustbak
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« Reply #3 on: April 05, 2010, 01:05:55 PM »
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Welcome to digital. You are experiencing more or less the same thing I did (as well as others) with my 503CW. It will get better over time.  I got the 45degree PME finder which was a true blessing as well as installing the better screen. Eventually I bit the bullit and went with the H.

I still find DoF has disappeared and only remained in a very thin slice that doesn't seem to do much even going from f4.0 to f16.0 (especially fairly close in).
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JRSmit
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« Reply #4 on: April 05, 2010, 01:14:12 PM »
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Quote from: John R Smith
Folks

I'm just looking for some general guidance here. Since Christmas, I have been shooting digital for the first time on my beloved Hasselblads using a CFV-39 back. I suppose that there are not that many people in my position, where I am using exactly the same cameras, lenses and accessories which I have used for many years, and now instead of a film magazine there is a 39MP digital device hung on there instead. Well, only users of Hasselblad V-system and Contax 645, perhaps.

By now I have shot about 150 frames I suppose (the CFV had to go back to Denmark to be fixed under warranty, so I lost a month). And I am having so much trouble with focus and depth of field it is driving me insane. Where before, with scanned film, I would reckon to get at least 90% or more of my shots correctly focused and with adequate DOF, now it is about 50% if I am lucky. My DOF seems to have disappeared - using the DOF scale on the lens is pointless, and hyperfocal focusing (which I used to use a lot) is a total write-off. The other crazy thing is how sensitive the camera has become to camera shake - I am even getting blur from camera shake when shooting off a tripod, unless I am terribly careful and use the mirror pre-release religiously.

The really annoying thing is, that some shots are absolutely perfect, even hand-held at lowish shutter speeds. I try just as hard to get the focus pulled on every shot, but my results have become completely inconsistent, so I will get one brilliant result and the next frame will be pants.

Are digital sensors really so demanding?

John

John, i have similar experience, be it in 35mm format. I use a Nikon D700 (full frame) with my set of Leica R lenses, so i do have to manually focus.
I even went back to use the Leica R5 with a slide film to figure out if it was me or that a digital sensor is so much more demanding. Turns out that it is indeed more demanding. Also made clear that quite a few of my slides are not perfectly focused after all :~)
Now i am used to it and a considerable percentage of shots is correctly focused, so i even do not want autofocus lenses anymore. Difficult to find autofocus and leica quality optics combined into one lens anyhow, so i am quite happy now. ;-)


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Jan R. Smit
John R Smith
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Still crazy, after all these years


« Reply #5 on: April 05, 2010, 01:54:42 PM »
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Yes, Jan, I should certainly stick with your Leica glass.

Well, this is one of the really good things about this Forum - now I know that it is not just me. Thank heaven.

I have had to up my game by a good 100% since I started using this thing, and at times I have wondered if I was completely mad to have spent so much money on it. I should perhaps clarify things a bit -

Close-up still-life shots off a tripod using a prism and my 120mm S-Planar have been no problem. They have mostly been perfect. Equally, distant views at infinity using my longer lenses have also been good -I have one from the 150mm Sonnar where there is a power line about 1/4 mile away, and you can clearly see the insulators and dropper wires on the pole. And that was hand-held!

The difficult part is with the standard 80mm or the 60mm lens where the subject is neither particularly close nor very far away - about 15 to 40 feet, say. Then I am having real trouble, because the sensor is insisting on focusing to within about a foot, and often the wrong foot. And even using a split prism I cannot distinguish the plane of focus accurately enough, especially in low light or contre-jour.

John
« Last Edit: April 05, 2010, 02:18:58 PM by John R Smith » Logged

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bcooter
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« Reply #6 on: April 05, 2010, 01:55:35 PM »
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Agree with everything written above.

I also think most digital backs have a small shutter lag, at least my contact/phase does and it changes the rhythm in how we work.

A contax with film use to go click, click, click, with a p31 it goes push shutter, click, push shutter click.  Not much of a difference but enough to throw you off if  you've been shooting with film for years.  You get used to it and the success rate goes up.

I think we just shoot more and faster.  Digital is far from free, actually I believe if I count the costs of storage, processing time, computers, software, calibrators,  monitors, etc. etc. etc., I know for a absolute fact that it costs me more per frame than film.

Regardless we shoot more and probably shoot some things we might not attempt with film.

Also it's just damn hard to read most lcds on any digital camera unless you use something like the 5d2 and live view, or you tether your digital back to a computer, running focus check all the time.

The last thing is we hand hold more.  I don't know why we do this with digital when in the film days almost everything was shot with a tripod, but we do, so there is more room for error.

With medium format I've gone back to almost all tripod shooting and the focus rate goes up 10 fold, but given that sometimes things just look screwy.  We'll shooting autofocus and boom one scene just doesn't go into focus, so I switch to manual and boom everything is fine, then 2 hours later everything flops.

Still, nothing improves focus like a tripod.

BC

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Barry Goyette
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« Reply #7 on: April 05, 2010, 02:18:20 PM »
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I really don't know how you'd manually focus on the 39mp back with any confidence. When I stepped up from the 22mp imacon to the 31 mp H3d...I quickly became aware that I couldn't focus the damn thing. It wasn't my eyes...it's simply the limitations of the prism optical system, specifically the focusing screen. I'd attempt to focus on a point...letting the screen "moire" at the point where high frequency detail "pixelated"..but I noticed that I could rotate the focusing ring a little in each direction from that spot, with no real change in the apparent focus...and sure enough....my focusing was randomly all over the place.

I contacted some folks at Hasselblad, eventually getting connected to Paul Claesson, who suggested that I try the autofocus ("it's very good" he said.) I scoffed at first, but when he finally told me that he was not capable of focusing his camera manually, I figured I'd give it a try. Since then, I rarely have any out of focus frames.

Now this doesn't help you with you're camera back combination...but hopefully it let's you know that it's not you...it's just the world of high end digital

(on the DOF situation...again...it's simply the state of being...the catch 22 is the visible diffraction on most f stops over 11.5...we need to stop down more with these cameras...but we can't, as the sensor is picking up diffraction in a way film never did.)
« Last Edit: April 05, 2010, 02:30:38 PM by Barry Goyette » Logged
TMARK
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« Reply #8 on: April 05, 2010, 02:27:10 PM »
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Quote from: Barry Goyette
I really don't know how you'd manually focus on the 39mp back with any confidence. When I stepped up from the 22mp imacon to the 31 mp H3d...I quickly became aware that I couldn't focus the damn thing. It wasn't my eyes...it's simply the limitations of the prism optical system, specifically the focusing screen. I'd attempt to focus on a point...letting the screen "moire" at the point where high frequency detail "pixelated"..but I noticed that I could rotate the focusing ring a little in each direction from that spot, with no real change in the apparent focus...and sure enough....my focusing was randomly all over the place.

I contacted some folks at Hasselblad, eventually getting connected to Paul Claesson, who suggested that I try the autofocus ("it's very good" he said.) I scoffed at first, but when he finally told me that he was not capable of focusing his camera manually) I figured I'd give it a try. Since then, I rarely have any out of focus frames.

Now this doesn't help you with you're camera back combination...but hopefully it let's you know that it's not you...it's just the world of high end digital

(on the DOF situation...again...it's simply the state of being...the catch 22 is the visible diffraction on most f stops over 11.5...we need to stop down more with these cameras...but we can't, as the sensor is picking up diffraction in a way film never did.)

I never tried to MF an H.  I always used MF on my Mamiya AFd with a P30 and the 45mm lens.  I had a 90% success rate using MF on that camera.  Much better than using AF, in most cases.  
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John R Smith
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Still crazy, after all these years


« Reply #9 on: April 05, 2010, 02:30:30 PM »
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Quote from: Barry Goyette
I really don't know how you'd manually focus on the 39mp back with any confidence. When I stepped up from the 22mp imacon to the 31 mp H3d...I quickly became aware that I couldn't focus the damn thing. It wasn't my eyes...it's simply the limitations of the prism optical system, specifically the focusing screen. I'd attempt to focus on a point...letting the screen "moire" at the point where high frequency detail "pixelated"..but I noticed that I could rotate the focusing ring a little in each direction from that spot, with no real change in the apparent focus...and sure enough....my focusing was randomly all over the place.

Oh, great. Thanks, Barry. In other words, it's impossible. What you have described is exactly my experience. And yes, even worse, stopping down to f16 doesn't help too much because the centre goes soft. I proved this a few days back shooting a test frame of a pebble-dashed wall. The teensy little snagette, chaps, is that there is no autofocus available for a forty-year old 500 C/M (and two of my lenses are almost fifty years old).

Maybe I shall just have to resort to taking six shots of everything in the hope that one is OK.

John
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vandevanterSH
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« Reply #10 on: April 05, 2010, 02:56:01 PM »
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Quote from: John R Smith
Oh, great. Thanks, Barry. In other words, it's impossible. What you have described is exactly my experience. And yes, even worse, stopping down to f16 doesn't help too much because the centre goes soft. I proved this a few days back shooting a test frame of a pebble-dashed wall. The teensy little snagette, chaps, is that there is no autofocus available for a forty-year old 500 C/M (and two of my lenses are almost fifty years old).

Maybe I shall just have to resort to taking six shots of everything in the hope that one is OK.

John

Are you using the latest AcuteMatte D focusing screen?  If not, the 42215 has both microprism/split image.

Steve
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John R Smith
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« Reply #11 on: April 05, 2010, 03:07:02 PM »
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Quote from: vandevanterSH
Are you using the latest AcuteMatte D focusing screen?  If not, the 42215 has both microprism/split image.

Steve

Steve

Yes, I have the latest screen (microprism & split-image) which was supplied with the CFV. And all sorts of othe AcuteMatte screens, too. And two prisms and a magnifying hood. Perhaps I should go in for a type of pictorialist style where everything is kind of soft . . .

Actually, now it occurs to me that I read somewhere that the plane of focus for MFD has to be accurate to within 0.02mm. It strikes me that a forty-year old body where the back is just held on by two sort of hooks is not too likely to be within that sort of tolerance anyway, however one would wish that it was. And you know that awfully nice man from Hasselblad UK who called to give me a demo mentioned absolutely none of these things. And I gave him two cups of tea and some nice biscuits.

John
« Last Edit: April 05, 2010, 03:27:16 PM by John R Smith » Logged

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Nick-T
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« Reply #12 on: April 05, 2010, 03:37:43 PM »
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Quote from: John R Smith
I suppose that there are not that many people in my position, where I am using exactly the same cameras, lenses and accessories which I have used for many years, and now instead of a film magazine there is a 39MP digital device hung on there instead. Well, only users of Hasselblad V-system and Contax 645, perhaps.

I (and many others) did exactly what you have done putting a 6MP back on a 503CWD and my experiences mirror yours.

Couple of things I have learnt.

First off there is a fair bit of tolerance in V system kit. Shoot a ruler running away from camera (on a tripod) and see if where you think you are focussing is what is sharp on screen. Repeat at different distances.
This will tell you if the mirror back latches are out of whack or not. My 503CW needed adjusting.

Beyond that I'm pretty convinced that very little of my film stuff was actually perfectly in focus, it looked just fine under an 8X Schneider loupe tho'

Perhaps one of the clever chaps here could work out what the equivalent loupe would be on 6X^ film vs 100% on a 39MP file, I'm betting it's a big old loupe.

Regards from NY
Nick-T
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« Reply #13 on: April 05, 2010, 04:19:35 PM »
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I spent years shooting 500 series cameras with film and found it increasingly difficult to focus. The mere thought of using MF and digital capture was enough to persuade me to change to the H series.

For most applications I now use AF, but the H viewfinder and screen are so good that I do enjoy switching to MF when needed.

John, sorry, probably not what you wanted to hear.

Disclaimer, camera permanently bolted to tripod and pointed at stationary subjects.
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« Reply #14 on: April 05, 2010, 04:42:19 PM »
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Some points..

1) try downrezzing and blurring your files in photoshop to the resolution of a bad scan or an A4 mag page- you may find your focus errors dissapear

2) you should run some formal tests of your mirror chip allignment focusing on fence posts or whatever - you mirror/chip/back may be a bit wonky if you see consistent front or rear focus

3) in general I think that digital is outresolving what the human eye can decern inside a mirror box - ie resolve over a 645 area - live view on a good screen with pixel to pixel zoom is the future

Frankly the 5dmk2 has that which makes it the winner over my hosselblot in so many situations

4) When I used to shoot the blad a lot I bracketed focus all the time

When I shot on a square mamiya I just prayed !

S
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« Reply #15 on: April 05, 2010, 06:17:56 PM »
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Quote from: John R Smith
The really annoying thing is, that some shots are absolutely perfect, even hand-held at lowish shutter speeds. I try just as hard to get the focus pulled on every shot, but my results have become completely inconsistent, so I will get one brilliant result and the next frame will be pants.

John,

The thing to understand though is that for a given print size you will at least get with digital the same quality you had with film, and sometimes much better. Looking at files on screen at 100% can indeed be a frustrating experience though since it makes you feel how much untapped resolution potential is wasted due to inaccurate focusing.

It has been my experience too that once you get in 7 or 6 micron photosites consistent manual focus is simply not possible.

The only 2 solutions known to mankind are:

1. An accurate/tunable AF. Unfortunately none of the MF camera currently offer per lens user tunable AF as far as I know,
2. Live view for those situation where a tripod can be used. Unfortunately the CCD used by MF camera these days don't enable in camera live view.

All in all, you might be better off with a high end DSLR in terms of achieved image quality even if the specs on paper are lower.

Cheers,
Bernard
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« Reply #16 on: April 05, 2010, 08:13:56 PM »
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A similar experience here although with different camera gear. Use of MFDB often leads to low ISO, low shutter speed, and open shooting, with limited DOF. Using 400 ISO might seem like a high number in film, but digitally, to get both stable and DOF is very hard.

I ended up getting a significantly powerful lupe on the WLF, and also a split-image focusing screen (the matte isn't good enough to tell in from out of focus). Change of gear gets a focus confirmation, which works very well with the manual focus lenses.

yes, check the back alignment, also focus shift can occur on the lenses, so do the ruler test and see where focus really is.

The combination of being a bit off, looking at 100%, and realizing those wonderful film shots weren't always on either leads to greater understanding, but not necessarily solving the problem. Some of it can often be blur from shake, some from DOF, or OOF. Greater precision will cure the OOF, and slowly you will get this under control.
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Geoff
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« Reply #17 on: April 06, 2010, 01:17:30 AM »
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First off there is a fair bit of tolerance in V system kit. Shoot a ruler running away from camera (on a tripod) and see if where you think you are focusing is what is sharp on screen.
*********
I did a quick ruler shot with a Lens Align which I had purchased for my Nikon.  203 FE, 110 F/2 and CFV back.  Shot at about 10 feet and images significantly cropped.  Not sure what it means but looks as if at f/2, there is slight front focus and at f/5.6 and f/16 slight back focus??

Steve

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« Reply #18 on: April 06, 2010, 04:47:36 AM »
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Quote from: Geoffreyg
so do the ruler test and see where focus really is.

The reason i suggested a fence not a ruler is I think our OP is not into macro and I geuss there may be some shitft from maro to infinity

S
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« Reply #19 on: April 06, 2010, 04:48:41 AM »
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I would suggest a simple test in the studio using Live View; With the lens wide open do the "ruler test" and focus on a certain mark, then drop the mirror back and look through the finder. Be sure to do is at a close enough distance so that ti will be easy to see the shift.

This at least will tell you if the mirror and/ or your focusing screen need any adjustment...

HTH

Yair


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e: ysh@mamiyaleaf.com | m: +44(0)77 8992 8199 | www.mamiyaleaf.com | yaya's blog
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