Pentax 645D and Leica S2

[BillOConnor]

After reading Mark Dubavoy's posting on medium format digital cameras, and following his links, it seems that the Mamiya/Phase One cameras have issues with their backs not being properly mounted for accurate focus, but the Leica S2, owing to it's design does not suffer from these problems. Has anyone had
the chance to look at the Pentax 645D in this regard since it is closer in design to the Leica than to the other cameras of its ilk?

[Doug Peterson]

After reading Mark Dubavoy's posting on medium format digital cameras, and following his links, it seems that the Mamiya/Phase One cameras have issues with their backs not being properly mounted for accurate focus, but the Leica S2, owing to it's design does not suffer from these problems. Has anyone had
the chance to look at the Pentax 645D in this regard since it is closer in design to the Leica than to the other cameras of its ilk?

In three years heading Tech Services for one of the largest Phase One dealers I've seen six or so lenses need to be sent in to Phase/Mamiya for focus calibration. So I'm here to tell you it's not a non issue, but:
1) it's much much more rare than your statement implies
2) it's not impossible with Leica either [search forum posts here and at getdpi for at least one report of similar with S2]
3) Focus recalibration is covered under warranty, can be done in the US, and takes only 2-3 days to turn around once received at the service center

I would love to see a feature similar to Nikon/Canon micro-adjust on a future Phase One body (or Leica/Hassy/Sinar etc).

Doug Peterson (e-mail Me)
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[hsteeves]

Doesn't the Pentax have micro-adjust?

[Doug Peterson]

Doesn't the Pentax have micro-adjust?

It's listed in the tech specs for the K-5, but not the 645D. Can an owner confirm?

[icemansven]

It's listed in the tech specs for the K-5, but not the 645D. Can an owner confirm?

The 645D has custom function C33 AF Fine Adjustment. But this is for the whole body, not for individual lenses.

[BillOConnor]

I know you have all read Mark's (Dubovoy, sorry Mark) piece where he says the Alpa system allows the backs to be shimmed, which implies to me that
the issue is not with the lenses. I'm sure it could be. I wonder if the Leaf backs also benefit from shimming. It seems that a person would have to design
a test that isolated the variables--and there are several. The tests showing images made with shimmed and un-shimmed backs on an Alpa camera
were sobering, to say the least, considering the costs of the equipment we're dealing with.

[David Klepacki]

After reading Mark Dubavoy's posting on medium format digital cameras, and following his links, it seems that the Mamiya/Phase One cameras have issues with their backs not being properly mounted for accurate focus, but the Leica S2, owing to it's design does not suffer from these problems. Has anyone had
the chance to look at the Pentax 645D in this regard since it is closer in design to the Leica than to the other cameras of its ilk?

Bill,

I have the 645DF and the Schneider LS lenses.  Not once has this camera missed focus for me, not even at F2.8. 

David

[ErikKaffehr]

Hi,

The Leica is shimmed at the factory, but I'd think that also applies to most professional equipment. I was surprised that Mark needed do as much shimming. Maybe the Alpa is intended to be customer adjusted. I have read that Phase One sensors are adjusted to with 0.015 mm but that's only the tolerance on the sensor vs. the mounting plate at the time the back leaves the factory.

You may checks this very fine article: http://www.josephholmes.com/news-medformatprecision.html

It seems that different persons have very different experience with AF-performance.

Best regards
Erik

I know you have all read Mark's (Dubovoy, sorry Mark) piece where he says the Alpa system allows the backs to be shimmed, which implies to me that
the issue is not with the lenses. I'm sure it could be. I wonder if the Leaf backs also benefit from shimming. It seems that a person would have to design
a test that isolated the variables--and there are several. The tests showing images made with shimmed and un-shimmed backs on an Alpa camera
were sobering, to say the least, considering the costs of the equipment we're dealing with.

[BillOConnor]

I guess the best plan is simply to buy the camera you like and use it.

[bcooter]

It seems that different persons have very different experience with AF-performance.

I think a lot of what we see with focus comes from the style/way we shoot.  If I go to a tripod, (with any camera) my focus improves 4 fold.

If I hand hold close to wide open, obviously the results are more limited, (once again with any camera).

What I do find amazing is I have multiple Contax bodies and two Phase backs and previous to this had two different Leaf backs.

I've never seen an issue with focus on any of them and when I had the Leaf, Leaf of America was kind enough to take my bodies and lenses and check all of them.

When I think about a third party back fitting on a out of production camera and the focus is tack sharp, I find that somewhat amazing, given the critical nature of digital.

IMO

BC.

[ErikKaffehr]

Hi,

It's also my experience that AF works reasonably well, but I mostly shoot at f/8.

Some people get absolutely top of the class lenses from Leica and Zeiss and shoot them at near full aperture and expect to have exact focus. The persons (Lloyd Chambers, Joseph Holmes and Mark Dubovoy) complaining about focusing and misalignment are known for meticulous work. They also have the best lenses with the highest resolving sensors.

I guess that our mileage may vary, even if I'm somewhat surprised it varies that much.

Best regards
Erik

I think a lot of what we see with focus comes from the style/way we shoot.  If I go to a tripod, (with any camera) my focus improves 4 fold.

If I hand hold close to wide open, obviously the results are more limited, (once again with any camera).

What I do find amazing is I have multiple Contax bodies and two Phase backs and previous to this had two different Leaf backs.

I've never seen an issue with focus on any of them and when I had the Leaf, Leaf of America was kind enough to take my bodies and lenses and check all of them.

When I think about a third party back fitting on a out of production camera and the focus is tack sharp, I find that somewhat amazing, given the critical nature of digital.

IMO

BC.

[baudolino]

In reply to Doug's comment above, the Sinar Hy6 has focus micro adjust, in the latest firmware (update needs to be done in Zurich). I had this done, all my lenses were calibrated on a bench and I was given a certificate showing the adjustments for all three of my lenses (+1 for the 80 mm, -6 for the 180mm and -7 for the 50 mm). Regards, Martin

[bcooter]

Some people get absolutely top of the class lenses from Leica and Zeiss and shoot them at near full aperture and expect to have exact focus. The persons................

All I can tell you is owning Contax, Leica, about every canon, Panasonic, Nikons, the only lens I've seen that had definate focus issues was the 90mm Leica on the M8, I sent it in, waited a month, and it still back focused.

Now, I'll admit sometimes autofocus on the Contax can be off, then I switch to manual and it's on, sometimes manual seems off, I switch to autofocus and it's on, but never have I had both auto and manual on the Contax be out of focus.

Still, everytime somebody tells me about focus, I say get a tripod.   Even if you shoot moving subjects (I only shoot people) a tripod will increase the focus by 1000%.

I am almost sure that nearly every modern camera, from the blad, the Phase has very good focus.  I doubt seriously at those price points that focus would be an issue any company would want publicized.

IMO

BC

[eronald]

All I can tell you is owning Contax, Leica, about every canon, Panasonic, Nikons, the only lens I've seen that had definate focus issues was the 90mm Leica on the M8, I sent it in, waited a month, and it still back focused.

Now, I'll admit sometimes autofocus on the Contax can be off, then I switch to manual and it's on, sometimes manual seems off, I switch to autofocus and it's on, but never have I had both auto and manual on the Contax be out of focus.

Still, everytime somebody tells me about focus, I say get a tripod.   Even if you shoot moving subjects (I only shoot people) a tripod will increase the focus by 1000%.

I am almost sure that nearly every modern camera, from the blad, the Phase has very good focus.  I doubt seriously at those price points that focus would be an issue any company would want publicized.

IMO

BC

Hah! the fallacy of induction!

Edmund

[tbosley]

I wonder if the Leaf backs also benefit from shimming.

I would think that any back system could be shimmed.  After all, its just mylar/laminates/etc. of different thicknesses inserted between back and body. 
Issue would be if back is already too far from sensor plane where shims would only place unit further...

You can do the "Alpha infinity" on any system if you want to know for sure (search for videos on youtube).   Worth doing, if for no other reason than to clear your mind.

[Rob C]

As in 'inductive reasoning'?

Happy New Year, Keith; did Mini manage the snows? Did you manage the snows?

Rob C

[eronald]

As in 'inductive reasoning'?

Yeah, Bertrand Russell's chicken

Edmund

[bcooter]

Yeah..................

Edmund

A few years ago a 3rd assistant smugly told me he knew he would be a great photographer because he always sees better images than the photographers he works with.

I kind of thought about that and and said, yea, I'm sure you do, but keep in mind that you don't have "your" 80 grand resting on the shot.  At that point the world gets different.

I can't tell you what works for focus for others, I just know that sometimes autofocus on all cameras is brilliant, other times, it's dead stupid and usually what will manual focus for one session doesn't  work as well for the others . . . and vice-versa.

I think that's why you constantly read one photographer who says my ____  ____ is just dead on perfect and the next one says the same camera is for s**t.

It all depends on the circumstance.

IMO

BC

[Rob C]

A few years ago a 3rd assistant smugly told me he knew he would be a great photographer because he always sees better images than the photographers he works with.

I kind of thought about that and and said, yea, I'm sure you do, but keep in mind that you don't have "your" 80 grand resting on the shot.  At that point the world gets different.

I can't tell you what works for focus for others, I just know that sometimes autofocus on all cameras is brilliant, other times, it's dead stupid and usually what will manual focus for one session doesn't  work as well for the others . . . and vice-versa.

I think that's why you constantly read one photographer who says my ____  ____ is just dead on perfect and the next one says the same camera is for s**t.

It all depends on the circumstance.

IMO

BC

You left out the best bit: what's the assistant doing now?

Rob C

[bcooter]

Assisting.

But in all fairness he does have what it takes if the cards fall right.


BC