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240LS - autofocus issues?

gerald.d

Well-known member
Hi all -

I've recently got hold of a DF+ and 240LS for a specific job - needed something just a little longer than what I have for my Alpas.

Took the combo out this afternoon for the first time to do some test shots with my trusty old IQ180.

Auto focus:


Manual focus:


I tested this multiple times - there's definitely nothing else influencing this.

So I was wondering what might be going on here.

(a) Is it the back - not calibrated correctly?
(b) Is this what can be expected from auto focus on the 240LS?
(c) Is it a lens problem?

I'd be interested to hear from others who shoot with this lens - I am extremely impressed with the quality of the files at all shutter speeds (including the usually challenging ones in the 1/5th to 1/30th region) with this lens when manually focused, but I am very disappointed with the AF performance for obvious reasons.

Kind regards,


Gerald.
 

Chris Valites

New member
Is it just this lens that you've seen the focus issues with? Do you have any others to try?

If you're seeing the same sort of focus issues with other lenses, you might want to play with your DF+'s Custom function for Focus adjust. It's CF 20, and you can use Option one for minus adjustments (to move closer) or option 2 to move the focal point away.

You can check out our top custom functions here: https://captureintegration.com/top-10-df-df-custom-functions/

I've done it here with a lens align chart in the studio as well to check lenses, but the first thing I'd do is try another lens. That'll tell you pretty quickly if it's the body or back, or if it's the lens.
 

Paul2660

Well-known member
I thought the DF+ has AF microadjustments, if so you may need to tweak the AF a bit. Based on MF, the lens looks fine.

It's been a while since I used the DF+, so I might have imagined the AF micro adjustment.

Paul
 

Bill Caulfeild-Browne

Well-known member
I have the opposite problem! AF is very accurate but MF is not. (This is on a DF, not DF+). I have to assume that the focussing screen is not in the same plane as the AF sensor, as all my lenses exhibit this.

I have contemplated sending the camera in for alignment but keep waiting for a new Phase body!

It's rarely an issue as (a) the margin is very small and (b) I almost always shoot for significant DOF so I'm at f8 or f11.

The two lenses where I shoot wide open are the 150 and the 240 - with them, I just let the AF do the work.
 

GrahamWelland

Subscriber & Workshop Member
Gerald,

Do you have the DF/DF+ set for precision focus mode? I set focus to be off the AE Lock button on the rear of the camera vs off the shutter release and will tap this a couple of times to get it to seek to focus.

Aside this, perhaps you need to adjust fine focus in the DF+ body?

My experience with the 240LS is like Bill's - it is sharp as a tack but I do have to double or sometimes triple tap the AF to get it to lock on.
 

gerald.d

Well-known member
Thanks all.

This is the only autofocus lens I have for the DF+, I'll work through all your suggestions today.

(Bill - I don't think my eyes are good enough to be able to see that kind of difference through the viewfinder, I was adjusting focus after checking 100% review on the IQ180 back.)

Kind regards,


Gerald.

/edit

Should also add that the images are 1/400th at f/8. The autofocus is going beyond infinity - I'm having to dial it back a little.
 

Steve C

Member
I don't think there is a problem with your lens as I see the same autofocus issues with my DF+ and the 240LS, even with the precision custom function selected and multiple focus taps. Getting the best possible focus requires Live View in my opinion (and tethered confirmation if absolute accuracy is required). Focus is very sensitive near infinity with the slightest nudge between success and failure. When the lens is properly focused, it is razor sharp, but it rarely gets there with autofocus. The micro-focus adjustment is only once per camera body and I found that my lenses all required different values. The zooms even required different values within their zoom range. My camera has been to Mamiya service and found to be "in spec." Good luck!
 

Don Libby

Well-known member
Thought I've jump in here about the 240LS and auto focus. These were all shot within days of getting the lens and I used it on a DF with IQ160. I routinely shot the 240 on auto focus while the 240 and 2x require manual and a very stead mount.


A little "before and after" this is the full size image taken with the 240LS handheld, f/16 1/250 ISO 400


And the crop from above.


240 auto focus handheld. f/16 1/320 ISO 400 (not a crop)

And some samples of the 240 and 2x extender...


Blowing snow made focusing even more of a challenge. Shot at the same place as the following image. Again used the 2x extender and Kirk window mount. f/12 1/500 ISO 200


These Otters were playing/fishing in an open area new Oxbow Bend inside Grand Teton Nat'l Park. Shot using a Kirk widow pod and remote release. Manual focus and cropped in, f/16 1/400 ISO 200

Love using the 240 both in auto focus and manual focus; with and without the 2x extender. The 240 by itself can be handheld however you need to mount it to a sturdy tripod when using the 2x. I bought this lens primarily for wildlife however I have used it with landscape and got excellent results. I quickly found that adding a RRS long lens holder brought up the number of keepers.

The thing to remember is that auto and manual focus with medium mate is a combination of luck, science and art.


Don
 

Nutcracker

New member
I have problems at times with autofocus on my DF body, improved since getting powerpack battery instead of AA. The lens is so sharp when all comes together, making it more frustrating when autofocus fails. Manual focus is challenging due to maturing eyeballs!.
I keep chasing Alpa for auto Phase/Mam adapter to use with FPS; I fear neither it nor new Phase body will appear in the short term!!
 

gerald.d

Well-known member
OK, so I've had a play with CF20 indoors, and with it set to 30, autofocus nails it up close.

Will hopefully get a chance to take it out and try infinity later!

Kind regards,


Gerald.
 
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