Home · Register · Software · Software · Join Upload & Sell

Moderated by: Fred Miranda
Username  

  New fredmiranda.com Mobile Site
  New Feature: SMS Notification alert
  New Feature: Buy & Sell Watchlist
  

FM Forums | Micro Four Thirds Forum | Join Upload & Sell

  

Force E-M1 MkII to autofocus stopped down - possible?
  
 
Jonas B
Offline
• • • •
Upload & Sell: Off
p.1 #1 · p.1 #1 · Force E-M1 MkII to autofocus stopped down - possible?


Hi,

I might be lost in the menu... and any help is appreciated:

Is there a way to force the E-M1 MkII to autofocus and (and of course meter the light) with the lens stopped down to working aperture? Obviously this is a question regarding Olympus and Panasonic 4/3 lenses.
The reason for asking is mainly the focus shift problem with the Micro Zuiko 25/1.2 but also an habit I have learned from using the Sony RX1 for some years.

/Jonas



Jan 03, 2017 at 12:01 PM
kwalsh
Offline
• • •
Upload & Sell: Off
p.1 #2 · p.1 #2 · Force E-M1 MkII to autofocus stopped down - possible?


Depth of field preview should do this. Not by my camera but there is a way to set it for DoF preview to be on continuously.


Jan 03, 2017 at 12:15 PM
Jonas B
Offline
• • • •
Upload & Sell: Off
p.1 #3 · p.1 #3 · Force E-M1 MkII to autofocus stopped down - possible?


OK, sounds good.
Is it about making the DOF preview button (it's a little hard to reach) to be sticky? I didn't know that was possibly. Let me read the f-n manual...
Thank you.



Jan 03, 2017 at 12:28 PM
Jonas B
Offline
• • • •
Upload & Sell: Off
p.1 #4 · p.1 #4 · Force E-M1 MkII to autofocus stopped down - possible?


No dice yet.

I found the setting (aperture blades half closed symbol) in the D2 menu. Setting it to ON and pressing the DOF preview button makes the aperture close down to the chosen aperture value but then the blades stay there also when changing the value with the aperture control wheel.
What I want is a function allowing me to have the blades set to working aperture all the time when a native lens is mounted.

Did I miss something?



Jan 03, 2017 at 12:39 PM
Jonas B
Offline
• • • •
Upload & Sell: Off
p.1 #5 · p.1 #5 · Force E-M1 MkII to autofocus stopped down - possible?


Checking the above again shows the aperture blades indeed changes when I change the aperture setting. Good. But the camera opens up when focusing thus making this specific setting useless for its intended function (in my case). I can't find anything else in the manual referring to aperture blades or DOF or "depth".
This seem problematic.



Jan 03, 2017 at 12:47 PM
DamC.Licks
Offline

Upload & Sell: Off
p.1 #6 · p.1 #6 · Force E-M1 MkII to autofocus stopped down - possible?


I would guess that the camera wants as much light as possible for focusing and therefore opens up. Makes sense, even if it is not what you want it to do.


Jan 03, 2017 at 02:32 PM
 

Search in Used Dept. 

        


kwalsh
Offline
• • •
Upload & Sell: Off
p.1 #7 · p.1 #7 · Force E-M1 MkII to autofocus stopped down - possible?


Jonas B wrote:
Checking the above again shows the aperture blades indeed changes when I change the aperture setting. Good. But the camera opens up when focusing thus making this specific setting useless for its intended function (in my case). I can't find anything else in the manual referring to aperture blades or DOF or "depth".
This seem problematic.


Doh! Sorry my idea didn't work.

Seems the camera is trying to be extra smart and focus wide open even in DoF preview - which for 99% of the cases is the "smart" thing to do but of course not what you want to fight SA induced focus shift.

Based on that behavior I'm guessing you are unlikely to find a work around. I doubt they've implemented something like that since it hasn't been a problem with any native lens so far.

What about MF with peaking on in DoF preview mode? I know that doesn't give you the AF you want but I wonder does it at least leave the aperture stopped down in that case or does it actually open it up when you move the focus ring too?

The smarter the cameras get the harder it is to out smart them...



Jan 03, 2017 at 04:31 PM
Jonas B
Offline
• • • •
Upload & Sell: Off
p.1 #8 · p.1 #8 · Force E-M1 MkII to autofocus stopped down - possible?


Hi again,

I tried the focus peaking function but it isn't exact enough for the purpose of setting the focus exactly right. I use the enlarging function instead, at around 7x works fine for me when critical. Both enlargement and peaking works, and simultaneously to that, when focusing manually. (The help text in the setup says peaking shouldn't work but it does.)

OK, I'll try to live with this. All I need to do is focus manually, stopped down, when super critical and using f/2 and f/2.8. Another thing that happens when doing this is a certain amount of aperture dance. Annoying but that's the way the smart camera works: when focusing manually with the DOF preview button set to sticky the aperture quickly opens up and closes down again when pressing the shutter release. Sometimes more than once.

Now what?
And here I was, buying the opposite I thought, to my RX1. I thought the E-M1 MkII shouldn't get in the way for me when shooting. Other quirks I have stumbled upon is that the aperture value doesn't change when turning the control wheel unless you have the camera lifted to the eye, you can't change the aperture when in enlarged view and perhaps something more. I'll give the camera a real try but if I can't get around these annoyances I'll sell it and search for something else.

Thanks again.



Jan 03, 2017 at 05:52 PM
kwalsh
Offline
• • •
Upload & Sell: Off
p.1 #9 · p.1 #9 · Force E-M1 MkII to autofocus stopped down - possible?


I hadn't realized the 25/1.2 had a focus shift issue but I haven't really been following reviews on that lens so far. My 42.5/1.2 doesn't seem to suffer from such.

Since apparently the 25/1.2 does then what should really be happening in the "smart" camera is adjusting for the shift. A bunch of zoom lenses already do something similar in MF mode. When you zoom they shift focus to make the lens act parfocal even though optically it isn't. If the 25/1.2 has focus shift they should take the same approach.

Yeah you can work around, but really that would suck since to me what makes m43 so functional is its really excellent AF - especially on really fast lenses.

Is focus shift on the 25/1.2 something people have been noticing or complaining about on various forums yet? I just haven't seen much traffic on that lens to date. Thanks for bringing it up here!



Jan 03, 2017 at 08:40 PM
Jonas B
Offline
• • • •
Upload & Sell: Off
p.1 #10 · p.1 #10 · Force E-M1 MkII to autofocus stopped down - possible?


The focus shift is minor, not anything in the size of what the Canon 50/1.2 does (own experience). But it is there. I have checked whole aperture stops only this far and the problem exists at f/2 and f/2.8. At f/4 it looks much better again, possibly thanks to the larger DOF.

The focus shift... I became suspicious when reading Castleman's review seeing how his MTF-valus didn't increase from f/1.2 to f/2.8. Sure enough, when focusing manually stopped down you get a somewhat better result.

The lens also exhibits a somewhat bent focus plane making the edges seem softer in reviews than they can be if focused there (or as far towards the edge you can get within the focusing pattern). Luckily the focus plane bends (just a little but enough to be easily identified) towards to the camera and not the other way round (like the ZM 35/1.4). The focus plane is still pretty much plane and one of the reasons for me to buy the lens. That together with the decreased purple fringe and softer bokeh made it a winner.

Maybe the shift is small enough to make Olympus not bother about it. My guess is that not many will complain.

EDIT: Yes, I agree. If they can make a zoom look parfocal they should be able to do something similar with a prime lens. That was discussed a lot in Canon forums when the 50/1.2 was released.



Jan 03, 2017 at 08:54 PM
kwalsh
Offline
• • •
Upload & Sell: Off
p.1 #11 · p.1 #11 · Force E-M1 MkII to autofocus stopped down - possible?


Thanks for the details, I hadn't seen Castleman's review before even though it looks like it has been out for a few months. Must have missed it!

I don't know if Castleman owns the lens or just rented/borrowed it for the test. If he still has it I'm sure he'd happily retest for focus shift - he seems pretty interested in getting to the bottom of things when oddities are pointed out. I agree with you the MTF curve sure looks like focus shift so I suspect his tests are affected by exactly what you've observed yourself.



Jan 03, 2017 at 09:18 PM







FM Forums | Micro Four Thirds Forum | Join Upload & Sell

    
 

You are not logged in. Login or Register

Username     Reset password