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Phase One XF vs 645DF Auto Focus Performance

Mgreer316

Member
The auto focus accuracy on my 645DF has always driven me crazy. In 2.5 years I've gotten better, but still I never know what's going to be tack sharp on my portrait shoots. How is the XF in this regard? I don't really care about focus speed, I just need predictable accuracy. Especially at wider apertures where focus location on the face is critical.
 

dougpeterson

Workshop Member
The auto focus accuracy on my 645DF has always driven me crazy. In 2.5 years I've gotten better, but still I never know what's going to be tack sharp on my portrait shoots. How is the XF in this regard? I don't really care about focus speed, I just need predictable accuracy. Especially at wider apertures where focus location on the face is critical.
The XF is, in every way, a large step up from the DF or DF+. It should be easy to get your hands on one for your own testing. We'd be glad to help with that of course.
 

Mgreer316

Member
My impressions of autofocus and other matters interspersed throughout this thread:

http://forum.luminous-landscape.com/index.php?topic=110119.0
I read through the Luminous Landscape thread. Question, how big is the focus circle? If I'm shooting fairly tight and a wide aperture and want to nail focus on an eye, is the circle too big such that it might focus on something other than the eye? Or does it have a spot/dot instead of a circle? That's what I rarely need.
 

Wayne Fox

Workshop Member
I read through the Luminous Landscape thread. Question, how big is the focus circle? If I'm shooting fairly tight and a wide aperture and want to nail focus on an eye, is the circle too big such that it might focus on something other than the eye? Or does it have a spot/dot instead of a circle? That's what I rarely need.
It’s actually a rectangle, and in spot mode it’s pretty small ... in this thread if you scroll down a few replies you can see the two boxes that represent the two areas used with AutoFocus. Neither are large but the spot mode box seems like it would work pretty well.

When you actually use the camera the size of the spot mode box visually appears smaller than the image in that link ... hard to describe.
 

dougpeterson

Workshop Member
I read through the Luminous Landscape thread. Question, how big is the focus circle? If I'm shooting fairly tight and a wide aperture and want to nail focus on an eye, is the circle too big such that it might focus on something other than the eye? Or does it have a spot/dot instead of a circle? That's what I rarely need.
The inside rectangle ("spot focus" mode) is very small and clearly marked. Easy to pick out something specific (even if it's quite small in the frame) to focus on.
 

Mgreer316

Member
Ok, so I read another thread in this forum about an XF focus screen that somebody bought. I saw a box and a center spot. I thought that was part of the purchased screen?
 

aztwang

Member
Can u show me the new grip
? Photo and description will be helpful. My xf is on the way.

Thanks
I am actually awaiting my XF, the original one had to be replaced due to an electrical malfunction. but the original grip material was a smooth black material that was still hard enough
you could not dig your fingernail into it. The new material has a texture to it, more grippy and if my memory
serves me right was a bit thicker. Best I can do at this point.

Don
 

Chipcarterdc

New member
I've never used the old, only the new. It does indeed provide a very secure and comfortable gripping surface, one of the very best I've ever used.

(Looking at the comparison pictures above, though, the old style seems to look sleeker/blacker. I'd obviously rather have a slightly more utilitarian look and a camera that still works because I didn't drop it! Just sayin'.)
 

DrakeJ

New member
I have demoed both the XF and the H5D and doing close headshots and half body my spot on AF was about 50% with the XF and 90% with the H5D.

The XF consistently back focused when it missed, lighting conditions were "ok" but not more. I tried to chalk it off as bad focus-recompose technique, but even without true focus, the H5D had a much better hit rate. I even managed to get spot on focus with my 5 year old wide open with the 100mm f/2.2 - consistently.

There were a few things that could contribute to this discrepancy:

- LED light assist is slightly off to the right with XF so when you are close to your subject the assist light doesn't help (?). This is not the case with the H5D

- Even with all the bells and whistles of a brand new XF CMOS AF sensor handles low light worse than H5D

- The lens/body wasn't calibrated properly, didn't have time to do my own autofocus fine-tune
 

dougpeterson

Workshop Member
I have demoed both the XF and the H5D and doing close headshots and half body my spot on AF was about 50% with the XF and 90% with the H5D.

The XF consistently back focused when it missed, lighting conditions were "ok" but not more. I tried to chalk it off as bad focus-recompose technique, but even without true focus, the H5D had a much better hit rate. I even managed to get spot on focus with my 5 year old wide open with the 100mm f/2.2 - consistently.

There were a few things that could contribute to this discrepancy:

- LED light assist is slightly off to the right with XF so when you are close to your subject the assist light doesn't help (?). This is not the case with the H5D

- Even with all the bells and whistles of a brand new XF CMOS AF sensor handles low light worse than H5D

- The lens/body wasn't calibrated properly, didn't have time to do my own autofocus fine-tune
Was this comparison made before or after the XF 1.2 Feature Update which specifically improved handheld autofocus and lower light autofocus?

Did the body have the older or newer focus screen?

Where you using the normal or spot focus mode?
 

Christopher

Active member
Was this comparison made before or after the XF 1.2 Feature Update which specifically improved handheld autofocus and lower light autofocus?

Did the body have the older or newer focus screen?

Where you using the normal or spot focus mode?

For me it sounds quite simple. The XF wasn't probably adjusted for the lens. ( in other words there was no fine tuning with focus trim.)

Which on an official event is sad, but not spur surprising. I nearly have never seen any demo with adjustments, while I have nearly never seen a lens which does not need it.

They might be fine for general use but for closeup it is really important that they are probably trimmed.

Just my 5cent
 
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Bill Caulfeild-Browne

Well-known member
For me it sounds quite simple. The XF wasn't probably adjusted for the lens. ( in other words there was fine tuning with focus trim.)

Which on an official event is sad, but not spur surprising. I nearly have never seen any demo with adjustments, while I have nearly never seen a lens which does not need it.

They might be fine for general use but for closeup it is really important that they are probably trimmed.

Just my 5cent
As I've said in another thread, ALL my lenses needed Focus Trim. Once tuned, focus at full aperture is right on.
 

DrakeJ

New member
Doug, there was a fourth thing yes which was that the XF had the old focusing screen. I used both average and spot, both were not as reliable as I had hoped.

It's possible that focus trim played a role, but focus was dead on when focusing in good light on static subjects. But there is a possibility that there was play in the pairing of lens/body which was amplified when doing focus recompose.

Anyway, I was offered a new demo with the new focus screen and will do a proper focus fine tune this time.
 
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