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Phase One 645DF "AF ON" rear button focus

adamduckworth

New member
On my Nikon and Canon DSLRs, I use the "rear button AF ON" method of using autofocus. ie. Half-pressing the shutter doesn't activate the AF, but pushing the rear AF ON button does.

I leave the AF mode to continuous, so it's continuous AF if you keep your thumb on the button, and single shot/ manual focus when you take your thumb off it. I've used all my cameras like this for years.

So, I followed a recent thread where (Guy, I think) explained how to set up the 645 DF to do this. By swapping AFL for AEL and disabling the shutter button from doing any AF.

This method initially seems to work, but the AF hunts virtually all the time. In, like, 95% of photos. It just doesn't lock focus on properly and the lens hunts back and forth for a few seconds - sometimes more. It does this in C or S modes on the lens.

The AF is set to accurate, and it doesn't seem to matter if the AF area is centre spot or the other options.It does this with all my LS lenses. Haven't tried other lenses.

Anyone got this 'AF ON' method to work on a 645DF? (Well, actually you're using the AEL button). I have a V-Grip fitted, and using it in portrait mode and using its thumb button also has the same effect.

When I put the camera back to normal (ie shutter release half-push to focus), then it's all perfectly normal. It's with a P40+ back, by the way, of that matters.

Thanks!
 

Guy Mancuso

Administrator, Instructor
This is from Doug at CI

Rear-Button-Focus-Only on DF Body
December 23, 2009 | Tech, Top Articles

In the Miami office our customers very frequently want to set a camera so that a button on the rear (used with your thumb) will activate the Autofocus system but the shutter release does not. This is useful if you wish to shoot multiple frames after a focus-and-recompose.

More Information on why you would want to set the camera this way.

On just about every camera this requires changing a custom function or two. Soon owners of P40+ and P65+ digital backs will be able to set the custom functions of a DF body using the digital back’s LCD. Until then here is way to set this configuration using the DF Body.

Summary
Set CF#12 to Option 1
Set CF#9 to Option 1
Set CF#10 to Option 2

Step-by-step
1) Rotate your Mode dial to “CF” to access the custom function list.

2) Under CF#00 rotate the thumb dial to select Custom Function Set A. This allows you to make changes from the defaults which will be stored in Set A. This also allows you to set up three different custom function sets (e.g. for three styles of shooting or for three different photographers sharing a camera) and also allows you to always return to the default settings (by selecting — instead of A B or C) without having to “reset” the camera.

3) Rotate the front finger dial to function #12 and then the thumb dial to set custom function #12 to option 1. This sets the AF-L button to be an AF-On button so instead of locking focus it engages the AF engine.

4) Rotate the front finger dial to function #9 and then the thumb dial to set custom function #9 to option 1. This switches the AEL (normally on the rear) and AFL (normally on the front) so that now the rear button engages Autofocus.

5) Rotate the front finger dial to function #10 and then the thumb dial to set custom function #10 to option 2. This removes autofocus from the shutter release.
 

adamduckworth

New member
Thanks Guy and yes, following this post is exactly what I did to get the rear button "AF ON" method to work.

And set like this, the focus hunts 99% of the time and refuses to lock on. Like, really, really badly despite loads of light and contrast.

Has anyone got any experience of it working properly? And any settings to make it work properly?

Thanks

Adam
 

Jack

Sr. Administrator
Staff member
And do you have your AF set to "Speed" or "Accuracy" ? In earlier body FW, the "Accuracy" mode hunted. I find Speed (CF 19-0) is great, and if you need accurate just press the button two or three times and it will zero in like a laser.
 

GrahamWelland

Subscriber & Workshop Member
Thanks Guy and yes, following this post is exactly what I did to get the rear button "AF ON" method to work.

And set like this, the focus hunts 99% of the time and refuses to lock on. Like, really, really badly despite loads of light and contrast.

Has anyone got any experience of it working properly? And any settings to make it work properly?

Thanks

Adam
Adam,

Your experience mirrors my own. I just got my DF back from Phase One and it arrived with the latest v1.23 firmware and appears to be better. Make sure that you have the latest firmware and see how it works for you. I also noticed the significant difference between pressing the half shutter vs AF ON on the rear, particularly if in C mode.

Try also Jack's recommendation of letting go of the button and pressing / release as described. I have a tendency to keep it pressed some times and maybe this is enough with slight movement (and that tiny button!) to trigger the AF to reacquire more often than simply pressing the shutter half way?
 

Bob

Administrator
Staff member
And be sure that CF19 is set to 0 (speed mode). As Jack pointed out, the accuracy mode tends to hunt more.
OTOH, I have had once case of a repair being required to eliminate continuous hunting, but this was not just some of the time, it was ALL of the time.
-bob
 

Guy Mancuso

Administrator, Instructor
For me the button is too small and I do not use this feature but have tried it several times. I shoot a lot of handheld work and it just does not work for me.
 

Bob

Administrator
Staff member
We all work a bit differently.
I personally hate the half press to focus; especially when shooting models when you desire to keep the eyes sharp and have a thin DOF. I pretty much operate now with the back button (the one facing the shooter) for AF operation and then recompose and keep shooting for several frames before focusing again.

Also, it might just be me, but I have never been comfortable with "C" mode AF. I am not really sure what it is good for when you effectively have one large central AF sensor.
-bob
 

Guy Mancuso

Administrator, Instructor
Bob I use C mode for runway stuff as the models are walking towards me with mostly my 300mm and it works pretty good but its not a perfectly fluid focus either, sometime there are some gaps in following. If that back button was bigger I would use it more just can't seem to get my thumb on it 100 percent of the time. I think some of this is due to hand size and i have short fingers so its like stretching for me.

But going back to C mode you have to be half pressed the whole time. I usually start at a slight pose before they walk and follow down the runway. Guess the real issue here is it is not Canon speed so it will depend on subject speed. Or maybe better said subject can outrun it faster than canon type continuous. I would say in studio under lights maybe not a great option.
 

Bob

Administrator
Staff member
Yeah that is for sure, and the AF sensor seems to lock on the closest item in its view when for me as you know would produce some weird results in the studio. So that is why I like S mode and back button focus.
I tried front button focus which I liked a bit better due to the size of the button, but with the V-Grip it just won't work well for me since the front button is just in an unreachable place for me but the back button works fine.
I guess in this situation you might say "YFLMV" Your finger length may vary LOL
-bob
 

Guy Mancuso

Administrator, Instructor
LOL yea in the studio and just about everything else the S mode seems to be the ticket. C mode would be a more continuous flow of movement. Models in studio don't move fluid enough and to short a distance for C mode. In general I say real continous movement for C mode.

Okay putting my fingers in a stretcher machine today. LOL
 

adamduckworth

New member
My back's firmware is 5.1.8 and my 645DF is 1.1.4.

Can I upgrade firmware myself via V-Grip air?

I couldn't find any mention of it on the Phase website or forum.
 

GrahamWelland

Subscriber & Workshop Member
If you have the V-Grip or access to one you can upgrade your camera body firmware yourself. You will need to download the firmware updater from the Phase One site and connect a USB cable to the v-Grip. The app should see the camera if all is connected. From there you can upload the latest firmware (you download this) and just follow the instructions. You should end up with firmware 1.23.
 
Last edited:

adamduckworth

New member
The Power of DPI!

I just upgraded the firmware for the P40+ back and the DF camera and now everything seems to work perfectly! Result!

(However, it seems a bit strange having to upgrade the DF firmware via the VGrip air and USB, then unplug it, plug the back in via Firewire to upgrade the back's firmware. But that's Phase for you!)

Now if they'd only make the AEL button a suitable size it would be spot on!

Thanks everyone

Adam
 

dougpeterson

Workshop Member
The Power of DPI!

I just upgraded the firmware for the P40+ back and the DF camera and now everything seems to work perfectly! Result!

(However, it seems a bit strange having to upgrade the DF firmware via the VGrip air and USB, then unplug it, plug the back in via Firewire to upgrade the back's firmware. But that's Phase for you!)
It sounded like a firmware quirk (older body firmware with newer back firmware). Glad to see that's all it was.

Yes, body firmware updating is not one of the most elegant part of Phase One's system. Still; it works.

Doug Peterson (e-mail Me)
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faneuil

Member
I just AF focus with shutter release, switch lens to MF, recompose and shoot.
a little kludgey. Will try the other method.

Eric
 
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