phase one focus confirmation

[alifatemi]

is iQ280/260 focus confirmation accurate enough to be reliable when using them with Technical camera  like Alpa?

[Paul2660]

If you are referring to the focus Mask, I would say it's a good asset, but I still don't rely on it 100%.  I still prefer to zoom in 100% on the LCD or iPad (via wifi).   However it can only be used after a shot is taken, not before like a DSLR's focus confirmation light.

Focus mask can be fooled in low light and you can spend time chasing your tail, at least I have when using it.  It works best in good light with a lot of contrast.  Then I feel it's an excellent tool.  You can tweak it from the back and that helps a bit. 

You also have this tool in the older IQ 1st generation of backs, IQ140, 160 and 180. 

True Focus confirmation would be possible only with a DF or DF+ type of camera where the light in the viewfinder goes solid green. 

Paul Caldwell

[Doug Peterson]

Focus mask is NOT an absolute indicator of focus. If you use it like this you will become frustrated very quickly.

What it does do, amazingly well (better than any tool I've used for this purpose) is the rapid and reliable comparison of two similar images. This relative-focus analysis leads to some very excellent workflows for establishing hyperfocal focus, range focus (to specific near and far points) and correct amounts of tilt.

Establish an area of the frame as sharp (call this the ROI) via 100% review (or high-confidence preset) and then take another shot with a slight variation (e.g. adding tilt or moving focus closer). If the focus mask on the ROI becomes smaller then that ROI is now less sharp; if it is unchanged then your ROI is still equally sharp.

This is a process we often demonstrate using our Remote Demo Center.

[julienlanoo]

@aligatemi, you don t need it if you can correctly calculate tilt, and work with a laser pointer, confirmation helps bit i find its better to correctly camculate your settings ..

[julienlanoo]

Ah and the DF bodies autofocus is Far from correct, and the focus assist in manual does not work everytime with new firmware , and some Mamiya lenses

[Paul2660]

Focus Confirmation on a DF+ (AF in general) is much much better than the older DF body, enough so that if I still was shooting a DF style body I would definitely make the upgrade from DF to DF+.    The lack of more then 3 focus points is still a consideration but the 3 that are there are much more accurate.  No more hunting back and forth, aim, hit shoot. 

Paul Caldwell

[Ken R]

is iQ280/260 focus confirmation accurate enough to be reliable when using them with Technical camera  like Alpa?

Focus mask works well if there is enough contrast in the scene and if the image is bright enough. Sometimes one needs to overexpose the image a bit for it to work. It is good for comparing images after making changes in tilt and or focus. It is always best to image review at 100% to be sure of focus. That is where the awesome screen in the IQ backs absolutely rules.

[narikin]

is iQ280/260 focus confirmation accurate enough to be reliable when using them with Technical camera  like Alpa?

No.